Science
Spotlight
Century-long butterfly range expansions in northern Europe depend on climate, land use and species traits Markus Franzén, Per-Eric Betzholtz, Yannick Francioli, Lars B. Pettersson, Juha Pöyry, Nils Ryrholm & Anders Forsman Article HERE
This study analyses of spatiotemporal variation in species richness and reconstructed range expansions of butterflies in 51 provinces throughout Sweden and Finland signal an overall dramatic increase in insect biodiversity over the past 120 years in this northern part of Europe with a 21% increase in lareg part due to climate change of approx 2'C but also habitat changes have had a significant impact.The results further support that the ability of butterflies to colonise new areas in pursuit of favourable conditions increases according to certain species attributes, specifically range size, thermal niche breadth, larval diet breadth, and habitat use, thus ultimately leading to more generalist and species rich communities.
The last leg of the longest butterfly migration has now been identified.
It was long thought that the Painted Lady wintered in the Atlas mountains but it seems they fly on many more 1000's kms. A new monitoring scheme south of the equator has revealed that from December through February, after flying across the Sahara in the autumn they breed in savannas and highlands across central Africa, a further 3000km south, in Camaroon, Benin and Uganda! As the rainy season brings greenery to the region, the butterflies have food in their wintering spots until they dry up. Then at the end of February the butterflies fly north to Europe see the maps of their movement below. More HERE and paper HERE
A Painted Lady butterfly that has traveled thousands of kilometers from Europe to Africa, and crossed the Sahara, rests on a lion footprint in Benin, West Africa
Scientists at Imperial college unravel the long running mystery of why Moths ( and other insects) fly around lights.
Very simply light allows an insect to orientate up and down movement by always having the light(sun or moon) on its back allowing it to fly straight and level. If it encounters artificial light then it trys the same turning its back (and bum) towards the light, in effect flying backwards in a rough circle around the source attempting to keep its back towards the light which you can clearly see from the stop motion movie below. As we know lots of accidents happen moving fast butt first, like falling into a moth trap as your legs are facing the wrong way! The article continues with a possible practical fix for the growing problem of light pollution is to direct all the light downwards and none sideways or upwards which would confuse nocturnal flyers. More HERE
moth-video01_wg_720p.mp4Use of a ultraviolet torch as a survey method by Sussex University for surveying one of the UK’s rarest butterflies – The Black Hairstreak
The article concludes that nocturnal UV flashlight surveys have the potential to serve as a reliable and consistent methodology for determining presence, population density and distribution for Black Hairstreak butterflies and potentially other cryptic or elusive species. Article HERE This method could prove useful for the other rarer hairstreaks in addition. The best time to try this is around now as the overwintered larvae begin to grow very quickly., this can also be used for finding many other caterpillar species and their pupa.
One of the most uplifting sights of spring is the rich orange of the male Orange Tip. It is beautifully complemented by the green 'parsley' of its underside that works as a brilliant camoflage when roosting on the flower heads of Cow Parsley and with the orange tucked away beneath it becomes near invisible. The closer you get the more beautiful and intricate patterns become... Can you see the bright yellow eye liner? The green colouration is actually made up of a variable dusting of black scales mixed with yellow scales along with white and is not green at all.
Yorkshire has always been near the northern limit for this species which declined to a low point by 1940 when it was largely confined to South Yorkshire and a few sheltered woods and valleys elsewhere. As global warming accelerated especially during the warm spells of 1975-76 and 1983-84 rapid expansion occured which continues to this day (10% in the last 20 years see graph below). Over the same 80 years the Orange Tip has largely lost its prefered foodplant: Cuckoo flower or Cardamine pratensis from which the butterfly gets the second part of its latin name. This plant was once common on damp meadows but is now a threatened species in parts of Europe. Agricultural intensification has caused the loss of 98% of our traditional meadows and along with drainage and laterly nitrogen pollution cause stronger growing sedges and grasses to outcompete and stifle Cuckoo flower. Nitrogen is one of the gravest threats to many of our butterfly species. Over the last 40 years Orange Tip has succesfully switched more and more to Garlic Mustard as its foodplant which has thrived in the recent run warmer wet springs and prefers a rich soil helping the butterfly population boom near fourfold in the last 20 years (See graph) This boom is mirrored through Europe with the switch to Garlic Mustard . Eggs are laid on Honesty, Dames Violet and Hedge Mustard but larvae do not often survive. 2019 was the last boom year and this next week will see the peak of its flight period ..Could 2023 beat it??
3rd April How hot dry summer impacts UK butterfly populations : take a look at the grim predictions from BC of the likely consequences of last year drought and long hot summer see HERE
Do Moths have Pupils?
To work effectively, the eyes of nocturnal insects have a problem they must overcome. During the night, the light levels are low, so their eyes need to be very sensitive; but they also need a way of adapting to environmental light conditions, and protecting those sensitive organs, if a bright light is encountered. Human eyes have a pupil that changes size to regulate light input to the eye. Moths (Lepidoptera) use a light absorbing pigment that moves position to limit the light within the eye. This article looks closely at how this works demonstrating for the first time the process. Interstingly it takes 10 mins for the moth to adapt.
28th October Lancaster University Conference 2022
Entitled 'Can we save our rare butterflies and moths' it took place on 29th October and was an exceptional butterfly experience with near 200 attendees! Bringing together academics, farmers, recorders, students, conservationists, authors, lepidopterists and a host of butterfly enthusiasts from across northern england it was a showcase for the scientific research going on in the north west to save our scarce species. Highlights included an introduction by Matthew Oates with his colourful review of this year, weather facts and his unique experience of our species; absolutely fascinating insights. The real highlight of the day were the students presentations over a whole range of species and topics (some of them in the carousel above). They covered the serious negative effects of nitrogen disposition as well as conserving the High Brown Fritillary and the Small/Pearl-bordered Fritillary. Not forgetting moths with a study of rare species on the Limestone pavement and the habitat of the Forester Moth. Chris Winnick summarised the success story in Cumbria of the Marsh Fritillary which has gone from 1 dieing colony back to to now a naturally expanding 30 plus utilising hybridisation/ captive breeding.
Lee Scholfield gave an impassioned heart warming talk about the RSPB Hawswater rewilding project. He described how the project and how it combined with sustainable agriculture and included hypnotic images from his book 'High Fell. With beautiful descriptions of the fragments of this original upland landscape that still exists he guided you to see how rewilding was going to work based on how the highlands used to look to bringing back nature after the ravages of sheep farming under the CAP. A full report will appear in the Spring edition of the Argus
Why do dryer/chalky sites give Meadow Brown an earlier start plus a much extended flight period?
