Predatory beetles on seeds, fruits, and flower buds in a tropical forest of Panama

Abstract

Fruit and seed predators determine plant populations dynamics and community structure of tropical forests. Its impact can have drastic consequences on the development of plants and their ability to reproduce. Among the main causes of damage to fruits, and seeds, Coleoptera of the Curculionidae and Bruchidae families and other groups of beetles stand out. The research was carried out in the Metropolitan Natural Park (PNM), considered as the "lung of the City of Panama" which has deciduous trees that reach up to 36 m in height and an average annual temperature of 28° C. The work consisted of collecting samples of fruits and seeds of all plant species encountered in the fruiting condition in the park from August 2015 to July 2016. Additionally, flower buds of Anacardium excelsum L. attacked by two species of Anthonomus Germar, 1817 were also included in the analyses. A total of 797 beetles were collected from 3091 samples (seeds, fruits, flower buds) reared at environmental conditions. The Curculionidae and Bruchidae families presented the highest abundance of individuals and species richness. One species of Hypothenemus Westwood, 1836 (Scolytinae), was the most abundant within the Curculionidae family and in the Bruchidae family one species of Acanthoscelides Schilsky, 1905. Tree species such as Oenocarpus mapora H. Karst. 1857 and Guazuma ulmifolia Lam presented higher predation of their fruits or seeds. On average only 5% of dissected seeds were predated across 32 host plant species. In total, 31 genera of beetles were reared from flower buds, seeds, and fruits of 17 plant species. Host-specificity was moderated, with 47% of flower bud, fruit and seed predator genera associated with just one plant species. Sixty one percent of the coleopterans were collected in the dry season (December to March).