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.
