Why small is beautiful: wing colour is free from thermoregulatory constraint in the small lycaenid butterfly, Polyommatus icarus

We examined the roles of wing melanisation, weight, and basking posture in thermoregulation in Polyommatus Icarus, a phenotypically variable and protandrous member of the diverse Polyommatinae (Lycaenidae). Under controlled experimental conditions, approximating to marginal environmental conditions for activity in the field (= infrequent flight, long duration basking periods), warming rates are maximised with fully open wings and maximum body temperatures are dependent on weight. Variation in wing melanisation within and between sexes has no effect on warming rates; males and females which differ in melanisation had similar warming rates. Posture also affected cooling rates, consistent with cooling being dependent on convective heat loss. We hypothesise that for this small sized butterfly, melanisation has little or no effect on thermoregulation. This may be a factor contributing to the diversity of wing colours in the Polyommatinae. Because of the importance of size for thermoregulation in this small butterfly, requirements for attaining a suitable size to confer thermal stability in adults may also be a factor influencing larval feeding rates, development time and patterns of voltinism. Our findings indicate that commonly accepted views of the importance of melanisation, posture and size to thermoregulation, developed using medium and large sized butterflies, are not necessarily applicable to small sized butterflies

Historical and current patterns of gene flow in the butterfly Pararge aegeria

Aim. We have investigated the phylogeography and genetic structure of the Speckled Wood butterfly (Pararge aegeria) across its entire distribution range and studied its dispersal both on mainland and across sea straits. The apparent lack of gene flow between Sardinia and Corsica was further investigated by means of mating experiments. Location. Europe and North Africa. Methods. We sampled 345 individuals and sequenced one mitochondrial gene (Cytochrome c Oxidase subunit I, COI) for all samples and two nuclear genes (wingless and zerknullt) for a subset of the specimens. A total of 22 females from Corsica and Sardinia were used to establish a series of crosses to investigate reproductive compatibility and were screened for the presence of Wolbachia. Bayesian inference (BI) and haplotype networks were employed to infer phylogenetic relationships and a Principal Coordinate Analysis (PCoA) was used to represent 4 geographical patterns of genetic diversity. Mating and courtship data were analysed using linear mixed effect models. Results. We detected two main COI lineages separated by the Mediterranean Sea and maintained over relatively short sea straits. While nuclear gene variation was generally in agreement with that of COI, this was not the case in all areas (e.g. Iberian Peninsula and Corsica/Sardinia). Mating experiments revealed no evidence of reproductive isolation between the lineages, nor clear relation to Wolbachia infection status. Main conclusions. We propose that following the post-glacial recolonisation of Europe, the ancestral COI lineage of P. aegeria was maintained in North Africa and Mediterranean islands, while a new lineage colonised from Eastern Europe, replacing and apparently outcompeting the ancestral variant. Several hypotheses are discussed that may explain the local discordance between the nuclear genes and COI, including sex-specific dispersal, selection and differential rates of gene evolution

Rise and fall of island butterfly diversity : understanding genetic differentiation and extinction in a highly diverse archipelago

Aim. We describe fine-scale diversity patterns of the entire butterfly fauna occurring on the Tuscan Archipelago. By assessing the traits associated with population diversification, haplotype uniqueness and extinction, we aim to identify the factors determining the origin and maintenance of genetic diversity, and population vulnerability to environmental changes. Location. Tuscan Archipelago, Sardinia, Tuscany (Italy) and Corsica (France). Methods. We built a mtDNA dataset (1,303 COI sequences) for the 52 butterfly species reported in the Archipelago, also including specimens from neighbouring areas, and compiled data on 12 species traits and on the apparent extinction of species from the main islands. We calculated indices that measure genetic differentiation, and using phylogenetic regressions we evaluated the relationships between these indices and species traits. Finally, we inferred which traits are associated with disappearance of species on individual islands using phylogenetic regression. Results. The overall spatial pattern of genetic diversity corresponded with the proximity of the areas, but strong contrasts were also identified between geographically close areas. Together with the island endemics, several common and widespread species had a high genetic diversification among islands and mainland. Phylogenetic regressions revealed that smaller-sized, more specialized species, with a preference for drier regions, displayed greater genetic structure and/or haplotype uniqueness. Species that disappeared from islands had a higher population diversification. Capraia has experienced a notable loss of diversity, which significantly affected species with shorter flight periods. Main conclusions. Tuscan island butterflies are characterized by strong genetic contrasts and species differ in their contribution to the overall genetic diversity. By ranking the species for their contribution to genetic diversity and identifying the traits linked to the emergence and maintenance of diversity, we have developed a valuable tool for prioritizing populations as targets for monitoring and conservation action. The dataset constructed also represents a valuable resource for testing biogeographical hypotheses

Cross-water transfer by common butterflies (Lepidoptera: Rhopalocera): clear examples of ignoring the highway

Clear examples of ignoring landscape corridors are given for allegedly sedentary butterflies observed in the process of dispersing from habitats; these are discussed in the context of the provision of corridors in managing the British landscape for maintaining populations of Lepidoptera

Phylogenetic, habitat, and behavioural aspects of possum behaviour in European lepidoptera

Volume: 39Start Page: 80End Page: 8

Phylogenetic, habitat, and behavioural aspects of possum behaviour in European Lepidoptera

We describe the behaviour of playing possum, or thanatosis, in mate rejection by non-receptive female butterflies of the Satyrinae of the Palearactic. In this behaviour females feign death with closed wings and release themselves from the substrate on which they are settled. This behaviour only occurs with extreme male persistence and is the final part of a mate-rejection behavioural sequence. We suggest that this behaviour may be relatively rare, possibly restricted to the tribes Elymiini and Maniolini. There are potential associations with female mating frequency, male mate-locating mechanisms and the physical structure of habitats where attempted mating occurs. We suggest that the behaviour occurs in species where females occasionally mate more than once, where the predominant male mating strategy is a perching sit-and-wait tactic and the species occupy woodland structures. In such circumstances males have relatively few opportunities to mate, male-female encounter rates may be relatively infrequent and the physical structure of the habitat allows females that adopt possum mate-rejection to escape from males by dropping into vegetation. We encourage further observations on this behaviour to allow a thorough analysis of its frequency amongst species in order to allow a phylogenetic analysis

Habitats and resources: The need for a resource-based definition to conserve butterflies

Current definitions of habitat are closely allied to the concept of patch and matrix. This concept is, for instance, central to the prevailing metapopulation models of population dynamics. But, butterfly population dynamics, mobility and spatial structure can only properly be understood in the context of a resource-based definition of habitats. In criticising current definitions of habitat, we illustrate how habitat is best understood in terms of resource distributions. These transcend vegetation-based definitions of habitat and lie at the root of life history strategies, the vulnerability of butterflies to environmental changes and extinction, and govern conservation status. We emphasise the need for a resource-use database and demonstrate the shortcomings of current data for conserving butterflies; patch based definitions of habitats are inappropriate for some species and for others do not provide a universal panacea, inadequately explaining spatial occurrence when scaled over space and time. A resource-based habitat definition challenges the bipolar, patch vs. matrix view of landscape; the alternative is to view landscape as a continuum of overlapping resource distributions. We urge greater attention to the details of butterfly behaviour and resource use as the keys to understanding how landscape is exploited and therefore to successful conservation at the landscape scale

Middleton Welling et al. UK butterfly traits

This spreadsheet details the available trait data for UK butterflies from six representative sources. Each trait source is coded on a separate sheet. Detailed trait descriptions and references for each source are provided within the spreadsheet itself on a supplementary sheet