Vanessa Cardui Research Articles

Trans-Saharan migratory patterns in Vanessa cardui and evidence for a southward leapfrog migration

Trans-Saharan migratory patterns in Vanessa cardui and evidence for a southward leapfrog migration

A trans-oceanic flight of over 4,200 km by painted lady butterflies

The extent of aerial flows of insects circulating around the planet and their impact on ecosystems and biogeography remain enigmatic because of methodological challenges. Here we report a transatlantic crossing by Vanessa cardui butterflies spanning at least 4200 km, from West Africa to South America (French Guiana) and lasting between 5 and 8 days. Even more, we infer a likely natal origin for these individuals in Western Europe, and the journey Europe-Africa-South America could expand to 7000 km or more. This discovery was possible through an integrative approach, including coastal field surveys, wind trajectory modelling, genomics, pollen metabarcoding, ecological niche modelling, and multi-isotope geolocation of natal origins. The overall journey, which was energetically feasible only if assisted by winds, is among the longest documented for individual insects, and potentially the first verified transatlantic crossing. Our findings suggest that we may be underestimating transoceanic dispersal in insects and highlight the importance of aerial highways connecting continents by trade winds.

Pollen metabarcoding reveals the origin and multigenerational migratory pathway of an intercontinental-scale butterfly outbreak

Migratory insects may move in large numbers, even surpassing migratory vertebrates in biomass. Long-distance migratory insects complete annual cycles through multiple generations, with each generation's reproductive success linked to the resources available at different breeding grounds. Climatic anomalies in these grounds are presumed to trigger rapid population outbreaks. Here, we infer the origin and track the multigenerational path of a remarkable outbreak of painted lady (Vanessa cardui) butterflies that took place at an intercontinental scale in Europe, the Middle East, and Africa from March 2019 to November 2019. Using metabarcoding, we identified pollen transported by 264 butterflies captured in 10 countries over 7months and modeled the distribution of the 398 plants detected. The analysis showed that swarms collected in Eastern Europe in early spring originated in Arabia and the Middle East, coinciding with a positive anomaly in vegetation growth in the region from November 2018 to April 2019. From there, the swarms advanced to Northern Europe during late spring, followed by an early reversal toward southwestern Europe in summer. The pollen-based evidence matched spatiotemporal abundance peaks revealed by citizen science, which also suggested an echo effect of the outbreak in West Africa during September-November. Our results show that population outbreaks in a part of species' migratory ranges may disseminate demographic effects across multiple generations in a wide geographic area. This study represents an unprecedented effort to track a continuous multigenerational insect migration on an intercontinental scale.

Sensitivity of Vanessa cardui to Temperature Variations: A Cost-Effective Experiment for Environmental Education.

Temperature increases mediated through climate change threaten the survival of species. It is of foremost importance to engage citizens and future generations in understanding the mechanisms through which temperatures impose their effects. For educators, this is not straightforward, as tools for examining the impact of temperature over the lifetime of an animal are prohibitively expensive. At the same time, environmental educators need guidance on the appropriate study systems to use with a balance between the species having an obvious response and ensuring the outcomes are ethical and sustainable. In our study, we created and tested a cost-effective experiment meant to be used for environmental education purposes. More specifically, we tested the sensitivity of the painted lady butterfly Vanessa cardui to temperature variations using a homemade incubator. We describe the design of this experiment and report findings on survival rate, morphological variations, development time of various stages and wingspan of adults across a range of biologically relevant temperatures. The information provided gives educators options for testing a variety of hypotheses with regards to the impacts of temperature using an affordable and flexible set-up. Furthermore, the findings can be used by students to develop an understanding of the ramifications of the butterflies' responses in an ecological context.

