Dung Beetles (Scarabaeinae)
Primarily coprophages but some species also feed on decaying plant and animal matter and occasionally fallen fruit.

Ants
They compete with carabid beetles for the forest floor and are important for dispersing plant seeds.
The total weight of ants in the tropical rainforest exceeds the total weight of all the other insects, despite the ant's small size. In the jungle there are over 240 types of army ants. Some of them travel in columns of as many as 20 million ants: these columns may be 12 inches (30 cm) wide but several city blocks in length. During the day, they fan out, devouring scorpions, millipedes, katydids, and cockroaches. They even climb the nests of termites wasps and other ant species to eat their young. At night, they form living bivouacs from their own bodies to protect the queen and larvae.
Tribal peoples welcome these ants because they kill the cockroaches and other pests from their homes before moving on.
Leaf-cutter ants climb trees in single file and scissor out leaf pieces with their mandibles. The underground colonies may be home to more than a million ants of different sizes and types. Inside the colony, the ants chew up the leaf pieces and feed them to a fungus which is the only food source for their larva.

Leaf Beetles (Chrysolmelidae)
These are very essential herbivores in rainforest ecosystems.

Stick insects
They feed on foliage but are not necessarily confined to one plant species. However, they are sedentary and slow-moving. They remain in the same area for food and are reluctant to cover large distances. Males posses fully-developed wings; females have reduced wings and are flightless.

Grasshoppers/Katydids (Orthoptera)
Most are herbivorous, but some are predacious. Many are nocturnal though. King crickets (Stenopelmatidae) can grow to more than 8 cm in body length.

Flightless beetles are herbivorous scavengers but most hide under logs and in forest debris to hide from small animals that feed on them

Light-producing insects:
Glow worms (mycetophilid fly larvae) usually reside in rock overhangs and rain forest stream banks. Luminous Arachnocampa glow worms spin a sticky, silky web of threads to snare insects that are lured by the light produced by the fly larvae.

Firefly beetles (Lampyridae)
They emit light in controlled flashes to attract mates. Adult lampyrid beetles in the genus Atyphella fly at dusk on the rain forest borders and within the forest interiors. Lampyrid larvae prey on terrestrial mollusks.