A puzzle investigated by Reading scientists in a wide ranging study. They prove that this is not genetic or adaption but drought/steepeness along with the presense of chalk is key. Chalk sites are not only earlier but have a long slow tail off sometimes reaching into October with a peak considerably later than non chalk sites They conclude that this is largely due to warm chalk slopes producing adults earlier but then delays in development of larvae on dryer areas produce much later. Fresh males and females presently being seen around Yorkshire are likely to be due to later devloping larvae forced to hibernated in the hot weather. Full article HERE
Complex patterns of trends in UK moth populations
Black Arches(above) is one of the winners in a new study led by Butterfly Conservation scientists, in collaboration with Rothamsted Research, has revealed HERE the complex patterns of change among Britain’s larger moths. Woodland moths tend to be faring well, whereas moths associated with moorland show stronger declines than those breeding in other habitats. There are several possible factors at work including the increasing frequency of moorland burning and the impacts of nitrogen pollution on plant communities. Clouded Buff and Grey Mountain Carpet are moorland species declining strongly in distribution. Woodland moths are responding positively to an overall increase in woodland cover in the UK in recent decades including Black Arches, Red-green Carpet and Maiden’s Blush.
How to conserve butterflies and moths
Moth traps work better with interception vanes,
nicely shown in this study comparing the three different designs above: rods, black veins or white reflective vanes all with the LepiLED standard moth light more HERE
The Wall Butterfly genetically adapts as it moves north with climate change in order to hibernate at the correct time:
Does this kill the 'suicide' generation theory we have used to explain the widescale disappearance of this species in the UK ?
A Swedish study on the endangered Wall looks at how it is adapting with shifting its range in northwards with climate change. In particular Finland, Sweden and Estonia has seen considerable range movement as temperatures increase but daylength, the trigger for hibernation, changes as you move north. So how has it adapoted? They prove that caterpillars are indeed using daylength as their trigger but has moved more than hour longer compared to the southern population they recently left behind to compensate for longer summer days, plus, this trait was also inherited. Does this finally dismiss the lost (3rd) generation theory due to climate warming often touted as the reason for the Wall's decline ? Article HERE
What works in conservation of Butterflies and moths
Complex pattern of trends in UK's large Moths are tricky to unravel
A new study led by Butterfly Conservation scientists, in collaboration with Rothamsted Research, has revealed HERE the complex patterns of change among Britain’s larger moths. Woodland moths tend to be faring well, whereas moths associated with moorland show stronger declines than those breeding in other habitats. There are several possible factors at work including the increasing frequency of moorland burning and the impacts of nitrogen pollution on plant communities. Clouded Buff and Grey Mountain Carpet are moorland species declining strongly in distribution. Woodland moths are responding positively to an overall increase in woodland cover in the UK in recent decades including Black Arches, Red-green Carpet and Maiden’s Blush.
Radio tracker moths reveal the extreme distance, precision and ability to control their direction of flight
Moth Tracked by Exeter University 80km in just 4 hours! Each year, trillions of insects make long-range seasonal migrations. These movements are relatively well understood at a population level, but how individual insects achieve them remains elusive. Menz et al. used micro-transmitters to track the flight of death’s-head hawkmoths that migrate between Europe and sub-Saharan Africa. The Moths are fitted with the device weighing just 0.27 gm and measuring 11 x 5 x 2.8mm including its tiny battery and a 15cm antenna (See below) .With a life of 12 days and range of 15 miles tracking was in a light aircraft ; one transmitter was recovered from inside a bee hive, raided by the moth for honey. see Here and paper Here
A Swedish study on the endangered Wall looks at how it is adapting with shifting its range in northwards with climate change.
Finland, Sweden and Estonia has seen considerable range movement as temperatures increase but daylength, the trigger for hibernation, changes as you move north. So how has it adapoted? This study prove that caterpillars are indeed using daylength as their trigger but has moved more than hour longer compared to the southern population they recently left behind to compensate for longer summer days, plus, this trait was also inherited. Does this finally dismiss the lost (3rd) generation theory due to climate warming often touted as the reason for the Wall's decline ? Article HERE
The first Genetic Atlas of European and North African Butterfly species
The first genetic atlas of European and North African Butterfly species has been produced and will become a fanastic tool to exploring our ever changing butterflies. It covers 532 species of butterfly. Below shows the map for Northern Brown Argus and the different races that have evolved and haplotype network shows how they are related and the genetic diversity beyond species level shows how they are interelated . More HERE (warning 572 pages) Each circle on the map is a pie chart with segments corresponding to the number of samples with identical haplotype(genes) coloured as in the side diagram. It basiically shows the genetic assemblages and how closely they are related to each other. So English ones look closest to Eastern european ie Bulgaria but only two differences on the gene from the high Alps and 1 gene different from central Europe.
Recorder decision-making when recording species and observations into recorder motivations
Citizen scientists play an increasingly important role in biodiversity monitoring. Most of the data, however, are unstructured—collected by diverse methods that are not documented with the data. Insufficient understanding of the data collection processes presents a major barrier to the use of citizen science data in biodiversity research. Respondents were most often motivated by improving species knowledge and supporting conservation, but there were no linkages between motivations and data collection methods. By contrast, variables related to experience and knowledge, such as membership of a natural history society, were linked with a greater propensity to conduct planned searches, during which typically all species were reported. Our findings have implications for how citizen science data are analysed in statistical models; highlight the importance of natural history societies
A insightful report in the authorative 'Nature' journal about Recorder decision-making when recording species and observations into recorder motivations. Nearly 80% of all data collected is unstructured; collected by diverse methods that are not documented with the data. Insufficient understanding of the data collection processes presents a major barrier to the use of citizen science data in biodiversity research. Respondents were most often motivated by improving species knowledge and supporting conservation, but there were no linkages between motivations and data collection methods. By contrast, variables related to experience and knowledge, such as membership of a natural history society, were linked with a greater propensity to conduct planned searches, during which typically all species were reported. More HERE
Motivations of respondents to collect species observation data. Respondents were asked to rate the importance of each item. Items are ordered in the plot by the % responding ‘important’ or ‘very important’.
Survey patterns: (a) the proportion of species observation data that are made by an active/planned search compared with observations that were opportunistic; (b) species that are reported during an active/planned search; (c) triggers of an opportunistic observation; (d) locations/habitats in which people actively look for species.
Emerging technologies revolutionise insect ecology and monitoring Roal van Klink
Recent technological advances have the potential to revolutionise insect ecology and monitoring. We describe the state of the art of four technologies (computer vision, acoustic monitoring, radar, and molecular methods), and assess their advantages, current limitations, and future potential. We discuss how these technologies can adhere to modern standards of data curation and transparency, their implications for citizen science, and their potential for integration among different monitoring programmes and technologies. We argue that they provide unprecedented possibilities for insect ecology and monitoring, but it will be important to foster international standards via collaboration.
