Cardenolide content of Danaus chrysippus butterflies from three areas of East Africa

The African butterfly Danaus chrysippus , like other members of the family Danaidae, feeds as a larva on species of milkweeds (Asclepiadaceae). It has been demonstrated in a sample from a West African population that only a minority of adult D. chrysippus accumulated detectable amounts of poisonous and presumably emetic cardenolides from their larval foodplants. It has also been shown in D. chrysippus and the related monarch butterfly ( D. plexippus ) that the cardenolide content of adults varies with that of their respective milkweed foodplants.
Three population samples of D. chrysippus from sites in East Africa are analysed for cardenolides using the spectrophotometric technique refined by Brower, Edmunds & Moffitt (1975), which allows the assay of individual butterflies. The East African samples all have a palatability spectrum with a considerably higher percentage of cardenolide-containing individuals than the West African one.
This is discussed in terms of its effect on potential bird predators and the 'automimicry' of emetic by palatable individuals. In East Africa D. chrysippus is polymorphic and appears to act as a model in a complex mimicry ring, whereas in West Africa it is monomorphic and may have 'shed' most of its mimics. This latter hypothesis is discussed in the light of our results.     

A danaid mullerian mimic, Euploea core amymone (Cramer) lacking cardenolides in the pupal and adult stages

Euploea core amymone , a Mullerian Mimic, when reared on Serium oleander and Asclepias curassavica , stores emetic cardiac glycosides only in the larval stages, and not as pupa and adult. Danaus plexippus erippus. which exhibits less cardioactivity if tested on the isolated rat heart than E. c. amymone , nevertheless stores them at all three stages of development; polar cardenolides not present in its food plant A. curassavica , were found in the pupa and imago.     

Spatial metabolomics reveal divergent cardenolide processing in the monarch (Danaus plexippus) and the common crow butterfly (Euploea core)

Although being famous for sequestering milkweed cardenolides, the mechanism of sequestration and where cardenolides are localized in caterpillars of the monarch butterfly (Danaus plexippus, Lepidoptera: Danaini) is still unknown. While monarchs tolerate cardenolides by a resistant Na⁺/K⁺-ATPase, it is unclear how closely related species such as the nonsequestering common crow butterfly (Euploea core, Lepidoptera: Danaini) cope with these toxins. Using novel atmospheric-pressure scanning microprobe matrix-assisted laser/desorption ionization mass spectrometry imaging, we compared the distribution of cardenolides in caterpillars of D. plexippus and E. core. Specifically, we tested at which physiological scale quantitative differences between both species are mediated and how cardenolides distribute across body tissues. Whereas D. plexippus sequestered most cardenolides from milkweed (Asclepias curassavica), no cardenolides were found in the tissues of E. core. Remarkably, quantitative differences already manifest in the gut lumen: while monarchs retain and accumulate cardenolides above plant concentrations, the toxins are degraded in the gut lumen of crows. We visualized cardenolide transport over the monarch midgut epithelium and identified integument cells as the final site of storage where defences might be perceived by predators. Our study provides molecular insight into cardenolide sequestration and highlights the great potential of mass spectrometry imaging for understanding the kinetics of multiple compounds including endogenous metabolites, plant toxins, or insecticides in insects.     

Larval mortality and population regulation in the butterfly Danaus chrysippus in Ghana

An ecological study was made of a population of caterpillars of the African queen butterfly (Danaus chrysippus) feeding on three species of asclepiad plants at Nungua, Ghana, over a nine month period in 1972-73. The principal sources of mortality of caterpillars are probably the parasitic hymenopterans Apanteles chrysippi and Charops sp. There is an inverse correlation between the population of caterpillars and incidence of parasitization. This, and other evidence, suggests that the two parasites are important in limiting the population of Danaus chrysippus below the level imposed by the available food supply. Early instar caterpillars are probably palatable to birds but later instars may be edible or emetic depending on the toxicity of their food plant. It is suggested that the early instar caterpillars are cryptic whilst late instars are cryptic from a distance but conspicuous from nearby, and these may be aposematic or mimetic according to the nature of the food plant. Caterpillars parasitized by Apanteles are paler and hence more cryptic than normal caterpillars. There is also a green, cryptic morph present in the population at low frequency. It is suggested that there is a correlation between colour of caterpillars and the principal source of mortality: i.e., cryptic caterpillars are palatable to birds, suffer heavy predation but a low incidence of parasitization, whilst conspicuous caterpillars are unpalatable to many birds, suffer little predation but have a high incidence of parasitization.     

