A Study of Two Ant (Hymenoptera: Formicidae) Sampling Methods in Tropical Rain Forest

Abstract

Abstract: The effectiveness of two ant sampling methods, ie, pitfall and yellow-pan traps in three forest habitats in Sungai Lalang Forest Resenre, Malaysia were investigated. A total of nine sub-families were captured using both methods, namely Ponerime, Mymicime, Dolichoderime, Cerapachyme, Pseudomynnicinae, Fomicinae, Aenictime, Dovlinae and Leptanilime. More Ponerinae indwiduals were collectedusq pitfall trap whle more Dolichoderiane were collected using yellow-pantrap. Pitfall trap collected hgher number of indwiduals (31,501) than yellow-pan trap (1,963 individuals), which indicated that pitfall trap was relatively an effective method for estimating the species abundance over the yellow-pan trap. Even though less number of indwiduals were collected by yellow-pan trap, this method evidently caught a more diverse of ant species compared to pitfall trap. This indcated that yellow-pan trap is relatively a better method for estimating the diversity over the pitfall trap. Results indcated that none of the tested sampling methods has an advantage over the other in collecting ant. Thus, the use of all suitable sampling methods for certain habitats is still considered the best suggestion in order to get a representative sampling of ant species. Key words: Ground ant, diversity, pitfall, yellow-pan INTRODUCTION The precise methods used to estimate the abundance and composition of insect in biodwersity assessment is of critical importance. Owing to the inevitable limitations of field methods, these estimation are often biased. Some species in a given habitat are either over or under represented in relative to their tree abundance. The estimates obtained from different sampling techniques or from variations in the execution of a particular techmque may result in data that is biased in different ways. A number of studes has quantitatively assessed the efficacy of diverse methods of sampling ground- dwellq ants, including pitfall trap', w~nkler extracti~n'~' baits', and hand collection from quadrats'. However, vev few studes have addressed the question of which traps is efficient to trap ants. The need of various methods in order to get better estimates of species diversity within a particular habitat was evidenced in Sulawesi, Indone~ia'~'. The use of all suitable sampling methods for certain habitats per unit time is the best suggestion in order to get enough collection and a better estimation of diversity'6'. The objective of this study was to investigate the effectiveness of two sampling methods of collecting ants. MATERIALS AND METHODS The study was conducted at the Sungai Lalang Forest Resenre, Semeny~h, Selangor kom Feb- 1999 to Janw 2000. The forest covers an area 729 ha and the elevation ranges from 50-800 m above sea level. The average annual temperature is 265°C and the total annual precipitation ranges from 432 to 514 mm. The Sungai Lalang Forest Resenre covers a number of forest types ranging from lowland to hll dpterocarp forest that is dominated by