Study of the Cannibalistic Cohorts Among the Various Life Stages of Confused Flour Beetle Tribolium confusum DuVal (Coleoptera: Tenebrionidae) Under Laboratory Conditions

Abstract

The confused flour beetle is a cannibalistic insect, and all its cannibalistic pathways are important in affecting survival of the population life stages or membership. A large number of T. confusum eggs and a total of 550 adults, 660 larvae, and 270 pupae were used in this study. The study showed that the phenomenon of eggs cannibalism by adults and larvae is consistently present. Adult females are more voracious cannibal of eggs than male beetles, while larval cannibalism on eggs was clearer and even more than males. The ANOVA test showed that there are high significant differences at 1% level among periods (24 and 48 hrs), life stages, food types and life stages and food type interaction. Significant differences at 5% level were also obtained for the same parameters. For pupal cannibalism, ANOVA test, similarly showed that there is high significant difference at 1% and 5% levels for the same parameters. The present study demonstrated that internally generated processes, namely cannibalistic cohorts among the various life stages of the insect, can explain many aspects of population dynamics of T.confusum under controlled laboratory conditions. However, adults as cannibals on adults, either male or female, were not observed in this study. Cannibalism in this flour beetle is always present and, therefore, regarded as a sort of regulatory mechanism; a mechanism that tends to reduce the probability of extinction when the population is small or alternatively, to reduce the probability of disastrous crowding when population is large.