Economic Tropical Forest Entomology

Abstract

Various aspects of forest entomology have been considered in nearly all past issues of the Annual Review of Entomology, but references to work in the tropics are few indeed. There are, I feel, several reasons for this pauc­ ity. Two of the main reasons are: 1. There have been relatively few tropical forest entomologists-at present they number less than 50. Prior to World War II there was not much demand for them, and only after that war has considerable interest been shown in the vast tropical timber stands which constitute an estimated 45-55 percent of the world's timber resources, and in establishing plantations of mainly fast-growing commercial tree species. This postwar growth in tropical forestry is indicated clearly in Table 1. Concomitant with these developments has been the establishment of forest entomology sections and the expansion of existing ones because insect pests are proving most troublesome (80, 120). 2. Much of the information pub­ lished on the subject has appeared in national, institutional, or trade jour­ nals and bulletins or reports which s.eldom enjoy a wide circulation among entomologists. Most tropical forests are found in developing countries and they fall largely within the Tropics of Cancer and Capricorn. For purposes of this review I have adopted Kuchler's delimitation of humid tropical forests of the world, in which he employed vegetation as a criterion (97) ; however, I have also included those subtropical forests in which it is difficult to delin­ eate between subtropical and tropical forest entomology of a region as in parts of Africa, Australia, and in India, for example. The tropical forest is usually a rich complex of plant species and numbers that has been little studied (207), and which has been classified by various means (272). This complexity and variable classification combined with an inadequate knowl­ edge of nearly all commercial tree species makes it hard for the entomolo­ gist to study the intimate relationships between insects and their hosts that are often vital to the development of suitable control measures. Most tropical forest entomologists have worked under harsh climatic and sometimes dangerous environmental conditions, with a serious lack of skilled technical staff, proper equipment, and communication with other ex­ perienced scientists (120). In addition, the insect fauna of tropical forests, except for macro-lepidoptera, is poorly known ; even less information' is available on the species biology, ecology, and economic status. This has re-