Conspecifics and Their Posture Influence Site Choice and Oviposition in the DamselflyArgia moesta

Abstract

Finding a suitable oviposition site can be costly because of energy and time requirements, and ovipositioning can be dangerous because of the risk of predation and harassment by males. The damselfly Argia moesta oviposits, contact‐guarded by her mate, on vegetation in streams. Oviposition aggregations are commonly observed in this species, despite their territorial nature during other behaviors. We conducted experiments in the field to test the hypothesis that aggregations are the result of conspecific attraction. In the first experiment, two oviposition sites (sycamore leaves) were provided, one with models of ovipositing pairs, and one without. In the second experiment, one leaf again had ovipositing models, while the other had models of uncoupled males and females in a resting posture. In both experiments, damselfly pairs preferred the site with ovipositing models. In general, they visited the ovipositing models first more often than expected by chance, stayed longer there, were more likely to oviposit there, and laid a greater total number of eggs there. These results support the hypothesis that conspecific attraction is responsible for ovipositing aggregations in A. moesta and that posture is an important cue for attraction. Using conspecific cues could be a beneficial strategy to save in search costs while taking advantage of the presence of ovipositing conspecifics to dilute the effects of harassment and predation.

Range shifting species reduce phylogenetic diversity in high latitude communities via competition

“…This result suggests that behavioural traits, such as aggressive behaviour, might act as the mechanism of competition. At present we lack sufficient evidence to conclude that this is the competitive mechanism, although competition for basking sites via aggressive behaviour has been observed in larger territorial odonata species (Lefevre & Muehter 2004;Worthen & Patrick 2004;Byers & Eason 2009). Moreover, it is unlikely that there is only one mechanism by which I. elegans and L. sponsa compete, as the adult stage represents a relatively short (but critical) period of interaction between these two species.…”

Volatile cues can drive the oviposition behavior in Odonata

“…It is often difficult to infer whether these groups result from the attractiveness of oviposition sites, ovipositing conspecifics, or both (Corbet, 1999). On this account, Argia modesta pairs have been demonstrated to lay their eggs preferentially (initial site choice, how much time pairs spent at sites , and the number of eggs deposited in sites) where ovipositing conspecifics are present, and this behavior is related with pure visual stimuli represented by other pairs of the same species (Byers and Eason, 2009). We can exclude the effect of an "attractiveness of conspecifics" in our experiments, because females of I. elegans typically oviposit alone and they are aggressive toward males or females that encroach on their oviposition sites (Miller, 1987).…”

Female Choice in Damselflies and Dragonflies

“…In this case, it is hard to visualize how males would be able to assess oviposition quality and one way males could do that is by looking whether other couples are also present. Such copying of oviposition decisions is actually used by females when these look for an oviposition site that is safe (e.g., McMillan 2000a) or of good quality (e.g., Byers and Eason 2009). The copying could be a proxy, for example, of predation risk (e.g., Rehfeld 1992).…”