On the Effectiveness of Hand Collection to Complement Baits When Studying Ant Vertical Stratification in Tropical Rainforests

Abstract

Choosing an appropriate sampling method to study ants is a key factor since distinct sampling methods can capture distinct ant fauna and, therefore, leading to bias in the interpretation and conclusion of the patterns observed. Despite it is well known that the ant fauna is vertically stratified, some of the sampling methods cannot be used throughout the whole vertical stratum (e.g., fogging and Winkler extractor). Here we compared the complementarity of hand collecting and baiting (with tuna or honey) in ant surveys focused on the stratification of the ant fauna in a tropical rainforest in Mexico. We found a total of 44 ant species, belonging to 17 genera and five subfamilies. The three sampling methods were clearly complementary at both the forest floor and canopy levels, even with as little as 10 minutes of search time for hand collecting. The ant species composition differed among sampling methods at both vertical strata. Hand collecting yielded higher ant species richness and more exclusive species than either bait at both vertical strata, but both tuna and honey baits also led to the detection of some (though fewer) exclusive ant species. The combination of hand collecting, tuna, and honey baits should thus be considered complementary tools for ant inventories, since using the two methods together yielded more complete inventories at both vertical strata. An additional advantage is that both methods can be used in both strata, ensuring that data in different vertical strata are comparable and allowing more reliable comparisons among these different habitats.