Abstract:The use of human mediated translocations has been an increasing component of many species recovery initiatives, including for numerous imperiled Lepidopteran species. Despite the identified need for this ex situ strategy, few such programs are conducted in a scientifically repeatable way, are executed with a structured decision-making process, are well documented throughout, or are documented only in gray literature. The International Union for Conservation of Nature's Guidelines for Reintroductions and Other Conservation Translocations are an important tool for conservation practitioners to help implement comprehensive translocation planning. These generalized guidelines are intended to be applicable to all taxa. Though there is a growing body of literature and supplementary guidelines for many vertebrate classes, other proposed standards fail to capture the specific biology of many invertebrate groups, like Lepidoptera. Here, we present a targeted list of detailed recommendations that are appropriate for Lepidopteran translocation programs to expand on the broad and tested guidelines developed by the IUCN. We assert that the increased standardization and repeatability among Lepidopteran translocations will improve the conservation outcomes.

With only ~1% of native prairie remaining in North America, populations of many prairie-obligate species, including the imperiled Dakota skipper butterfly, have drastically declined in recent decades. Unfortunately, population recovery is impeded by an insufficient understanding of Dakota skipper biology. Because larvae have never been naturally observed in the wild, even basic life history elements including preferred host plant(s) are not well understood, and potential hosts have been inferred from grasses inhabiting remnant sites rather than direct observations. To improve our understanding of Dakota skipper biology and habitat needs and inform recovery efforts, we conducted a no-choice performance experiment offering larvae 1 of 5 commonly occurring native grasses and 2 pervasive invasive grass species found across their historic range. We monitored larvae during key life history intervals and evaluated host plant quality by measuring larval and pupal mass, time to pupation, and survivorship. Larvae fed on all offered host grasses, but mass, phenology, and survivorship varied among treatments. Larvae reared on prairie dropseed and porcupine grass had the highest survival, the shortest time to adulthood, and the greatest mass, whereas larvae provided smooth brome and Kentucky bluegrass fared poorly for all observed metrics. All other grasses offered during the study were deemed ‘medium’ quality. Our results suggest that although larvae can feed on a variety of potential host plants, these hosts vary in quality. Invasive grasses across prairies in North America may pose an ecological trap to the conservation of Dakota skipper and other prairie-obligate Lepidoptera.

Aim Few studies of comparative phylogeography have been conducted at very large spatial scales, encompassing species that are distributed across multiple continents. Several Pan-American butterfly species associated with weedy, human-modified habitats were studied using comparative phylogeographic tools to test for the congruence of demographic histories across a range of spatial scales and to investigate the effects of human-facilitated range expansion.Location North and South America, mainly the southern United States, Brazil and Argentina.Methods The mitochondrial DNA cytochrome c oxidase subunit II region (COII) was sequenced for Hylephila phyleus, Lerodea eufala, Erynnis funeralis and Agraulis vanillae across their North and South American ranges. Data from these conspecifics were compared with variation in COII sequences between allopatric congener pairs on both continents whose ranges approximate the conspecifics and also share similar weedy habitat associations: Ancyloxypha numitor versus Ancyloxypha nitedula, Vanessa annabella versus Vanessa carye, and Euptoieta claudia versus Euptoieta hortensia. We tested for similarities in demographic histories within and across continents for each species using pairwise distances, population genetic statistics, mismatch distributions and deviations from mutation-drift equilibrium.Results Mean pairwise divergence across continents was lower for Lerodea eufala and Hylephila phyleus (with several shared Pan-American haplotypes each) compared with Erynnis funeralis and Agraulis vanillae (both with no shared haplotypes). Differentiation between congeneric species pairs was generally significantly higher than conspecific divergence across continents, but North and South American populations of A. vanillae were more divergent than V. annabella and V. carye. We found deviations from mutation-drift equilibrium in A. vanillae. Population-level variation was greater than the variation across continents for H. phyleus and L. eufala. Main conclusionsWe find little congruence in phylogeographic patterns among these taxa across continents, although similar demographic patterns can be detected at smaller regional levels. Except for Californian populations of some species, the North American distributions of these weedy butterfly species appear to largely pre-date the influences of human-facilitated range expansion.

Insect declines have become pronounced in prairie ecosystems, particularly in areas of agricultural intensification. Non-target pesticide exposure has been raised as a key concern for prairie remnant health. We do not understand the extent of that exposure risk, particularly across seasons and multi-year timeframes. Over nine years, we analyzed grass and soil samples for the presence of hundreds of pesticides from five prairies in Minnesota and South Dakota that are designated as Critical Habitat for two endangered butterflies: Poweshiek skipperling and Dakota skipper. We found dozens of pesticides across all sites and years on their larval host grasses. Interiors of prairies were not less likely to have detectable pesticides than prairie-agriculture edges. Broad-spectrum organophosphate and pyrethroid insecticides were common in late season. Chlorpyrifos quantities were higher at sites where both endangered species have been extirpated. Few pesticides were detected in soil or early season grass samples. The risk associated with the prevalence and quantities of pesticides we observed likely underestimates the overall risk. Implications for Conservation: Our work demonstrates protected prairies are not immune to the risk of pesticide exposure, and that this may impact planned efforts to re-establish lost populations of imperiled prairie insect species, including endangered butterflies.

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