Novel sexual coercion avoidance behavior in the terrestrial tiger beetle Sophiodela japonica: From resistance on land to escape in water

Abstract

Sexual coercion such as prolonged copulation and harassment by males can impose large costs on females. In tiger beetles (Coleoptera: Cicindelidae), the male grasps the female's metathorax with their mandibles during mating, making it difficult to escape from sexual coercion by males. Here, we observed novel sexual coercion avoidance behaviors in the terrestrial tiger beetle Sophiodela japonica. Females employed two distinct behaviors: escape by entering water during copulation, and resistance on land by assuming a motionless state in a characteristic posture during mounting. The use of water to avoid sexual coercion has not been reported among terrestrial insects, suggesting a remarkable counter-adaptation to male grasping with mandibles. These findings highlight behavioral diversity in female resistance and provide new insights into the evolution of such behaviors across insect taxa.