Nesting Biology and Male Behavior of Trypoxylon (Trypargilum) tenoctitlan in Costa Rica (Hymenoptera: Sphecidae)

The behavior and biology of Trypoxylon (Trypargilum) tenoctitlan are described. Observations indicate that females initiate nests, but each one obtains a mate before provisioning cells; females will not forage unless a male guard is in the nest. Pairing occurs when a male follows a female to the nest or locates a female in her nest. Thereafter, the male guards the nest throughout the day, until the female terminates her foraging. At night, the female remains in the nest, but the male may or may not be present. Limited observations suggest that mating takes place in the nest shortly before oviposition. When nests near completion males leave and aggressively attempt to displace other males. The evolution of male guarding behavior is discussed. Nests were obtained from trap-nests with 4.8, 6.4, and 9.5 × 152 mm tubes. Cells were provisioned with an average of 20 paralyzed spiders in the families Araneidae, Anyphaenidae, Clubionidae, Sparassidae, Salticidae, and Thomisidae. Natural enemies reared from nests included Messatoporus sp., Trichrysis nigropolita, Neochrysis postica, N. lecointei, Lepidophora vetusta, Anthrax angustipennis, A. argyropygus, Pyemotes sp., and an unidentified Dermestidae.