Hover interaction and assessment based on wing length in adult male damselflies, Calopteryx maculata (Odonata: Calopterygidae).

Abstract

In the study of male competitive behavior, the resource-polygynous odonate, Calopteryx maculata, has received much attention. Although early studies seemed to suggest that males of this species compete utilizing a persistence-dependent, 'war of attrition' strategy, more recent work indicates that 'physical assessment,' specifically relative assessment, actually underlies male competition. There is evidence that damselflies use 'fluctuating asymmetry'as a cue of individual quality, and a 'fluctuating asymmetry' hypothesis may predict escalation in male damselfly competition. Size advantage has also been linked to success, and so a size-dependent hypothesis may also describe assessment. As evidence has shown lipid or mass residuals to have some predictive power of escalation, a correlation between wing size and these body components is not implausible. We measured wing lengths and massed various body components of males involved in 27 contests along the Maple River at UMBS. Results failed to support either the assessment by fluctuating asymmetry hypothesis, or assessment by wing size. Wing size did not correlate with lipid or water predictors.