A comparison of methods for sampling aquatic insects (Heteroptera and Coleoptera) of different body sizes, in different habitats using different baits

Abstract

Although various methods exist for sampling aquatic Heteroptera and Coleoptera in standing water, there are very few comparisons of their performance in different types of habitat. In this study, we evaluated and compared the efficiency and selectivity of three sampling methods: hand netting, bottle traps baited with canned tuna and bottle traps baited with canned cat food. The methods were compared over the period 2010-2012 in two different habitats (temporarily flooded areas and canals) in the Nature Park Kopački rit, a floodplain on the banks of the River Danube. The results show that the effectiveness of the method differed in the two habitats. Overall, hand netting was the most successful method, mainly in canals. Tuna fish bait was more efficient than the commonly used cat food, especially for large and highly mobile species of Dytiscidae. These findings indicate that knowing the type of habitat and the habitat preferences of aquatic insects and their activity it is possible to predict which of these methods are the best for estimating species richness.