Euphydryas Phaeton Research Articles

Dose-dependent dynamics of densovirus infection in two nymphalid butterfly species utilizing native or exotic host plants

Insects are attacked by a diverse range of microbial pathogens in the wild. In herbivorous species, larval host plants frequently play a critical role in mediating susceptibility to infection. Characterizing such plant-mediated effects on herbivore-pathogen interactions can provide insight into patterns of infection across wild populations. In this study, we investigated the effects of host plant use by two North American butterflies, Euphydryas phaeton (Nymphalidae) and Anartia jatrophae (Nymphalidae), on entomopathogen infection across a range of three doses. Both of these herbivores recently incorporated the same exotic plant, Plantago lanceolata (Plantaginaceae), into their host range and are naturally infected by the same entomopathogen, Junonia coenia densovirus (Parvoviridae), in wild populations. We performed two factorial experiments in which E. phaeton and A. jatrophae were reared on either P. lanceolata or a native host plant [Chelone glabra (Plantaginaceae) for E. phaeton; Bacopa monnieri (Plantaginaceae) for A. jatrophae] and inoculated with either a low, medium, or high dose of the virus. In E. phaeton, the outcomes of infection were highly dose-dependent, with inoculation with higher viral doses resulting in faster time to death and greater mortality. However, neither survival nor postmortem viral burdens varied depending upon the host plant that was consumed. In contrast, host plant use had a strong effect on viral burdens in A. jatrophae, with consumption of the exotic plant appearing to enhance host resistance to infection. Together, these results illustrate the variable influences of host plant use on herbivore resistance to infection, highlighting the importance of investigating plant-herbivore relationships within a tritrophic framework.

Caterpillar movement mediates spatially local interactions and determines the relationship between population density and contact.

While interactions in nature are inherently local, ecological models often assume homogeneity across space, allowing for generalization across systems and greater mathematical tractability. Density-dependent disease models are a prominent example of models that assume homogeneous interactions, leading to the prediction that disease transmission will scale linearly with population density. In this study, we examined how the scale of larval butterfly movement interacts with the resource landscape to influence the relationship between larval contact and population density in the Baltimore checkerspot (Euphydryas phaeton). Our study was inspired by the recent discovery of a viral pathogen that is transmitted horizontally among Baltimore checkerspot larvae. We used multi-year larvae location data across six Baltimore checkerspot populations in the eastern U.S. to test whether larval nests are spatially clustered. We then integrated these spatial data with larval movement data in different resource contexts to investigate whether heterogeneity in spatially local interactions alters the assumed linear relationship between larval nest density and contact. We used Correlated Random Walk (CRW) models and field observations of larval movement behavior to construct Probability Distribution Functions (PDFs) of larval dispersal, and calculated the overlap in these PDFs to estimate conspecific contact within each population. We found that all populations exhibited significant spatial clustering in their habitat use. Subsequent larval movement rates were influenced by encounters with host plants and larval age, and under many movement scenarios, the scale of predicted larval movement was not sufficient to allow for the "homogeneous mixing" assumed in density dependent disease models. Therefore, relationships between population density and larval contact were typically non-linear. We also found that observed use of available habitat patches led to significantly greater contact than would occur if habitat use were spatially random. These findings strongly suggest that incorporating larval movement and spatial variation in larval interactions is critical to modeling disease outcomes in E. phaeton. Epidemiological models that assume a linear relationship between population density and larval contact have the potential to underestimate transmission rates, especially in small populations that are already vulnerable to extinction.

Host plant-mediation of viral transmission and its consequences for a native butterfly.

