Shen-Horn Yen

The evolution of alternative parasitic life histories in large blue butterflies

Large blue (Maculinea) butterflies are highly endangered throughout the Palaearctic region, and have been the focus of intense conservation research. In addition, their extraordinary parasitic lifestyles make them ideal for studies of life history evolution. Early instars consume flower buds of specific host plants, but later instars live in ant nests where they either devour the brood (predators), or are fed mouth-to-mouth by the adult ants (cuckoos). Here we present the phylogeny for the group, which shows that it is a monophyletic clade nested within Phengaris, a rare Oriental genus whose species have similar life histories. Cuckoo species are likely to have evolved from predatory ancestors. As early as five million years ago, two Maculinea clades diverged, leading to the different parasitic strategies seen in the genus today. Contrary to current belief, the two recognized cuckoo species show little genetic divergence and are probably a single ecologically differentiated species. On the other hand, some of the predatory morphospecies exhibit considerable genetic divergence and may contain cryptic species. These findings have important implications for conservation and reintroduction efforts.

A molecular phylogeny for the pyraloid moths (Lepidoptera: Pyraloidea) and its implications for higher‐level classification

Pyraloidea, one of the largest superfamilies of Lepidoptera, comprise more than 15 684 described species worldwide, including important pests, biological control agents and experimental models. Understanding of pyraloid phylogeny, the basis for a predictive classification, is currently provisional. We present the most detailed molecular estimate of relationships to date across the subfamilies of Pyraloidea, and assess its concordance with previous morphology‐based hypotheses. We sequenced up to five nuclear genes, totalling 6633 bp, in each of 42 pyraloids spanning both families and 18 of the 21 subfamilies, plus up to 14 additional genes, for a total of 14 826 bp, in 21 of those pyraloids plus all 24 outgroups. Maximum likelihood analyses yield trees that, within Pyraloidea, differ little among datasets and character treatments and are strongly supported at all levels of divergence (83% of nodes with bootstrap ≥80%). Subfamily relationships within Pyralidae, all very strongly supported (>90% bootstrap), differ only slightly from a previous morphological analysis, and can be summarized as Galleriinae + Chrysauginae (Phycitinae (Pyralinae + Epipaschiinae)). The main remaining uncertainty involves Chrysauginae, of which the poorly studied Australian genera may constitute the basal elements of Galleriinae + Chrysauginae or even of Pyralidae. In Crambidae the molecular phylogeny is also strongly supported, but conflicts with most previous hypotheses. Among the newly proposed groupings are a ‘wet‐habitat clade’ comprising Acentropinae + Schoenobiinae + Midilinae, and a provisional ‘mustard oil clade’ containing Glaphyriinae, Evergestinae and Noordinae, in which the majority of described larvae feed on Brassicales. Within this clade a previous synonymy of Dichogaminae with the Glaphyriinae is supported. Evergestinae syn. n. and Noordinae syn. n. are here newly synonymized with Glaphyriinae, which appear to be paraphyletic with respect to both. Pyraustinae and Spilomelinae as sampled here are each monophyletic but form a sister group pair. Wurthiinae n. syn., comprising the single genus Niphopyralis Hampson, which lives in ant nests, are closely related to, apparently subordinate within, and here newly synonymized with, Spilomelinae syn. n.

A molecular phylogeny for the oldest (nonditrysian) lineages of extant Lepidoptera, with implications for classification, comparative morphology and life-history evolution

Within the insect order Lepidoptera (moths and butterflies), the so‐called nonditrysian superfamilies are mostly species‐poor but highly divergent, offering numerous synapomorphies and strong morphological evidence for deep divergences. Uncertainties remain, however, and tests of the widely accepted morphological framework using other evidence are desirable. The goal of this paper is to test previous hypotheses of nonditrysian phylogeny against a data set consisting of 61 nonditrysian species plus 20 representative Ditrysia and eight outgroups (Trichoptera), nearly all sequenced for 19 nuclear genes (up to 14 700 bp total). We compare our results in detail with those from previous studies of nonditrysians, and review the morphological evidence for and against each grouping The major conclusions are as follows. (i) There is very strong support for Lepidoptera minus Micropterigidae and Agathiphagidae, here termed Angiospermivora, but no definitive resolution of the position of Agathiphagidae, although support is strongest for alliance with Micropterigidae, consistent with another recent molecular study. (ii) There is very strong support for Glossata, which excludes Heterobathmiidae, but weak support for relationships among major homoneurous clades. Eriocraniidae diverge first, corroborating the morphological clade Coelolepida, but the morphological clades Myoglossata and Neolepidoptera are never monophyletic in the molecular trees; both are contradicted by strong support for Lophocoronoidea + Hepialoidea, the latter here including Mnesarchaeoidea syn.n. (iii) The surprising grouping of Acanthopteroctetidae + Neopseustidae, although weakly supported here, is consistent with another recent molecular study. (iv) Heteroneura is very strongly supported, as is a basal split of this clade into Nepticuloidea + Eulepidoptera. Relationships within Nepticuloidea accord closely with recent studies based on fewer genes but many more taxa. (v) Eulepidoptera are split into a very strongly supported clade consisting of Tischeriidae + Palaephatidae + Ditrysia, here termed Euheteroneura, and a moderately supported clade uniting Andesianidae with Adeloidea. (vi) Relationships within Adeloidea are strongly resolved and Tridentaformidae fam.n. is described for the heretofore problematic genus Tridentaforma Davis, which is strongly supported in an isolated position within the clade. (vii) Within Euheteroneura, the molecular evidence is conflicting with respect to the sister group to Ditrysia, but strongly supports paraphyly of Palaephatidae. We decline to change the classification, however, because of strong morphological evidence supporting palaephatid monophyly. (viii) We review the life histories and larval feeding habits of all nonditrysian families and assess the implications of our results for hypotheses about early lepidopteran phytophagy. The first host record for Neopseustidae, which needs confirmation, suggests that larvae of this family may be parasitoids.