More HERE
Threats to insects @ RES conference July 2022
Investigating the mechanisms behind moth declines: plants, landscape, pollution and climate
Moth declines are most severe in broadleaf woodlands despite a net gain in habitat availability
Dan Blumgart,Marc S. Botham,Rosa Menéndez,James R. Bell First published: 28 April 2022
While agricultural intensification and habitat loss are cited as key drivers of moth decline, these alone cannot explain declines observed in UK woodlands – a habitat that has expanded in area since 1968.
We quantified how moth communities changed across habitats and regions and determined how species traits interacted with habitat in predicting moth abundance change. We hypothesised that, in woodlands, species more vulnerable to shading and browsing by deer (species specialising on forbs, shrubs and shade-intolerant plants) had declined more severely than other species, and that moth decline in woodlands was more severe at sites more susceptible to deer damage.
We modelled abundance, biomass, species richness and diversity from 1968 to 2016 and explored how these interacted with habitat and region. We also modelled the interaction between habitat and two moth species traits: larval feeding guild and shade-tolerance of hostplant.
Moth declines were consistently highest in broadleaf woodland. Abundance, biomass, species richness and diversity declined significantly by −51%, −52%, −14% and −15% in woodlands, respectively, compared to national trends of −34%, −39%, −1% (non-significant) and +10%. Declines were no greater in woodlands more susceptible to deer browsing damage. Traits based analysis found no evidence that shading and intensive browsing by deer explained moth declines in woodland.
Moth decline was more severe in broadleaf woodlands than in intensively managed farmlands. We found no evidence that deer browsing or increased shading has driven these trends: the primary cause of the decline of moths in woodlands remains unclear.
FULL ARTICLE HERE
Where and why are species' range shifts hampered by unsuitable landscapes?
First published: 19 May 2022 https://doi.org/10.1111/gcb.16220
There is widespread concern that species will fail to track climate change if habitat is too scarce or insufficiently connected. Targeted restoration has been advocated to help species adapt, and a “conductance” metric has been proposed, based on simulation studies, to predict effective habitat configurations. However, until now there is very little empirical evidence on how the configuration of habitat is affecting expansion at species' cool range margins. We analysed the colonisation events that have occurred in continuously monitored trap locations for 54 species of southerly distributed moths in Britain between 1985 and 2011. We tested whether the time until colonisation was affected by attributes of each species, and of intervening landcover and climate between the trap and the baseline distribution (1965–1985). For woodland species, the time until colonisation of new locations was predicted by the “conductance” of woodland habitat, and this relationship was general, regardless of species' exact dispersal distances and habitat needs. This shows that contemporary range shifts are being influenced by habitat configuration as well as simple habitat extent. For species associated with farmland or suburban habitats, colonisation was significantly slower through landscapes with a high variance in elevation and/or temperature. Therefore, it is not safe to assume that such relatively tolerant species face no geographical barriers to range expansion. We thus elucidate how species' attributes interact with landscape characteristics to create highly heterogeneous patterns of shifting at cool range margins. Conductance, and other predictors of range shifts, can provide a foundation for developing coherent conservation strategies to manage range shifts for entire communities. more HERE
Woodland species can spread orders of magnitudes faster through habitats with high 'conductance'
Have you ever wondered how butterflies evolved?
A huge piece of work by 90 scientists mapped 390 genes from 2000 species to piece togther the answer. The first butterflies evolved 100 million years ago in what is now America and for a considerable period fed on legumes (the pea family) From the tropics they spread into the temperate crossing from America into Europe via the Bering land bridge. Most of the families we know today existed before the extinction of the dinasaurs 55 million years ago. More Here
Airborne DNA used to detect insect species in breakthrough for ecologists
One of the biggest challenges in wildlife conservation is getting an accurate picture of what species are living where. To protect any environment, scientists and policymakers need to know what is there to begin with. Normally, surveys involve going out and looking for species of plants, birds or mammals. But in recent decades, the advancement of DNA sequencing technology has given scientists an entirely new way to monitor wildlife. Rather than going out to find the animals themselves, all that is needed is a tiny sample of their eDNA.
Insect DNA has been gathered from the air and for the first time used to detect 85 insect species, according to scientists from Lund University in Sweden.
Bees, moths, flies, beetles, wasps and ants have been identified in a study which raises hopes that airborne environmental DNA (eDNA) could become a useful tool in monitoring insect abundance and declines in biodiversity. The study, which sampled air from three sites in Sweden, also detected evidence of plants, algae, fungi and vertebrates, including a woodpigeon, fieldfare, hedgehog, red squirrel and short-tailed field vole, alongside the presence of domesticated animals – chickens, cows and dogs. The results, which have yet to be peer-reviewed, are this week presented at the British Ecological Society’s Ecology Across Borders conference by the lead author, Fabian Roger.
“In the face of the biodiversity crisis, we desperately need better information on the status and distribution of species,” said Roger. “Our study is a proof of concept that shows that we can detect DNA from insects and vertebrates from air collected under natural conditions. This opens many exciting possibilities for species monitoring and detection, which could allow us to comprehensively monitor biodiversity at large spatial and temporal scales.”
Sampling of eDNA has so far focused on aquatic ecosystems, and is undertaken by ecological consultants surveying for great crested newts. In this study, researchers compared airborne eDNA sampling with traditional insect surveys, including moth light traps and transect walks, which usually only pick up larger insect species. While traditional light traps detected 48 species of moth, just nine moth species were detected with eDNA, although five of these were missed by the traditional traps. Of the 36 species of butterfly and bee identified by a transect walk, eDNA sampling detected five species. The eDNA sampling was more successful at picking up a wider range of arthropod species, finding a total of 67 species at the light trap and 20 at the transect site. According to Roger, developing airborne eDNA sampling to complement traditional methods will require increasing the sensitivity of the sampling to achieve more reliable detection and developing a greater understanding of how airborne eDNA is generated, transported and how it degrades.
“We are at the very beginning of exploring airborne environmental DNA for anything other than bacteria, pollen or spores – and even there we have only scratched the surface,” he said. “Just because it doesn’t work perfectly out of the box doesn’t mean it won’t work ever, and the potential is huge.”