Pathogens play a key role in insect population dynamics, contributing to short-term fluctuations in abundance as well as long-term demographic trends. Two key factors that influence the effects of entomopathogens on herbivorous insect populations are modes of pathogen transmission and larval host plants. In this study, we examined tritrophic interactions between a sequestering specialist lepidopteran, Euphydryas phaeton, and a viral pathogen, Junonia coenia densovirus, on its native host plant, Chelone glabra, and a novel host plant, Plantago lanceolata, to explore whether host plant mediates viral transmission, survival, and viral loads. A two-factor factorial experiment was conducted in the laboratory with natal larval clusters randomly assigned to either the native or novel host plant and crossed with either uninoculated controls or viral inoculation (20% of individuals in the cluster inoculated). Diapausing clusters were overwintered in the laboratory and checked weekly for mortality. At the end of diapause, all surviving individuals were reared to adulthood to estimate survivorship. All individuals were screened to quantify viral loads, and estimate horizontal transmission postmortem. To test for vertical transmission, adults were mated, and the progeny were screened for viral presence. Within virus-treated groups, we found evidence for both horizontal and vertical transmission. Larval clusters reared on the native host plant had slightly higher horizontal transmission. Survival probability was lower in clusters feeding on the native host plant, with inoculated groups reared on the native host plant experiencing complete mortality. Viral loads did not differ by the host plant, although viral loads decreased with increased sequestration of secondary compounds on both host plants. Our results indicate that the use of a novel host plant may confer fitness benefits in terms of survival and reduced viral transmission when larvae feeding on it are infected with this pathogen, supporting hypotheses of potential evolutionary advantages of a host range expansion in the context of tritrophic interactions.

Novel host plant use by a specialist insect depends on geographic variation in both the host and herbivore species

Understanding the circumstances under which insect herbivores will adopt a novel host plant is a longstanding question in basic and applied ecology. While geographic variation in host use can arise through differences in both herbivore preference and plant characteristics, there is a tendency to attribute geographic variation in host use to regional differences in herbivore preference alone. This is especially true for herbivores specialized to one or a few plant species. We compared how geographic variation in herbivore preference and host plant origin shape regional differences in host plant use by the specialized herbivore, Euphydryas phaeton. In parts of its range, E. phaeton uses only a native host, Chelone glabra, while in others, it also uses an introduced host, Plantago lanceolata. We offered female butterflies from each region the non-native host plant sourced from both regions and compared their oviposition behavior. The non-native host was almost universally rejected by butterflies in the region where only the native plant is used. In the region where butterflies use both hosts, females accepted non-native plants from their natal region twice as often as non-native plants from the other region where they are not used. Acceptance differed substantially among individual butterflies within regions but not among plants within regions. Thus, both individual preference and regional differences in both the insect and non-native host contributed to the geographic variation in different ways. These results highlight that, in addition to herbivore preference, regional differences in perceived plant suitability may be an important driver of diet breadth.

Use of an exotic host plant shifts immunity, chemical defense, and viral burden in wild populations of a specialist insect herbivore.

Defense against natural enemies constitutes an important driver of herbivore host range evolution in the wild. Populations of the Baltimore checkerspot butterfly, Euphydryas phaeton (Nymphalidae), have recently incorporated an exotic plant, Plantago lanceolata (Plantaginaceae), into their dietary range. To understand the tritrophic consequences of utilizing this exotic host plant, we examined immune performance, chemical defense, and interactions with a natural entomopathogen (Junonia coenia densovirus, Parvoviridae) across wild populations of this specialist herbivore. We measured three immune parameters, sequestration of defensive iridoid glycosides (IGs), and viral infection load in field‐collected caterpillars using either P. lanceolata or a native plant, Chelone glabra (Plantaginaceae). We found that larvae using the exotic plant exhibited reduced immunocompetence, compositional differences in IG sequestration, and higher in situ viral burdens compared to those using the native plant. On both host plants, high IG sequestration was associated with reduced hemocyte concentration in the larval hemolymph, providing the first evidence of incompatibility between sequestered chemical defenses and the immune response (i.e., the “vulnerable host” hypothesis) from a field‐based study. However, despite this negative relationship between IG sequestration and cellular immunity, caterpillars with greater sequestration harbored lower viral loads. While survival of virus‐infected individuals decreased with increasing viral burden, it ultimately did not differ between the exotic and native plants. These results provide evidence that: (1) phytochemical sequestration may contribute to defense against pathogens even when immunity is compromised and (2) herbivore persistence on exotic plant species may be facilitated by sequestration and its role in defense against natural enemies.

Reevaluation of the described subspecies of Euphydryas phaeton (Drury, 1773) with a replacement name for Melitaea phaeton schausi (Clark, 1927).

Reevaluation of the described subspecies of Euphydryas phaeton (Drury, 1773) with a replacement name for Melitaea phaeton schausi (Clark, 1927).