Struggling to survive: A comparison of Vanessa cardui larval survivorship on putative host plants

AbstractThe painted lady butterfly (Vanessa cardui) is a generalist herbivore with a global distribution. In North America, over 100 species have been identified as V. cardui larval host plants. This cosmopolitan species is commercially available in all life stages and can be reared on an artificial diet. As a result, V. cardui commonly serves as a model organism for education and outreach. However, gaps in our knowledge remain with regard to V. cardui ecology and larval host plant suitability for supporting complete development of larvae to reproductive adulthood. In a laboratory setting, we tested host plant suitability of five reported host plants commonly found in California sage scrub ecosystems by assessing survival of V. cardui caterpillars in its entirety. We also assessed how commercially sourced larvae survived on artificial diet: both raising the caterpillars exclusively on artificial diet as well as switching diets from artificial to thistle (a commonly reported host plant) and switching from thistle to artificial diet. We found that all commercially sourced caterpillars exhibited both high larval mortality and low pupation rates when reared on host plants, although larvae reared on Malacothamnus fasciculatus and Sphaeralcea ambigua survived longest. Moreover, M. fasciculatus and S. ambigua were the only host plants tested that supported successful pupation. This contrasted with 63% higher survival of wild‐collected larvae. Our findings suggest that commercially obtained V. cardui may struggle to utilize wild host plants and that future investigations into host plant suitability in wild populations are needed. Additionally, future research using commercial larvae should consider the implications for interpreting host plant suitability as larvae may exhibit adaptations to artificial diet or the loss of adaptation to consuming plant material.

Food and time: dietary plasticity of different sources of a generalist insect herbivore.

Painted lady butterflies (Vanessa cardui L.,Nymphalidae) are generalist herbivores and serve as a model system across several fields of biology. While it has been demonstrated that V. cardui caterpillars can develop on different host plants, much of this work has been done on commercially sourced caterpillars, which could limit our understanding of wild V. cardui populations. In this study, we sought to explore possible differences in how commercial and wild V. cardui caterpillars may respond to feeding on different host plants, and subsequently, how their diet impacts immune response and survival. Here, we analyzed performance, survival, and immune response of wild and commercially sourced V. cardui caterpillars over several generations on diets that consisted of either 1 of 4 different host plant species or a mixed diet including all 4 species. Qualitatively, we observed that wild larvae had a better larval performance and hemocyte counts compared to the commercial larvae. The results demonstrate that both wild and commercially sourced caterpillars grew and survived best on the same diet treatments (mallow, narrowleaf plantain, and a mixed diet) during development across generations. Immune responses showed similar patterns across host plants between wild and commercial populations, with individuals showing lowered immune responses on dandelion and lupine and higher ones on mallow, plantain and the mixed diet; although the relative rankings on those 3 diets varied. Survival also demonstrated similar patterns, in that individuals reared on dandelion and lupine had the lowest survival.

Viral Infection Induces Changes to the Metabolome, Immune Response and Development of a Generalist Insect Herbivore.

Host plant consumption and pathogen infection commonly influence insect traits related to development and immunity, which are ultimately reflected in the behavior and physiology of the insect. Herein, we explored changes in the metabolome of a generalist insect herbivore, Vanessa cardui (Lepidoptera: Nymphalidae), in response to both dietary variation and pathogen infection in order to gain insight into tritrophic interactions for insect metabolism and immunity. Caterpillars were reared on two different host plants, Plantago lanceolata (Plantaginaceae) and Taraxacum officinale (Asteraceae) and subjected to a viral infection by Junonia coenia densovirus (JcDV), along with assays to determine the insect immune response and development. Richness and diversity of plant and caterpillar metabolites were evaluated using a liquid chromatography-mass spectrometry approach and showed that viral infection induced changes to the chemical content of V. cardui hemolymph and frass dependent upon host plant consumption. Overall, the immune response as measured by phenoloxidase (PO) enzymatic activity was higher in individuals feeding on P. lanceolata compared with those feeding on T. officinale. Additionally, infection with JcDV caused suppression of PO activity, which was not host plant dependent. We conclude that viral infection combined with host plant consumption creates a unique chemical environment, particularly within the insect hemolymph. Whether and how these metabolites contribute to defense against viral infection is an open question in chemical ecology.

