Structure of the beetle fauna (Insecta: Coleoptera) in forest remnants of western Puerto Rico

Abstract

We studied the richness and abundance of beetle families in two successional forest fragments located in close proximity on the campus of the University of Puerto Rico at Mayagüez (UPRM), western Puerto Rico. The study period extended from April to December 2005 and included nine monthly repetitions of quantitative samples using necrophilous, pitfall, and light traps. A total of 30 beetle families—48% of the families reported on the Island—and 38,126 individuals were obtained. The among-site variation was low, as both sites were dominated by beetles belonging to the families Curculionidae, Nitidulidae, Staphylinidae, Scarabaeidae, and Hydrophilidae (in order of abundance). These families represent a range of feeding habits and jointly constituted more than 93% of the samples. The light traps were most effective in maximizing the sampled beetle diversity. The abundance of most groups was correlated with the seasonal changes in climate and resource availability, and peaked in the middle of the rainy season in August. In summary, the forest fragments of the UPRM campus harbor a surprisingly diverse and temporally dynamic beetle fauna. More wide-ranging assessments of coleopteran communities residing in successional forests in Puerto Rico are needed to characterize and preserve these valuable habitats.