Full article HERE
Anti-Bat Ultrasound Production in Moths
JR Barber, D Plotkin, JJ Rubin, NT Homziak, BC Leavell, P Houlihan, KA Miner, JW Breinholt, B Quirk-Royal, PS Padrón, M Nunez, AY Kawahara published 1/10 2021 and released HERE
This fascinating and fine detailed article looks in depth at how prevalent moths are in giving ultrasonic response to echo-locating bat attack This study trapped moths with UV lights and broadcast pre-recorded bat sonar attack sequences to moths in tethered flight, across the world’s tropics. The study played representative calls from bat species of both frequency-modulated and constant-frequency bats calls . We recorded moth responses to playback of sonar attack and found that 52 of 252 tested genera respond acoustically to both types of bat sonar. Far more than was known before where most studies looked at Tiger and Hawk Moths with their known reponse. The study reports that this striking anti-predator behavior is widespread across the tapestry of lepidopteran diversity (Fig 2). In fact, if we extrapolate from our sample, ∼20% of the estimated 100,000 species. In addition to playback of bat attack, we also queried moths for ultrasonic response to handling. We simulated a physical predatory attack by grasping the thorax, abdomen, and head. Nearly all moth species that broadcast anti-bat sounds upon hearing sonar also produced ultrasonic disturbance sounds when handled. Three subfamilies from three different families (Erebidae: Erebinae, Crambidae: Spilomelinae, Sphingidae: Smerinthinae) produced ultrasound only in response to tactile stimulation. Producing ultrasound to touch may be a generalized anti-predator response intended to startle attackers.
A molecular phylogeny of Lepidoptera indicating anti-predator ultrasound production across the order. Bars and nodes with magenta outlines represent taxa associated with sufficiently large duty cycle values (>18%) for sonar jamming. Asterisks indicate taxa known to produce ultrasound, but not in response to either tactile stimuli nor bat ultrasound. Grayscale images indicate taxa that do not produce ultrasound. This phylogeny is meant to illustrate the diversity of ultrasound production and offer broad strokes on the origins of anti-predator sounds at the family and subfamily level.
The study went on to discover three new ways moths produce ultrasound in addition to the two methodes known previously :
Anti-bat ultrasound-producing structures. A-D. Mittonia hampsoni (Pyralidae: Pyralinae) produces ultrasonic clicks in flight via modified scales on the tegula; A. Scale bar = 1.0 cm; B. Tegula, 0.2 mm; C. Tegular scales, 50 μm; D. Response to bat sonar playback (Mittonia hampsoni), 100 ms). E-H. Lymantria sp. (Erebidae: Lymantriinae) generates ultrasound with paired tymbals recessed in abdominal pockets; E. Scale bar = 1.0 cm; F. Arrow indicates one of the tymbal pair, 1.0 mm; G. Close up of one tymbal, 0.5 mm; H. Response to bat sonar playback (Lymantria sp.), 100 ms. I-L. Melese sp. (Erebidae: Arctiinae) emits ultrasound with paired thoracic tymbals; I. Scale bars = 1.0 cm; J. Tymbal 0.5 mm; K. Close-up of microstriations on tymbal surface, 0.1 mm; L. Response to bat sonar playback (Melese peruviana), 100 ms. M-P. Gonodonta sicheas (Erebidae: Calpinae) produces ultrasound by stridulating modified abdominal scales; M. Scale bar = 1.0 cm; N. Patch of stridulatory scales, 0.5 mm; O. Stridulatory scale, Scale bar = 50 μm; P. Response to bat sonar playback (Gonodonta bidens), 100 ms. Q-T. Xylophanes falco (Sphingidae: Macroglossinae) produces ultrasound by stridulating modified genital valves; Q. Scale bar = 1 cm; R. Patch of stridulatory scales on genital valve, 0.5 mm; S. Stridulatory scales, 0.2 mm; T. Response to bat sonar playback (Xylophanes amadis), 100 ms.
Street lighting has detrimental impacts on local insect populations
Douglas H. Boyes, Darren M. Evans, Richard Fox, Mark S. Parsons and Michael J. O. Pocock Science Advances 25 Aug 2021
Many of us might remember Callum McGregor's excellent talk this Spring about the effects of street lighting on adult moths and their behaviour and of course the behaviour of their main predators see HERE. He pointed out the blue element of lighting is the most important and old orange sodium lamps are much less disruptive Douglas's work builds on that by examining the effects on the next stage, the caterpillars, which are often the most critical part of an insects life and most easily disrupted. Reported declines in insect populations have sparked global concern, with artificial light at night (ALAN) identified as a potential contributing factor. Despite strong evidence that lighting disrupts a range of insect behaviours, the empirical evidence that ALAN diminishes wild insect abundance is limited. Using a matched-pairs design, we found that street lighting strongly reduced moth caterpillar abundance compared with unlit sites (47% reduction in hedgerows and 33% reduction in grass margins (see diagram below) and affected caterpillar development. A separate experiment in habitats with no history of lighting revealed that ALAN disrupted the feeding behaviour of nocturnal caterpillars. Negative impacts were more pronounced under white light-emitting diode (LED) street lights compared to conventional yellow sodium lamps. This indicates that ALAN and the ongoing shift toward white LEDs (i.e., narrow- to broad-spectrum lighting) will have substantial consequences for insect populations and ecosystem processes. The work begs the question whether cool white LED is a good choice and since LED's can produce any colour we should change to warmer tones of yellow or orange, they are also more efficient at single frequency Full article HERE also Douglas' Blog HERE
The Diopsis Project:
Automated Insect and Moth Recording in Holland
A camera takes pictures of the screen every 10 seconds and is illuminated by UV LED's at night. In the first step of the process, the software analyzes where the photo shows insects. The software distinguishes between insects and other objects in the image, such as mud, grass and shadow by means of a deep learning system. Once the insects have been recognized, their numbers can be easily counted. Insects that were also observed in the previous picture are not counted again. Insects that remain on the screen for hours and are photographed every 10 seconds, count only once. On the right an example of a busy screen at night.
Image recognition
COSMONiO's specialised deep learning software looks at the photo and compares it with a large database of all kinds of insects brought to name by specialists. Just like the familiar 'facial recognition' in humans, the software searches for certain recognition points, which it extracts itself from the good examples database. In many cases this leads to a good recognition of the insect, sometimes even at the species level, for example moths. In small insects, such as mosquitoes, recognition down to family level is often possible. Not only does the software provide an identification, but also an estimate of the (im)accuracy of that identification. If desired, insufficiently certain identifications can be excluded. The image recognition 'pipeline' is shown on the right. Below is a video of COSMONiO platform 'NOUS' showing how the model is trained by means of manual annotation.
The ambition of DIOPSIS is to create a monitoring network of insect cameras all over the Netherlands, in order to map the trend of insects for many years to come. We want to know if the decline of insects continues and if there are groups of insects that are doing better or worse than average. In addition to this general monitoring objective, the cameras can also be used for targeted research.