Feeding on migratory butterflies: opportunistic observations of birds preying on the Painted Lady Vanessa cardui

Many butterfly species are often seen with severe wing damage, which is regarded as evidence of unsuccessful predation, most likely by insectivorous birds. However, observations of bird predation are rare for the vast majority of butterflies. During a long-term study of the ecology of the Painted Lady Vanessa cardui, a common migratory butterfly, a high frequency of wing damage was noted, especially in North African populations. Attacks by several bird species were confirmed during fieldwork which, along with a number of published and unpublished records from ornithological colleagues, are reported in this note. Twenty-four bird species have been recorded preying on the Painted Lady in the Palaearctic-Afrotropical region. Records from eight additional species from the Nearctic region were obtained from photographs and from the literature. With 16 families (13 passerines and three non-passerines), this bird community embraces a notable diversity of morphologies and prey-capture techniques. The most represented families were the Tyrannidae, the Sylviidae and the Turdidae while the species most frequently recorded as predators were European Bee-eater Merops apiaster, Blue-cheeked Bee-eater Merops persicus, White-crowned Wheater Oenanthe leucopyga, and Cattle Egret Bubulcus ibis. Most observations occurred in March–April and October when the Painted Lady migrates in large numbers, suggesting that a sudden increase in abundance may lead to a regular use of this resource by predators. Moreover, unsuccessful attacks are common, which suggests that butterflies may quite often escape with some form of wing damage. The consequences these interactions have on butterfly populations are speculative but deserve further study.

Divergent impacts of the neonicotinoid insecticide, clothianidin, on flight performance metrics in two species of migratory butterflies.

Long-distance flight is crucial for the survival of migratory insects, and disruptions to their flight capacity can have significant consequences for conservation. In this study, we examined how a widely used insecticide, clothianidin (class: neonicotinoid), impacted the flight performance of two species of migratory butterflies, monarchs (Danaus plexippus) and painted ladies (Vanessa cardui). To do this, we quantified the free-flight energetics and tethered-flight velocity and distance of the two species using flow-through respirometry and flight mill assays. Our findings show differential effects of the pesticide on the two species. For painted ladies, we found that clothianidin exposure reduced average free-flight metabolic rates, but did not affect either average velocity or total distance during tethered flight. Other studies have linked low flight metabolic rates with reduced dispersal capacity, indicating that clothianidin exposure may hinder painted lady flight performance in the wild. Conversely, for monarchs, we saw no significant effect of clothianidin exposure on average free-flight metabolic rates but did observe increases in the average velocity, and for large individuals, total distance achieved by clothianidin-exposed monarchs in tethered flight. This suggests a potential stimulatory response of monarchs to low-dose exposures to clothianidin. These findings indicate that clothianidin exposure has the potential to influence the flight performance of butterflies, but that not all species are impacted in the same way. This highlights the need to be thoughtful when selecting performance assays, as different assays can evaluate fundamentally distinct aspects of physiology, and as such may yield divergent results.

The reasons of spreading and measures of fighting painted lady butterfly (Vanessa cardui L.) on soybean sown areas in Poltava region

The reasons of spreading and measures of fighting painted lady butterfly (Vanessa cardui L.) on soybean sown areas in Poltava region

Laboratory Determination of Particulate-Matter-Bound Agrochemical Toxicity among Honeybees, Mason Bees, and Painted Lady Butterflies.

Pollinator population declines are global phenomena with severe consequences for native flora and agriculture. Many factors have contributed to pollinator declines including habitat loss, climate change, disease and parasitism, reductions in abundance and diversity of foraging resources, and agrochemical exposure. Particulate matter (PM) serves as a carrier of toxic agrochemicals, and pollinator mortality can occur following exposure to agrochemical-contaminated PM. Therefore, laboratory-controlled experiments were conducted to evaluate impacts of individual PM-bound agrochemicals. Honeybees (Apis mellifera), blue orchard mason bees (Osmia lignaria), and painted lady butterfly (Vanessa cardui) larvae were exposed to bifenthrin, permethrin, clothianidin, imidacloprid, abamectin, and ivermectin via suspended, airborne PM. Agrochemical concentrations in PM to which pollinators were exposed were based on concentrations observed in fugitive beef cattle feedyard PM including a "mean" treatment and a "max" treatment reflective of reported mean and maximum PM-bound agrochemical concentrations, respectively. In general, pollinators in the mean and max treatments experienced significantly higher mortality compared with controls. Honeybees were most sensitive to pyrethroids, mason bees were most sensitive to neonicotinoids, and painted lady butterfly larvae were most sensitive to macrocyclic lactones. Overall, pollinator mortality was quite low relative to established toxic effect levels derived from traditional pollinator contact toxicity tests. Furthermore, pollinator mortality resulting from exposure to individual agrochemicals via PM was less than that reported to occur at beef cattle feedyards, highlighting the importance of mixture toxicity to native and managed pollinator survival and conservation. Environ Toxicol Chem 2023;42:2642-2650. © 2023 SETAC.

