Oviposition Events Research Articles

Transcriptional profiling and physiological roles of Aedes aegypti spermathecal-related genes

BackgroundSuccessful mating of female mosquitoes typically occurs once, with the male sperm being stored in the female spermatheca for every subsequent oviposition event. The female spermatheca is responsible for the maintenance, nourishment, and protection of the male sperm against damage during storage. Aedes aegypti is a major vector of arboviruses, including Yellow Fever, Dengue, Chikungunya, and Zika. Vector control is difficult due to this mosquito high reproductive capacity.ResultsFollowing comparative RNA-seq analyses of spermathecae obtained from virgin and inseminated females, eight transcripts were selected based on their putative roles in sperm maintenance and survival, including energy metabolism, chitin components, transcriptional regulation, hormonal signaling, enzymatic activity, antimicrobial activity, and ionic homeostasis. In situ RNA hybridization confirmed tissue-specific expression of the eight transcripts. Following RNA interference (RNAi), observed outcomes varied between targeted transcripts, affecting mosquito survival, egg morphology, fecundity, and sperm motility within the spermathecae.ConclusionsThis study identified spermatheca-specific transcripts associated with sperm storage in Ae. aegypti. Using RNAi we characterized the role of eight spermathecal transcripts on various aspects of female fecundity and offspring survival. RNAi-induced knockdown of transcript AeSigP-66,427, coding for a Na+/Ca2+ protein exchanger, specifically interfered with egg production and reduced sperm motility. Our results bring new insights into the molecular basis of sperm storage and identify potential targets for Ae. aegypti control.

Life history and ecology of the endangered Poweshiek skipperling Oarisma poweshiek in Michigan prairie fens

Poweshiek skipperling (Oarisma poweshiek, Lepidoptera: Hesperiidae) has experienced a range-wide decline resulting in six reported extant sites. Critical knowledge gaps related to Poweshiek skipperling adult behavior, phenology, habitat structure, and potential larval host plants are limiting the ability to manage this federally endangered species. To address these information needs, we conducted extensive surveys in the last remaining stronghold of four extant prairie fens in Michigan. We used point transect surveys to collect data on plant structure, and Poweshiek skipperling behavior and detection. We estimated Poweshiek skipperling abundance and modeled the influence of local vegetation on Poweshiek skipperling presence/absence. We estimated the abundance of adult Poweshiek skipperling in Michigan prairie fens to be 231 (95% CI 160–332), further highlighting the imperiled status of this species. Presence of Poweshiek skipperling along our transects was negatively associated with obstructive vegetation and positively associated with the availability of the nectar source Dasiphora fruticosa. Our observation data indicated females nectared most frequently on D. fruticosa, whereas males nectared most often on Rudbeckia hirta. Across the field season we observed 7 oviposition events on four plant species (Muhlenbergia richardsonis, Muhlenbergia glomerata, Carex sterilis, and D. fruticosa), three of which had no previous documentation as a possible host plant. Results from this study can be used to evaluate management decisions and inform both in situ and ex situ conservation efforts. It is critical to continue monitoring remaining populations, not only to assess conservation efforts, but also to discern the patterns and processes influencing species extinction.

Effect of Temperature on Oviposition Behavior and Egg Load of Blow Flies (Diptera: Calliphoridae).

Making optimal oviposition decisions is especially important for female carrion colonizing insects whose larvae often depend on ephemeral resources. Optimal oviposition theory predicts that females should exhibit behaviors that will maximize the performance of their offspring. Oviposition can be influenced by a variety of factors, including temperature. The aim of this study was to investigate the effects of temperature on the oviposition behavior and egg load of two blow fly species native to southern Ontario: Phormia regina Meigen, and Lucilia sericata Meigen (Diptera: Calliphoridae). Using fetal pig carcasses as an oviposition substrate, we assessed the length of time until the first oviposition event, preferred oviposition sites, and the total number of eggs oviposited. For each of the two species, five different temperature treatments ranging from 15 to 35°C were used. Temperature influenced time to the first oviposition event, as well as the number of eggs deposited by L. sericata and P. regina. As temperature increased, oviposition occurred faster with more eggs deposited for these two species. Female P. regina, in particular, demonstrated a higher egg load with increasing temperature. Differences in optimal temperatures for reproduction, including egg load and oviposition, may be a mechanism driving seasonal temporal resource partitioning leading to species coexistence utilizing ephemeral resources.

