Heliconiini

Abstract: Mullerian mimicry among Neotropical Heliconiini butterflies is an excellent example of natural selection, associated with the diversification of a large continental-scale radiation. Some of the processes driving the evolution of mimicry rings are likely to generate incongruent phylogenetic signals across the assemblage, and thus pose a challenge for systematics. We use a data set of 22 mitochondrial and nuclear markers from 92% of species in the tribe, obtained by Sanger sequencing and de novo assembly of short read data, to re-examine the phylogeny of Heliconiini with both supermatrix and multispecies coalescent approaches, characterize the patterns of conflicting signal, and compare the performance of various methodological approaches to reflect the heterogeneity across the data. Despite the large extent of reticulate signal and strong conflict between markers, nearly identical topologies are consistently recovered by most of the analyses, although the supermatrix approach failed to reflect the underlying variation in the history of individual loci. However, the supermatrix represents a useful approximation where multiple rare species represented by short sequences can be incorporated easily. The first comprehensive, time-calibrated phylogeny of this group is used to test the hypotheses of a diversification rate increase driven by the dramatic environmental changes in the Neotropics over the past 23 myr, or changes caused by diversity-dependent effects on the rate of diversification. We find that the rate of diversification has increased on the branch leading to the presently most species-rich genus Heliconius, but the change occurred gradually and cannot be unequivocally attributed to a specific environmental driver. Our study provides comprehensive comparison of philosophically distinct species tree reconstruction methods and provides insights into the diversification of an important insect radiation in the most biodiverse region of the planet. (Amazonia; diversification rate; incongruence; Lepidoptera; Miocene; mimicry; multispecies coalescent.)

Abstract: Analysis of the known and recently discovered differentiation patterns of 58 forest butterfly species (of the total 66) in the tribe Heliconiini, including over 300 races and forms, has led to the drawing of a map of core areas for evolution in the group. The majority of these are not isolated by any obvious modern physiogeographic barriers to dispersal of these butterflies, and probably correspond to forest refugia during the two or three most recent Quaternary dry periods. The map is in good accord with the results of similar studies in other groups of animals (forest vertebrates and invertebrates) and in forest trees, but indicates a larger number of significant operative refugia (38) than other analyses. Bases for the understanding of differentiation patterns in polytypic continental species are developed, in accord with the refuge theory and using intensive and extensive data on local monomorphic populations and secondary contact zones between differentiated forms. The known forms discussed include: Dione juno miraculosa Hering, Eueides libitina Staudinger, Heliconius xanthocles explicata Stichel, H. eleuchia (Hewitson) and H. leucadia Bates together with a supplementary revision of the tribe giving information published since 1972. The following new forms are described: Eueides emsleyi sp. n. and nine new subspecies of Heliconius: H. aoede philipi, H. wallacei araguaia, H. pardalinus orteguaza, H.p. butleri, H. hecale australis, H.h. barcanti, H. clysonymus tabaconas, H. congener aquilionaris, H. sapho candidus. Geographical details of the refugia are given in Appendix I, and in Appendix II the heliconians are assigned to the postulated refugia.

Abstract: Two new minute egg parasitoid wasp species belonging to the genus Trichogramma (Hymenoptera: Trichogrammatidae), T. chagres sp. nov. and T. soberania sp. nov., were found in a tropical lowland rainforest in Panama, Central America. In this paper, we describe, illustrate and discuss the biology and morphological and molecular characterization of the two new Trichogramma wasp species. Both species were collected from eggs of passion vine butterflies, Agraulis vanillae vanillae (Lepidoptera: Nymphalidae: Heliconiinae) and unidentified Heliconiini species, laid on different Passiflora species (Malpighiales: Passifloraceae). A female T. soberania sp. nov. wasp was observed on the wings of a female Heliconius hecale melicerta butterfly caught in the wild. This suggests that this species may occasionally be phoretic on adult female butterflies to find suitable host eggs. Our study adds two more species identifications to the scarce record of Trichogramma wasps from the widespread Heliconiini butterflies in Central America.

Abstract: Proboscis length, the length of the tip, the number and length of the various sensilla throughout the proboscis, and the size and shape of the labial palpi were compared in 25 species of pollen-feeding and non-pollen-feeding Heliconiinae (Lepidoptera, Nymphalidae). The mouthparts of pollen-feeding species (all belonging to the genera Heliconius and Laparus ) do not have structures exclusive to them. However, in comparison with non-pollen-feeding Heliconiiti, the pollen-feeding species have a significantly longer proboscis without elongation of the tip-region ; the bristle-shaped sensilla trichodea were found to be significantly more numerous and longer on the proximal and mid-region of the proboscis, while the sensilla of the tip-region are significantly shorter. In addition to these proboscis features, the labial palpi were shorter in the pollen-feeding species, which is likewise possibly associated with pollen-feeding behavior. The biological role of these features is discussed and the evolution of this unique feeding behavior among Lepidoptera is considered in the context of the phylogenetic relationships among genera of Heliconiini.