Temperature alters the toxicological impacts of plant terpenoids on the polyphagous model herbivore Vanessa cardui

Terpenes are a major class of secondary metabolites present in all plants, and long hypothesized to have diversified in response to specific plant-herbivore interactions. Herbivory is a major biotic interaction that plays out across broad temporal and spatial scales that vary dramatically in temperature regimes, both due to climatic variation across geographic locations as well as the effect of seasonality. In addition, there is an emerging understanding that global climate change will continue to alter the temperature regimes of nearly every habitat on Earth over the coming centuries. Regardless of source, variation in temperature may influence herbivory, in particular via changes in the efficacy and impacts of plant defensive chemistry. This study aims to characterize temperature-driven variation in toxicological effects across several structural classes of terpenes in the model herbivore Vanessa cardui, the painted lady butterfly. We observed a general increase in monoterpene toxicity to larvae, pupa, and adults at higher temperatures, as well as an increase in development time as terpene concentration increased. Results obtained from this study yield insights into possible drivers of seasonal variation in plant terpene production as well as inform effects of rising global temperatures on plant-insect interactions. In the context of other known effects of climate change on plant-herbivore interactions like carbon fertilization and compensatory feeding, temperature-driven changes in plant chemical defense efficacy may further complicate the prediction of climate change impacts on the fundamental ecological process of herbivory.

Environmental stress during larval development induces DNA methylation shifts in the migratory painted lady butterfly (Vanessa cardui).

Seasonal environmental fluctuations provide formidable challenges for living organisms, especially small ectotherms such as butterflies. A common strategy to cope with harsh environments is to enter diapause, but some species avoid unsuitable conditions by migrating. Despite a growing understanding of migration in the life cycles of some butterfly species, it remains unknown how individuals register and store environmental cues to determine whether and where to migrate. Here, we explored how competition and host plant availability during larval development affect patterns of DNA methylation in the migratory painted lady (Vanessa cardui) butterfly. We identify a set of potentially functional methylome shifts associated with differences in the environment, indicating that DNA methylation is involved in the response to different conditions during larval development. By analysing the transcriptome for the same samples used for methylation profiling, we also uncovered a non-monotonic relationship between gene body methylation and gene expression. Our results provide a starting point for understanding the interplay between DNA methylation and gene expression in butterflies in general and how differences in environmental conditions during development can trigger unique epigenetic marks that might be important for behavioural decisions in the adult stage.

A geometric morphometrics and genetics characterization of Vanessa carye in an extreme elevational gradient in the Chilean Altiplano

The Western Painted Lady butterfly, Vanessa carye (Hüber, 1812), in addition to pre-senting an extensive distribution in South America, has been observed flying in the Chilean Alti-plano from the coast to the highlands, from 0 to 5200 m.a.s.l. and it is suggested that could be a migratory insect. Some animal species move from one place to another by migration searching for favorable conditions. Wings of flying migratory animals are the principal trait involved in move-ment, and their shape has been documented to change between migratory and non-migratory species or populations. In this sense, little is known about the adaptations of butterflies to elevational gradients, so the V. carye's wide latitudinal and altitudinal range coupled with the different climatic conditions makes this species an interesting subject for adaptation studies. This research studies V. carye at different elevational ranges in extreme environments at the Chilean Altiplano and Atacama Desert to determine the presence of morphotypes through geometric morphometrics associated with altitudinal patterns, and to determine the genetic diversity and population structure of this species by using COI molecular marker. Subtle morphometric changes between populations were found, so two morphometric lineages were defined: a “coastal” lineage with more elongated wings and an “altiplano” lineage with more rounded wings. Nevertheless, low genetic diversity and no genetic structure associated to these morphological differences were found. Understanding the processes underlying the wing shape of V. carye morphological adaptations will help to understand its natural history. Results here may be a first approach of evidence to answer the question “Is this butterfly a migratory species?”