Belgium : Citizen Science Data Reveal That the Peacock Butterfly Aglais io Recently Became Bivoltine
Marc Herremans ,* , Karin Gielen , Jos Van Kerckhoven , Pieter Vanormelingen , Wim Veraghtert , Kristijn R.R. Swinnen and Dirk Maes
The Peacock butterfly is abundant and widespread in Europe. It used to have a single generation per year: adults born in summer overwintered and reappeared in spring to reproduce. However, recent flight patterns in western Europe show three peaks during the year: a first one in spring (overwintering butterflies), a second one in early summer (offspring of the spring generation), and a third one in autumn. Hitherto, it was unclear whether this third autumn flight peak was a second new generation or consisted of butterflies flying again in autumn after a summer rest. Based on hundreds of thousands of observations and thousands of pictures submitted by naturalists from the public to the online portal ‘observation’ in Belgium, we demonstrate that Peacocks shifted towards two new generations per year in recent decades. Mass citizen science data has become increasingly important in tracking the response of biodiversity to rapid environmental changes (e.g., climate change).
Full Article HERE
Nitrogen deposition negatively affects butterfly species richness and butterfly abundance, particularly in species of conservation concern. : A Discussion from Chris van Swaay in Holland
Based on " Negative effects of nitrogen deposition on Swiss butterflies " by Tobias Roth, Lukas Kohli, Beat Rihm, Reto Meier, Valentin Amrhein First published: 08 April 2021 https://doi.org/10.1111/cobi.13744
Why has Nitrogen deposition become such an important threat for butterflies?
N-deposition (mainly due to high local ammonia emissions from intensive livestock farming) reaches dozens of km's from the source to deep into even the biggest nature reserves
It acts as a fertilizer increasing the growth rate of plants that can deal with a high N-load, as grasses. This changes the vegetation, succession speeds up and low vegetation and open soil is soon covered by tall grasses.
In combination with climate change this leads to microclimatic cooling creating unsuitable conditions, esp. for larval and egg hibernators (https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2006.01202.x…) as this Glanville Fritillary (Melitaea cinxia).
Nitrogen deposition in host plants increases the mortality of common Lepidoptera species (https://pubmed.ncbi.nlm.nih.gov/30288608/), e.g. with the Sooty Copper (Lycaena tityrus). This is probably caused by a shift in the N:P ratio in the foodplants (https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2435.12707…).
This imbalance by overabundance of Nitrogen has a big effect on the nutritional quality of foodplants and its subsequent effects on consumers (https://edepot.wur.nl/530421). Butterflies are more affected by this, a full metamorphosis means a high need of amino acids.
Nitrogen deposition also leads to acidification and a decline in the availability of other nutrients and elements (https://research.wur.nl/en/publications/continuous-and-cumulative-acidification-and-n-deposition-induce-p…).
For a more detailed overview of all pathways for the effects of increased nitrogen deposition on fauna see https://natuurkennis.nl/Uploaded_files/Publicaties/nijssen-etal-2017.0b6d7c.pdf…
We developed a nitrogen index to track changes in butterfly species assemblages under nitrogen deposition (https://research.wur.nl/en/publications/a-nitrogen-index-to-track-changes-in-butterfly-species-assemblage…).
Removing N from nature reserves is almost impossible as that also removes P and other elements. However N is quickly replenished leaving the area in a worse state as before (N:P ratio get further unbalanced).
The only solution is to reduce the Nitrogen emission at the source. This however, is still a step too far for our food producers?
Identifying fine‐scale habitat preferences of threatened butterflies using airborne laser scanning
Jan Peter Reinier de Vries Zsófia Koma Michiel F. WallisDeVries W. Daniel Kissling First published: 03 April 2021 https://doi.org/10.1111/ddi.13272
Associations of two grassland butterflies with LiDAR metrics. (a) Typical habitats of the Small pearl‐bordered fritillary (Boloria selene; a wet grassland species, left) and the Grayling (Hipparchia semele; a dry grassland species, right). (b) Relative variable importance, showing the contribution of each LiDAR metric to explain butterfly distributions by the mean and standard deviation of 100 model runs (empty rows are metrics discarded from the model). (c) Response curves of included LiDAR metrics, showing how they are associated with the species’ probability of occurrence by the mean and confidence interval of 100 model runs. In (b) and (c), colours indicate LiDAR metrics related to low vegetation (green), medium‐to‐high vegetation (orange) and landscape‐scale habitat structure (purple).
Light Detection And Ranging (LiDAR) is a promising remote sensing technique for ecological applications because it can quantify vegetation structure at high resolution overlarge areas like a country Using country‐wide airborne laser scanning (ALS) data, we test to what extent fine‐scale LiDAR metrics capturing low vegetation, medium‐to‐high vegetation and landscape‐scale habitat structures can explain the habitat preferences of threatened butterflies at a national extent.
All Species distribution models showed a good to excellent fit, with woodland butterflies performing slightly better than those of grassland butterflies. Grassland butterfly occurrences were best explained by landscape‐scale habitat structures (e.g., open patches, microtopography) and vegetation height. Woodland butterfly occurrences were mainly determined by vegetation density of medium‐to‐high vegetation, open patches and woodland edge extent. The importance of metrics generally differed between wet and dry habitats for both grassland and woodland species.
Vertical variability and horizontal heterogeneity of vegetation structure are key determinants of butterfly species distributions, even in low‐stature habitats such as grasslands, dunes and heathlands. LiDAR thus offers great potential for predictive habitat distribution modelling and other studies on ecological niches and invertebrate–habitat relationships particularly important for difficult to reach, and where habitat assessment like phase 1 are incomplete.
More HERE
Moths are strongly attracted to ultraviolet and blue radiation published: 16 March 2021
Gunnar Brehm, Julia Niermann, Luisa Maria Jaimes Nino, David Enseling, Thomas Jüstel, Jan Christoph Axmacher, Eric Warrant , Konrad Fiedler,
3 experiments were carried out with 6116 nocturnal lepidopteran individuals (95 species, 7 families, 32 075 counts), each replicated 105 times during the seasons of 2 years. Moths were released indoors at the centre of a 10 × 10 m area with different lamps placed at each corner.
In experiment 1, lamps emitted ultraviolet (UV) (peak at 365 nm), blue (450 nm), green (520 nm) or cool white (450 and 520 nm) radiation. In experiment 2, UV was replaced by red (640 nm). In experiment 3, we used UV and three mixed radiation lamps of different emission intensities (365–520 nm).
An appropriate model was applied to test for differences in attraction to the light sources.
