The time‐course of behavioural phase change in nymphs of the desert locust, <i>Schistocerca gregaria</i>

Abstract

Abstract. The time‐course of behavioural phase change was investigated in nymphs of Schistocerca gregaria , using logistic regression analysis of behaviour recorded in a standard assay. Gregarization occurred very rapidly. Solitary‐reared nymphs became markedly gregarious in behaviour within 1‐4h of being placed in a crowd. These insects re‐solitarized equally quickly if removed from the crowd. Crowd‐reared locusts also solitarized within l‐4h, but this effect was not complete. Results indicate that, while behavioural gregarization is maximal within a few hours of crowding, solitarization is a two‐stage process, changing rapidly at first, then more slowly as a function of the period of previous crowding.