Contents - LAC Biosafety

ole in the ecology of tropical forests as pollinators, and parasitoids of injurious
insects. The many species of tropical honeybees alone have provided subsistence
and economic benefits to the tribal, rural and urban societies of the tropics since
ancient times. The role played by parasitoids in the families Ichneumonidae,
Braconidae, Chalcidae, Elasmidae, Eulophidae, Bethylidae, Trichogrammatidae
etc. in keeping the populations of the several tree pests within bounds, by
parasitising their eggs, larvae and pupae, is immeasurable. Although the leafcutting
ants of tropical America are pests in general, large populations of ants
are important predators and scavengers in the tropical forests. In the canopy of
tropical forests in Panama, Erwin (1983b) found that among the 18 orders of
canopy insects present 50.8% of the individuals were hymenopterans, of which
84% were ants. In addition to the leaf-cutting ants, a small number of
hymenopterans such as sawflies, gall wasps and wood wasps are also pests of
trees, although these are more important in temperate than in tropical forests.
In addition, over 100 species of the genus Tetramesa belonging to the
predominantly parasitic family Eurytomidae (subfamily Chalcidoidea) are
phytophagous; T. gigantochloae infests the stem of some bamboos in Malaysia
(Narendran and Kovac, 1995). Among the tropical sawflies (suborder Symphyta),
Shizocera sp. (Argidae) is a defoliator of Manglietia conifera in Vietnam (Tin, 1990)
and several species of Sericoceros (Argidae) feed on the leaves of some trees in
tropical America (Ciesla, 2002).
Order Hemiptera (bugs)
2.2 The diversity of tropical forest insects 43
This order includes bugs that can be distinguished into three main
groups (suborders): Heteroptera or the ‘true bugs’ which includes water skaters,
belostomatids, bed bugs, tingids, lygaeids, pentatomids etc.; Sternorrhyncha
which includes whiteflies, scale insects, aphids and jumping plant lice (psyllids);
and Auchenorrhyncha which includes the leaf hoppers, tree hoppers and
cicadas. In Heteroptera, the forewings are thick and stiff at the basal half and
thin and membraneous at the distal half, and the abdomen has scent or stink
glands. In all bugs, the mouthparts are of a piercing and sucking type. Generally,
the bugs suck the sap of plants, but members of some families such as
Reduviidae and Pentatomidae are predators and suck the fluid of other animals
including insects. The major families of importance to tropical forestry are
Cicadidae, Coccidae, Psyllidae and Tingidae. Cicadas are well-known insects of
the tropical forests and feed on the sap of tender shoots and twigs of trees. They
feed gregariously for long hours and the copious fluid excreta ejected by them
from the tree tops drops on the ground like an incessant spray. The shrill but
loud noise produced by the male cicadas in chorus is characteristic of tropical
forests. The Coccidae include the economically beneficial lac insect on which