The evolutionary origins of ritualized acoustic signals in caterpillars

Animal communication signals can be highly elaborate, and researchers have long sought explanations for their evolutionary origins. For example, how did signals such as the tail-fan display of a peacock, a firefly flash or a wolf howl evolve? Animal communication theory holds that many signals evolved from non-signalling behaviours through the process of ritualization. Empirical evidence for ritualization is limited, as it is necessary to examine living relatives with varying degrees of signal evolution within a phylogenetic framework. We examine the origins of vibratory territorial signals in caterpillars using comparative and molecular phylogenetic methods. We show that a highly ritualized vibratory signal—anal scraping—originated from a locomotory behaviour—walking. Furthermore, comparative behavioural analysis supports the hypothesis that ritualized vibratory signals derive from physical fighting behaviours. Thus, contestants signal their opponents to avoid the cost of fighting. Our study provides experimental evidence for the origins of a complex communication signal, through the process of ritualization.

The Complete Mitochondrial Genome of the Near-Threatened Swallowtail, Agehana maraho (Lepidoptera: Papilionidae): Evaluating Sequence Variability and Suitable Markers for Conservation Genetic Studies

ABSTRACT: Agehana maraho (Shiraki and Sonan, 1934) is a near-threatened swallowtail butterfly endemic to Taiwan. As a first step in evaluating the most variable molecular markers for further population genetic and conservation studies of this and other insects, the entire mitochondrial genome (mitogenome) was sequenced (16,094bp). The most distinctive structure of the Agehana mitogenome is the control region (CR; 1,270bp). This is the longest CR found so far in any lepidopteran, and it also represents the first known case of two units of macro repeats within a tandem region. In a comparison with another 12 lepidopteran mitogenomes, the genes atp8, atp6, and nad6 were found to be more variable than cox1, suggesting an undue focus on cox1 (COI) in identification and phylogeographic studies. A combination of these first three genes plus the CR, comprising micro as well as macro repeats, may thus provide more suitable markers for conservation genetic studies, not only of this near-threatened species, but also of many other insects.

Austromusotima, a New Musotimine Genus (Lepidoptera: Crambidae) Feeding on Old World Climbing Fern, Lygodium microphyllum (Schizaeaceae)

Abstract During the search for natural enemies of Old World climbing fern, Lygodium microphyllum (Cav.) R. Br. (Schizaeaceae), in Australia and southeastern Asia, Cataclysta camptozonale (Hampson) was found to be highly specific to this aggressive vine and was tested as a biological control agent. This musotimine moth species has long been misplaced in a European acentropine genus; therefore, we propose Austromusotima, new genus, to accommodate Austromusotima camptozonale, new combination, as the type species. The syntype series of Oligostima camptozonale is a mixture of specimens of the former species (sensu stricto) and its sibling, Austromusotima metastictalis (Hampson), new combination. A lectotype is designated for A. camptozonale to stabilize the use of the name. The immature stages of A. camptozonale are described and compared with other known musotimine immatures. The immatures of Eugauria albidenta (Hampson) and Cataclysta angulata Moore are illustrated for the first time. Austromusotima is most closely related to Cataclysta seriopunctalis Hampson based on adult morphological characters, but immatures of C. seriopunctalis are unknown, and therefore, this species is not included in Austromusotima. The important, yet incongruent, results between immature and adult characters are discussed in the context of phylogenetic relationships of Austromusotima to other taxa.