On the trail of the painted lady butterfly

On the trail of the painted lady butterfly

The Afrotropical breeding grounds of the Palearctic-African migratory painted lady butterflies (Vanessa cardui)

Migratory insects are key players in ecosystem functioning and services, but their spatiotemporal distributions are typically poorly known. Ecological niche modeling (ENM) may be used to predict species seasonal distributions, but the resulting hypotheses should eventually be validated by field data. The painted lady butterfly (Vanessa cardui) performs multigenerational migrations between Europe and Africa and has become a model species for insect movement ecology. While the annual migration cycle of this species is well understood for Europe and northernmost Africa, it is still unknown where most individuals spend the winter. Through ENM, we previously predicted suitable breeding grounds in the subhumid regions near the tropics between November and February. In this work, we assess the suitability of these predictions through i) extensive field surveys and ii) two-year monitoring in six countries: a large-scale monitoring scheme to study butterfly migration in Africa. We document new breeding locations, year-round phenological information, and hostplant use. Field observations were nearly always predicted with high probability by the previous ENM, and monitoring demonstrated the influence of the precipitation seasonality regime on migratory phenology. Using the updated dataset, we built a refined ENM for the Palearctic-African range of V. cardui. We confirm the relevance of the Afrotropical region and document the missing natural history pieces of the longest migratory cycle described in butterflies.

Sipping on Nectar: Butterflies and Flowers in Oak Savannas on Vancouver Island, British Columbia

Photo 1. View of a Garry oak savanna field site in Camrose Park, Victoria, BC, Canada. Oak savannas in the region are characterized by rocky outcroppings, a dense understory of forbs, and an open canopy of mostly Garry oak trees (Quercus garryana) mixed in with Douglas Firs (Pseudotsuga menziesii) and Arbutus (Arbutus menziesii). In front of the treeline, the nectar-less yellow flowers of invasive Scotch Broom (Cytisus scoparius) can be seen. Photo credit: Stephanie A. Rivest. Photo 2. Examples of flowering plants recorded in Garry oak savannas around Victoria, BC. Western Buttercup (top left panel: Ranunculus occidentalis) and Sea Blush (top right panel: Plectritis congesta) are native to the region, while Himalayan Blackberry (bottom right panel: Rubus armeniacus) and Cornflower (bottom right panel: Centaurea cyanus) are non-native. Photo credit: Stephanie A. Rivest. Photo 3. A native Propertius Duskywing (Erynnis propertius) butterfly foraging for nectar on a native White Brodiaea (Triteleia hyacinthine) flower in an oak savanna in Victoria, BC. Photo credit: Stephanie A. Rivest. Photo 4. A native Painted Lady (Vanessa cardui) butterfly foraging for nectar on a native Oceanspray (Holodiscus discolor) flower in an oak savanna in Victoria, BC. Photo credit: Stephanie A. Rivest. Photo 5. A native Lorquin's Admiral (Limenitis lorquini) perched on a researcher's hand during a field survey of an oak savanna in Victoria, BC. The butterfly's proboscis explores the researcher's skin, hoping to collect the sodium from sweat. Photo credit: Stephanie A. Rivest. Source paper: These photographs illustrate the article “Flowering phenology influences butterfly nectar foraging on non-native plants in an oak savanna” by Stephanie A. Rivest, E.M. Wolkovich, and Heather M. Kharouba published in Ecology. https://doi.org/10.1002/ecy.4004

Mass migration, population genetics and historical population expansion in the Neotropical butterflyKricogonia lyside(Lepidoptera: Pieridae)

