ADAPTIVE STRATEGIES OF LARVAL PARASITOIDS OF THE ALFALFA WEEVIL (COLEOPTERA: CURCULIONIDAE)

Abstract

AbstractThree species of Hymenoptera comprise the guild of parasitoids utilizing alfalfa weevil, Hypera postica, larvae in Ohio. Where all three coexist, there has been a yearly increase in parasitization by Bathyplectes anurus and concomitant decreases in Bathyplectes curculionis and Tetrastichus incertus. We conclude that B. anurus dominance is due to its precise synchronization with peak host numbers, its high reproductive capacity, competitive superiority, and rapid search and handling. Domination of ephemeral hosts by such a parasitoid is in agreement with the general conclusions of Force, and Ehler and van den Bosch. B. curculionis and T. incertus compensate for imperfect synchrony with multivoltism and vagility (both spp.), aggregation and rapid search (B. curculionis), or random search and gregarious development (T. incertus).