Influence of temperature and body weight on mosquito predation by the dragonfly nymph Mesogomphus lineatus

Abstract

Different weight classes (25, 50, 100 and 160 mg) of the dragonfly nymph Mesogomphus lineatus were allowed to predate on constant density (15 larvae/aquarium of 500 ml capacity) of healthy fourth instar larvae of Culex fatigans at 10, 15, 20, 25, 30, 35 and 40 ±0.5°C to study the interactions of body weight and temperature on satiation time, maximum food intake (C max), and return to maximum appetite. Satiation time is not a temperature dependent factor, but it is significantly influenced by weight; it lasts for 12.0, 16.6 and 39.4 min in the nymphs weighing 50, 100 and 160 mg, respectively. Number of larvae predated (C max) by a 50 mg nymph increases linearly from 1 larva at 10°C to 8 larvae at 35°C; the corresponding increases are from 2 to 11 larvae for the 100 mg nymph and 5 to 24 larvae for the largest nymph (160 mg). Statistical analysis of the data reveals that the maximum food intake of the nymph is significantly dependent on weight as well as temperature. Critical period of food deprivation permitting the return of maximum appetite in these nymphs is a temperature-dependent phenomenon but it was not influenced by weight. At 10°C, the maximum appetite returns after a food-deprivation period of about 60 hrs in all weight classes of the nymph; the corresponding values are about 53, 45, 37, 30 and 22 hrs in the nymphs exposed to 15, 20, 25, 30 and 35°C, respectively.