Associations between lycaenid butterflies and ants in Australia

A comprehensive and critical review of all available literature on associations between Australian lycaenid butterflies and ants was undertaken to establish an accurate database of the partners involved. Collections and observations of lycaenids and ants were used to augment this review, resulting in a significant number of newly documented association (and non-association) records. Twenty published records considered to be erroneous or doubtful are noted, with justifications given for their deletion from the association database. In total, 265 different associations between lycaenids and ants, plus 65 non-attendance records are documented for Australia. Nearly 80% of the lycaenid species in Australia, for which the early stages are known, are recorded associating with ants and half of these are obligately ant-associated. Patterns of association are examined from the perspective of both lycaenids and ants, with a focus on ant systematics and ecology. Lycaenids are recorded with five ant subfamilies, including the first record of an association with the Pseudomyrmecinae. The Dolichoderinae, and to some extent the Formicinae, have a disproportionately high percentage of genera that associate with lycaenid butterflies. All ant species that tend lycaenids spend at least some portion of their time foraging on vegetation to collect plant and insect nectar. There is a robust relationship between the competitive status of ants within a community, and their frequency and degree of association with lycaenids. Obligate ant-association is accompanied by a high degree of specificity for ant partner, but two notable exceptions, Ogyris aenone and O. amaryllis are discussed. Facultative myrmecophiles tend to associate with a broad range of ants, although interactions with ecologically dominant ants are less frequent than might be expected based on the abundance of dominant ant species in Australian communities.     

PHENOLOGICAL ISOLATION,GENE FLOW AND DEVELOPMENTAL DIFFERENCES AMONG LOW- AND HIGH-ELEVATION POPULATIONS OF EUPHILOTES ENOPTES (LEPIDOPTERA: LYCAENIDAE)

Populations of the specialist herbivore, Euphilotes enoptes (Lepidoptera: Lycaenidae), along three elevational transects in the mountains of central Washington state, differed markedly in the phenology of adult flight. In spite of this apparent limitation to gene flow, six allozyme loci revealed substantial gene exchange among populations along these gradients. The elevational difference, and thus the phenological difference, between populations has not influenced the extent of gene flow between them. Because the direct exchange of genes between low- and high-elevation populations is very unlikely, gene flow between them has probably occurred in a stepwise fashion via intermediate populations. It is hypothesized that such gene flow has been biased in an uphill direction due to the combined effects of source size and oviposition behavior. Adult emergence times of populations in the same region are positively correlated with elevation in a nonlinear fashion, consistent with the hypothesis that gene flow from low-elevation populations has been swamping selection at higher altitudes.     

Host-ant trail following by myrmecophilous larvae of Liphyrinae (Lepidoptera,Lycaenidae)

In this study we report a case of ant-trail following by lycaenid caterpillars. Euliphyra mirifica and E. leucyana caterpillars are involved in a commensal association with the weaver ant Oecophylla longinoda. The host nests are made with leaves which over the course of time dry out or are broken open by storms, forcing the ants to migrate and build a new nest elsewhere. Euliphyra caterpillars are stimulated by recruitment behaviour which triggers the migration of their host. They then follow the host trails leading to the new nesting site. Laboratory experiments showed that these caterpillars are able to follow host trails under varied conditions: (1) fresh trails actually used by workers, (2) fresh trails in the absence of workers, (3) heterocolonial, 2-month-old trails, and (4) fresh trails washed with water (to simulate the effect of tropical rains). They can also bridge trail gaps of more than 1 cm. Under natural conditions, the trails are frequently situated along thin twigs. The forward progress of the ants in such a situation is not impeded by the presence of large Euliphyra larvae. Workers just climb over the caterpillars, even on larger trails where there is enough room to pass alongside them. This suggests that an allomone is secreted on the dorsal part of the caterpillars. When crawling along heterocolonial trails, the caterpillars are not attacked, even if about 21% of the workers from the new colony spread their mandibles when encountering them. They are then adopted and are admitted to the nest of the new host colony of O. longinoda.     

Museum genomics reveals the Xerces blue butterfly (Glaucopsyche xerces) was a distinct species driven to extinction

The last Xerces blue butterfly was seen in the early 1940s, and its extinction is credited to human urban development. This butterfly has become a North American icon for insect conservation, but some have questioned whether it was truly a distinct species, or simply an isolated population of another living species. To address this question, we leveraged next-generation sequencing using a 93-year-old museum specimen. We applied a genome skimming strategy that aimed for the organellar genome and high-copy fractions of the nuclear genome by a shallow sequencing approach. From these data, we were able to recover over 200 million nucleotides, which assembled into several phylogenetically informative markers and the near-complete mitochondrial genome. From our phylogenetic analyses and haplotype network analysis we conclude that the Xerces blue butterfly was a distinct species driven to extinction.     

Functional analysis of the myrmecophilous relationships between ants (Hymenoptera: Formicidae) and lycaenids (Lepidoptera: Lycaenidae)

Summary Mature larvae of the myrmecophilous lycaenid Polyommatus coridon produce an average of 30.9 droplets of a honeydew-like secretion per hour. They occur in population densities of about 20/m². The volume of secretion over the whole larval period is estimated to be 22–44 l with an energy content of 55–110 J. Thus, P. coridon larvae produce carbohydrate secretions with an energy equivalent of 1.1–2.2 kJ/m². Using data from the literature on ant metabolism, it is shown that these carbohydrate secretions may contribute significantly to the nutrition of attending ants. The myrmecophilous relationship between the larvae of P. coridon and ants should therefore be regarded as a mutualistic symbiosis.     

Pupation site choice of a North American lycaenid butterfly: the benefits of entering ant nests

Abstract.

