Bioefficacy of Catamiarus brevipennis (Servile) against two cotton pests in relation to starvation level

Abstract

Considering starvations an important physiological aspect which influence the predatory behavior of insects, this study was performed to document the possible impact that starvation (2days, 4days, 6days, 8days and 10days) has on the feeding acts and prey consumption efficiency of a polyphagous predator: Catamiarus brevipennis (Servile) (Hemiptera: Reduviidae) adults. Ten-day-old adult male and female C. brevipennis fed on two common cotton pests, Dysdercus cingulatus (Fab.) adult males and females and Spodoptera litura (Fab.) third instar larvae, under laboratory conditions. The 0-day, 2-day, 4-day, 6-day, 8-day and 10-day starved predators were separately placed in transparent plastic containers containing three each of adult male and female D. cingualtus or six third instar S. litura larvae. Feeding events (capturing time and handling time) and food consumption efficiency (number of prey consumed and weight gained) were recorded. Results revealed that irrespective of the prey species, and starvation levels, C. brevipennis females captured the prey quicker, handled more prey items in time and gained more food than males. The capturing time and weight gain of the predator were directly proportion to starvation levels regardless of whether the predator was offered D. cingulatus or S. litura as food. However, after 4-day starvation, handling time was decreased when D. cingulatus was offered as a prey. Handling time increased from predators starved 0day to 2days, then decreased gradually up to 6days and again increased to 10days starved predators. C. brevipennis consumed more S. litura and subsequently gained more food than D. cingulatus. This study revealed that starvation significantly reduced the prey-capturing time and increased the food consumption and that C. brevipennis can tolerate up to 10days without any prey under field conditions, indicating that it has good biological control potential against the cotton pests.