Butterflies as an indicator group of riparian ecosystem assessment

Riparian ecosystems play an important role in modulating a range of ecosystem processes that affect aquatic and terrestrial organisms. Butterflies are a major herbivore in terrestrial ecosystems and are also common in riparian ecosystems. Since butterflies use plants for larval food and adult nectar sources in riparian ecosystems, butterfly diversity can be utilized to evaluate riparian ecosystems. We compiled butterfly data from 33 sites in three riparian ecosystem types across the country and compared butterfly diversity in terms of number of species and quality index in relation to riparian environmental variables. Number of butterfly and plant species was not different among three riparian habitat types. Additionally, there was no significant ecological variable to distinguish the butterfly communities on three riparian habitats. Non-metric multi-dimensional scaling ordination showed that butterfly communities in three riparian ecosystem types differed from each other, and butterfly riparian quality index was the main variable for butterfly assemblages. Five indicator species for moor and another five species for riverine riparian ecosystems were identified. Three and one indicator species for moor and riparian ecosystems, respectively, were plant specialists, while 44 butterflies were general feeders, feeding on a wide range of hostplants in several habitats. These results suggest that butterfly species use actively riparian habitats for nectar and larval food, and the butterfly riparian quality index can be employed to track faunal change in riparian habitats, which are frequently threatened by disturbances such as water level and climate changes, and invasive species.     

Food plant density,patch isolation and vegetation height determine occurrence in a Swedish metapopulation of the marsh fritillary <Emphasis Type="Italic">Euphydryas aurinia</Emphasis> (Rottemburg, 1775) (Lepidoptera,Nymphalidae)

The occurrence pattern of the marsh fritillary was studied within a patch network on the Baltic island Öland, Sweden. Presence/absence was established for potentially suitable habitat patches (n = 158) on calcareous moist grassland and analyzed in a multiple logistic regression model where patch area, patch isolation and nine habitat quality variables were included as explanatory variables. Larval food plant density was positively, and patch isolation negatively, correlated to the presence of Euphydryas aurinia. Area did not contribute to the explanation of the occurrence pattern. Significant interactions between larval food plant density times patch isolation, and larval food plant density times vegetation height, show that with low food plant density the butterfly primarily occurs in patches with a vegetation height of 4–10 cm, within a distance of 250 m from nearest occupied patch. In patches with a high food plant density the butterfly occurs in patches where the vegetation height is higher, 4–16 cm, and the distance to nearest occupied patch can be longer, up to 1.4 km. This study supports earlier findings in other regions, suggesting that a network of adjacent patches with a high food plant density and a vegetation height within the preferred threshold, despite their size, is an apparent conservation goal.     

Persistence of a frugivorous butterfly species in Venezuelan forest fragments: the role of movement and habitat quality

We studied the factors affecting the persistence of a frugivorous butterfly species, Hamadryas februa, in a set of forested islands located in Lago Guri, a reservoir in eastern Venezuela. The roles of isolation, area and habitat quality (larval host plant density, light conditions and presence of fruiting trees) in determining island butterfly densities were investigated through observations and experiments. Butterfly densities increased significantly with increase in both island area and local larval host plant density, but were not related to distance from colonizing sources, light conditions or presence of fruiting trees. Butterfly populations on even distant islands were not augmented by the experimental introduction of adults. Butterfly residence times were higher on sites located on a large island than on small islands. However, there was no evidence that the positive correlation between adult density and host plant density was caused by increased reproduction. The results indicate that butterfly densities are not constrained by colonization capabilities but rather, by lack of appropriate host plants and high rates of emigration from islands. The study indicates the importance of considering patterns in movement and habitat heterogeneity when designing conservation strategies for insects in fragmented landscapes.     

