Insects around us

The word insect date back to 1600 from the latin word insectum meaning with divided body (head, body thorax) There are nearly 1.4 to 1.8 million species of insects in the world today. The most numerous of the insect species are beetles.

The life cycles of insects vary but most hatch from eggs. Insect growth is constrained by the inelastic exo-skeleton and development involves a series of molts. The immature stages can differ from the adults in structure, habit and habitat and can include a passive pupal stage in those groups that undergo complete metamorphosis .

Insects that undergo incomplete metamorphosis lack pupal stage and adults develop through a series of nympal stages

Insects typically move about by walking, flying or occasionally swimming. 

Insects are the only invertebrates to have evolved flight and most of them lead a solitary lifestyle but some such as the African honey bee (honey comb picture with bees) and Atta cephaloles are social and live in large, well organized colonies.

Insects can communicate with each other in a variety of ways. Male moths can sense the pheromones of female moths. Other species communicate with sounds. Crickets stridulate or rub their wings together. In the beetle order coleptera they communicate with light.

Humans regard certain insects as pests and attempt to control them using insecticides and a host of other techniques. Some insects like the fruit fly damage mango fruits. Female anopheles mosquitoes bite humans and transmit malaria causing vector called plasmodia, tse tse flies bite livestock and infect them with nagana and sleeping sickness after transmitting the trypanasoma.

Nevertheless without insects to pollinate flowers, the human race would soon run out of food because many of the crop plants that we rely on would not be able to reproduce. Commercial insects with economic benefit include silk worms and honey bees.

Below are some of the insect species in Kenya,

Oryctes sp., (Rhinoceros Beetle) Most of the Rhinoceros beetles develop in dung, including thst of elephants. Adults are normaly large and the males are famous for the horns that develop on their heads and from which the common is derived.

Milkweed bugs- These true bugs feed on the seeds of poisonous asclepiad plants such as calotropis, in the process sequestering cardiac glycosides that are extremely toxic to potential predators. The bugs toxicity is advertised by its conspicuous warning colouration.

Dragonfly Trithemis sp. This species is a close relative of the violet drowping. Dragon flies are among the most ancient of insects, having evolved about 300 million years ago.

Rhiniidae cf. Fainia sp. Rhiinid flies play an important role in nutrient recycling, and many are scavengers on decaying organic matter.

Pontia helice is an elegant butterfly in the family pieridae, and like the African migrant it flies year round.

Hodebertia testalis. Caterpillars of this beautiful moth feed on the poisonous tissues of the fruits of the asclepiad climber pergularia daemia. Presumably, the adult moth are distasteful to bird predators.