Jadranka Rota

The butterfly plant arms-race escalated by gene and genome duplications

Significance This research uncovers the mechanisms of an ancient arms race between butterflies and plants, seen today in countless gardens as caterpillars of cabbage butterflies that devour cabbage crop varieties. Nearly 90 million years ago, the ancestors of Brassica (mustards, cabbage) and related plants developed a chemical defense called glucosinolates. While very toxic to most insects, humans experience glucosinolates as the sharp taste in wasabi, horseradish and mustard. Here we report that this triggered a chemical arms race that escalated in complexity over time. By investigating the evolutionary histories of these plants and insects, we found that major increases in chemical defense complexity were followed by butterflies evolving countertactics to allow them to continue to attack and feed on the plants. Coevolutionary interactions are thought to have spurred the evolution of key innovations and driven the diversification of much of life on Earth. However, the genetic and evolutionary basis of the innovations that facilitate such interactions remains poorly understood. We examined the coevolutionary interactions between plants (Brassicales) and butterflies (Pieridae), and uncovered evidence for an escalating evolutionary arms-race. Although gradual changes in trait complexity appear to have been facilitated by allelic turnover, key innovations are associated with gene and genome duplications. Furthermore, we show that the origins of both chemical defenses and of molecular counter adaptations were associated with shifts in diversification rates during the arms-race. These findings provide an important connection between the origins of biodiversity, coevolution, and the role of gene and genome duplications as a substrate for novel traits.

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.

Integrative Taxonomy Recognizes Evolutionary Units Despite Widespread Mitonuclear Discordance: Evidence from a Rotifer Cryptic Species Complex

Mitonuclear discordance across taxa is increasingly recognized as posing a major challenge to species delimitation based on DNA sequence data. Integrative taxonomy has been proposed as a promising framework to help address this problem. However, we still lack compelling empirical evidence scrutinizing the efficacy of integrative taxonomy in relation to, for instance, complex introgression scenarios involving many species. Here, we report remarkably widespread mitonuclear discordance between about 15 mitochondrial and 4 nuclear Brachionus calyciflorus groups identified using different species delimitation approaches. Using coalescent-, Bayesian admixture-, and allele sharing-based methods with DNA sequence or microsatellite data, we provide strong evidence in support of hybridization as a driver of the observed discordance. We then describe our combined molecular, morphological, and ecological approaches to resolving phylogenetic conflict and inferring species boundaries. Species delimitations based on the ITS1 and 28S nuclear DNA markers proved a more reliable predictor of morphological variation than delimitations using the mitochondrial COI gene. A short-term competition experiment further revealed systematic differences in the competitive ability between two of the nuclear-delimited species under six different growth conditions, independent of COI delimitations; hybrids were also observed. In light of these findings, we discuss the failure of the COI marker to estimate morphological stasis and morphological plasticity in the B. calyciflorus complex. By using B. calyciflorus as a representative case, we demonstrate the potential of integrative taxonomy to guide species delimitation in the presence of mitonuclear phylogenetic conflicts.

Predator mimicry: metalmark moths mimic their jumping spider predators.

Cases of mimicry provide many of the natures most convincing examples of natural selection. Here we report evidence for a case of predator mimicry in which metalmark moths in the genus Brenthia mimic jumping spiders, one of their predators. In controlled trials, Brenthia had higher survival rates than other similarly sized moths in the presence of jumping spiders and jumping spiders responded to Brenthia with territorial displays, indicating that Brenthia were sometimes mistaken for jumping spiders, and not recognized as prey. Our experimental results and a review of wing patterns of other insects indicate that jumping spider mimicry is more widespread than heretofore appreciated, and that jumping spiders are probably an important selective pressure shaping the evolution of diurnal insects that perch on vegetation.

Exploration of data partitioning in an eight-gene data set : Phylogeny of metalmark moths (Lepidoptera, Choreutidae)

Rota, J. & Wahlberg, N. (2012). Exploration of data partitioning in an eight‐gene data set: phylogeny of metalmark moths (Lepidoptera, Choreutidae). —Zoologica Scripta, 41, 536–546.

