Natural history of a gall-inducing weevil Collabismus clitellae (Coleoptera : Curculionidae) and some effects on its host plant Solanum lycocarpum (Solanaceae) in southeastern Brazil

Abstract

The phenology, general characteristics, and mortality factors acting upon the weevil Collabismus clitellae Boheman in a population of Solanum lycocarpum St. Hil. (Solanaceae) were investigated in southeastern Brazil, as well as its distribution and impact on the host plants. Mating and oviposition of the weevils were observed in the beginning of the summer, with larval development until the autumn and emergence in spring. Most galls were found toward the base on plants 0.9-1.2 m high, a distribution perhaps the result of physiological differences between plants of different height. Natural enemies also may influence this pattern; logistic regressions showed that greater gall size and increased height above the ground increased mortality caused by the woodpecker Colaptes campestris (Vieillot). Larger galls also were more frequently attacked by the fungus Penicillium sp. Gall attack rates were correlated with S. lycocarpum stem mortality (43.4% of plants analyzed), because galls could act as nutrient sinks or favor the breaking of stems. The possible effect of C. clitellae on the population dynamics of S. lycocarpum is discussed.