Among all counts, 12.2% (males) and 9.2% (females) were attracted to a lamp. Among the lamp counts, 84% were made at the UV lamp in experiment 1. In experiment 2, 63% of the counts were made at the blue lamp. In experiment 3, most counts were made at the strongest mixed radiation lamp (31%), and the UV lamp (28%). Patterns were generally similar across Lepidopteran families, and for both sexes.
Moths are clearly preferentially attracted to short‐wave radiation. Even small quantities of UV radiation, emitted, for example, by metal halide lamps and certain mercury vapour tubes, will disproportionately contribute to light pollution. Since blue light also attracts moths strongly, lamps with a low proportion of blue light should be given priority in lighting planning.
Read the article HERE
The experimental setup and of the light trap used in the experiments with its 1 m2 background
Key Conclusions:
With insects disappearing at alarming rates globally it is becoming imperative to closely monitor their population and community dynamics as a basis for their effective conservation. Our results demonstrate that this can best be achieved by using lamps that emit significant radiation in the UV range, and that take advantage of the many practical advantages of LED lamps over other alternative light sources.
Lamps that emit in the Blue, Green and UV bandwidth should therefore be totally avoided from outside use and the results strongly argue for the banning of UV‐emitting Fluorescent. Longer‐wave alternative LED types with primary peaks in similar ranges to sodium vapour lamps should be tested and considered as suitable future replacements.
Are Grizzled Skippers stuck in the south?
Population‐level responses of an early‐successional specialist butterfly to climate across its UK range over 40 years
Authors: Fiona Bell Marc Botham Tom M. Brereton Andy Fenton Jenny Hodgson First published: 09 February 2021 https://doi.org/10.1111/ddi.13245
Climate change has been predicted to facilitate poleward (northern) expansion of many early‐successional specialist invertebrates. The Grizzled Skipper, Pyrgus malvae, is a threatened butterfly in long‐term decline that has not met expectations of northern expansion in Britain, possibly indicating that climate change has not improved northern habitat suitability or that another driver (e.g. land use change) is masking its effects. The article explores the effect of climate on population size trends over four decades, and whether any regions show an improving population trend that may be a precursor to northern expansion.
We found that P. malvae population size declined more over time in the north and west of its UK range than in the south and east, and was negatively related to high December temperature and summer rainfall. However, the effect sizes of temperature and rainfall were minimal
This seminal global report tackles the fundamentals of our realtionship with Nature . He outlines the drastic changes required for our survival and avoid another COVID 19
Our economies, livelihoods and well-being all depend on our most precious asset: Nature. We have collectively failed to engage with Nature sustainably, to the extent that our demands far exceed its capacity to supply us with the goods and services we all rely on. We require 1.6 Earths to maintain the world’s current living standards. Our unsustainable engagement with Nature is endangering the prosperity of current and future generations. At the heart of the problem lies deep-rooted, widespread institutional failure. The solution starts with understanding and accepting a simple truth: our economies are embedded within Nature, not external to it. We need to change how we think, act and measure success. We need to ensure that our demands on Nature do not exceed its supply, and that we increase Nature’s supply relative to its current level. To change our measures of economic success to guide us on a more sustainable path.
He concludes "Transformative change is possible – we and our descendants deserve nothing less!" It needs a plan in excess of the Marshall plan that rebuilt shattered Europe after WW2 as well as instilling an appreciation of nature through education is vital.
The papers say: "Landmark report says GDP should be ditched as measure of wealth and nature valued to protect wildlife and humans" . The review’s focus on completely rewiring mainstream economic and financial models is key to moving the nature debate on to the agenda of governments, financial regulators and individual financial firms
Produced capital has doubled since 1990 while natural capital has nearly halved .
Butterflies fly using efficient propulsive clap mechanism owing to flexible wings L. C. Johansson† and P. Henningsson
Butterflies look like no other flying animal, with unusually short, broad and large wings relative to their body size. Previous studies have suggested butterflies use several unsteady aerodynamic mechanisms to boost force production with upstroke wing clap being a prominent feature. When the wings clap together at the end of upstroke the air between the wings is pressed out, creating a jet, pushing the animal in the opposite direction. Although viewed, for the last 50 years, as a crucial mechanism in insect flight, quantitative aerodynamic measurements of the clap in freely flying animals are lacking. Using quantitative flow measurements behind freely flying butterflies during take-off and a mechanical clapper, we provide aerodynamic performance estimates for the wing clap. We show that flexible butterfly wings, forming a cupped shape during the upstroke and clap, thrust the butterfly forwards, while the downstroke is used for weight support. We further show that flexible wings dramatically increase the useful impulse (+22%) and efficiency (+28%) of the clap compared to rigid wings. Combined, our results suggest butterflies evolved a highly effective clap, which provides a mechanistic hypothesis for their unique wing morphology. Furthermore, our findings could aid the design of man-made flapping drones, boosting propulsive performance. Full Article here
Moths to the rescue with another british produced Covid vaccine
Well...how about rescue us from Covid 19? Yes!
The second wave of Covid Vaccines are expected to be approved after phase 3 trials in 1st quarter 2021. They include one manufacturered using a moth, the Noctuid Spodoptera frugiperda or 'Fall Army Worm'. Cells extracted from the formimg ovaries of a caterpillar (backin the 70's) can be cultured with the advantage they never change and are immortal. In an extremely safe process moth cells are brewed in 2000 ltr. bioreactors at Fujifilm's bio-pharmaceutical site at Billingham. The cells are then infected with a moth Baculovirus that has been modified to carry the DNA code to make the moth produce the antigen protein. The Baculovirus inserts this DNA into the moth cell's DNA who start to make spike proteins. After a few days the protein can be harvested form the cells onto a synthetic particles that closely resembles the Covid virus and mixed with a saponin, a natural adjuvant from Horse chesnuts, to make the final vaccine. This vaccine then causes our bodies to make antispike antibodies that that bind to the Covid virus spikes deactivating it. Proven now to be 1st in its class it produces a response in humans significantly greater than catching the Covid itself see below: Thank you Moths!
The First known Riodinid 'Cuckoo' Butterfly : Lucas Kaminski
Mutualistic interactions between butterflies and ants can evolve into complex social parasitism. 'Cuckoo' caterpillars, known only in the Lycaenidae, use multimodal mimetic traits to achieve social integration into ant societies. Here, we present the first known 'cuckoo' butterfly in the family Riodinidae. Aricoris arenarum remained in taxonomic limbo for > 80 years, relegated to nomen dubium and misidentified as Aricoris gauchoana. We located lost type material, designated lectotypes and documented the morphology and natural history of the immature stages. The multifaceted life cycle of A. arenarum can be summarized in three phases: (1) females lay eggs close to honeydew-producing hemipterans tended by specific Camponotus ants; (2) free-living caterpillars feed on liquids (honeydew and ant regurgitations); and (3) from the third instar onward, the caterpillars are fed and tended by ants as 'cuckoos' inside the ant nest. This life cycle is remarkably similar to that of the Asian lycaenid Niphanda fusca, despite divergence 90 Mya. Comparable eco-evolutionary pathways resulted in a suite of ecomorphological homoplasies through the ontogeny. This study shows that convergent interactions can be more important than phylogenetic proximity in shaping functional traits of social parasites.