Seasonal Variation in Host Plant Chemistry Drives Sequestration in a Specialist Caterpillar

Sequestration of plant secondary metabolites by herbivores can vary across both host plant phenology and herbivore ontogeny, but few studies have explored how they concurrently change in the field. We explored variation in iridoid glycoside concentration and composition in white turtlehead, Chelone glabra, as well as sequestration of iridoid glycosides by its specialist herbivore, the Baltimore checkerspot, Euphydryas phaeton, across the development of both herbivore and host plant. In 2012 we sampled plants to describe seasonal variation in the concentrations of two iridoid glycosides, aucubin and catalpol. In 2017, we sampled both host plants and caterpillars over an entire growing season and explored the relationship between plant chemistry and herbivore sequestration. We also compared iridoid glycoside concentrations of plants with and without herbivory to gain insight into whether levels of secondary compounds were impacted by herbivory. We found that total plant iridoid glycosides varied across the season and that total sequestered iridoid glycosides in caterpillars closely mirrored concentration patterns in plants. However, the magnitude of sequestration by caterpillars ranged from 2 to 20 times the concentrations in host plants, with different proportions of aucubin and catalpol. In addition, plants with herbivory had lower iridoid glycoside concentrations than plants without herbivory, although this difference changed over time. These results suggest that while variation in host plant secondary metabolites may be a dominant factor driving sequestration, other ecological factors may mitigate the relationship between host plant chemistry and herbivore sequestration.

Estimating abundance and phenology from transect count data with GLMs

Estimating population abundance is central to population ecology. With increasing concern over declining insect populations, estimating trends in abundance has become even more urgent. At the same time, there is an emerging interest in quantifying phenological patterns, in part because phenological shifts are one of the most conspicuous signs of climate change. Existing techniques to fit activity curves (and thus both abundance and phenology) to repeated transect counts of insects (a common form of data for these taxa) frequently fail for sparse data, and often require advanced knowledge of statistical computing. These limitations prevent us from understanding both population trends and phenological shifts, especially in the at‐risk species for which this understanding is most vital. Here we present a method to fit repeated transect count data with Gaussian curves using linear models and show how robust abundance and phenological metrics can be obtained using standard regression tools. We then apply this method to nine years of Baltimore checkerspot data using generalized linear models (GLMs). This case study illustrates the ability of our method to fit even years with only a few non‐zero survey counts, and identifies a significant negative relationship between population size and growing degree days (GDD) each year. We believe our new method provides a key tool to unlock previously‐unusable data sets, and may provide a useful middle ground between ad hoc metrics of abundance and phenology, and custom‐coded mechanistic models.

Phenology of feeding preference in post‐diapause Baltimore checkerspot (Euphydryas phaeton) caterpillars

1. Host plant use has important life history impacts for caterpillars, and this can change throughout development. Although food quality is important for all caterpillar instars, previous work has found a decreased diet preference in late instars, possibly owing to greater intake requirements.2. Baltimore checkerspot butterflies are highly specialised in their diet as pre‐diapause caterpillars but are less specialised post‐diapause. This study investigated phenological changes in Baltimore checkerspot caterpillar preference and performance on different post‐diapause host plants in the field and lab.3. Caterpillar preference and performance in the lab on four post‐diapause host plants followed the same rank order. The highest ranked plant was their main host plant, followed by an alternative host used for oviposition in some populations, then a commonly observed post‐diapause‐only host, and finally a previously unrecorded post‐diapause host plant.4. In contrast to lab results, field observations showed a decrease throughout the season in the use of the main host plant, turtlehead.5. This study's findings suggest that necessity and food availability drive the post‐diapause Baltimore checkerspot caterpillar diet in the field more than preference. These results also highlight that, even in relatively well‐studied species, field and laboratory observations can yield conflicting results. In this case, the contrast is most likely due to the different constraints in lab versus field conditions, such as the costs of finding preferred plants in the field.

Ozark Baltimore Checkerspot Euphydryas phaeton ozarkae (Nymphalidae) Oviposition Selection Favors More Vigorous Hosts