The impact of habitat fragmentation on trophic interactions of the monophagous butterfly <Emphasis Type="Italic">Polyommatus coridon</Emphasis>

Theory predicts that habitat fragmentation, including reduced area and connectivity of suitable habitat, changes multitrophic interactions. Species at the bottom of trophic cascades (host plants) are expected to be less negatively affected than higher trophic levels, such as herbivores and their parasitoids or predators. Here we test this hypothesis regarding the effects of habitat area and connectivity in a trophic system with three levels: first with the population size of the larval food plant Hippocrepis comosa, next with the population density of the monophagous butterfly species Polyommatus coridon and finally with its larval parasitism rate. Our results show no evidence for negative effects of habitat fragmentation on the food plant or on parasitism rates, but population density of adult P. coridon was reduced with decreasing connectivity. We conclude that the highly specialized butterfly species is more affected by habitat fragmentation than its larval food plant because of its higher trophic position. However, the butterfly host species was also more affected than its parasitoids, presumably because of lower resource specialization of local parasitoids which also frequently occur in alternative hosts. Therefore, conservation efforts should focus first on the most specialized species of interaction networks and second on higher trophic levels.     

Larval starvation reduces responsiveness to feeding stimuli and does not affect feeding preferences in a butterfly

It is commonly assumed that holometabolic insects such as Lepidoptera rely primarily on larval storage reserves for reproduction. Recent studies though have documented a prominent role of adult-derived carbohydrates for butterfly reproduction. Moreover, a few studies have shown that adult butterflies may also benefit from adult-derived amino acids, at least when larval storage reserves are reduced. Given that in holometabolous insects larval deficiencies are carried over into the adult stage, reduced storage reserves have the potential to modulate adult feeding preferences and responses in order to allow for a successful compensation. We tested this hypothesis here in the fruit-feeding butterfly Bicyclus anynana using larval food stress to manipulate storage reserves. Alcohols (methanol, ethanol, butanol, propanol), sugars (maltose, glucose, fructose, sucrose), and acetic acid acted as feeding stimuli, while butterflies did not respond to other substances such as amino acids, yeast, salts, or vitamins. Contrary to expectations, stressed butterflies showed a weaker response than controls to several feeding stimuli. In preference tests, butterflies preferred sugar solutions containing proline, arginine, glutamic acid, acetic acid, or ethanol over plain sugar solutions, but discriminated against salts. However, there were no general differences among starved and control butterflies. We conclude that larval food-stress does not elicit compensatory feeding behavior such as a stronger preference for amino acids or other essential nutrients in B. anynana. Instead, the stress imposed by a period of starvation yielded negative effects.     

On the evolution of egg placement and gregariousness of caterpillars in the Lepidoptera

Drawing heavily upon natural history data from the Neotropical butterfly fauna, an attempt is made to develop a model, with testable hypotheses, to account for the evolution of egg-clustering and larval gregariousness. Given the high diversity of both plant and butterfly species in the American tropics, there is a higher incidence of egg-clustering there, including some species with aposematically-colored immature stages. Emphasis is placed on the need to examine both the physical (mechanical) toughness of larval food plants for larval feeding success, and the spatial structuring of food plant populations. It is argued that when food plant spatial patchiness is high, the breadth of local food plant species usage low, plant growth rates high, fed-upon structures tough, butterfly dispersal low, and reproductive potential low, egg-clustering evolves. Such ecological character states, coupled with the occurrence of food plant patches in large sizes relative to the nutritional and fecundity needs of the butterfly specialist on the species, select for egg-clustering to ensure survival of the butterfly population in that habitat. It is emphasized that the model proposed here requires considerable examination through field studies.     

Elevated temperature and periodic water stress alter growth and quality of common milkweed (<Emphasis Type="Italic">Asclepias syriaca</Emphasis>) and monarch (<Emphasis Type="Italic">Danaus plexippus</Emphasis>) larval performance

In this study, we examined the independent and interactive effects of temperature and water availability on the growth and foliar traits of common milkweed (Asclepias syriaca) and performance of a specialist herbivore, larvae of the monarch butterfly (Danaus plexippus). Milkweed from multiple population sources collected across a latitudinal gradient in Wisconsin, USA, were grown under all combinations of ambient or elevated temperature and the presence or absence of periodic water stress. Elevated temperature marginally increased, while water stress decreased plant growth. Milkweed from more northerly latitudes experienced larger growth responses to elevated temperature and were more resistant to water stress, especially under higher temperatures. Elevated temperature and water stress also altered milkweed composite foliar trait profiles. Elevated temperature generally increased leaf nitrogen and structural compounds, and decreased leaf mass per area. Water stress also elevated foliar nitrogen, but reduced defensive traits. Monarch larvae performed well on milkweed under elevated temperature and water stress, but gained the most mass on plants exposed to both treatments in combination. Our findings suggest that milkweed populations from more northerly latitudes in the upper Midwest may benefit more from rising temperatures than those in southerly locations, but that these beneficial effects depend on water availability. Monarch larvae grew larger on plants from all experimental treatments relative to ambient condition controls, indicating that future changes in milkweed presence on the landscape will likely influence monarch populations more than the effects of future changes in plant quality on larval performance.     

