Genetic differentiation and dispersal among populations of the damselfly Lestes viridis (Odonata)

We investigated genetic differentiation among 8 populations of the protecte d damselfly Lestes viridis (Vander Linden, 1825) in permanent ponds in nort hern Belgium by means of allozyme electrophoresis and isoelectric focusing, and estimated levels of gene flow using F-statistics. In addition, we did a capture-mark-recapture experiment to estimate direct levels of gene flow. Our aim was to test whether populations of L. viridis represented a single , large panmictic population or formed a series of demographically isolated populations, which may be defined as appropriate management units (MU). No ne of the marked individuals moved among the ponds, indicating a strong fid elity for adults to their breeding pond. Only 1 population was genetically strongly differentiated, whereas little or no differentiation was observed among the 7 other ponds. Absence of adult dispersal but genetic homogeneity between ponds thus suggested substantial teneral dispersal. We observed la rge heterozygote deficiencies at 2 loci (Fdh and Est). Significant differen ces in allele frequencies among ponds suggests that populations of L,. viri dis in northern Belgium may consist of >1 MU. Management plans for conserva tion should therefore take into consideration the presence of several MUs i n this species.