Predation strategy of the brown widow spider Latrodectus geometricus Koch, 1841 against prey with different defensive mechanisms

Abstract

Predators, such as spiders, may modulate their predatory behavior according to the defensive mechanisms of their prey. This study analyzed the prey capture behavior of Latrodectus geometricus spiders, specifically through the parameter’s acceptance of the prey, immobilization time, and bitten areas. A total of 80 adult female spiders were used, and they were fed cockroach nymphs and fasted for seven days. After this period, spiders were divided into four groups where prey with different defensive mechanisms were offered: cricket nymphs, ants, juvenile scorpions, and cockroach nymphs. Spiders were successful in catching prey in 86.25% of the observations, with crickets and scorpions being the prey having the highest and lowest acceptance rates, respectively. Our results showed that crickets and cockroaches were the prey most rapidly immobilized, and scorpions were the prey that required more time to be immobilized. These results indicate that L. geometricus individuals prefer prey with more fragile defenses. We also observed that spiders prefer to bite areas away from the defensive mechanisms of dangerous prey. Thus, our findings suggest that the spider L. geometricus possesses the ability to modulate its predatory behavior according to the defensive mechanism of its prey.