Evolution and Ecological Aspects of Parthenogenetic and Sexual Bagworm Moths (Lepidoptera: Psychidae: Naryciinae)

Chevasco, Veronica Evolution and ecological aspects of parthenogenetic and sexual bagworm moths (Lepidoptera: Psychidae: Naryciinae) Jyväskylä: University of Jyväskylä, 2012, 50 p. (Jyväskylä Studies in Biological and Environmental Science ISSN 1456–9701, 242) ISBN 978-951-39-4808-5 (nid.) ISBN 978-951-39-4809-2 (PDF) Yhteenveto: Näkökulmia partenogeneettisten ja seksuaalisesti lisääntyvien pussikehrääjien (Lepidoptera: Psychidae: Naryciinae) ekologiaan ja evoluutioon Diss. The prevalence of sex could be explained by the benefits of recombination. Due to the inherent advantages of sex, parthenogens are considered as an evolutionary dead–end. However, the apparent success of some parthenogenetic species constitutes one of the most intriguing questions in evolutionary biology and deserves investigation. In this dissertation I investigated the origin of parthenogenesis and examined factors contributing to its maintenance in bagworm moths. A DNA barcoding approach was conducted as an accurate way to identify species. The identification of sexual species was vital to test the hypothesis of a possible hybrid origin leading to allopolyploidy in parthenogenetic species. Nonetheless, the phylogenetic results rejected the possibility of hybridization. An alternative scenario for the origin of parthenogenetic D. fennicella is the possibility of autopolyploidization of a closely related sexual species, such as D. lazuri. Parthenogenesis may be favored if the sexual wingless females face a high risk of remaining unfertilized. The results showed that male sperm limitation may not have a significant role as a selective force to promote the spread of parthenogenesis, because females tend to re–mate if the first mating fails. Continuing to investigate potential reasons for the success of parthenogenetic species, D. fennicella was found to be less vulnerable to parasitoid attacks than sexual species, which contradicted one prediction of the parasite hypothesis of sex. Parthenogens could be avoiding parasitoid attacks due to differences in phenology between sexual and parthenogenetic species. An alternative explanation might be the unexpected genetic variability that was found in parthenogenetic D. fennicella. In conclusion, a plausible explanation for the occurrence of the parthenogenetic D. fennicella could be that its polyploid status might provide enough advantages to overcome a higher mutational load, lower genotypic variation, and parasitoid attacks in the absence of sexual reproduction.