• 1 Larvae of the North American lycaenid butterfly Hemiargus isola Reakirt tended by the ant Formica perpilosa Wheeler often enter nests of this ant species, and pupate in tunnels and chambers near the surface. Untended larvae and those tended by the ants Dorymyrmex Forel sp. (smithi complex), Forelius foetida (Buckley), and Myrmecocystus mimicus Wheeler pupate in crevices in the ground, under bark, and on leaves; but rarely inside ant nests.
• 2 The location and structure of F.perpilosa nests facilitates discovery by H.isola prepupae. At the southeast Arizona study site, F.perpilosa nests are located at the base of H.isola's host plant, whereas other species’nests are in open ground. Also, F.perpilosa nest openings are wide, whereas those of other species may be too narrow for prepupae to enter.
• 3 Prepupae associated with F.perpilosa spent 67% less time on the ground searching for pupation sites than prepupae associated with other ant species. Pupae in artificial chambers connected to F.perpilosa nests were 4–5 times less likely to disappear overnight, presumably due to predation, than those not connected to nests.
• 4 Formica perpilosa ants tend pupae inside nests. However, in the laboratory experiments tended pupae did not lose more weight prior to eclosion than untended ones, suggesting that chemicals or sounds produced by pupae as ant attractants are inexpensive, or are produced whether or not ants are present.
• 5 Newly-eclosed butterflies exited nests unmolested by ants in the field, but were attacked if confined with ants for several minutes after eclosion in the laboratory.

     

Irregular diapause, apparency and evaluating conservation status: anomalies from the Australian butterflies

Examples of irregular development (diapause regimes) are reported in three families (Lycaenidae, Nymphalidae, Papilionidae) of butterflies in Australia. The importance of understanding such irregularities is emphasized, and their relevance to interpreting conservation status and needs discussed. Expectations of incidence or abundance may not be met, and unexpected declines or losses resulting from irregular diapause can cause unnecessary conservation concerns.     

Effects of local and landscape factors on the abundance of an endangered multivoltine butterfly at riverbanks

Plebejus argyrognomon is one of the grassland‐dwelling butterflies undergoing rapid decline in recent decades. Grassland habitats for butterflies are generally threatened by fragmentation and invasive species, hence are among the most vulnerable ecosystems. We studied the seasonal abundance of P. argyrognomon at habitat patches along the banks of the Kinugawa River in eastern Japan, to identify environmental factors suitable for population persistence of this species, including habitat patch connectivity. Results showed that the patch's host plant cover had a positive effect on abundance in all three seasons, while the shading of the host plants by surrounding non‐host plants and nearby forested area showed negative effects. Additionally, habitat patch connectivity and nectar richness could be considered as positive factors in autumn and summer, respectively. Analysis of habitat connectivity also showed that the Kinugawa River did not appear to act as a dispersal barrier for P. argyrognomon. Our findings emphasize the importance of understanding environmental factors that may vary among seasons, and such understanding could contribute to habitat management of multivoltine butterflies in fragmented landscapes.     

Six new species of Philiris R?ber, 1891 (Lepidoptera,Lycaenidae) from Papua New Guinea

Six new species of the large lycaenid genus Philiris Röber, 1891 (Philiris petriei sp. n., Philiris bubalisatina sp. n., Philiris baiteta sp. n., Philiris radicala sp. n., Philiris hindenburgensis sp. n. and Philiris parsonsi sp. n.), from Papua New Guinea, are described and illustrated, as are the early stages of the former taxon, with Litsea sp. near callophyllantha K. Schum (Lauraceae) recorded as the larval food plant. The holotypes of all but the latter are deposited in the ANIC, with that of P. parsonsi located in the BMNH. The external facies and male genitalia of all new species are compared in detail to putative known related species, and the types of these, in nearly all cases, are also illustrated.     

CLIMBER: Climatic niche characteristics of the butterflies in Europe

Detailed information on species’ ecological niche characteristics that can be related to declines and extinctions is indispensable for a better understanding of the relationship between the occurrence and performance of wild species and their environment and, moreover, for an improved assessment of the impacts of global change. Knowledge on species characteristics such as habitat requirements is already available in the ecological literature for butterflies, but information about their climatic requirements is still lacking. Here we present a unique dataset on the climatic niche characteristics of 397 European butterflies representing 91% of the European species (see Appendix). These characteristics were obtained by combining detailed information on butterfly distributions in Europe (which also led to the ‘Distribution Atlas of Butterflies in Europe’) and the corresponding climatic conditions. The presented dataset comprises information for the position and breadth of the following climatic niche characteristics: mean annual temperature, range in annual temperature, growing degree days, annual precipitation sum, range in annual precipitation and soil water content. The climatic niche position is indicated by the median and mean value for each climate variable across a species’ range, accompanied by the 95% confidence interval for the mean and the number of grid cells used for calculations. Climatic niche breadth is indicated by the standard deviation and the minimum and maximum values for each climatic variable across a species’ range. Database compilation was based on high quality standards and the data are ready to use for a broad range of applications.It is already evident that the information provided in this dataset is of great relevance for basic and applied ecology. Based on the species temperature index (STI, i.e. the mean temperature value per species), the community temperature index (CTI, i.e. the average STI value across the species in a community) was recently adopted as an indicator of climate change impact on biodiversity by the pan-European framework supporting the Convention on Biological Diversity (Streamlining European Biodiversity Indicators 2010) and has already been used in several scientific publications. The application potential of this database ranges from theoretical aspects such as assessments of past niche evolution or analyses of trait interdependencies to the very applied aspects of measuring, monitoring and projecting historical, ongoing and potential future responses to climate change using butterflies as an indicator.