Arbuscular mycorrhizal fungi influence life history traits of a lepidopteran herbivore

Results from pot and microcosm studies in the greenhouse have shown that plant growth and foliar chemistry is altered by the presence and species composition of arbuscular mycorrhizal fungi (AMF). The growth and survival of herbivores which feed on plants could, as a consequence, also be affected by these mutualistic soil fungi. Consequently, interactions between AMF, plants and herbivores could occur. To test this, larvae of the common blue butterfly, Polyommatus icarus (Lycaenidae), were fed with sprigs of Lotus corniculatus (Fabaceae) plants which were inoculated with one of two different AMF species, with a mixture of these AMF species or with sprigs of plants which were not inoculated with AMF. Survival and larval weight of third instar larvae fed with plants colonised by AMF were greater than those of larvae fed with non-mycorrhizal plants. Survival of larvae feeding on non-mycorrhizal plants was 1.6 times lower than that of larvae feeding on plants inoculated with a mixture of AMF species and 3.8 times lower than that of larvae feeding on plants inoculated with single AMF species. Furthermore, larvae fed with non-mycorrhizal plants attained only about half the weight of larvae fed with mycorrhizal plants after 11 days of growth. These differences in larval performance might be explained by differences in leaf chemistry, since mycorrhizal plants had a 3 times higher leaf P concentration and a higher C/N-ratio. Our results, thus, show that the presence of belowground mutualistic soil fungi influences the performance of aboveground herbivores by altering their food quality. Larval consumption, larval food use and adult lipid concentrations of the common blue butterfly differed between larvae which were fed with plants inoculated with different AMF species. This suggests that the performance of herbivores is not only influenced by the presence of AMF but also depends on the identity of the AMF species colonising the host plants. Moreover, a significant interaction term between AMF species and maternal identity of the larvae occurred for adult dry weight, indicating that the performance of offspring from different females was differently influenced by AMF species composition. To our knowledge, these results show for the first time that the species composition of AMF communities can influence life-history traits of butterfly larvae and possibly herbivores in general.     

Positive effects of cyanogenic glycosides in food plants on larval development of the common blue butterfly

Cyanogenesis is a widespread chemical defence mechanism in plants against herbivory. However, some specialised herbivores overcome this protection by different behavioural or metabolic mechanisms. In the present study, we investigated the effect of presence or absence of cyanogenic glycosides in birdsfoot trefoil (Lotus corniculatus, Fabaceae) on oviposition behaviour, larval preference, larval development, adult weight and nectar preference of the common blue butterfly (Polyommatus icarus, Lycaenidae). For oviposition behaviour there was a female-specific reaction to cyanogenic glycoside content; i.e. some females preferred to oviposit on cyanogenic over acyanogenic plants, while other females behaved in the opposite way. Freshly hatched larvae did not discriminate between the two plant morphs. Since the two plant morphs differed not only in their content of cyanogenic glycoside, but also in N and water content, we expected these differences to affect larval growth. Contrary to our expectations, larvae feeding on cyanogenic plants showed a faster development and stronger weight gain than larvae feeding on acyanogenic plants. Furthermore, female genotype affected development time, larval and pupal weight of the common blue butterfly. However, most effects detected in the larval phase disappeared for adult weight, indicating compensatory feeding of larvae. Adult butterflies reared on the two cyanogenic glycoside plant morphs did not differ in their nectar preference. But a gender-specific effect was found, where females preferred amino acid-rich nectar while males did not discriminate between the two nectar mimics. The presented results indicate that larvae of the common blue butterfly can metabolise the surplus of N in cyanogenic plants for growth. Additionally, the female-specific behaviour to oviposit preferably on cyanogenic or acyanogenic plant morphs and the female-genotype-specific responses in life history traits indicate the genetic flexibility of this butterfly species and its potential for local adaptation.     