Enhancing road verges to aid pollinator conservation: A review
Benjamin B. Phillipsa,⁎ , Claire Wallaceb , Bethany R. Robertsa , Andrew T. Whitehousec , Kevin J. Gastona , James M. Bullockd , Lynn V. Dicksb,e , Juliet L. Osbornea Road verges provide habitats that have considerable potential as a tool for pollinator conservation, especially given the significant area of land that they collectively cover. Growing societal interest in managing road verges for pollinators suggests an immediate need for evidence-based management guidance. We used a formal, global literature review to assess evidence for the benefits of road verges for pollinators (as habitats and corridors), the potential negative impacts of roads on pollinators (vehicle-pollinator collisions, pollution, barriers to movement) and how to enhance road verges for pollinators through management. We identified, reviewed and synthesised 140 relevant studies. Overall, the literature review demonstrated that: (i) road verges are often hotspots of flowers and pollinators (well established), (ii) traffic and road pollution can cause mortality and other negative impacts on pollinators (well established), but available evidence suggests that the benefits of road verges to pollinators far outweigh the costs (established but incomplete), and (iii) road verges can be enhanced for pollinators through strategic management (well established). Future research should address the lack of holistic and large-scale understanding of the net effects of road verges on pollinators. We provide management recommendations for enhancing both individual road verges for pollinators (e.g. optimised mowing regimes) and entire road networks (e.g. prioritising enhancement of verges with the greatest capacity to benefit pollinators), and highlight three of the most strongly supported recommendations: (i) creating high quality habitats on new and existing road verges, (ii) reducing mowing frequency to 0–2 cuts/year
Speckled Wood: Wing morphological responses to latitude and colonisation in a range expanding butterfly
Evelyn D. Taylor-Cox1, Callum J. Macgregor2,3, Amy Corthine1, Jane K. Hill2, Jenny A. Hodgson1, Ilik J. Saccheri1
A study of how the Speckled Wood butterfly has been able to achieve such a rapid expansion and what we can learn from this as climate change bites . Are northerners bigger and darker? Anecdotal evidence from our recorders suggests they are and has been assisted in its invasion even into our gardens by the trend towards wet warm summers and lush grass growth. This species swept through Yorkshire in the 1980's to become one of our most familiar butterflies not only common anywhere shady but by being on the wing almost continuously from April till October.
This study documents detailed wing morphological variation (size, shape and colour) in the Speckled Wood butterfly, P. aegeria, across two recently expanded populations in mainland Britain, suggesting differing responses to environmental and demographic factors. The size of P. aegeria increases with latitude, consistent with Bergmann’s rule, and during the range expansion process, with more recently colonised populations being larger than core populations. Shape changes, independent of size, are most strongly associated with colonisation history. Forewing shape becomes more rounded, whereas hindwing shape becomes longer, in more recently colonised populations and with latitude. The distribution of average lightness (opposite of melanism) is more strongly associated with temperature during development than it is to latitude, and runs contrary to the traditional thermal melanism hypothesis. Furthermore, the area of brown relative to cream increases with latitude, but not enough to overcome the general lightening in both areas. Finally, the contrast between brown and cream areas increases with latitude, accounting for the human perception that individuals become darker further north. Overall, this study sheds light on the interaction of temperature-sensitive plastic traits and selection during a mainly climate-driven range expansion.
" Populations undergoing rapid climate-driven range expansion experience distinct selection regimes dominated both by increased dispersal at the leading edges and steep environmental gradients. Characterisation of traits associated with such expansions provides insight into the selection pressures and evolutionary constraints that shape demographic and evolutionary responses. Here we investigate patterns in three components of wing morphology (size, shape, colour) often linked to dispersal ability and thermoregulation, along latitudinal gradients of range expansion in the Speckled Wood butterfly (Pararge aegeria) in Britain "
Resolving a 150 year old argument: Why do male and female butterflies differ in colour?
Males and females of many species are dimorphic; there are differences in the way the sexes look and function. One of the most studied types of dimorphism is dichromatism, where males and females have different colors.
It is often assumed that sexual selection is important to dichromatism, as choosy females often mate with colorful males. At the same time, natural selection by predators against elaborated colors can especially be strong for females, as they may need to carry eggs or provide maternal care making them more vulnerable.
For as long as we have known about natural and sexual selection, however, it has been debated which of these two forces initially creates dichromatism.
Charles Darwin argued that sexual selection drives male color away from female color, whereas contemporary Alfred Russel Wallace instead thought that natural selection pulled female color away from the male's.
Here, we revisit this debate using butterflies, one of the taxa Darwin and Wallace argued over, to determine whether Darwin's or Wallace's model is more important in the evolution of dichromatism.
We used drawings from a field guide to quantify the color difference between males and females of all European non‐hesperiid butterfly species, and modeled how their colors have evolved over time.
We show that the color of males generally evolves faster than that of females.
By using the direction of male and female color evolution along the phylogeny, we also determined that changes in male color are around twice as important to dichromatism evolution than changes in female color.
These results show that directional selection on males, likely due to sexual selection, is the main driver of dichromatism in butterflies.
This supports Darwin's, but not Wallace's, model of dichromatism evolution, resolving a 150‐year‐old argument.
(Summary Extract )
Opposite: Colour profiles of Male and Females
Bucking the trend - Why are some British moths on the rise?
Online talk with Douglas Boyes, Newcastle University ; one of our young scientists
Recently, there has been a surge of interest in insect declines, with several high-profile studies generating extensive media coverage (‘insectageddon’). However, not all insects are declining. Conservation scientists have understandably focused on decreasing species, though these only provide half the story of biodiversity change. Appreciating how some species are thriving despite unprecedented anthropogenic pressures could provide insights for mitigating wider declines. The talk is based on Douglas Boyes’s MSc project which examined changes in the prevalence of 51 moth species, using two national datasets. The ‘winners’ are diverse, including long-term residents, habitat specialists, and recent colonists. The causes of these trends are poorly understood. Whilst climate change is considered an important driver, the success of many ‘winners’ likely arises from numerous, intertwining factors.
