Factors responsible for behavioural and pigmentary gregarization in hatchling desert locust Schistocerca gregaria (Orthoptera: Acrididae) (Forskal)

Abstract

With a view to elucidating the factor(s) responsible for gregarization in locusts, the behavioural and pigmentary characteristics of hatchling Schistocerca gregaria (Forskal) have been quantified using logistic regression analysis and colour scores, respectively. Of the three factors reported here, sands previously used for egg-laying by the solitary- and crowd-reared females were not found to induce any gregarization in the progeny, whereas higher densities of the egg pods and ovipositing females were both indicative of having significant gregarizing effects on the offspring hatchlings. Results of this study suggest that the most likely source of the gregarization signal in S. gregaria could be the foam produced by the females during oviposition.