Resumen de Analysis of the leaf litter arthropod fauna of a lowland tropical evergreen forest site (La Selva, Costa Rica)

Susan Lieberman, Charles F. Dock

• español

  Los grupos de artrópodos más frecuentemente capturados con trampas cilíndricas de un galón (3.78 litros) en ambientes de suelo vegetal en un bosque húmedo de tierras bajas de Costa Rica fueron hormigas, ortópteros y colémbolos. Las muestras indican variaciones estacionales significativas en la abundancia de los grupos mayores. Los números de artrópodos fueron, mayores entre la iniciación de la tempo­rada lluviosa y el máximo de precipitación. Los colémbolos, moscas y grupos menos comunes misceláneos se capturaron en mayor cantidad durante el día, mientras que las hormigas, arañas, milpiés y cienpiés se colectaron en mayor cantidad durante la noche. Se capturó una mayor cantidad de artrópodos en los ambientes no perturbados que en los habitats modificados de cultivo de cacao. Los grupos más comunes en ambientes no perturbados fueron los ortópteros, arañas y homópteros. Los mayores números de artrópodos correspon­den a los espesores máximos de cubierta vegetal durante los trece meses de muestreo.

• English

  Leaf litter arthropod population changes were monitored by means of extensive can trapping over a thirteen month period at a lowland evergreen forest site in Costa Rica. Samples were taken within an undisturbed forest plot and an adjacent fallow cacao plantation. Comparisons of abundance were made between nocturnal and diurnal samples as well as between months. The dominant arthropod groups in the samples in order of abundance were the Formicidae, Apterygota, Orthoptera and Arachnida. Total numbers of individuals in all major groups were consistently greater in the initial stages of the rainy season and remained relatively constant throughout the remainder of the year. It is suggested that numbers increase in response to the onset be the rainy season. Greater numbers of individuals were collected in the undisturbed forest than the fallow cacao plantation. Significant diel differences in abundance were found for many of the major groups included in the study. Maximum arthropod abundance corresponded to the time of greatest leaf litter depth within the study plots.