(Lepidoptera: Psychidae: Naryciinae) Based on Mtdna-Markers
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Ann. Zool. Fennici 42: 141–160 ISSN 0003-455X Helsinki 26 April 2005 © Finnish Zoological and Botanical Publishing Board 2005 Phylogeny and evolution of parthenogenesis in Finnish bagworm moth species (Lepidoptera: Psychidae: Naryciinae) based on mtDNA-markers Alessandro Grapputo*, Tomi Kumpulainen & Johanna Mappes Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland (*e-mail: [email protected].fi) Received 25 Oct. 2004, revised version received 8 Dec. 2004, accepted 6 Dec. 2004 Grapputo, A., Kumpulainen, T. & Mappes, J. 2005: Phylogeny and the evolution of parthenogene- sis in Finnish bagworm moth species (Lepidoptera: Psychidae: Naryciinae) based on mtDNA- markers. — Ann. Zool. Fennici 42: 141–160. We investigated species diversity and evolution of parthenogenesis among bagworm moth species of Dahlica and Siederia using mitochondrial DNA sequencing. Par- thenogenesis is rare among Lepidoptera other than Psychidae. Genera Dahlica and Siederia form a confusing group with controversial species boundaries and widely overlapping morphological features that make species determination difficult. We evaluated the reliability of species determination based on wing scale morphology by comparing it with a phylogenetic tree obtained using mtDNA. Species determination based on morphological characteristics did not correspond to species determination based on mtDNA markers. On the basis of the molecular phylogeny, the status of these two genera is questionable. Our results indicate that parthenogenetic D. fennicella, D. triquetrella and D. lichenella evolved independently from different sexual ancestors suggesting that asexual reproduction is favoured in this group. Introduction organelles, or essential genes. Among Lepidop- tera, asexual reproduction is extremely rare and, Sexual reproduction is the dominant strategy in in most known examples, parthenogenesis is a higher animals (and plants) making the para- secondary reproductive strategy (Suomalainen dox of sex one of the most fundamental ques- 1962, Bell 1982). Among Naryciinae (Lepidop- tions in evolutionary research. One hypothesis tera: Psychidae) however, several parthenoge- is that females of sexually selected lineages netic species are known. These species can be are in a male-dependent trap and that the trap classified as strictly asexual lineages since no alone should often be enough to maintain sex males are known among them. Interestingly, both since females need males for normal reproduc- sexual and asexual species often co-exist and tion (West-Eberhard 2003). Depending on the there are no reliable morphological or ecological species, females may rely upon males to stimu- cues to separate parthenogenetically and sexu- late ovulation, to initiate embryonic develop- ally reproducing females (Kumpulainen et al. ment, or to provide essential genetic transcripts, 2004, Kumpulainen 2004). Thus, psychid moths 142 Grapputo et al. • ANN. ZOOL. FENNICI Vol. 42 offer an attractive opportunity to investigate the scale morphology of female pupa and abdominal evolution of parthenogenesis. If parthenogenesis spines of adult females. Also, certain differences has evolved several times in this group, we can in the structures of the front legs of adult males assume that some ecological, physiological or have been given as grounds for separating the environmental factors may favor parthenogen- species (Hättenschwiler 1997). However, there is esis in this group. too much variation among the species in the head Species determination, status and phyloge- scale morphology of the pupa for clear species netic relationships of many species in this sub- determination and all other feature differences are family are, however, still controversial (Suoma- also insufficient to reliably determine all species lainen 1970, Lokki et al. 1975, Suomalainen (Hättenschwiler 1997). Genital indices have been 1980, Hermann 1994, Hättenschwiler 1997, described for most of the species but these also Kullberg et al. 2002). The group is characterised overlap considerably (Hättenschwiler 1997). So by high endemism in mountain ranges in south- far, only the shape of wing scales from the central ern Europe and central Asia. There is a great area of the tip of male fore wings (Suomalainen number of morphologically similar species with 1980) has been shown to contain sufficient vari- several problematic species pairs and still unre- ation between adult specimens of most species, solved relationships between parthenogenetic even though the use of wing scales for species and sexual forms, which have caused confu- determination has led to controversial interpreta- sion in the nomenclature and ecological studies tion of species boundaries (Sauter 1956, Suoma- involving well known taxa as well. lainen 1980, Hättenschwiler 1997). Moreover, In Europe, the tribus Dahlicini (Naryciinae) this feature is inadequate for species determina- consist of 49 species in six genera (Sauter & tion of different parthenogenetic species. Hättenschwiler 1991). To date, 22 species of Current phylogenetic methods allow for test- bagworm moths (Dahlicini) have been recorded ing the validity of morphological and ecological in Finland. Of these, seven species are included features in constructing phylogenetic trees for a in two genera — Dahlica Enderlein and Sied- given taxon. The well-known problems of distin- eria Meier — which formerly were grouped in guishing between homologous and homoplasi- the genus Solenobia Duponchel) (Suomalainen ous features have made it difficult to interpret 1980). All Dahlica and Siederia moths are rela- the true phylogenetic relations of many systems tively small-sized (female body length 3–6 mm) (Brooks & McLennan 1991, Avise 1994). The and their larval cases are particularly similar in use of genetic markers together with ecologi- size. Most species have a wide range of similari- cal and morphological features, however, has ties in both morphological and ecological fea- revealed new information on the phylogeny of tures. Dahlica and Siederia are most abundant many controversial groups of animals, such as near forest edges and other semi-open parts of pandas (O’Brien 1987), flightless birds (Had- their habitats, where the microclimate is favour- drath & Baker 2001) and many insect groups able and larval food plants (several moss genera) (Brower 1997, Kruse & Sperling 2002). Among are abundant (Kumpulainen 2004). All species insects, and particularly among Microlepidop- have a very short adult phase, only 3–6 days. tera, many controversial groups of species still The longest stage of their life cycle, from one to remain (Hättenschwiler 1997, Kruse & Sperling two years, consists of five phases of larval devel- 2002). The phylogeny of such groups as well as opment (Hättenschwiler 1985, 1997). Larvae of the status of many species is subject to change Dahlica and Siederia moths usually live and feed when new studies applying more precise and freely on mosses on the forest floor, on stones or diverse methods are published. other similar semi-open habitat patches, often Due to the apparent lack of reliable mor- close to tree trunks. phological features for species determination in Species determination among Dahlica and the genera Dahlica and Siederia we conducted Siederia is very difficult due to the lack of distinct a phylogenetic analysis based on partial DNA morphological or ecological features. Current sequences of mitochondrial Cytochrome Oxidase attempts to classify the species are based on head genes and small ribosomal subunit gene (12S) to ANN. ZOOL. FENNICI Vol. 42 • Phylogeny and parthenogenesis in Psychidae 143 examine species diversity of solenobid bagworm throughout most temperate areas of Europe, from moths. We were particularly interested in com- Spain to Great Britain and Ireland in the west and paring the classification based on wing scale to Finland in the north. In southern and central morphology to the phylogeny based on mtDNA Finland, D. triquetrella is not rare, but can nor- markers. We were also interested in studying mally be found only in small numbers (Suoma- the evolution of parthenogenesis in this group. lainen 1980). This species has both sexually and MtDNA analysis provided a test of species deter- parthenogenetically reproducing forms of which mination independent of wing scale morphology, only the parthenogenetic, tetraploid form occurs reproductive strategy and ecological data. in Finland (Suomalainen 1980). Lokki et al. (1975) found two genotypically different forms (an eastern and a western form) in Finland using Materials and methods electrophoresis. D. triquetrella occurs mainly on the edges of warmer forest habitats, possibly For the phylogenetic study we included all preferring sandy and often south-facing habitats, seven species previously described in Finland. sometimes with a human influence (Arnscheid To obtain a more accurate phylogenetic analy- 1985, Hättenschwiler 1997). D. triquetrella is sis of Naryciinae, we also included samples slightly larger than other Dahlica or Siederia of Siederia rupicolella, Dahlica triquetrella species and as larvae it should be relatively easy and D. lichenella from the Alps. These species to distinguish by its larger size and also by the also occur in Finland. Moreover we added sev- triangulate larval case (Suomalainen 1980, Hät- eral endemic species (D. sauteri, D. wockei, D. tenschwiler 1997). vaudella and D. generosensis) from the Alps. From Sweden we included samples of D. triquet- rella, S. rupicolella