The Behavioral Ecology of Libellula luctuosa (Burmeister) (Odonata: Libellulidae)

Abstract

AbstractIn a pond dragonfly, Libellula luctuosa, the number of males at the mating site increased linearly during mating seasons. The number of fertilizable females in the population did not increase. An increasingly male biased operational sex ratio (OSR) therefore correlated with the increasing density of males. I predicted that this would cause increased male‐male competition and alter female mate choice.Competition for territories influenced mating success in L. luctuosa. Two different mating strategies were adopted by males of L. luctuosa: some flew and defended lengths of shoreline (territorial males), and some perched and avoided male‐male interactions (satellite males). Satellite males increased later in the season when all territories were occupied. However, no satellite ever switched to the territorial strategy and no territorial male ever became a satellite. At high male density, two males occasionally defended the same territory. The occupation of territories was nonrandom. The probability of any male mating depended on the time of year. Territory owners did most of the mating; satellite males rarely mated. Postmating guarding of females by males depended on the number of conspecific males present.Mating success of males was also influenced by female mating behavior, and female mating behavior was influenced by the number of males present. Females visited several males prior to mating. When fewer males were present females were more likely to reject male mating attempts. The length of copulation did not change during the mating season. At high male density, females spent less time ovipositing immediately after mating. Postcopulatory mate guarding by males increased the length of time the female spent ovipositing. These behavioral patterns may represent different strategies of mate choice, precopulatory mate choice at low male density and postcopulatory mate choice at high male density.