Kwaku Aduse-Poku

Out-of-Africa again: a phylogenetic hypothesis of the genus Charaxes (Lepidoptera: Nymphalidae) based on five gene regions.

Despite the long popularity of Charaxes among collectors and researchers, their evolutionary history is largely unknown. The current and accepted species groupings and relationships within the genus are based exclusively on adult morphology and life histories. Here, we examine the monophyly and evolutionary affinities of the species-groups within the genus Charaxes and explore how they relate to members of their closest genera (Euxanthe, Polyura and Palla) using 4167bp of sequence data from five (1 mitochondrial and 4 nuclear) gene regions. Within the proposed phylogenetic framework, we estimate ages of divergence within the genus and also reconstruct their historical biogeography. We included representatives of all known species-groups in Africa and Asia, all known species of Euxanthe and Palla and two exemplar species of Polyura. We found the genus Charaxes to be a paraphyletic group with regard to the genera Polyura and Euxanthe, contrary to the earlier assumption of monophyly. We found that 13 out of 16 morphologically defined species-groups with more than one species were strongly supported monophyletic clades. Charaxes nichetes is the sister group to all the other Charaxes. Polyura grouped with the Zoolina and Pleione species-groups as a well-supported clade, and Euxanthe grouped with the Lycurgus species-group. Our results indicated that the common ancestor of Charaxes diverged from the common ancestor of Palla in the mid Eocene (45 million years ago) in (Central) Africa and began diversifying to its extant members 15 million years later. Most of the major diversifications within the genus occurred between the late Oligocene and Miocene when the global climates were putatively undergoing drastic fluctuations. A considerable number of extant species diverged from sister species during the Pliocene. A dispersal-vicariance analysis suggests that many dispersal rather than vicariance events resulted in the distribution of the extant species. The genus Polyura and the Indo-Australian Charaxes are most likely the results of three independent colonizations of Asia by African Charaxes in the Miocene. We synonymize the genera Polyura (syn. nov.) and Euxanthe (syn. nov.) with Charaxes, with the currently circumscribed Charaxes subdivided into five subgenera to reflect its phylogeny.

Systematics and historical biogeography of the old world butterfly subtribe Mycalesina (Lepidoptera: Nymphalidae: Satyrinae)

BackgroundButterflies of the subtribe Mycalesina have radiated successfully in almost all habitat types in Africa, Madagascar, the Indian subcontinent, Indo-China and Australasia. Studies aimed at understanding the reasons behind the evolutionary success of this spectacular Old World butterfly radiation have been hampered by the lack of a stable phylogeny for the group. Here, we have reconstructed a robust phylogenetic framework for the subtribe using 10 genes from 195 exemplar taxa.ResultsWe recovered seven well supported clades within the subtribe corresponding to the five traditional genera (Lohora, Heteropsis, Hallelesis, Bicyclus, Mycalesis), one as recently revised (Mydosama) and one newly revised genus (Culapa). The phylogenetic relationships of these mycalesine genera have been robustly established for the first time. Within the proposed phylogenetic framework, we estimated the crown age of the subtribe to be 40 Million years ago (Mya) and inferred its ultimate origin to be in Asia. Our results reveal both vicariance and dispersal as factors responsible for the current widespread distribution of the group in the Old World tropics. We inferred that the African continent has been colonized at least twice by Asian mycalesines within the last 26 and 23 Mya. In one possible scenario, an Asian ancestor gave rise to Heteropsis on continental Africa, which later dispersed into Madagascar and most likely back colonised Asia. The second colonization of Africa by Asian ancestors resulted in Hallelesis and Bicyclus on continental Africa, the descendants of which did not colonise other regions but rather diversified only in continental Africa. The genera Lohora and Mydosama are derivatives of ancestors from continental Asia.ConclusionOur proposed time-calibrated phylogeny now provides a solid framework within which we can implement mechanistic studies aimed at unravelling the ecological and evolutionary processes that culminated in the spectacular radiation of mycalesines in the Old World tropics.

Expanded molecular phylogeny of the genus Bicyclus (Lepidoptera: Nymphalidae) shows the importance of increased sampling for detecting semi-cryptic species and highlights potentials for future studies

The genus Bicyclus is one of the largest groups of African butterflies, but due to the generally cryptic nature and seasonal variation of adult wing patterns, there has been a lot of systematic confusion. With a large research community working with the model species Bicyclus anynana there has been increasing interest in the evolutionary history of the genus. A previous phylogeny started to unravel interesting patterns, but only included 61% of the then known species. With a range of new species having been described in the last decade there has been a need for an updated phylogeny for the genus. We present the most complete phylogeny of Bicyclus yet, including 93% of the currently 103 recognized species and make a range of taxonomic revisions. We revise the status of four previous subspecies and synonymized taxa that in the light of the new genetic data are raised to species level. We also subsume two subspecies and describe a new species, Bicyclus collinsi sp. nov., based on both genetic and morphological evidence. A further new taxon is identified, but not described at this point due to lack of morphological data. Our phylogeny lays a solid foundation for better understanding the evolution of Bicyclus and highlights key species-groups and complexes with intriguing ecological patterns making them prime candidates for future studies. http://zoobank.org/urn:lsid:zoobank.org:pub:2F775351-097E-4CD7-8F8F-A90B26D52DE8

