Morphological and morphometrical analysis of Callosobruchus maculatus (Coleoptera: Bruchidae) reared on green gram (Vigna radiata L.), and black gram (Vigna mungo L.)

A research studies on morphology and morphometric analysis of cowpea beetle was supervised in Entomology lab, Department of Zoology, BSNV PG College, University of Lucknow, Lucknow during September to October 2023, when temperature is about 27±1 oC and 65±5% RH with a photoperiod of 12 h light: 12 h darkness is available. The developmental characters viz. body size, colour, abdomen, antennae, mobility, first egg lay time, fecundity, oviposition, incubation period, larval and pupal development, and longevity of cowpea weevil on green gram (Vigna radiata) and black gram (Vigna mungo) were studied in this experiment. The present study result revealed that the adult males were smaller in size, brownish in colour, with obtuse abdomen, pectinate antennae and hypermobility while females are larger in size, blackish in colour, pointed abdomen, serrate antenna and hypomobility. Mating took time within 40-60 minutes of adult emergence where male had a stimulant role in copulation and its duration was 30-40 seconds. The breeding period was 4-5 days duration in mung bean while 8-9 days in urad bean seeds. The larval (L1, L2, L3, L4) time span assorted from 4-5, 3-4, 3-4, 3-4 in Vigna radiata and in Vigna mungo was about 5-6, 4-5, 4-5, 4-5 days. Morphometric measurement revealed that the eggs length and breadth were measured in SE 0.48±0.08 mm and 0.13±0.22 mm reared on Vigna radiata whereas in Vigna mungo the length and breadth of eggs were 0.54±0.01 mm and 0.14±0.01 mm. The larval mean length and breadth of cowpea pulse beetle reared on Vigna radiata (Greengram) (L1, L2, L3, L4,) were 0.61±0.04 mm, 1.21±0.04 mm, 2.30±0.05 mm, 3.58±0.13 mm, and breadth were 0.24±0.02 mm, 0.79±0.03 mm, 1.24±0.08 mm, 1.96±0.07 mm whereas on Vigna mungo length were 0.69 ±0.03 mm, 1.26±0.04 mm, 2.35±0.10 mm, 3.62±0.15 mm, and breadth were 0.31 ±0.02 mm, 0.82±0.04 mm, 1.28±0.04 mm, 2.06±0.08 mm. Pupa of Male and female was about 4.08±0.01mm, 4.31±0.02 mm, and 2.36±0.08 mm, 2.62± 0.05 mm reared on Vigna radiata and in Vigna mungo had 4.11± 0.03 mm, 4.38±0.07 mm and 2.39±0.05 mm, 2.65±0.03 mm. The average length and breadth of male and female adult was about 3.22±0.06 mm, 3.58±0.24 mm and 1.93±0.07 mm, 2.10±0.08 mm reared on green gram seeds in 10 to 14 days whereas on black gram was 3.25±0.06 mm, 3.61±0.12 mm and 2.01±0.04 mm, 2.13±0.06 mm in 12-16 days duration respectively.