JYVÄSKYLÄ STUDIES IN BIOLOGICAL AND ENVIRONMENTAL SCIENCE 242 Veronica Chevasco Evolution and Ecological Aspects of Parthenogenetic and Sexual Bagworm Moths (Lepidoptera: Psychidae: Naryciinae) JYVÄSKYLÄ STUDIES IN BIOLOGICAL AND ENVIRONMENTAL SCIENCE 242 Veronica Chevasco Evolution and Ecological Aspects of Parthenogenetic and Sexual Bagworm Moths (Lepidoptera: Psychidae: Naryciinae) Esitetään Jyväskylän yliopiston matemaattis-luonnontieteellisen tiedekunnan suostumuksella julkisesti tarkastettavaksi yliopiston vanhassa juhlasalissa S212 heinäkuun 20. päivänä 2012 kello 12. Academic dissertation to be publicly discussed, by permission of the Faculty of Mathematics and Science of the University of Jyväskylä, in auditorium S212, on July 20, 2012 at 12 o’clock noon. UNIVERSITY OF JYVÄSKYLÄ JYVÄSKYLÄ 2012 Evolution and Ecological Aspects of Parthenogenetic and Sexual Bagworm Moths (Lepidoptera: Psychidae: Naryciinae) JYVÄSKYLÄ STUDIES IN BIOLOGICAL AND ENVIRONMENTAL SCIENCE 242 Veronica Chevasco Evolution and Ecological Aspects of Parthenogenetic and Sexual Bagworm Moths (Lepidoptera: Psychidae: Naryciinae) UNIVERSITY OF JYVÄSKYLÄ JYVÄSKYLÄ 2012 Editors Jari Haimi Department of Biological and Environmental Science, University of Jyväskylä Pekka Olsbo, Ville Korkiakangas Publishing Unit, University Library of Jyväskylä Jyväskylä Studies in Biological and Environmental Science Editorial Board Jari Haimi, Anssi Lensu, Timo Marjomäki, Varpu Marjomäki Department of Biological and Environmental Science, University of Jyväskylä URN:ISBN:978-951-39-4809-2 ISBN 978-951-39-4809-2 (PDF) ISBN 978-951-39-4808-5 (nid.) ISSN 1456-9701 Copyright © 2012 , by University of Jyväskylä Jyväskylä University Printing House, Jyväskylä 2012 To my parents, Carlos and Elsa ABSTRACT 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 pus- sikehrääjien (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 evolution- ary dead–end. However, the apparent success of some parthenogenetic species constitutes one of the most intriguing questions in evolutionary biology and de- serves investigation. In this dissertation I investigated the origin of partheno- genesis and examined factors contributing to its maintenance in bagworm moths. A DNA barcoding approach was conducted as an accurate way to iden- tify 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 pos- sibility 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 limita- tion 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. Con- tinuing to investigate potential reasons for the success of parthenogenetic spe- cies, D. fennicella was found to be less vulnerable to parasitoid attacks than sex- ual species, which contradicted one prediction of the parasite hypothesis of sex. Parthenogens could be avoiding parasitoid attacks due to differences in phe- nology 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 par- thenogenetic D. fennicella could be that its polyploid status might provide enough advantages to overcome a higher mutational load, lower genotypic var- iation, and parasitoid attacks in the absence of sexual reproduction. Keywords: Barcoding, genetic diversity, parthenogenesis, polyploidy, sex. Veronica Chevasco, University of Jyväskylä, Department of Biological and Environ- mental Science, P.O. Box 35, FI–40014 University of Jyväskylä, Finland Author’s address Veronica Chevasco Department of Biological and Environmental Science P.O. Box 35 FI–40014 University of Jyväskylä Finland [email protected] Supervisors Professor Alessandro Grapputo University of Padova 35121 Padova Italy Academy Professor Johanna Mappes Department of Biological and Environmental Science P.O. Box 35 FI–40014 University of Jyväskylä Finland Jelmer Elzinga, PhD Department of Biological and Environmental Science P.O. Box 35 FI–40014 University of Jyväskylä Finland Juan Galarza, PhD Department of Biological and Environmental Science P.O. Box 35 FI–40014 University of Jyväskylä Finland Reviewers Academy Research Fellow Anna–Liisa Laine Department of Biosciences PO Box 65 FI–00014 University of Helsinki Finland Docent Niklas Wahlberg, PhD Department of Biology University of Turku 20014 Turku Finland Opponent Professor emeritus Anssi Saura Umeå universitet SE–901 87 Umeå Sweden CONTENTS LIST OF ORIGINAL PUBLICATIONS 1 INTRODUCTION ................................................................................................... 7 1.1 The widespread occurrence of sex ............................................................... 7 1.2 The costs of sex ................................................................................................ 8 1.3 Is asexuality an evolutionary dead–end? .................................................... 9 1.4 Origin of asexual reproduction .................................................................. 10 1.5 Polyploidy and parthenogenetic reproduction ........................................ 11 1.6 Aims ................................................................................................................ 12 2 MATERIALS AND METHODS .......................................................................... 14 2.1 Study Species ................................................................................................. 14 2.2 Field Sampling .............................................................................................. 16 2.3 Laboratory rearing ........................................................................................ 17 2.4 Morphological Analyses .............................................................................. 17 2.4.1 Males .................................................................................................... 17 2.4.2 Females ................................................................................................ 18 2.5 Molecular Analyses ...................................................................................... 19 2.5.1 Genome size and ploidy level .......................................................... 19 2.5.2 Amplification of mitochondrial and nuclear genes ...................... 19 2.5.3 DNA barcoding .................................................................................. 20 2.5.4 Phylogenetic Reconstruction ............................................................ 21 2.5.5 Microsatellite Isolation ...................................................................... 22 2.6 Sperm limitation experiment ...................................................................... 23 2.7 Statistical Analyses ....................................................................................... 24 2.7.1 Morphology ........................................................................................ 24 2.7.2 Genome size and ploidy level .......................................................... 25 2.7.3 Mating Experiment ............................................................................ 25 2.7.4 Parasitism rates in D. fennicella ........................................................ 26 3 RESULTS AND DISCUSSION ............................................................................ 27 3.1 Identification criteria for bagworm moths (I) ........................................... 27 3.2 Origin of parthenogenesis in D. fennicella (II) ........................................... 29 3.3 Sperm limitation on female reproductive success (III) ........................... 31 3.4 Parasitism rates in D. fennicella (IV) ........................................................... 32 3.5 Patterns of genetic diversity in D. fennicella (V) ....................................... 33 4 CONCLUSIONS .................................................................................................... 34 4.1 Origin of parthenogenetic reproduction ................................................... 34 4.2 Maintenance of parthenogenesis ................................................................ 35 Acknowledgements .......................................................................................................... 37 YHTEENVETO (RÉSUMÉ IN FINNISH) .................................................................. 38 REFERENCES ................................................................................................................ 42 LIST OF ORIGINAL PUBLICATIONS