Oviposition search behaviors and host-plant selection play a critical role in the individual and population success of phytophagous insects. These characters are particularly important for specialists and metapopulations. The Ozark Baltimore Checkerspot Euphydryas phaeton ozarkae (Masters 1968) Nymphalidae specializes on Smooth Yellow False Foxglove Aureolaria flava (L. 1753, Farwell 1918) Orobanchaceae and has a metapopulation structure. We examined oviposition search behaviors of E. p. ozarkae using many of the same variables from a study on the nominate subspecies, the Baltimore Checkerspot Euphydryas phaeton phaeton (Drury 1773). Insight into host selection was obtained by comparing characteristics between plants with and without egg masses. Relationships among habitat conditions (and management therein) and the most selected plant characteristics were also determined. We found E. p. ozarkae to be highly selective of oviposition plants, expressing higher values associated with host-plant searching than E. p. phaeton. Butterflies consistently oviposited on plants with the greatest height, area, number of stalks, and number of leaves within a given study site. As average plant vigor increased, however, selection of the highest character values converged and became less prominent. In general, important plant characters were greater in habitats with a more open understory and canopy, which were associated with routine fire management. Continued habitat restoration in the Ozark and Boston Mountain regions and perpetual maintenance using prescribed fire (as appropriate seasonally) may positively affect the Ozark Baltimore Checkerspot by improving plant characters selected by these butterflies.

Heatwaves and Novel Host Consumption Increase Overwinter Mortality of an Imperiled Wetland Butterfly

Disruptive effects of climate change include range shifts, phenological mismatches among consumers and producers, and population declines. While these biological alterations have been widely documented, studies identifying specific mechanisms linking climate change to population declines are scarce. Extreme events, such as heatwaves can have devastating effects on living organisms and are increasing in frequency as Earth warms. Hence, understanding the effects of heatwaves on insects is necessary to inform conservation efforts and to develop predictions of population dynamics under future climate scenarios. Here, we experimentally evaluated the effects of heatwaves on the survival and phenology of the Baltimore Checkerspot (Euphydryas phaeton phaeton), a wetland butterfly with imperiled populations that has incorporated a novel host. We performed laboratory manipulations (implementing realistic temperature regimes) to assess the effect of heatwaves during summer and winter on the survival and phenology of E. p. phaeton. In addition, we analyzed historical temperature records to quantify the incidence of heatwaves within E. p. phaeton’s range to assess their potential role in the decline of southeastern populations. We found that winter heatwaves with maximum temperatures of 20°C can have more devastating effects on survival than summer heatwaves (up to 41°C). Eggs endured acute heat stress during summer with no significant effects on phenology and survival; similarly, pre-overwintering larvae were robust to heatwave exposure, as only the most intense heatwave treatment reduced their survival (37% reduction compared to control conditions). By contrast, dormant larvae were the most vulnerable stage, as they lost from 2 to 6% of their body mass after a three-day summer heatwave. Furthermore, their exposure to winter heatwaves resulted in 75% to 100% mortality. Feeding on the native host provided higher resilience under thermal stress than feeding on the invasive, recently acquired host. Finally, both heatwave incidence and severity have increased in the southern range of E. p. phaeton in the period from 1894 to 2011. We show that warm winter days induced severe mortality, providing a mechanistic explanation of how climate change can trigger population declines in E. p. phaeton and other insects.

Faster movement in nonhabitat matrix promotes range shifts in heterogeneous landscapes.

Ecologists often assume that range expansion will be fastest in landscapes composed entirely of the highest-quality habitat. Theoretical models, however, show that range expansion depends on both habitat quality and habitat-specific movement rates. Using data from 78 species in 70 studies, we find that animals typically have faster movement through lower-quality environments (73% of published cases). Therefore, if we want to manage landscapes for range expansion, there is a trade-off between promoting movement with nonhostile matrix, and promoting population growth with high-quality habitat. We illustrate how this trade-off plays out with the use of an exemplar species, the Baltimore checkerspot butterfly. For this species, we calculate that the expected rate of range expansion is fastest in landscapes with ~15% high-quality habitat. Behavioral responses to nonhabitat matrix have often been documented in animal populations, but rarely included in empirical predictions of range expansion. Considering movement behavior could change land-planning priorities from focus on high-quality habitat only to integrating high- and low-quality land cover types, and evaluating the costs and benefits of different matrix land covers for range expansion.

Deer Browsing Influences Population Dynamics of the Ozark Baltimore Checkerspot (Euphydryas Phaeton Ozarkae: Nymphalidae)