Differential Host Handling Behavior between Feeding and Oviposition in the Parasitic Wasp Haplogonatopus hernandezae

Lifetime fitness is directly influenced by the decision to use resources for either current or future reproduction. Thus, females should weigh the costs and benefits of each reproductive opportunity and allocate resources accordingly. Here, we explore decision-making and the time spent handling hosts of different instars in the parasitoid Haplogonatopus hernandezae, which uses a single planthopper host to either oviposit (i.e., current reproduction) or feed (i.e., future reproduction). Our results indicate that manipulation time in attacks that led to either oviposition and feeding increased with host instar and size. Consequently, attacks were less successful on older host instars than younger ones. Similarly, attack and handling time during oviposition was greater when manipulating fifth instar nymphs compared to younger ones, but oviposition time was similar. Surprisingly, host grasping by the chelate forelegs differed between oviposition and feeding events, and the specific chelate foreleg morphology of H. hernandezae facilitates the specific grasp of the clypeus and gena of the host. We also link this previously undescribed host grasping and differential handling behavior in this species to the final decision to oviposit or feed. Given the differences in handling time and effort among different host instars, we found that older hosts were more often chosen for consumption than younger hosts, and younger hosts were chosen more often for oviposition. Our study suggests that the tradeoff between current and future benefits is influenced by the investment in handling hosts of different instars, and the assessment of host suitability for successful offspring survival.

First record of oviposition event by Laemanctus longipes (Sauria: Corytophanidae) in Mexico

Oviposition in elusive reptiles has been poorly documented due to the difficulty in observing it in natural habitats. Here, we document the first egg-laying record in the Eastern Casque-headed Basilisk Laemanctus longipes in the wild. Our record adds novel information about the oviposition of this scarcely studied reptile species.

Coexistence between two fruit fly species is supported by the different strength of intra‐ and interspecific competition

1. Unravelling the strength and modes of interspecific interactions between resident and introduced species is necessary in order to understand the basis of their coexistence or the displacement of the former by the latter. In Argentina, the indigenous Tephritidae fly Anastrepha fraterculus overlaps its distribution and host fruit with the introduced species Ceratitis capitata.2. This study focused on the relative strength of intra‐ and interspecific competition during the larval stage as a potential factor supporting coexistence. Classical competition experiments (addition and substitution) were conducted between larvae of the two species reared in artificial larval diet. The study evaluated whether a temporal separation between oviposition events affects the outcome of the competition.3. When both species started to consume the resource at the same time, A. fraterculus experienced a negative effect in larval survival, pupal weight and duration of larval stage, while for C. capitata, pupal weight decreased. When A. fraterculus started feeding 1 day earlier than C. capitata, the negative effects became milder, and when the temporal separation increased, these effects were reversed. Substitution experiments showed an increase in pupal weight when larvae had to share the resource with heterospecific larvae, and showed negative effects suffered for both species when they shared the resource with conspecific individuals.4. These results suggest that intraspecific competition is stronger than interspecific competition, and a differential oviposition preference could generate an asynchrony of these species in nature. Such mechanisms could favour coexistence between A. fraterculus and C. capitata in an environment previously occupied only by the former.

Relationship between chorusing activity and number of oviposition events in the Otton frog

Abstract Call surveys are an effective technique for detecting the presence and activity of breeding male frogs. Such surveys have been used to quantify breeding activity at a site under the assumption that male chorusing activity appropriately reflects breeding consequences, such as the number of oviposition events. However, only a few studies have actually examined the relationship between chorusing activity and breeding consequences in the field. In this study, I examined the relationship between chorusing activity (the number of male calls recorded during a five-minute period every night) and the number of oviposition events (number of oviposited egg masses during the night) of the Otton frog, Babina subaspera, with regard to the time lag between calls and oviposition. I constructed nine generalized linear mixed models (GLMMs) to explain the number of oviposition events by chorusing activity on the same night and on nights 1 to 7 days before the oviposition events. The Akaike information criterion (AiC) of the GLMM was lowest when the number of calls from nights 2 days before the oviposition events was used, indicating that breeding consequences in Otton frogs reflect the chorusing activity of 2 days prior. This study shows that frog call surveys can be reliable tools with which to represent breeding activity at a site as long as the time lag between chorusing activity and breeding consequences is considered.

