Reproductive Biology of the Predatory Water Bug, Diplonychus annulatum (Fabricius) (Hemiptera: Belostomatidae) on Anopheles Mosquito as Prey Under Laboratory conditions

Abstract

The biology of the predatory water bug, Diplonychus annulatum (Fabricius) (Hemiptera: Belostomatidae), was studied under laboratory conditions using Anopheles (Diptera: Culicidae) wrigglers as prey. D. annulatum exhibits paurometabolous type of development passing through egg, nymph, and adult stages. An adult female lay about 6-14 egg batches with an average of 55.95±2.36 eggs per batch. Incubation period ranges from 8-11 days with a mean of 9.28±0.06 days and 79.63 % hatchability. The nymph passed through five instars before reaching the adult stage. The mean durations of the different instars were: 4.62±0.16, 4.22±0.15, 5.24±0.24, 8.06±0.58, and 15.86±0.61 days, respectively. The developmental period was 28-54 days (x̅=38.14±0.85 days). Longevity of females ranged from 110-283 days (x̅=196.76±12.53 days) while that of males was from 115-282 days (x̅=212.38±14.04 days). D. rusticus was found to be a voracious predator of Anopheles in the laboratory. The mean consumption rates for the respective instars were 10.0±0.35, 17.22±0.31, 36.48±0.73, 98.18±2.89, and 171.88±4.23 individual wrigglers per day.