Abstract

VIEIRA, Carmen. The prey capture behaviour of Metepeira gressa (Araneae, Araneidae) on mealworms, flies and ants. Rev. etol. [online]. 2005, vol.7, n.2, pp. 53-62. ISSN 1517-2805.

The prey-capture behavioral repertoire of females and juveniles of the araneid spider Metepeira gressa (Keyserling, 1892) was analyzed using mealworm larvae, flies, and ants as prey of the same size. Flies and ants are frequently encountered by the spider species, but the beetle larvae are not. During the experimental period each type of prey was offered only once to each spider. The first unit of immobilization is very important to subdue the prey. When capturing mealworms and ants, spiders performed “Wrap” as the first unit of the Immobilization phase, and while capturing flies the spiders used “Bites”. “Wrap” seems to be a discriminatory initial behavior on dangerous prey, such as ants. The discrimination between ants and mealworms was tested using the observed behavioral units in spite of both generated similar capture patterns. The only difference detected was the occurrence of the unit “Other Locomotion”, more frequently on mealworm. The spider has many difficulties in mealworm capture because of the large size of the prey and the strength and the peculiar defensive tactic (“wriggling”) that progressively destroys the spider web. In disagree with the expectations, the spiders spent more time and energy in the capture of mealworms.

Keywords : Prey-capture; Spider; Metepeira gressa; Comportamiento de captura; Arañas; Metepeira gressa.