White-tailed Deer (Odocoileus virginianus) have been shown to be detrimental to a number of Lepidoptera. Potential host plants for specialist butterfly species can be reduced and removed from native areas through deer browsing. The Ozark Baltimore Checkerspot (Euphydryas phaeton ozarkae) is a univoltine nymphalid butterfly endemic to the Ozark regions of Arkansas, Kansas, Missouri, and Oklahoma. In the area around the Buffalo River in Arkansas, the larval host for this butterfly is Smooth Yellow False Foxglove (Aureolaria flava). We examined the timing and quantified the effect that deer foraging had on A. flava in four E. p. ozarkae populations. Browsing occurred in late spring and reduced plant availability by as much as 87% over a two-month period. Browsed plants lost an average of 44 cm in height; data show taller plants were more likely to be browsed than shorter ones. Extensive herbivory caused early-fall-active and late-spring-active larvae to contend with reduced host plant availability, which likely resulted in increased mortality. We also found that browsed plants were less likely to be selected for oviposition. The amount of plant loss appeared to be associated with deer abundance and area attributes (i.e., slope, human activity, plant density, etc.). We found that browsing by White-tailed Deer that is too intense or prolonged can have important consequences for the Ozark Baltimore Checkerspot.

Using animal movement behavior to categorize land cover and predict consequences for connectivity and patch residence times

Landscape-scale population dynamics are driven in part by movement within and dispersal among habitat patches. Predicting these processes requires information about how movement behavior varies among land cover types. We investigated how butterfly movement in a heterogeneous landscape varies within and between habitat and matrix land cover types, and the implications of these differences for within-patch residence times and among-patch connectivity. We empirically measured movement behavior in the Baltimore checkerspot butterfly (Euphydryas phaeton) in three land cover classes that broadly constitute habitat and two classes that constitute matrix. We also measured habitat preference at boundaries. We predicted patch residence times and interpatch dispersal using movement parameters estimated separately for each habitat and matrix land cover subclass (5 categories), or for combined habitat and combined matrix land cover classes (2 categories). We evaluated the effects of including edge behavior on all metrics. Overall, movement was slower within habitat land cover types, and faster in matrix cover types. Butterflies at forest edges were biased to remain in open areas, and connectivity and patch residence times were most affected by behavior at structural edges. Differences in movement between matrix subclasses had a greater effect on predictions about connectivity than differences between habitat subclasses. Differences in movement among habitat subclasses had a greater effect on residence times. Our findings highlight the importance of careful classification of movement and land cover in heterogeneous landscapes, and reveal how subtle differences in behavioral responses to land cover can affect landscape-scale outcomes.

Losing a battle but winning the war: moving past preference-performance to understand native herbivore-novel host plant interactions.

Introduced plants can positively affect population viability by augmenting the diet of native herbivores, but can negatively affect populations if they are subpar or toxic resources. In organisms with complex life histories, such as insects specializing on host plants, the impacts of a novel host may differ across life stages, with divergent effects on population persistence. Most research on effects of novel hosts has focused on adult oviposition preference and larval performance, but adult preference may not optimize offspring performance, nor be indicative of host quality from a demographic perspective. We compared population growth rates of the Baltimore checkerspot butterfly, Euphydryas phaeton, on an introduced host, Plantago lanceolata (English plantain), and the native host Chelone glabra (white turtlehead). Contrary to the previous findings suggesting that P. lanceolata could be a population sink, we found higher population growth rates (λ) on the introduced than the native host, even though some component parameters of λ were higher on the native host. Our findings illustrate the importance of moving beyond preference-performance studies to integrate vital rates across all life stages for evaluating herbivore-host plant relationships. Single measures of preference or performance are not sufficient proxies for overall host quality nor do they provide insights into longer term consequences of novel host plant use. In our system, in particular, P. lanceolata may buffer checkerspot populations when the native host is limiting, but high growth rates could lead to crashes over longer time scales.

The Ozark Baltimore Checkerspot,Euphydryas phaeton ozarkae(Nymphalidae): Life History in Northern Arkansas

Ecological and geographical differences between eastern and western populations of the Baltimore Checkerspot have led to a division into two subspecies, E. p. phaeton and E. p. ozarkae. Research concerning E. p. ozarkae is sparse, and prior to our work, many aspects of the life history of this subspecies were not known. An accurate assessment of its status has been hindered and confused through the use of data obtained from the eastern subspecies (e.g., mesic habitats and larval food plant) to characterize Ozark populations (e.g., glade habitats and a different larval food plant). From 2011 to 2014 we studied this butterfly in the Ozark Mountains of northern Arkansas. We identified the availability of the primary larval host plant (Aureolaria flava) as a potential limiting factor and investigated limitations to the distribution of this plant. We found many similarities concerning the timing of development between the two subspecies but ample evidence to demonstrate the uniqueness of Ozark populations. Our findings provide valuable information for future research, management, and conservation of the Ozark Baltimore Checkerspot.