Molecular phylogeny and generic-level taxonomy of the widespread palaeotropical 'Heteropsis clade' (Nymphalidae : Satyrinae: Mycalesina)

The mycalesine butterfly genus Heteropsis Westwood, 1850 (Satyrinae: Mycalesina) has recently been conceived to be represented in three major palaeotropical regions (Madagascar, Africa and Asia), but there has been no formal taxonomic treatment covering this entire group. Studies aimed at understanding the evolutionary success of Mycalesina in the Old World tropics have been hampered by the lack of both a robust phylogeny and a stable nomenclature for this satyrine subtribe. Here, we present a well‐supported molecular phylogeny based on 10 genes and 133 exemplar taxa, representing almost all known species groups of Heteropsis (s.l.), and including all but four known species in Madagascar. We also combine sequences of the exemplars with a morphological matrix of 428 characters. The widespread ‘Heteropsis clade’ is confirmed as monophyletic, but lineages in different geographic regions also form endemic and well‐supported clades with deep divergences among them. Here we establish this group as comprising three genera, Heteropsis (Malagasy region only), Telinga Moore, 1880 (Asia), and Brakefieldia gen.n. (Africa). We recover the genera Telinga and Brakefieldia as sisters with high support. Each genus is taxonomically characterized and a revised synonymic checklist is appended with new combinations and some changes in rank. With a well‐resolved topology and updates to the taxonomy of the group, researchers are now in a position to explore the drivers of the spectacular radiation of the group, notably in Madagascar, where the highest phenotypic and species diversity occurs.

Conserved patterns of integrated developmental plasticity in a group of polyphenic tropical butterflies

BackgroundDevelopmental plasticity is thought to have profound macro-evolutionary effects, for example, by increasing the probability of establishment in new environments and subsequent divergence into independently evolving lineages. In contrast to plasticity optimized for individual traits, phenotypic integration, which enables a concerted response of plastic traits to environmental variability, may affect the rate of local adaptation by constraining independent responses of traits to selection. Using a comparative framework, this study explores the evolution of reaction norms for a variety of life history and morphological traits across five related species of mycalesine butterflies from the Old World tropics.ResultsOur data indicate that an integrated response of a suite of key traits is shared amongst these species. Interestingly, the traits that make up the functional suite are all known to be regulated by ecdysteroid signalling in Bicyclus anynana, one of the species included in this study, suggesting the same underlying hormonal regulator may be conserved within this group of polyphenic butterflies. We also detect developmental thresholds for the expression of alternative morphs.ConclusionsThe phenotypic plasticity of a broad suite of morphological and life history traits is integrated and shared among species from three geographically independent lineages of mycalesine butterflies, despite considerable periods of independent evolution and exposure to disparate environments. At the same time, we have detected examples of evolutionary change where independent traits show different patterns of reaction norms. We argue that the expression of more robust phenotypes may occur by shifting developmental thresholds beyond the boundaries of the typical environmental variation.

Evolution of Hypolimnas butterflies (Nymphalidae): Out-of-Africa origin and Wolbachia-mediated introgression

Hypolimnas butterflies (Nymphalidae), commonly known as eggflies, are a popular model system for studying a wide range of ecological questions including mimicry, polymorphism, wing pattern evolution, and Wolbachia-host interactions. The lack of a time-calibrated phylogeny for this group has precluded understanding its evolutionary history. We reconstruct a species-level phylogeny using a nine gene dataset and estimate species divergence times. Based on the resulting tree, we investigate the taxons historical biogeography, examine the evolution of host plant preferences, and test the hypothesis that the endosymbiotic bacterium Wolbachia mediates gene transfer between species. Our analyses indicate that the species are grouped within three strongly supported, deeply divergent clades. However, relationships among these three clades are uncertain. In addition, many Hypolimnas species are not monophyletic or monophyletic with weak support, suggesting widespread incomplete lineage sorting and/or introgression. Biogeographic analysis strongly indicates that the genus diverged from its ancestor in Africa and subsequently dispersed to Asia; the strength of this result is not affected by topological uncertainties. While the larvae of African species feed almost exclusively on Urticaceae, larvae of species found further east often feed on several additional families. Interestingly, we found an identical mitochondrial haplotype in two Hypolimnas species, H. bolina and H. alimena, and a strong association between this mitotype and the Wolbachia strain wBol1a. Future investigations should explore the plausibility of Wolbachia-mediated introgression between species.

Revision of the Bicyclus sciathis species group (Lepidoptera: Nymphalidae) with descriptions of four new species and corrected distributional records.