Testing the plant stress hypothesis: stressed plants offer better food to an insect herbivore

Temperature and nutrition are among the most important environmental factors affecting ectotherm growth. As temperature and host‐plant quality often co‐vary in nature, the interaction between the two is of potentially high ecological importance for herbivorous insects. We here use the temperate‐zone butterfly Pieris napi L. (Lepidoptera: Pieridae) to investigate interactive effects of larval rearing temperature and host‐plant quality (by manipulating water availability) on larval growth. As growth rates have been hypothesized to govern stress tolerance, we additionally assessed adult starvation resistance. Butterflies followed the ‘temperature‐size rule’, which states that body size increases at lower developmental temperatures, proximately caused by differences in growth increment, which resulted from increased consumption at the lower temperature. Larvae benefitted from feeding on stressed plants from the low‐water regime by having higher body mass, growth rate, and food conversion efficiency, thus supporting the plant stress hypothesis, which predicts that plant quality for herbivores should increase if stress is imposed on plants. Some effects of host‐plant quality on larval growth parameters were as strong as or even stronger than effects of temperature, whereas interactive effects between temperature and food quality were scarce. At the low temperature, adult starvation resistance was higher than at the higher temperature and females were more resistant than males, whereas plant water regime had no clear impact. No evidence was found for a trade‐off between growth rate and starvation resistance. This study illustrates the importance of considering effects of host‐plant quality along with variation in other environmental factors for estimating the impact of environmental changes on herbivorous species.     

Effects of larval starvation and adult diet-derived amino acids on reproduction in a fruit-feeding butterfly

Availability of adequate nutrition is among the most important factors affecting growth, development, and reproduction in animals. In holometabolous insects, diets and nutritional needs change between life stages, with larval storage, and adult feeding and reproduction being linked to one another. In several butterfly species, adult feeding is of fundamental importance to realize the full reproductive potential, primarily due to a prominent role of adult diet-derived carbohydrates. In contrast, the role of adult diet-derived amino acids is still under debate, despite the fact that butterflies were often found to preferentially feed on amino acid-rich substrates. Recently it was found that amino acids from adult income could compensate for adverse effects of larval food quality. In our study on the tropical butterfly Bicyclus anynana (Butler) (Lepidoptera: Nymphalidae), we used larval starvation to investigate corresponding effects on female reproductive output. Short periods of larval starvation prolonged development time and reduced larval survival, larval growth rate, pupal mass, and egg size. Regardless of the degree of larval starvation, access to amino acids in the adult diet increased egg size, whereas egg number remained largely unaffected. Thus, although there was some evidence for adult diet-derived amino acids being overall beneficial to reproduction, there was no indication that they can compensate for larval starvation.     

The influence of ants and water availability on oviposition behaviour and survivorship of a facultatively ant-tended herbivore

1. The lycaenid butterfly Hemiargus isola associates facultatively with the ant species Formica perpilosa in arid areas of south-western North America. Ants solicit liquid food rewards from butterfly larvae as larvae feed on the host plant, Acacia constricta . Previous studies have shown that tending by F. perpilosa enhances larval growth and pupal survivorship.
2. The effects of ants and plant water content on oviposition behaviour and survivorship to the last larval instar were tested by excluding ants and supplementing water to host plants in a two-way factorial experiment.
3. Butterflies, which lay eggs singly on host plant inflorescences, laid significantly higher egg numbers and densities (eggs/inflorescence) on plants with ants than on plants without ants. This is the first report of a facultative, generalized ant-associate using ants as oviposition cues. Water supplements increased the number, but not the density, of eggs laid on plants. Therefore, it appears that egg-laying butterflies responded to number of inflorescences, rather than plant tissue water per se .
4. Plants with ants had significantly greater numbers of inflorescences during the experiment than plants without ants. Water supplements increased number of inflorescences slightly, but not significantly.
5. Ants increased larval survivorship. Twice as many fourth-instar larvae survived per egg laid on plants with ants than on plants without ants. Ants did not reduce the number of predators present on acacias, but may have reduced predator effectiveness. Ants also did not reduce the numbers of potential H. isola competitors present.
6. Water supplementation affected neither the survivorship of H. isola larvae, nor the intensity of ant tending. Water supplementation did not affect the abundance of predators on plants, but did increase the abundance of several herbivorous insect taxa.     

