Barreras vivas como agente de restricción para la dispersión de un cicindélido tropical, Megacephala angustata Chevrolat 1841 (Coleoptera: Cicindelidae)

Resumen

Field boundaries may divide populations of predatory invertebrates into local populations at the fi eld scale by restricting between-field dispersal. This could reduce recolonisation rates after pesticide use or decrease the efficiency of numerical responses by natural enemies to pest outbreaks. The present study examines the impact of field boundaries on dispersal of the predatory tiger beetle, Megacephala angustata Chevrolat 1841 at a farm in coastal El Salvador. Pitfall trapping indicated that beetles occurred in most habitats on the farm. In pastures, captures were higher in open, unshaded areas than under field boundaries. Beetle dispersal was examined in a capture-mark-recapture study at the site. Movement between fields was very rare as indicated by a linear relationship between the accumulated number of marked beetles and the proportion of recaptures in each of three fi elds. In spite of frequent recaptures, three weeks after marking, only 2 of 401 beetles were found outside the fields where they had been originally captured and marked.