AbstractLittle is known of the migratory ecology and population genetics of the lyside sulphur butterfly Kricogonia lyside (Godart) (Pieridae: Coliadinae). Mass migrations involving huge numbers of these butterflies have long been known to occur in the southern USA, Mexico and Greater Antilles, but these reports have been based mainly on chance encounters. A review of the limited literature on migrations of K. lyside in North America is presented here, together with results from field observations of a recent mass migration in north-western Mexico. Overall, these data confirm that migrations of K. lyside are often unidirectional, but can change direction over relatively short time periods, and are most probably ‘triggered’ by substantial rainfall following a prolonged dry period. Several important questions on these enigmatic migrations, however, including, but not limited to, location of source populations, ultimate destinations, numbers of individuals involved and purpose, remain to be answered. Analysis of mitochondrial DNA barcodes revealed that genetic diversity of the cytochrome c oxidase subunit I (COI) gene is much higher in K. lyside than that seen in the long-distance migrating nymphalid butterflies, the monarch (Danaus plexippus) and painted lady (Vanessa cardui), and that a large historical population expansion occurred during the mid-Pleistocene.

Link between Energy Investment in Biosynthesis and Proteostasis: Testing the Cost-Quality Hypothesis in Insects.

The energy requirement for biosynthesis plays an important role in an organism's life history, as it determines growth rate, and tradeoffs with the investment in somatic maintenance. This energetic trait is different between painted lady (Vanessa cardui) and Turkestan cockroach (Blatta lateralis) due to the different life histories. Butterfly caterpillars (holometabolous) grow 30-fold faster, and the energy cost of biosynthesis is 20 times cheaper, compared to cockroach nymphs (hemimetabolous). We hypothesize that physiologically the difference in the energy cost is partially attributed to the differences in protein retention and turnover rate: Species with higher energy cost may have a lower tolerance to errors in newly synthesized protein. Newly synthesized proteins with errors are quickly unfolded and refolded, and/or degraded and resynthesized via the proteasomal system. Thus, much protein output may be given over to replacement of the degraded new proteins, so the overall energy cost on biosynthesis is high. Consequently, the species with a higher energy cost for biosyntheses has better proteostasis and cellular resistance to stress. Our study found that, compared to painted lady caterpillars, the midgut tissue of cockroach nymphs has better cellular viability under oxidative stresses, higher activities of proteasome 20S, and a higher RNA/growth ratio, supporting our hypothesis. This comparative study offers a departure point for better understanding life history tradeoffs between somatic maintenance and biosynthesis.

Effects of Host Plants on Development and Immunity of a Generalist Insect Herbivore.

Secondary plant chemistry mediates a variety of communication signals among species, playing a fundamental role in the evolutionary diversification of communities and ecosystems. Herein, we explored diet-mediated host plant effects on development and immune response of a generalist insect herbivore. Vanessa cardui (Nymphalidae) caterpillars were reared on leaves of three host plants that vary in secondary metabolites, Plantago lanceolata (Plantaginaceae), Taraxacum officinale (Asteraceae) and Tithonia diversifolia (Asteraceae). Insect development was evaluated by larval and pupal viabilities, survivorship, and development rate. Immune response was measured as phenoloxidase (PO) activity. Additionally, chemical profiles of the host plants were obtained by liquid chromatograph-mass spectrometry (LC-MS) and the discriminant metabolites were determined using a metabolomic approach. Caterpillars reared on P. lanceolata exhibited the highest larval and pupal viabilities, as well as PO activity, and P. lanceolata leaves were chemically characterized by the presence of iridoid glycosides, phenylpropanoids and flavonoids. Taraxacum officinale leaves were characterized mainly by the presence of phenylpropanoids, flavones O-glycoside and germacranolide-type sesquiterpene lactones; caterpillars reared on this host plant fully developed to the adult stage, however they exhibited lower larval and pupal viabilities compared to individuals reared on P. lanceolata. Conversely, caterpillars reared on T. diversifolia leaves, which contain phenylpropanoids, flavones and diverse furanoheliangolide-type sesquiterpene lactones, were not able to complete larval development and exhibited the lowest PO activity. These findings suggested that V. cardui have adapted to tolerate potentially toxic metabolites occurring in P. lanceolata (iridoid glycosides), however caterpillars were not able to cope with potentially detrimental metabolites occurring in T. diversifolia (furanoheliangolides). Therefore, we suggest that furanoheliangolide-type sesquiterpene lactones were responsible for the poor development and immune response observed for caterpillars reared on T. diversifolia.