Responses of neonicotinoid resistant and susceptible Frankliniella fusca life stages to multiple insecticide groups in cotton.

Detection of neonicotinoid resistance in populations of tobacco thrips, Frankliniella fusca Hinds, throughout the southeastern USA has motivated an examination of alternative insecticides to control problematic infestations on seedling cotton. The objective of this study was to refine understanding of stage-specific mortality and reduced oviposition of several common insecticides (acephate, abamectin, cyantraniliprole, spinetoram, imidacloprid, imidacloprid+thiodicarb, thiamethoxam) on neonicotinoid resistant and susceptible F. fusca populations under laboratory and field conditions. Laboratory studies revealed that the average number of eggs per female and larval or adult survivorship responses differed by insecticide and were dependent on the resistance status of the population. In the presence of neonicotinoids, the resistant F. fusca populations exhibited lower mortality and higher egg counts than the susceptible population. In the field study, similar patterns of oviposition suppression were observed, indicating that some insecticides may impact reproductive rate. This study shows that insecticides have different effects on F. fusca oviposition events, larval and adult mortality that are dependent on neonicotinoid resistance status. Because insecticides tested in this study have varied activity on specific F. fusca life stages (e.g. oviposition suppression, larvicidal activity, adulticidal activity), knowledge of stage-specific activity can be used to improve control and enhance long-term product stewardship. © 2017 Society of Chemical Industry.

Oviposition Preference and Survival of the Mexican Rice Borer (Lepidoptera: Crambidae) in Bioenergy and Conventional Sugarcane and Sorghum.

Oviposition preference and host suitability of the Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), on bioenergy and conventional cultivars of sugarcane, Saccharum spp., and sorghum, Sorghum spp., were examined in a series of greenhouse experiments. Two energycane cultivars, two sugarcane cultivars, two high-biomass sorghum cultivars, and one sweet sorghum cultivar were assessed at two phenological stages (immature and mature). Mature plants possessed greater availability of dry leaf material compared with immature plants, and all E. loftini eggs were observed exclusively on dry leaves. Oviposition did not vary among host combinations (cultivar by phenological stage); however, eggs per plant and eggs per oviposition event were numerically greater on mature plants than immature plants. In a no-choice experiment, survival from egg to adult did not vary among host combinations, with <2.0% of E. loftini larvae surviving to adulthood. Failed establishment by neonates on plants was 13.4- to 53.9-fold greater than successful establishment across all host combinations. Results from this study suggest that plant physical characteristics continue to play an important role in host selection, but further evaluations will be needed to quantify other characteristics which influence host suitability.

Oviposition in Heliconius erato (Lepidoptera, Nymphalidae): how Essential Is Drumming Behavior for Host-Plant Selection?

Quantitative studies on the behavioral events involved in oviposition by phytophagous insects are scant. One of these events is drumming behavior, a rapid extension of forelegs after landing on a host, which remains largely under studied. In this study, quali- and quantitative analyses of Heliconius erato phyllis (Lepidoptera: Nymphalidae) oviposition events and drumming behavior in relation to both preferred (Passiflora misera and P. suberosa) and non-preferred (P. caerulea and P. alata) hosts were performed. For the first time, drumming behavior is described by images made during the butterfly oviposition process. The same set of females was assigned to both single- and multiple-choice tests under insectary conditions, and their behaviors toward each host were recorded on video. The resulting images were analyzed frame by frame. Both frequency and duration of behavioral events related to oviposition varied on preferred vs non-preferred hosts. On preferred hosts, behaviors that were associated with egg deposition (inspecting flight, drumming and abdomen touching) were pronounced; subsequently, oviposition occurred within a few seconds. On non-preferred host plants, behaviors that did not predict oviposition (flying and resting) predominated, and oviposition on these hosts was negligible. Drumming occurred on all plants and resulted in a faster decision-making process on high-quality hosts (prompt acceptance) as well as on lethal hosts (prompt rejection) compared to the host that confers poor larval performance (delayed rejection). Thus, drumming is crucial for decision-making related in host-plant selection by H. erato phyllis, and influences other behaviors involved in the oviposition process.

Butterfly oviposition preference is not related to larval performance on a polyploid herb.