Individual variation changes dispersal distance and area requirements of a checkerspot butterfly.

Individual variation in movement can have important consequences for spatial population dynamics. For instance, individual variation increases leptokurtosis in dispersal distance, such that more individuals move very short and very long distances relative to a homogeneous population. We quantified individual variation in movement of the Baltimore checkerspot butterfly (Euphydryas phaeton) to investigate its importance for two conservation-related metrics: the expected dispersal distance and the critical minimum patch size, or the smallest area within which a population can persist based on loss due to emigration. All movement parameters showed among-individual variation, with the greatest variation in move lengths and time spent resting. Correlations in among-individual movement parameters indicated that some butterflies were generally more mobile than others. We incorporated empirically estimated movement and demographic parameters into two individual-based models (IBMs), one with homogeneity in movement among individuals, and one with heterogeneity in movement. As expected, individual variation in movement increased the leptokurtosis of lifetime movement distance; the maximum difference in distance moved was substantial (-850 m vs. -5800 m) and is likely of significance for conservation. Individual variation also affected the critical minimum patch size, but the difference (-0.7 ha vs. -0.5 ha) is unlikely to be ecologically significant. Notably, populations with individual variation had higher growth rates in small patches and lower growth rates in large patches, a logical consequence of increased leptokurtosis. Individual variation in movement is fairly straightforward to quantify using mixed effects models and is important for spatial population dynamics, thus we encourage its inclusion in studies of other systems.

Minimum area requirements for an at-risk butterfly based on movement and demography.

Determining the minimum area required to sustain populations has a long history in theoretical and conservation biology. Correlative approaches are often used to estimate minimum area requirements (MARs) based on relationships between area and the population size required for persistence or between species' traits and distribution patterns across landscapes. Mechanistic approaches to estimating MAR facilitate prediction across space and time but are few. We used a mechanistic MAR model to determine the critical minimum patch size (CMP) for the Baltimore checkerspot butterfly (Euphydryas phaeton), a locally abundant species in decline along its southern range, and sister to several federally listed species. Our CMP is based on principles of diffusion, where individuals in smaller patches encounter edges and leave with higher probability than those in larger patches, potentially before reproducing. We estimated a CMP for the Baltimore checkerspot of 0.7-1.5 ha, in accordance with trait-based MAR estimates. The diffusion rate on which we based this CMP was broadly similar when estimated at the landscape scale (comparing flight path vs. capture-mark-recapture data), and the estimated population growth rate was consistent with observed site trends. Our mechanistic approach to estimating MAR is appropriate for species whose movement follows a correlated random walk and may be useful where landscape-scale distributions are difficult to assess, but demographic and movement data are obtainable from a single site or the literature. Just as simple estimates of lambda are often used to assess population viability, the principles of diffusion and CMP could provide a starting place for estimating MAR for conservation.

Apparent power-law distributions in animal movements can arise from intraspecific interactions.

Lévy flights have gained prominence for analysis of animal movement. In a Lévy flight, step-lengths are drawn from a heavy-tailed distribution such as a power law (PL), and a large number of empirical demonstrations have been published. Others, however, have suggested that animal movement is ill fit by PL distributions or contend a state-switching process better explains apparent Lévy flight movement patterns. We used a mix of direct behavioural observations and GPS tracking to understand step-length patterns in females of two related butterflies. We initially found movement in one species (Euphydryas editha taylori) was best fit by a bounded PL, evidence of a Lévy flight, while the other (Euphydryas phaeton) was best fit by an exponential distribution. Subsequent analyses introduced additional candidate models and used behavioural observations to sort steps based on intraspecific interactions (interactions were rare in E. phaeton but common in E. e. taylori). These analyses showed a mixed-exponential is favoured over the bounded PL for E. e. taylori and that when step-lengths were sorted into states based on the influence of harassing conspecific males, both states were best fit by simple exponential distributions. The direct behavioural observations allowed us to infer the underlying behavioural mechanism is a state-switching process driven by intraspecific interactions rather than a Lévy flight.

Overcrowding Leads to Lethal Oviposition Mistakes in the Baltimore Checkerspot,Euphydryas phaetonDrury (Nymphalidae)

Overcrowding Leads to Lethal Oviposition Mistakes in the Baltimore Checkerspot,<i>Euphydryas phaeton</i>Drury (Nymphalidae)