Hypogaeic and epigaeic ant diversity on Borneo: evaluation of baited sieve buckets as a study method

Abstract

Numerous studies have been conducted to investigate the diversity of ground ant communities. However, despite their potential importance for tropical ecosystems, hypogaeically foraging ant species were often neglected or only marginally touched by these studies. This was mainly due to the difficult sampling of these cryptic species. We successfully used palm oil-baited sieve buckets to study ground and especially hypogaeically foraging ant species on Borneo. We suggest the inclusion of sieve buckets into future studies of ground ant communities to obtain a more comprehensive record of the hypogaeic ant fauna than could be sampled with the methods hitherto applied. As expected, the species yield (85 collected species from 32 genera) was lower than in studies employing several and more generalized sampling methods. However, a large proportion of our collected species (48%) had not been collected during a previous study that extensively sampled the same area. Of the collected species, 55% foraged at least partially below the soil surface, 47% of which had not been collected by Winkler litter sifting in a previous study in the same area. Furthermore, by employing sieve buckets, we could show different hypogaeic species to be undersampled by other studies using different methods in the same area. Although the oil was accessible to epigaeically as well as hypogaeically foraging species, only 45 species demonstrably fed on the oil. The attractiveness of oil for ant species of different genera is discussed. Since oil was not a generally attractive baiting substance, we tested sieve buckets baited with tuna and cookies. We conclude that sieve buckets baited with tuna and oil represent a quick and easy method well suited to supplement other methods, finally enabling the inclusion of hypogaeic ant species in ground ant diversity studies.

Subterranean Pitfall Traps: Is It Worth Including Them in Your Ant Sampling Protocol?

“…One way to collect hypogaeic species is to take soil-core samples and extract ants from soil manually or with the aid of the Berlese or the Winkler extractors [10,[16][17][18]. An alternative and increasingly used method is subterranean traps, such as the subterranean probe [15,19] or subterranean pitfall traps [14,[20][21][22][23].…”

Ground-dwelling ant diversity in Maliau Basin, Borneo: Evaluation of hand-sorting methods to estimate ant diversity

“…Furthermore, the samples from these methods include all animals extracted from the soil, with a lot of extracted soil particles and organic debris, therefore requiring a long sorting time to pick up ants from the samples. Owing to these problems in sampling, biodiversity inventory for the hidden ant fauna is often considered too difficult and consequently ignored or incompletely attempted in previous biodiversity studies of tropical ants (Berghoff et al 2003).…”

Subterranean ants (Hymenoptera, Formicidae) as prey of fossorial reptiles (Reptilia, Squamata: Amphisbaenidae) in Central Brazil

“…In the same locality and at the same time, Silvestre (2000) collected 15 ant species using 40 subterranean baits. On the other hand, in different localities, Berghoff et al (2003) found 85 ant species in 182 baited sieve buckets; Silva & Silvestre (2004) Our results suggest that traditional techniques of hypogaeic ants collection portray with much greater fidelity the underground ant fauna than the analysis of fossorial reptiles' stomach contents, due to the relatively low ant diversity found in this kind of samples, and also to the low observed frequencies in relation to the average size of ant colonies.…”

“…The techniques currently in use for the collection of hypogaeic ants are subterranean baited pitfall traps (Brandão et al, in press), subterranean baits (Silvestre, 2000;Morini et al, 2004), cylindrical probes (Ryder Wilkie et al, 2007), baited sieve buckets (using palm oil, tuna and cookies) (Berghoff et al, 2003), and soil submitted to Winkler extractor (Silva & Silvestre, 2004). However, these techniques reach relatively small depths, except for the cylindrical probes which can sample ants up to one meter below the surface soil.…”