Showing papers by "Niklas Wahlberg published in 2015"

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

Abstract: 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.

Multilocus Species Trees Show the Recent Adaptive Radiation of the Mimetic Heliconius Butterflies

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.)

Elusive ditrysian phylogeny: an account of combining systematized morphology with molecular data (Lepidoptera)

Abstract: Ditrysia comprise close to 99 % of all butterflies and moths. The evolutionary relationships among the ditrysian superfamilies have received considerable attention in phylogenetic studies based on DNA and transcriptomic data, but the deepest divergences remain for large parts unresolved or contradictory. To obtain complementary insight into the evolutionary history of the clade, and to test previous hypotheses on the subdivision of Ditrysia based on morphology, we examine the morphology of larvae, pupae and adult males and females of 318 taxa representing nearly all ditrysian superfamilies and families. We present the most comprehensive morphological dataset on Ditrysia to date, consisting of over 500 morphological characters. The data are analyzed alone and combined with sequence data (one mitochondrial and seven nuclear protein-coding gene regions, sequenced from 422 taxa). The full dataset consists of 473 exemplar species. Analyses are performed using maximum likelihood methods, and parsimony methods for the morphological dataset. We explore whether combining morphological data and DNA-data can stabilize taxa that are unstable in phylogenetic studies based on genetic data only. Morphological characters are found phylogenetically informative in resolving apical nodes (superfamilies and families), but characters serving as evidence of relatedness of larger assemblages are few. Results include the recovery of a monophyletic Tineoidea, Sesioidea and Cossoidea, and a stable position for some unstable taxa (e.g. Epipyropidae, Cyclotornidae, Urodoidea + Schreckensteinioidea). Several such taxa, however, remain unstable even though morphological characters indicate a position in the tree (e.g. Immidae). Evidence supporting affinities between clades are suggested, e.g. a novel larval synapomorphy for Tineidae. We also propose the synonymy of Tineodidae with Alucitidae, syn. nov. The large morphological dataset provides information on the diversity and distribution of morphological traits in Ditrysia, and can be used in future research on the evolution of these traits, in identification keys and in identification of fossil Lepidoptera. The “backbone” of the phylogeny for Ditrysia remains largely unresolved. As previously proposed as an explanation for the scarcity of molecular signal in resolving the deeper nodes, this may be due to the rapid radiation of Ditrysia in the Cretaceous.

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

Abstract: Butterflies 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. We 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. Our 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.

Adaptive radiations in butterflies: evolutionary history of the genus Erebia (Nymphalidae: Satyrinae)

Abstract: We studied the speciose butterfly genus Erebia by reconstructing its phylogenetic relationships using parsimony and Bayesian approaches. We estimated times and rates of diversification for its lineages and employed a biogeographical analysis in order to reconstruct its evolutionary history. DNA sequence data from one mitochondrial gene and three nuclear genes were analyzed for a total of 74 species in Erebia. The estimated dates of origin and diversification for clades, in combination with a biogeographical analysis, suggest that the genus originated in Asian Russia and started its diversification process around 23 Myr. An important event was the dispersal of a lineage from Asia to Western Europe between 23 and 17 Myr, which allowed the radiation of most of species in the genus. The diversification pattern is consistent with a model of diversity limited by clade richness, which implies an early rapid diversification followed by deceleration due to a decrease in speciation. We argue that these characteristics of the evolutionary history of Erebia are consistent with a density-dependent scenario, with species radiation limited by filling of niche space and reduced resources. We found that the Boeberia parmenio appears strongly supported in the genus Erebia and therefore we place Boeberia Prout, 1901 as a junior synonym of Erebia Dalman, 1816 (syn. nov.). (Less)

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

Abstract: 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 adult's 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. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:44393B52-1889-431A-AB08-6BBCF8F946B8. (Less)

Advances in Geometroidea phylogeny, with characterization of a new family based on Pseudobiston pinratanai (Lepidoptera, Glossata)

Abstract: Since its discovery and description, the oriental moth Pseudobiston pinratanai Inoue, 1994, could not be placed in any of the recognized families of Macroheterocera (Lepidoptera). Here, we used molecular and morphological data to infer the phylogenetic position of the species. These analyses indicate that Pseudobiston pinratanai is closely related to Epicopeiidae. Our analyses of morphological characters further show that Pseudobiston pinratanai+Epicopeiidae share synapomorphies with Sematuridae, Uraniidae and Geometridae. These observations lead us to redefine the superfamily Geometroidea and discuss its internal phylogenetic relationships. The isolated position of Pseudobiston pinratanai within Geometroidea supports a family status (Pseudobistonidae fam. n.) that we formally establish in this work.