In this paper we present a thorough revision of the sciathis species group of the butterfly genus Bicyclus (Kirby). Type materials are discussed and in several cases lectotypes are assigned to specimens from original type series. Four new, and morphologically distinct, species are described (B. elishiae Brattström sp.n., B. heathi Brattström sp.n., B. sigiussidorum Brattström sp.n. and B. subtilisurae Brattström sp.n.), along with a comprehensive molecular phylogeny that includes exemplar taxa of all currently recognized species. We also investigate the types of all previously synonymized taxa and in the process invalidate the name B. ewondo Libert. This was done after finding the previously missing holotype of B. makomensis (Strand), which clearly belongs to the same species and thereby gives the older name priority. The phylogeny showed that some distinctly different species were surprisingly closely related, suggesting a high rate of morphological evolution in parts of the sciathis group. The distributional records for the group are updated after investigating over 1700 specimens kept in a range of museum collections. Many species previously thought to be broadly sympatric were found to have much more restricted ranges, with the previous overestimations probably based on misidentified specimens. The higher level of allopatry now established will make identification of many morphologically similar species easier. The fact that species often have smaller ranges than previously known, meaning that the level of endemism for African butterflies is likely to be higher than current estimates, has important implications for conservation management. An identification key for males of all 13 currently recognized species in the species group is included.

Revision of the Bicyclus ignobilis species-group (Lepidoptera: Nymphalidae: Satyrinae) with descriptions of two new species

The ignobilis-group of the genus Bicyclus Kirby 1871 is revised. The species-group contains six species with a distinct wing pattern, but limited intraspecific variation, distributed across tropical African rainforest. We investigate a set of more than 1000 specimens from a range of museum collections, including some type material, and thoroughly update the biogeographical knowledge for the group. We also describe two new species as members of the group. The included species are: Bicyclus ignobilis (Butler 1870) stat. rev., B. rileyi Condamin 1961, B. maesseni Condamin 1971, B. brakefieldi Brattström 2012, B. ottossoni sp. nov. and B. vandeweghei sp. nov. Due to observing a gradual morphological cline within B. ignobilis without any sharp transitions we suppress the previously identified subspecies B. ignobilis eurini Condamin & Fox 1963 syn. nov. and B. ignobilis acutus Condamin 1965 syn. nov.

Relative contribution of neutral and deterministic processes in shaping fruit-feeding butterfly assemblages in Afrotropical forests

Abstract The unified neutral theory of biodiversity and biogeography has gained the status of a quantitative null model for explaining patterns in ecological (meta)communities. The theory assumes that individuals of trophically similar species are functionally equivalent. We empirically evaluate the relative contribution of neutral and deterministic processes in shaping fruit‐feeding butterfly assemblages in three tropical forests in Africa, using both direct (confronting the neutral model with species abundance data) and indirect approaches (testing the predictions of neutral theory using data other than species abundance distributions). Abundance data were obtained by sampling butterflies using banana baited traps set at the forest canopy and understorey strata. Our results indicate a clear consistency in the kind of species or species groups observed at either the canopy or understorey in the three studied communities. Furthermore, we found significant correlation between some flight‐related morphological traits and species abundance at the forest canopy, but not at the understorey. Neutral theorys contribution to explaining our data lies largely in identifying dispersal limitation as a key process regulating fruit‐feeding butterfly community structure. Our study illustrates that using species abundance data alone in evaluating neutral theory can be informative, but is insufficient. Species‐level information such as habitat preference, host plants, geographical distribution, and phylogeny is essential in elucidating the processes that regulate biodiversity community structures and patterns.

Molecular phylogeny and generic-level taxonomy of the widespread palaeotropical ‘Heteropsisclade’ (Nymphalidae: Satyrinae: Mycalesina): Molecular phylogeny ofHeteropsis

The mycalesine butterfly genus Heteropsis Westwood, 1850 (Satyrinae: Mycalesina) has recently been conceived to be represented in three major palaeotropical regions (Madagascar, Africa and Asia), but there has been no formal taxonomic treatment covering this entire group. Studies aimed at understanding the evolutionary success of Mycalesina in the Old World tropics have been hampered by the lack of both a robust phylogeny and a stable nomenclature for this satyrine subtribe. Here, we present a well‐supported molecular phylogeny based on 10 genes and 133 exemplar taxa, representing almost all known species groups of Heteropsis (s.l.), and including all but four known species in Madagascar. We also combine sequences of the exemplars with a morphological matrix of 428 characters. The widespread ‘Heteropsis clade’ is confirmed as monophyletic, but lineages in different geographic regions also form endemic and well‐supported clades with deep divergences among them. Here we establish this group as comprising three genera, Heteropsis (Malagasy region only), Telinga Moore, 1880 (Asia), and Brakefieldia gen.n. (Africa). We recover the genera Telinga and Brakefieldia as sisters with high support. Each genus is taxonomically characterized and a revised synonymic checklist is appended with new combinations and some changes in rank. With a well‐resolved topology and updates to the taxonomy of the group, researchers are now in a position to explore the drivers of the spectacular radiation of the group, notably in Madagascar, where the highest phenotypic and species diversity occurs.