Leaf Litter Traps for Sampling Orthopteroid Insects in Tropical Caves

In the dry tropics, the main nutrient influx into caves, which occurs during monsoonal flooding, is closely simulated by the deliberate introduction of wet leaf litter into the cave environment. We describe the construction and use of a wet leaf litter trap which exploits the attractiveness of wet leaf litter to orthopteroid insects inhabiting such caves. The traps collect a greater diversity of species per unit time and a greater total number of individuals per unit time than other techniques. Apart from the efficiency of the traps they can be used to allow sampling with replacement. This technique has a minimal impact on populations of cave invertebrates, and we therefore recommend its use where sampling is likely to pose a conservation threat to the fragile cave ecosystem.