Communication by surface waves

Summary

• 1. During mating behavior males and females of an Australian species ofRhagadotarsus (Gerridae) communicate with patterned sequences of surface waves (signals) produced by leg movements (Figs. 1, 3). Individuals produce signals while free on the surface or while grasping floating or fixed objects; these objects then become copulation and oviposition sites (Fig. 2). Wave patterns are produced during precopulation, copulation, postcopulation, and aggression (Fig. 3). In the laboratory, mating behavior occurs diurnally, nocturnally and in total darkness.

• 2. Females were attracted and stimulated to oviposit by artificial precopulatory signals. Visual cues were shown not to be necessary for precopulatory behavior and oviposition to occur (Table 1).

• 3. Female response to artificial calling signals of different frequencies corresponded to the frequency range (approximately 17–29 waves/sec) present in male calling signals; and females discriminated a difference in frequency of 1.5–2.0 waves/ sec (Table 2).