Disturbance by unpaired males prolongs postcopulatory guarding duration in the damselfly Lestes virens (Charpentier) (Zygoptera: Lestidae)

In L. virens, the tandem post-copulatory guarding varies from some minutes to more than 4 hours and appears correlated to the time of the day and disturbance by unpaired <J 6. Using a multiple regression analysis, with guarding duration as the dependent variable and time of day, temperature and disturbance as the independent variables, it is shown that only disturbance significantly explains the model. An experimental test, in which early-occurring tandem males were not disturbed, while late-occurring ones were disturbed (a reverse situation of what happens in the field), showed that the latter kept their ovipositing 9 9 for significantly longer times than the former. The capability of 6 6 of varying guarding duration accordingly to the density of solitary 6 6 allows them to invest more or less time for guarding, according to the actual risk of losing sperm precedence.