NONSEXUAL INTERACTIONS IN THE BIG-HEADED GRASSHOPPER AULOCARA ELLIOTTI (THOMAS) (ORTHOPTERA: ACRIDIDAE)

Abstract

Nonsexual interactions of the big-headed grasshopper, Aulocara elliotti (Thomas), were examined under natural conditions in context of intrinsic (age and conspecificity of grasshoppers, speed and direction of movement and duration of interaction) and extrinsic (date, time of day, soil and air temperature, relative humidity, wind speed and sunlight) factors. With respect of intrinsic factors, the developmental stage and conspecificity of interacting grasshoppers and the direction of approach by the individual initiating an interaction significantly affected interactive behaviors, including kicking, shifting, approaching, contact and pursuit. These three factors also influenced the outcome of interaction, especially the frequency of avoidance by residents. Among the extrinsic factors, time of day, soil temperature and relative humidity had the greatest affects on the aforementioned interactive behaviors. The time of year, relative humidity and wind speed significantly affected the outcome of interactions. Physical contact and pursuit were the only behaviors to significantly affect the outcome of interactions. Inferential evidence indicates that aggressive interactions may be the result of defense of territories based on limited, suitable microhabitats.