The life history traits viz. body size, colour, abdomen, antennae, mobility, mating time, mating duration, mating behaviour, first egg lay time, fecundity, oviposition, incubation period, larval and pupal development, and longevity of Callosobruchus maculatus (F.) on black gram (Vigna mungo L.) were studied in this experiment. The present results revealed that the adult males were smaller, brownish, with obtuse abdomen, pectinate antenna (larger) and hypermobility whereas the females were larger, blackish, pointed abdomen, serrate antenna (shorter) and hypomobility. Mating took place within 40 to 60 minutes of adult emergence where male had a stimulant role in copulation and its duration was 30-40 seconds. Sometimes male and female showed courtship behaviour before mating and the male always ran after the female. During mating the male gripped the female’s abdomen behind by its leg tightly and penetrated intromittent organ with single effort and sometimes took several efforts. The mated female showed no tendency to mate more than single time and started to lay eggs within 45-60 minutes after mating. The fecundity of females was gradually decreased with the increase of time and single egg was laid on single seed wherever seeds were adequate. The eggs were translucent in colour, glued with seed coats just after oviposition and became whitish in the next day. The incubation period of the egg was 3 days and in 4th day the developing larva cut the seed coat as a round structure. The duration of first, second, third and fourth larval instars were 6, 3, 4 and 4 days whereas pre-pupal and pupal were 1 and 5 days followed by 1 day of emergence. The first instar larvae were small and second and third were apparently similar except the growth and development. However, before pupation, the fourth instar larva started to change its morphology completely and ongoing development turned it to adult individual. The average longevity of virgin male and female was estimated as 6.5±1.5 days and 10.5±3.5 days. The findings of morphological, reproductive and developmental traits can be used as basic data which might keep a pivotal role to design the control measures of this insect pest to save the pulses from their infestation and damage.
Md. Anisur Rahman, Meherun Nesa, Sabina Sultana, Nuzhat Ara, Rezina Laz. Studies on the life history traits of Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) reared in black gram (Vigna mungo L.). International Journal of Entomology Research, Volume 7, Issue 4, 2022, Pages 1-10