Douglas has been recording moths since aged 12, finding over 800 species in his garden. He further developed his passion for moths at the University of Oxford, through undergraduate and postgraduate research. Douglas is currently undertaking a PhD at the UK Centre for Ecology & Hydrology. This investigates the impacts of light pollution on moths.
Watch here.
Provide shady spots to protect butterflies from climate change, say scientists at Cambridge + Lancaster
Researchers have discovered significant variations in the ability of different UK butterfly species to maintain a suitable body temperature. Species that rely most on finding a suitably shady location to keep cool are at the greatest risk of population decline. The results predict how climate change might impact butterfly communities, and will inform conservation strategies to protect them.
The results, published today in the Journal of Animal Ecology, show that larger and paler butterflies including the Large White (Pieris brassicae) and Brimstone (Gonepteryx rhamni) are best able to buffer themselves against environmental temperature swings. They angle their large, reflective wings in relation to the sun, and use them to direct the sun's heat either away from, or onto their bodies. These species have either stable or growing populations.
More colourful larger species such as the Peacock (Aglais io) and Red Admiral (Vanessa atalanta) have greater difficulty controlling their body temperature, but even they are better than their smaller relatives like the Small Heath (Coenonympha pamphilus).
The study found that some butterfly species rely on finding a spot at a specific temperature within a landscape -- termed a 'microclimate' -- to control their body temperature. Air temperatures vary on a fine scale: a shaded patch of ground is cooler than one in full sun, for example. These 'thermal specialists', including Brown Argus (Aricia agestis) and Small Copper (Lycaena phlaeas), have suffered larger population declines over the last 40 years.
All butterflies are ectotherms: they can't generate their own body heat. "Butterfly species that aren't very good at controlling their temperature with small behavioural changes, but rely on choosing a micro-habitat at the right temperature, are likely to suffer the most from climate change and habitat loss," said Dr Andrew Bladon, a Postdoctoral Research Associate in the University of Cambridge's Department of Zoology, and first author of the report.
He added: "We need to make landscapes more diverse to help conserve many of our butterfly species. Even within a garden lawn, patches of grass can be left to grow longer -- these areas will provide cooler, shady places for many species of butterfly. In nature reserves, some areas could be grazed or cut and others left standing. We also need to protect features that break up the monotony of farm landscapes, like hedgerows, ditches, and patches of woodland."
Landscapes with a diversity of heights and features have a greater range of temperatures than flat, monotonous ones. This applies on scales from kilometres to centimetres: from hillsides to flower patches. Such structural diversity creates different microclimates that many butterflies use to regulate their temperature.
The research involved catching nearly 4,000 wild butterflies in hand-held nets, and taking the temperature of each using a fine probe. The surrounding air temperature was measured, and for butterflies found perching on a plant, the air temperature at the perch was also taken. This indicated the degree to which butterflies were seeking out specific locations to control their body temperature. In total, 29 different butterfly species were recorded.
The study reveals that butterflies are either thermal generalists or thermal specialists, and this does not always correspond with their current categorisations as either habitat generalists or specialists.
"As we plan conservation measures to address the effects of climate change, it will be important to understand not only the habitat requirements of different butterfly species, but also their temperature requirements," said Dr Ed Turner in the University Museum of Zoology, Cambridge, who led the work.
He added: "With this new understanding of butterflies, we should be able to better manage habitats and landscapes to protect them, and in doing so we're probably also protecting other insects too."
Over the past thirty years, many species of butterfly have expanded their range northwards, as more northerly places have become warmer due to climate change. The ranges of species adapted to cooler environments are shrinking. These trends have been tracked for butterfly populations as a whole, but no previous study has investigated how the individual butterflies that make up these populations are able to respond to small scale temperature changes.
Full article here
Study identifies British butterflies most threatened by climate change
Scientists have discovered why climate change may be contributing to the decline of some British butterflies and moth species, such as Silver-studded Blue and High Brown Fritillary.
Many British butterflies and moths have been responding to warmer temperatures by emerging earlier in the year and, for the first time, scientists have identified why this is creating winners and losers among species.
The findings will help conservationists identify which species most at risk from climate change, the researchers say.
The study, led by the University of York, found that emerging earlier in the year may be benefiting species which have multiple, rapid breeding cycles per year and are flexible about their habitat (such as Speckled Wood), by allowing them more time to bulk up in numbers before winter and expand their range northwards.
In contrast, early emergence may be causing species that are habitat specialists and have only a single life-cycle per year, to shrink in numbers and disappear from northern parts of the country within their historical range.
Single-generation species that are habitat specialists (such as the rare High Brown Fritillary) are most vulnerable to climate change because they cannot benefit from extra breeding time. Emerging earlier may throw them out of seasonal synchrony with their restricted diet of food resources, the researchers suggest.
The researchers studied data on butterflies and moths, contributed by citizen scientists to a range of schemes including Butterflies for the New Millennium and the National Moth Recording Scheme (both run by Butterfly Conservation), over a 20 year period (1995-2014) when the average spring temperatures in Britain increased by 0.5 degrees.
Temperature increases are causing butterflies and moths to emerge on average between one and six days earlier per decade over this time period.
Lead author of the study, Dr Callum Macgregor, from the Department of Biology at the University of York, said: "Because butterflies in general are warmth loving, scientists predicted that the range margin of most species would move north as a result of global heating. However this hasn’t happened as widely or as quickly as expected for many species.
"Our study is the first to establish that there is a direct connection between changes in emergence date and impacts on the habitat range of butterflies and moths. This is because emerging earlier has caused some species to decline in abundance, and we know that species tend only to expand their range when they are doing well"
Professor Jane Hill, from the Department of Biology at the University of York, who leads the NERC Highlight project, said: "Our results indicate that while some more flexible species are able to thrive by emerging earlier in the year, this is not the case for many single generation species that are habitat specialists – these species are vulnerable to climate change."
Co-author Professor Chris Thomas, from the Leverhulme Centre for Anthropocene Biodiversity at the University of York, added: "These changes remind us how pervasive the impacts of climate change have already been for the world's biological systems, favouring some species over others. The fingerprint of human-caused climate change is already everywhere we look."
Professor Tom Brereton of Butterfly Conservation said: "The study shows that we urgently need to conduct ecological research on threatened butterflies such as High Brown Fritillary, to see if we can manage land in a new way that can help them adapt to the current negative effects of climate change."
Reference
Macgregor, C J, Thomas, C D, Roy, D B & 17 others. 2019. Climate-induced phenology shifts linked to range expansions in species with multiple reproductive cycles per year. Nature Communications 10, 4455, doi: 10.1038/s41467-019-12479-w