Phylogeny and Historical Biogeography of Asian Pterourus Butterflies (Lepidoptera: Papilionidae): A Case of Intercontinental Dispersal from North America to East Asia

The phylogenetic status of the well-known Asian butterflies often known as Agehana (a species group, often treated as a genus or a subgenus, within Papilio sensu lato) has long remained unresolved. Only two species are included, and one of them especially, Papilio maraho, is not only rare but near-threatened, being monophagous on its vulnerable hostplant, Sassafras randaiense (Lauraceae). Although the natural history and population conservation of “Agehana” has received much attention, the biogeographic origin of this group still remains enigmatic. To clarify these two questions, a total of 86 species representatives within Papilionidae were sampled, and four genes (concatenated length 3842 bp) were used to reconstruct their phylogenetic relationships and historical scenarios. Surprisingly, “Agehana” fell within the American Papilio subgenus Pterourus and not as previously suggested, phylogenetically close to the Asian Papilio subgenus Chilasa. We therefore formally synonymize Agehana with Pterourus. Dating and biogeographic analysis allow us to infer an intercontinental dispersal of an American ancestor of Asian Pterourus in the early Miocene, which was coincident with historical paleo-land bridge connections, resulting in the present “East Asia-America” disjunction distribution. We emphasize that species exchange between East Asia and America seems to be a quite frequent occurrence in butterflies during the Oligocene to Miocene climatic optima.

Phylogeny, systematics and evolution of mimetic wing patterns of Eterusia moths (Lepidoptera, Zygaenidae, Chalcosiinae)

Abstract.  The aim of the present study was to investigate the phylogeny, systematics and evolution of the mimetic wing patterns of Eterusia, a day‐flying moth genus that exhibits great morphological diversity, as well as the highest insular differentiation in eastern Asia and which has the most chaotic taxonomic history in the family Zygaenidae. We examined the wing patterns of the insects involved using visible and ultraviolet light (both reflectance and fluorescence). The phylogeny of thirty‐four taxa, including all the recognized species of Eterusia plus two species of Soritia as outgroups, was reconstructed based on eighty adult morphological characters, including forty‐one derived from colour patterns. Phylogenetic relationships based on the whole dataset revealed that (1) the most current concept of Eterusia is monophyletic, and (2) different types of mimetic pattern show different levels of phylogenetic conservation. To investigate the evolution of their colour patterns we inactivated all the relevant characters and reconstructed another phylogeny, which was found to differ significantly from the one based on the whole character set in the position of the E. risa species group. We used these phylogenetic hypotheses to test evolutionary predictions based on conventional Müllerian mimicry and quasi‐Batesian mimicry dynamics. The results of permutation–tail–probability tests showed that the coloration characters are phylogenetically conserved, thus justifying a Müllerian interpretation. However, when comparing the observed topologies with hypothetical trees constrained to fit perfect Müllerian or quasi‐Batesian scenarios using the Kishino–Hasegawa test, the observed phylogenies were more consistent with the phylogenetic prediction of quasi‐Batesian mimicry. Therefore, we consider that applying these two phylogenetic methods to justify mimicry models may not always be practical. Finally, the taxonomy of Eterusia is revised. In total, two new species (E. austrochinensis, E. guanxiana), one new subspecies (E. risa palawanica) and four new synonyms (E. lativitta and E. fasciata of E. sublutea, E. coelestina of E. subcyanea, E. angustipennis gaedei of E. angustipennis angustipennis) are established.

First host records for the rogadine genus Conspinaria (Hymenoptera:Braconidae)and notes on Rogadinae as parasitoids of Zygaenidae (Lepidoptera)

The parasitic wasp genus Conspinaria is recorded as parasitizing two species of chalcosiine zygaenid moths, Chalcosia thaivana owadai Wang and Erasmia pulchella hobsoni Butler in Taiwan. Parasitism of Zygaenidae and of Limacodidae by rogadine braconids is discussed in the light of possible phylogenetic relationships.

EXTERNAL MORPHOLOGY OF THE LAST INSTAR LARVA OF PHAUDA MIMICA STRAND, 1915(LEPIDOPTERA : ZYGAENOIDEA)

The external morphology of last instar larvae of Phauda mimica Strand, 1915, from Taiwan is described. The slug-like larvae are glossy brownish white in coloration. Dorsally they are covered by a tergal cap consisting of a dense mesh of irregularly interwoven silk fibres with additional cellular elements and hardened incrustations. This peculiar structure is not known from other Lepidoptera. According to the present morphological findings, the genus (along with allied genera) does probably not belong to the Zygaenidae, as hitherto suggested, but rather represents the sister group of the limacodid-group families currently comprising the (Megalopygidae/Somabrachyidae + (Aididae + (Dalceridae + Limacodidae))).