Revised systematics and higher classification of pierid butterflies (Lepidoptera: Pieridae) based on molecular data

The butterfly family Pieridae comprises approximately 1000 described species placed in 85 genera, but the higher classification has not yet been settled. We used molecular data from eight gene regions (one mitochondrial and seven nuclear protein‐coding genes) comprising a total of ~6700 bp from 96 taxa to infer a well‐supported phylogenetic hypothesis for the family. Based on this hypothesis, we revise the higher classification for all pierid genera. We resurrect the tribe Teracolini stat. rev. in the subfamily Pierinae to include the genera Teracolus, Pinacopteryx, Gideona, Ixias, Eronia, Colotis and most likely Calopieris. We transfer Hebomoia to the tribe Anthocharidini and assign the previously unplaced genera Belenois and Dixeia to the subtribe Aporiina. Three lineages near the base of Pierinae (Leptosia, Elodina and Nepheronia + Pareronia) remain unplaced. For each of these, we describe and delineate new tribes: Elodinini Braby tribus nova, Leptosiaini Braby tribus nova and Nepheroniini Braby tribus nova. The proposed higher classification is based on well‐supported monophyletic groups and is likely to remain stable even with the addition of more data.

A new extant family of primitive moths from Kangaroo Island, Australia, and its significance for understanding early Lepidoptera evolution

We report the first discovery since the 1970s of a new extant family (Aenigmatineidae fam.n.) of homoneurous moths, based on the small Aenigmatinea glatzella sp.n. from Kangaroo Island off southern Australia. It exhibits a combination of extraordinary anatomical characters, and, unlike most homoneurous moths, its larva is a conifer‐feeder (stem mining in Callitris, Cupressaceae). While the adults mouthparts are strongly regressed, evidence from other morphological characters and from a Bayesian analysis of 25 genetic loci convincingly places the taxon among Glossata (‘tongue moths’). An unexpected tongue moth clade including Acanthopteroctetidae and Neopseustidae, suggested with low support in recent molecular analyses, remarkably becomes strongly supported when Aenigmatinea is included in the molecular analysis; the new taxon becomes subordinated in that clade (as sister group to Neopseustidae) and the clade itself appears as the sister group of all Heteroneura, representing the vast majority of all Lepidoptera. Including Aenigmatinea into the analysis thereby strengthens the surprising indication of non‐monophyly of Myoglossata, and the new phylogeny requires an additional number of ad hoc assumptions of convergence/character reversals in early Lepidoptera evolution.

Data partitioning in Bayesian analysis : Molecular phylogenetics of metalmark moths (Lepidoptera: Choreutidae)

In this study a multilocus phylogenetic analysis of metalmark moths (Lepidoptera: Choreutidae) focused on resolving the higher‐level phylogeny of this group is presented. Through the analysis of this dataset, I explore different data‐partitioning strategies in Bayesian phylogenetic inference, and find that a partitioning strategy can have a large influence on the results of phylogenetic analysis. Depending on how the data are partitioned, there can be significant differences in branch support. I also test for the existence of the Bayesian star tree paradox, and its importance in this dataset, and find that it appears to inflate support for the clade including Rhobonda gaurisana, Hemerophila houttuinialis, H. diva and H. felis, but plays no role in other cases where the differences between maximum‐likelihood bootstraps and Bayesian posterior probabilities are large. The results of all the phylogenetic analyses strongly suggest that including Millieriinae in Choreutidae renders the family polyphyletic. The monophyly of the other two subfamilies, Brenthiinae and Choreutinae, as well as their sister‐group relationship, is strongly supported. Similarly, the monophyly of all the genera examined except Hemerophila is also well supported. To bring the classification of Choreutidae in line with our current understanding of the phylogenetic relationships in the family, I propose to exclude Millieriinae from Choreutidae, elevate it to Millieriidae Heppner, and place it as incertae sedis within Ditrysia.

