Resumen en español

The tiger beetle genus Pseudoxycheila (Cicindelidae) currently contains 21 species, distributed in mid and high elevations in the Andes from Bolivia to Venezuela and in mountains in Panama and Costa Rica. The center of origin of the genus is in the Andes of Colombia and Ecuador. In this study we describe the mating behavior of two species, P. chaudoiri and P. confusa, that co-occur at an elevation of 1900 m on the western Andean range of Colombia (3° 30' N 76° 34' W). The two species used similar habitats, which are inclined surfaces with bare, clay soils, but were spatially segregated by microclimatic differences. The mating behavior of both species was similar. It was characterized by haphazard encounters of males and females at oviposition sites, and males attempting to mount females. When females were not laying, mounting was followed by a precopulatory struggle (female attempting to dislodge male), copulation, a postcopulatory association (PCA), a postcopulatory struggle, and finally dislodging of the male by the female. About half of the mating attempts occurred with females that were starting to lay eggs; in theses cases usually there was no Boletín del Museo de Entomología de la Universidad del Valle 9(1): 22-28, 2008 23 precopulatory struggle and after copulation the female usually continued egg laying with the male in amplexus. PCA likely represented mate-guarding behavior, but males in PCA were dislodged by intruding males. In some cases, however, males in PCA were probably able to fertilize several eggs that were laid in sequence. The mating behavior of these two species is possibly a result of a sexual conflict of interests, in which males try to mate with any female they encounter and females resist, but only to the point at which struggling and interrupting egg-laying is more costly than accepting copulation.