Predator Avoidance and Signaling Behavior of Water Striders

Abstract

Ripple communication is used among semi-aquatic insects. Water striders produce ripple signals on the water surface for courtship, copulation, sex-discrimination, territoriality and mate guarding. Not all species of water striders, however, make signals for the same purpose. I investigated in which situation G. latiabdominis makes ripple signals. Females, but not males, used the ripple signals more often when they were hungry, suggesting that the signaling is used in securing food resources by hungry females to repel competitors away. The use of signals, however, is not directly related to density, indicating that this signaling is not affected by the density and the correlated frequency of interactions among individuals. Prey species should avoid areas where predation risk is high. However, if this is impossible, prey should reduce activities that may make them conspicuous and attract predators present in the habitat, such as foraging or mating. Thus, predation risk should change behavioral pattern of prey species. Not all species have same anti-predator behavioral patterns because they have evolved in the presence of different types or number of predators in their habitat. Hence some species, living in high predation risk habitats, probably developed efficient ways to avoid predation, while other species, living in low predation risk habitats, may have not evolved the most efficient ways to avoid predation. I hypothesized that survival rate of three species of water striders, originating from different types of habitats, will be affected by their species specific responses to predators, and that species specific morphology will contribute to the efficiency of predation avoidance. I compared the effect of predators presence on microhabitat use. I also compared responses to predators (escape initiation distance), and jumping performance of the three species. The survivorship was related to microhabitat use and to the escape initiation distance, rather than on the jumping ability. I predicted that a species with the best survival rate will have superior jumping ability in order to escape from predators at the moment when they were attacked by predators. The jumping ability, however, was probably limited by hydrodynamic and morphological constraints, so jumping appears to contribute little to successfully escaping from predators attacks.