The preference–performance hypothesis predicts that female insects maximize their fitness by utilizing host plants which are associated with high larval performance. Still, studies with several insect species have failed to find a positive correlation between oviposition preference and larval performance. In the present study, we experimentally investigated the relationship between oviposition preferences and larval performance in the butterfly Anthocharis cardamines. Preferences were assessed using both cage experiments and field data on the proportion of host plant individuals utilized in natural populations. Larval performance was experimentally investigated using larvae descending from 419 oviposition events by 21 females on plants from 51 populations of two ploidy types of the perennial herb Cardamine pratensis. Neither ploidy type nor population identity influenced egg survival or larval development, but increased plant inflorescence size resulted in a larger final larval size. There was no correlation between female oviposition preference and egg survival or larval development under controlled conditions. Moreover, variation in larval performance among populations under controlled conditions was not correlated with the proportion of host plants utilized in the field. Lastly, first instar larvae added to plants rejected for oviposition by butterfly females during the preference experiment performed equally well as larvae growing on plants chosen for oviposition. The lack of a correlation between larval performance and oviposition preference for A. cardamines under both experimental and natural settings suggests that female host choice does not maximize the fitness of the individual offspring.

Intrinsic competition between primary hyperparasitoids of the solitary endoparasitoidCotesia rubecula

1. In nature, competitive interactions occur when different species exploit similar niches. Parasitic wasps (parasitoids) often have narrow host ranges and need to cope with competitors that use the same host species for development of their offspring. When larvae of different parasitoid species develop in the same host, this leads to intrinsic and often contest com.petition. Thus far, m.ost studies on intrinsic competition have focused on primary parasitoids. However, competition among primary.hyperparasitoids, parasitic wasps that use primary parasitoids as a host, has been little studied. 2. This study investigated intrinsic competition between two primary hyperparasitoids, the gregarious Baryscapus galactopus and the solitary Mesochoru,s gemellu,s, which lay their eggs in primary parasitoid larvae of tesla rubecula, while those in turn are developing inside their herbivore host, Pieris rapae. The aims were to identify: (i) which hyperparasitoid is the superior competitor; and (ii) whether oviposition sequence affects the outcome of intrinsic competition. 3. The results show that B. galactopus won 70% of contests when the two hyperparasitoids parasitised the host at the same time, and 90% when 13. galactopus oviposited first. When M. gemellus had a 48 h head start, the two hyperparasitoids had an equal chance to win the competition. This suggests that M. galactopus is an intrinsically superior competitor to M. gemellu,s, Moreover, the outcome of competition is affected by time lags in oviposition events. 4. In contrast to what has been reported for primary parasitoids, we found that a. gregarious hyperparasitoid species had a competitive advantage over a solitary species.

Effect of lifespan and age on reproductive performance of the tardigrade Acutuncus antarcticus: minimal reproductive senescence

Reproductive output is one of the central attributes of life history, and knowledge of age-specific reproduction can enhance the understanding of population performance and dynamics. Tardigrades are microscopic invertebrates that live in marine, freshwater and terrestrial ecosystems. While changes in fertility in relation to age are known to occur in other invertebrate groups, the subject has not been specifically addressed in tardigrades. The current study demonstrates for the first time the effect of lifespan and age on reproductive characteristics of the tardigrade species, Acutuncus antarcticus (Richters 1904), based on the observation of individuals over their entire lifespan under constant environment conditions in the laboratory. Clutch size of A. antarcticus fluctuated conspicuously throughout individual lifespans. Weak effects of age were observed on oviposition interval and hatching success, with the former increasing slightly and the latter decreasing slightly with age. Numbers of oviposition events and eggs produced per individual varied greatly and were correlated with lifespan. No significant relationships between clutch size, hatching time or hatching success with lifespan were detected. The majority of the individuals continued oviposition until shortly before death, with no suggestion of a post-reproductive lifespan. Our observations suggest that any decline in fertility with age in this species of tardigrade is minimal. The study provides new insight into the reproductive biology and ageing of invertebrate species.