Natural history and systematic position of Rhetus belphegor (n. comb.) (Lepidoptera: Riodinidae), an endangered butterfly with narrow distribution in Southeast Brazil

Abstract: The riodinid Rhetus belphegor (Westwood) (n. comb., previously in the genus Nirodia) is a critically endangered butterfly confined to the “campos rupestres”; a high-altitude rocky outcrop vegetation from southeast Brazil. The aim of this study is to unveil its biology and evaluate its systematic position. Based on museum data and public contribution of data (in the context of citizen science), R. belphegor is restricted to the “Espinhaco Mountain Chain”, and occurs exclusively above 1000 m. Adults were found resting upside down on rock walls. Females searched for host plants during the hottest hours of the day, depositing 1–2 eggs on leaves of the herbaceous subshrub Microstachys serrulata (Euphorbiaceae). The non-myrmecophilous larvae developed through six instars and the developmental time from egg to adult was ~50 days. Larvae are covered with abundant setae. Morphology of immature stages and molecular phylogenetic analysis showed that Nirodia is part of Rhetus, justifying the generic change. Our data supports that Nirodia is the only species in its clade associated with high mountains, in contrast to its lowland congeners. The description of the immature biology and clarification on its systematic position are essential steps for the establishment of better and more effective conservation efforts for this magnificent Brazilian butterfly.

Morphological variation between populations of the expanding ectoparasitic deer ked Lipoptena cervi (Diptera: Hippoboscidae) in Fennoscandia

Abstract: We examined morphological and genetic differences among Fennoscandian deer ked (Lipoptena cervi L, Hippoboscidae) populations with varying expansion history: the eastern population (Finland) has expanded rapidly, whereas the western population is divided into an old and relatively stationary sub-population in Sweden and a newly established and more expansive sub-population in Norway The genetic analysis suggests that the distinct populations represent a single species Individuals from expansive populations were characterized by a large body size, relatively large and robust thorax shape, and wing shape with an exaggerated basal posterior margin Yet, there was no among population variation in relative wing size or its elongated shape after variation in overall size was controlled for Although certain size and shape variables showed thermal sensitivity, the degree of plasticity did not differ between the populations In general, we observed that shape is more sensitive to external thermal conditions at the pupal stage than size per se, with the thermal sensitivity of the latter depending on the trait under examination We conclude that the possible adaptive value of morphological differences relies on variation in survival during the off-host life stages or short-distance flight to reach a susceptible host instead of long-distance dispersal ability

A New Subspecies of Anthanassa (Nymphalidae: Nymphalinae: Melitaeini) from Southeastern Brazil

Abstract: . A new subspecies of Anthanassa drusilla, ssp rioverde, is described from Minas Gerais, Southeastern Brazil. This new subspecies is isolated from all other known subspecies of A. drusilla by at least 2000 km, and its closest taxon based on wing pattern is Anthanassa drusilla higginsi, from Cerro Neblina, Venezuela. To our knowledge, the species is endemic to the region of Pocos de Caldas Plateau (Minas Gerais), a region of high natural radiation and heavily impacted by mining. Since the entire geographic distribution and conservation status of this subspecies is unknown, it is highly recommended that immediate measures are taken to minimize the environmental impact on the area of occurrence of this butterfly.

A new species of Niganda Moore, 1879 from Thailand, with descriptions of variation in male genitalia and female facies of N. radialis Moore (Lepidoptera: Notodontidae, Ceirinae)

Abstract: Niganda phichai Pellinen, sp. n., is described from northern Thailand. The new species is diagnosed and illustrated, including details of the genitalia and DNA sequencing. Variability in the male genitalia of Niganda radialis Gaede is reviewed, and notes are presented on the facies of female N. radialis.