A relationship between handling and a developmental abnormality in the flour beetle, Tribolium spp

Abstract

In this experimental analysis of the teratology of Tribolium, we studied the effect of crowding and handling on a disorder associated with pupal eclosion. Handling increased the incidence of the abnormality which occurred infrequently in controls: the crowding level tested by us had no effect. T. confusum Duv., strain b-I produced more abnormal beetles than T. castaneum (Hbst.), strain c-IV-a. Handling older pupae increased the disorder to a greater extent than in young and non-pupae.The handling procedure was quite vigorous and the threshold level required to produce the effect is not known. The phenomenon might be important in population ecology but the pathway through which handling produces it is unknown.