Differential survival and reproduction in colour forms of Philaenus spumarius give new insights to the study of its balanced polymorphism

1. Colour polymorphisms are common across animals and are often the result of complex selection regimes. Philaenus spumarius (Linnaeus) (Hemiptera, Aphrophoridae) shows a widely studied dorsal colour polymorphism with several described phenotypes whose variation in their occurrence and frequency, as well as their maintenance across time, have been reported. Several selective influences have been suggested to play a role, but the mechanisms underlying the maintenance of this polymorphism are still poorly understood.2. To explore the adaptive significance of the colour polymorphism of P. spumarius, an experiment was conducted in captivity under semi‐natural conditions to measure survival, reproductive success, and duration of egg maturation.3. It was found that there was higher longevity, a higher number of oviposition events, and a higher number of eggs laid by trilineatus phenotype females than by typicus and marginellus, supporting previous reports of an increase in trilineatus frequency during the season. The duration of egg maturation did not differ among phenotypes.4. The higher longevity and fertility of the trilineatus phenotype may compensate, for example, the higher rate of attack by parasitoids and/or higher solar radiation reflectance in this phenotype, which have already been reported in previous studies, constituting a possible mechanism for the maintenance of this polymorphism.

Evidence For Plant-mediated Competition Between Defoliating and Gall-forming Specialists Attacking Solidago altissima

Abstract Phytophagous insects from different feeding guilds may compete indirectly via altering the chemical defenses or nutritional quality of their shared host plants. Gall-formers are understudied in this context but may be susceptible to this mode of competition early in their life history, when they may be particularly sensitive to changes to the specific reactive tissue needed for gall development. Here, we conducted a natural experiment to investigate the effect of folivory of Canada goldenrod, Solidago altissima, by Trirhabda beetles on gall induction success for the goldenrod gall fly, Eurosta solidaginis. We monitored oviposition events and gall development on individual Solidago ramets at sites differing in their levels of Trirhabda folivory. We found a strong inverse relationship between Trirhabda leaf damage and successful gall induction rates. These results suggest Trirhabda beetles may negatively impact Eurosta demographics and highlight the need for further study on how factors affecting g...

The Role of Olfactory Cues for the Search Behavior of a Specialist and Generalist Butterfly

Searching for resources is often a challenging task, especially for small organisms such as insects. Complex stimuli have to be extracted from the environment and translated into a relevant behavioral output. A first step in this process is to investigate the relative roles of the different senses during search for various resources. While the role of olfaction is well documented in nocturnal moths, the olfactory abilities of the closely related diurnal butterflies are poorly explored. Here we investigated how olfactory information is used in the search for host plants and asked if these abilities varied with levels of stimulus complexity. Thus, we tested two nymphalid butterfly species with divergent host plant range in a two-choice olfactometer testing different combinations of host and non-host plants. The experiments show both the monophagous Aglais urticae and the polyphagous Polygonia c-album could navigate towards an odor source, but this ability varied with context. While mated females exhibited a preference for their host plant, unmated females of both species did not show a preference for host plant cues. Furthermore, both species showed inabilities to make fine-tuned decisions between hosts. We conclude that olfactory cues are important for butterflies to navigate towards targets. We argue that there are limitations on how much information can be extracted from host volatiles. These results are discussed in the light of neural processing limitations and degree of host plant specialization, suggesting the necessity of other sensory modalities to sharpen the decision process and facilitate the final oviposition event.

Nesting ecology of East Pacific green turtles at Playa Cabuyal, Gulf of Papagayo, Costa Rica

AbstractEast Pacific green turtles (Chelonia mydas), often referred to as black turtles, are smaller and exhibit a lower reproductive output than other populations of green turtles in the Atlantic, Indian and Western Pacific Oceans. Knowledge of nesting ecology of East Pacific green turtles is limited to general descriptions. We conducted an exhaustive analysis of the nesting ecology of East Pacific green turtles at Playa Cabuyal, North Pacific Costa Rica. Compared with other populations of green turtles, East Pacific turtles exhibited smaller clutch sizes (mean ± SD: 76.9 ± 18.2 eggs per clutch), but the number of clutches (estimated clutch frequency (ECF): 4.3 ± 2.3 clutches) fell within the upper limit reported for green turtles. Clutch size and seasonal reproductive output (409 ± 135 eggs per female), but not ECF, increased with female size. The observed internesting period (OIP) between consecutive oviposition events (mean ± SD: 15.4 ± 2.9 days) increased as the season progressed and was approximately 2 days longer than the mean OIP reported for the species. Most clutches were laid in the upper vegetated part of beach (zone 3, 75%) and within this zone, tended to be located underneath trees (79%). Hatching success of clutches laid underneath trees was significantly higher (0.89 ± 0.17) than that of clutches laid in the exposed areas of zone 3 (0.75 ± 0.33). Mean duration of the nesting process (3:14 h) was on average 45 min longer than previously reported for the species. Frequency of false crawls was high (49% of nesting activities), and nesting success was low (54% of nesting attempts). Poaching of eggs, tourism and predation by dogs were important threats to this population. Conservation actions were being successfully implemented at the local level due to presence of beach patrollers, but official protection is needed for the preservation of the nesting population into the future.

