Differential dispersal propensities between individuals in male Leucorrhinia intacta (Odonata: Libellulidae)


I compared males of Leucorrhinia intacta collected at two permanent and two previously dried ponds to assess whether males colonizing formerly dried sites differed in morphology or level of mite parasitism from males at permanent sites. Males colonizing sites that had local extinctions in the previous year due to pond drying were more similar to each other in body size and levels of parasitism than to males at sites which had not dried. Males at the two permanent sites differed significantly from each other in body size and these differences appear to reflect different local conditions. Comparison of males at two adjacent sites, one permanent and one which previously dried, found that the males colonizing the previously dried site were larger, in better condition, and had lower rates and numbers of mite parasites than males at the permanent site. Results from this study suggest two non-exclusive hypotheses about dispersal and colonization in this species. First, dispersal is condition dependent in this species with size and body condition positively correlated and mite parasitism negatively correlated with dispersal. Second, some permanent sites produce more males with the characteristics associated with dispersal than other potential source populations and therefore may contribute greater numbers of individuals to the dispersal pool.

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