Genetic diversity in populations of asexual and sexual bag worm moths (Lepidoptera: Psychidae).
BACKGROUND
Despite the two-fold cost of sex, most of the higher animals reproduce sexually. The advantage of sex has been suggested to be its ability, through recombination, to generate greater genetic diversity than asexuality, thus enhancing adaptation in a changing environment. We studied the genetic diversity and the population structure of three closely related species of bag worm moths: two strictly sexual (Dahlica charlottae and Siederia rupicolella) and one strictly asexual (D. fennicella). These species compete for the same resources and share the same parasitoids.


RESULTS
Allelic richness was comparable between the sexual species but it was higher than in the asexual species. All species showed high heterozygote deficiency and a large variation was observed among FIS values across loci and populations. Large genetic differentiation was observed between populations confirming the poor dispersal ability of these species. The asexual species showed lower genotype diversity than the sexual species. Nevertheless, genotype diversity was high in all asexual populations.


CONCLUSIONS
The three different species show a similar population structure characterised by high genetic differentiation among populations and low dispersal. Most of the populations showed high heterozygote deficiency likely due to the presence of null alleles at most of the loci and/or to the Wahlund effect. Although the parthenogenetic D. fennicella shows reduced genetic diversity compared to the sexual species, it still shows surprisingly high genotype diversity. While we can not totally rule out the presence of cryptic sex, would explain this high genotype diversity, we never observed sex in the parthenogenetic D. fennicella, nor was there any other evidence of this. Alternatively, a non-clonal parthenogenetic reproduction, such as automictic thelytoky, could explain the high genotypic diversity observed in D. fennicella.
Grapputo
Alessandro
A
Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland. grapputo@cc.jyu.fi
Kumpulainen
Tomi
T
Mappes
Johanna
J
Parri
Silja
S
D000818:Animals; D014644:Genetic Variation; D005838:Genotype; D019476:Insect Proteins / Q000235:genetics; D007527:Isoenzymes / Q000235:genetics; D009036:Moths / Q000201:enzymology / Q000235:genetics* / Q000502:physiology*; D010312:Parthenogenesis / Q000502:physiology; D012098:Reproduction / Q000502:physiology
D019476:Insect Proteins; D007527:Isoenzymes