An annotated list of insect herbivores foraging on the seedlings of five forest trees in Guyana

Abstract

An annotated list of the free-living insect herbivores collected on the seedlings of five rainforest tree species of economic importance near Mabura Hill, Guyana, is presented. The host plants were Chlorocardium rodiei (Scomb.) (Lauraceae), Mora gonggrijpii (Kleinh.) Sandw. (Caesalpiniaceae), Eperua rubiginosa Miq. (Caesalpiniaceae), Pentaclethra macroloba (Willd.) Kuntze (Leguminosae,) and Catostemma fragrans Benth. (Bombacaceae). During the monitoring of approximately 10,000 seedlings at monthly intervals during two years, 27,735 insect individuals were collected representing 604 species. Leaf-chewing insects were further tested in captivity, to remove transient and non-feeding species. The most common higher taxa included Psyllidae, Cicadellinae, Derbidae, Membracidae and Achilidae for sap-sucking insects and Galerucinae, Eumolpinae, Alticinae, Cryptocephalinae, Gelechiidae and Entiminae for leaf-chewing insects. Most of the common species collected (n > 22 individuals) were generalists. At the onset of the second collecting year, half of the parent trees ("stations", n = 125) were felled to mimic selective logging. Preliminary tests comparing the abundance of the most common species during the successive collecting years and at the non-felled vs. felled stations are also presented. These tests suggest that moderate levels of disturbance increased the abundance of a few species only and these patterns were not necessarily similar for congeneric species. The present survey represents one of the few studies of insect herbivores on seedlings in tropical rain forests.