Almond moth oviposition patterns in continuous layers of peanuts

The spatial distribution of eggs laid over a 48-h period by individual female almond moths, Cadra cautella Walker (Lepidoptera: Pyralidae), was examined in bioassays where peanuts covered either the center quarter (quarter-coverage) or the whole (whole-coverage) of a 120-cm square arena gridded into 3 by 3-cm cells. The mean total of eggs laid in quarter-coverage bioassays was not significantly different from the mean in whole-coverage bioassays, i. e., neither food coverage limited oviposition. However, the maximum count of eggs laid in any cell was higher in whole- than in quarter-coverage bioassays, and eggs were more aggregated near edges of the arena in whole-coverage bioassays than near edges of the peanuts in quarter-coverage bioassays. In addition, eggs were aggregated near the release point where females initially encountered food cues. These results suggest that almond moth oviposition behavior in continuous areas of peanuts was similar to patterns observed previously for stored-product insect oviposition in small, scattered food patches. In both cases, females walked or flew between separate oviposition events where eggs were laid in small clumps or lines. Possible behaviors resulting in aggregations of eggs near edges of food, walls, boundaries, or entrances are discussed and implications for precision targeting of insects in food storage areas are considered.

Paternal effects correlate with female reproductive stimulation in the polyandrous ladybirdCheilomenes sexmaculata

Components of male seminal fluids are known to stimulate fecundity and fertility in females of numerous insect species and paternal effects on offspring phenotype are also known, but no studies have yet demonstrated links between male effects on female reproduction and those on progeny phenotype. In separate laboratory experiments employing 10-day-old virgin females of Cheilomenes sexmaculata (F.), we varied male age and mating history to manipulate levels of male allomones and found that the magnitude of paternal effects on progeny phenotype was correlated with stimulation of female reproduction. Older virgin males remained in copula longer than younger ones, induced higher levels of female fecundity, and sired progeny that developed faster to yield heavier adults. When male age was held constant (13 days), egg fertility declined as a function of previous male copulations, progeny developmental times increased, and the adult weight of daughters declined. These results suggest that male epigenetic effects on progeny phenotype act in concert with female reproductive stimulation; both categories of effects increased as a consequence of male celibacy (factor accumulation), and diminished as a function of previous matings (factor depletion). Male factors that influence female reproduction are implicated in sexual conflict and parental effects may extend this conflict to offspring phenotype. Whereas mothers control the timing of oviposition events and can use maternal effects to tailor progeny phenotypes to prevailing or anticipated conditions, fathers cannot. Since females remate and dilute paternity in polyandrous systems, paternal fitness will be increased by linking paternal effects to female fecundity stimulation, so that more benefits accrue to the male's own progeny.

Do mothers always know best? Oviposition mistakes and resulting larval failure of Pieris virginiensis on Alliaria petiolata, a novel, toxic host

Alliaria petiolata is a European biennial herb that invades North American forests and has direct negative effects on associated flora and fauna. In some places, A. petiolata has invaded the habitat of Pieris virginiensis, a rare, univoltine butterfly that normally uses native spring ephemeral crucifer hosts. There are occasional observations of P. virginiensis laying eggs on A. petiolata, but the frequency and effects of these “mistake oviposition events” are not yet known. We investigated P. virginiensis oviposition preference through field observations in three locations (NY, OH, PA), and also through laboratory experiments measuring egg deposition of adult females on either a native or invasive crucifer. In addition, we examined neonate larval performance through no-choice feeding assays on both A. petiolata leaves and cabbage leaves painted with A. petiolata leaf extracts. We found that P. virginiensis lays significantly more eggs on the exotic A. petiolata than on its native host Cardamine diphylla in both field and laboratory experiments. Caterpillars fed either A. petiolata leaf tissue or its ethanol extract did not survive to pupation, and most died after only a few days. Continual invasion and persistence of A. petiolata in P. virginiensis habitats may lead to genetic bottlenecking and possibly local extinctions without human intervention.