Linking nectar amino acids to fitness in female butterflies

Nectar of butterfly-pollinated flowers contains generally higher levels of amino acids than does nectar of flowers pollinated by most other animal types. One proposed explanation is that these amino acids promote butterfly fitness, although the evidence has been equivocal. In a new study, Mevi-Schütz and Erhardt showed that nectar amino acids enhanced fecundity in the butterfly Araschnia levana, but only when the larval diet was poor. Their results support the hypothesis that butterflies are agents of selection for higher nectar amino acid production, suggest that the larval food plant has a key role in the evolution of the flower-butterfly mutualism, and demonstrate that the importance, to butterfly reproduction, of different nutrient sources varies with butterfly nutritional state.     

How do two specialist butterflies determine growth and biomass of a shared host plant?

Although insect herbivory can modify subsequent quantity and quality of their host plants, change in plant quantity following herbivory has received less attention than plant quality. In particular, little is known about how previous herbivore damage determines plant growth and biomass in an insect species-specific manner. We explored whether herbivore species-specific food demand influences plant growth and biomass. To do this, we conducted a series of experiments and field survey using two specialist butterflies, Sericinus montela and Atrophaneura alcinous, and their host plant, Aristolochia debilis. It is known that A. alcinous larva requires four times more food resources to fulfill its development than S. montela larva. Despite that A. alcinous larvae imposed greater damage on plants than S. montela larvae, plant growth did not differ due to herbivory by these species both in single and multiple herbivory events. On the other hand, total aboveground biomass of the plants was reduced more by A. alcinous than S. montela feeding regardless of the number of herbivory events. Feeding on plants with a history of previous herbivory neither decreased nor increased larval growth. Our results suggest that food demand of the two butterfly species determined subsequent plant biomass, although the plant response may depend on tolerance of the host plant (i.e., ability to compensate for herbivore damage). Such difference in the effects of different herbivore species on host plant biomass is more likely to occur than previously thought, because food demand differs in most herbivore species sharing a host plant.     

Similarity and specialization of the larval versus adult diet of European butterflies and moths

Many herbivorous insects feed on plant tissues as larvae but use other resources as adults. Adult nectar feeding is an important component of the diet of many adult herbivores, but few studies have compared adult and larval feeding for broad groups of insects. We compiled a data set of larval host use and adult nectar sources for 995 butterfly and moth species (Lepidoptera) in central Europe. Using a phylogenetic generalized least squares approach, we found that those Lepidoptera that fed on a wide range of plant species as larvae were also nectar feeding on a wide range of plant species as adults. Lepidoptera that lack functional mouthparts as adults used more plant species as larval hosts, on average, than did Lepidoptera with adult mouthparts. We found that 54% of Lepidoptera include their larval host as a nectar source. By creating null models that described the similarity between larval and adult nectar sources, we furthermore showed that Lepidoptera nectar feed on their larval host more than would be expected if they fed at random on available nectar sources. Despite nutritional differences between plant tissue and nectar, we show that there are similarities between adult and larval feeding in Lepidoptera. This suggests that either behavioral or digestive constraints are retained throughout the life cycle of holometabolous herbivores, which affects host breadth and identity.     

A Hollywood drama of butterfly extirpation and persistence over a century of urbanization

Few long-term examples exist of wildlife population trends in urban environments despite the recent recognition of the importance of biodiversity in cities. Founded in 1896, Griffith Park’s over 1,700 ha in Los Angeles adjacent to Hollywood represent the largest municipal park in California. Through the 1920s, biologists studied the natural area with great interest but in the decades that followed, little fieldwork was conducted here as Los Angeles developed into a megacity surrounding the park. We combined thorough examination of Griffith Park historical field notes and specimen records (1900–1960) with recent field surveys (2011–2012) to determine (1) the extent of urbanization impacts on butterfly extirpation and persistence and (2) how butterfly traits and host plant relationships might be contributing to butterfly species status. Here we document multiple local butterfly extinctions in Griffith Park; 10 species or 18 % of the historically reconstructed community. Many of these species were lost early in the twentieth century, highlighting the importance of the historical record in understanding urban biodiversity patterns and trends. An analysis of larval host plant status and relationships suggests that a primary factor determining butterfly presence or extirpation is the abundance of the larval host plant in the park, in addition to host plant specificity. Despite these extirpations, we also found that the majority (over 80 %) of native butterfly species have persisted including species of conservation interest. While urban parks certainly suffer from surrounding anthropogenic pressure and impacts, this study also demonstrates the potentially high and underappreciated conservation and ecological value of urban parks.