Larva of Abablemma (Noctuidae) with notes on algivory and lichenivory in Macrolepidoptera

Abstract The larva of Abablemma brimleyana (Dyar) (Noctuidae) is described and illustrated based on ex ova larvae reared on green algae (Protococcus viridis). A last instar Abablemma duomaculata (Barnes & Benjamin), collected from and reared on Physcia, a foliose lichen, and its lichen-encrusted cocoon, as well as a last instar Nigetia formosalis Walker ex ova reared on Protococcus, also are figured. Beating samples of lichens in the thorn scrub that yielded the A. duomaculata larva also produced multiple individuals of Cisthene subrufa (Barnes & McDunnough) (Noctuidae: Arctiinae: Lithosiini) and Glenoides lenticuligera A. Blanchard (Geometridae: Ennominae), both of which were reared to maturity on lichens. Abablemma, presently classified in the Araeopteroninae, is shown to be closely related to Nigetia formosalis, a Scolecocampinae according to Fibiger and Lafontaine. Shared larval and life history characters among the Araeopteroninae Fibiger 2005, Eublemminae Forbes 1954, Hypenodinae Forbes 1954, and Scolecocampinae Grote 1883 are discussed: the similarities between Abablemma, Hypenodes, and other genera suggest that the subfamilial classification for these basal quadrifids has been oversplit. The article concludes with a brief review of lichen and algal feeding in Macrolepidoptera and provides a listing of 38 macrolepidopterans that T.L.M. and D.L.W. have reared from green algae and foliose lichens; included are members of Geometridae: Ennominae (n = 1); and five subfamilies of Noctuidae: Arctiinae (n = 13) (12 of which are lithosiines), Eublemminae (n = 6) (all Metalectra Hübner), Herminiinae (n = 2) (both Zanclognatha Lederer), Scolecocampinae (n = 1), Araeopteroninae (n = 3), Hypenodinae (n = 1), Nolinae (n = 1), and Xyleninae: Elaphriini (n = 10) (all but two of which are Elaphria Hübner).

Phylogenetic relationships of Acronictinae with discussion of the abdominal courtship brush in Noctuidae (Lepidoptera)

We present results of an eight‐gene molecular study of the subfamily Acronictinae and related Noctuidae. Amphipyrinae are recovered as sister to Acronictinae, but with weak support – not surprisingly, the content of the two subfamilies has often been mixed in classifications. Balsinae, previously placed near Acronictinae or within Noctuinae, is recovered within an unresolved polytomy of Cuculliinae, Eustrotiinae, Raphiinae and Dilobinae. Gerbathodes Warren, Moma Hübner and Nacna Fletcher are excluded from Acronictinae. Three genera recently transferred into the subfamily – Cerma Hübner, Chloronycta Schmidt & Anweiler and Comachara Franclemont – are confirmed as acronictines. Lophonycta Sugi (the type genus of Lophonyctinae) is returned to the Acronictinae. Sinocharis Püngeler, formerly considered to be Acontiinae or as the basis of its own subfamily Sinocharinae, is nested within early diverging Acronictinae genera. Both subfamilies are formally synonymized: i.e. Lophonyctinae syn.n. and Sinocharinae syn.n. Nine acronictine genus‐level taxa were found to nest within the nominate genus Acronicta Ochsenheimer: Eogena Guenée, Hyboma Hübner, Hylonycta Sugi, Jocheaera Hübner, Oxicesta Hübner, Simyra Ochsenheimer, Subacronicta Kozhanchikov, Triaena Hübner, and Viminia Chapman. Eogena, Oxicesta, and Simyra, currently treated as valid genera, nest within terminal clades of the genus Acronicta and are here subsumed within the genus: Eogena syn.n., Oxicesta syn.n. and Simyra syn.n. Four well‐supported species groups within Acronicta are identified: the alni clade, the leporina clade, the nervosa clade and the psi clade. While many previous treatments have stated explicitly that Acronictinae lack abdominal scent brushes, or excluded genera with brushes from the subfamily, we show that well‐developed brushes are present in three early diverging acronictine genera: Cerma, Lophonycta, and Sinocharis. We illustrate and describe the brushes of all three genera, and briefly review the taxonomic distribution of the anterior abdominal courtship brushes in Noctuidae, emphasizing the labile evolutionary distribution of these structures.