Zoological Studies

Vol. 51 No. 5, 2012

Individual Specialization in the Hunting-wasp Trypoxylon (Trypargilum) agamemnon Richards (Hymenoptera: Crabronidae)

Renan B. Pitilin1,*, Márcio S. Araújo2, and Maria L.T. Buschini1

1Programa de Pós Graduação em Biologia Evolutiva, Departamento de Biologia, UNICENTRO, Rua Padre Salvatore Renna 875, 85015-430, Guarapuava (PR), Brazil
2Departamento de Ecologia, UNESP, Avenida 24-A, 1515, Rio Claro (SP) 13506-900, Brazil

Renan B. Pitilin, Márcio S. Araújo, and Maria L.T. Buschini (2012) Individuals of a population may differ with respect to resource use.  This among-individual variation in resource utilization is called ‘individual specialization’ and may substantially impact the ecological and evolutionary dynamics of a population.  The aim of this study was to evaluate whether females of 1 population of the hunting-wasp Trypoxylon agamemnon differed in their preferences for spider size and/or taxa.  To observe the behavior of wasps, trap-nests were installed in an araucaria forest fragment in the Parque Municipal das Araucárias, Guarapuava (PR), southern Brazil.  The indices within-individual component (WIC)/total niche width of a population (TNW) and average of values of the proportional similarity index (IS) were used to measure the degree of individual specialization.  We found evidence of strong, significant individual specialization in T. agamemnon in terms of both prey size (WIC/TNW = 0.43) and taxa (IS = 0.45).  We hypothesized that individual specialization in this species resulted from cognitive tradeoffs that limit individuals to exploring a small subset of available resources.

Key words: Anyphaenidae, Apoidea, Cognitive tradeoffs, Intra-population variation, Niche variation.

*Correspondence: E-mail:pitilin_tj@hotmail.com