| This study used two complementary methods to evaluate the extent of vampire bat predation and screwworm infestations on cattle in Guanacaste, Costa Rica, as well as interactions between the two species. Results were compared from farms in three different climatic regions based on the Holdridge (1967) system of life zones.;The most common types of wounds occurring on cattle were vampire bites and wounds from ticks and botflies. Vampire bats' predation on cattle was rarely based on the animals' breed, sex or age. Vampire bites were used by screwworm flies as oviposition sites in proportion to their overall availability, as were tick bites. The screwworm flies' selection of host animals' vampire bites did not match the distribution of vampire bites by breed, sex or age characteristics of cattle.;Higher vampire predation and screwworm infestations were predicted for the wet season in all regions, but this prediction is supported only partly, and only in some regions. At farms in the tropical dry forest (low altitude) region, vampire bites were a higher proportion of all wounds, and a higher proportion of cattle were bitten. Some evidence suggests a seasonal occurrence of multiple bites on cattle.;Concerns about control of vampire predation may not be warranted in areas where animals are relatively unstressed by parasites such as ticks and botflies. The issue of control of vampire bats and screwworm flies must include a consideration of environmental issues. Both pests depend on forest habitat for survival, and education about the ecological importance of non-vampire bats species and the habitat itself can temper indiscriminate destruction of trees and forest in which vampire bats reside. (Abstract shortened by UMI.)... |
