Complete metamorphosis(left): adult (1), eggs (2), larvae (3), pupae(4). Incomplete metamorphosis (right): adult (1), eggs (2), nymph stages (3) 

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... Agrodok describes several insect species that you can collect, cook and eat. It provides information on collecting and preparing these selected species. The focus is on the collection of insect species in the field. For several edible insect species, cultivation is also an alternative. The introduction chapter provides information on host plant management and on possible adverse effects of edible insect consumption. The next chapter gives a short introduction on insect biology, anatomy and taxonomy. Following this introductory material are case studies, grouped by insect order. Each chapter starts with a description of the insect order, followed by the description of an edible insect species, how to recognize it, and how to collect and cook it. A few recipes are presented in a final chapter. Chapter 1- Introduction / host-plant management / potential toxicity of edible insects Chapter 2- Insect biology, anatomy and taxonomy Chapter 3- Beetles ( Coleoptera ) Chapter 4- Caterpillars ( Lepidoptera ) Chapter 5- True bugs ( Hemiptera ) Chapter 6- Locusts and Grasshoppers ( Orthoptera ) Chapter 7- Termites ( Isoptera ) Chapter 8- Recipes In the appendices you will find: • a calendar showing when to collect each of the insect species discussed • tips for further reading • useful addresses • a glossary Insects can be found in all types of environments except the oceans. They are enormously divers in both anatomy and appearance. Many features, however, are common to all. Adult insects have six legs. They all have an external skeleton: the cuticula. The hard external exoskeleton serves to protect the insect and to attach the muscles from the inside. The hard, non-elastic exoskeleton limits the growth of the insect larva: after a period of growth, the larval exoskeleton no longer fits. It is replaced during the process of moulting. First, a new, large, chitin exoskeleton is produced from the inside out. The older, outgrown exoskeleton tears apart and the insect discards it. At first the new cuticula is soft, but within a few hours it hardens and darkens. The insect’s body is divided into three sections: the head, thorax and abdo- men (Figure 1). Insects breathe through small openings along the sides of their body. The oxygen (O 2 ) they inhale and the carbon dioxide (CO 2 ) they exhale moves through small tubes throughout the body. Insects have a blood-like fluid called haemolymph, which is usually green - ish or yellow. The blood is not red (from haemoglobin): insect haemolymph does not have to transport oxygen, only sugar and fat from its food. The haemolymph is pumped around by the heart in the abdomen. It floats freely inside the body around the gut, muscles and organs. Several sense organs are located in the head: the eyes and antennae. Insects have compound eyes, which are a number of small eyes grouped togeth- er. In addition, small single eyes can be present elsewhere on the head. Antennae allow the insect to smell and to sense the environment. The an- tennae can vary greatly between species. Antennae of the male and female of the same species can also differ. There is great variation in mouth types, all related to the type of food con- sumed by each species or insect stage. Major differences are observed be- tween larvae and adults. For instance, caterpillars eat leaves with chewing mouthparts called mandibles, yet adult butterflies suck honey from flowers with a tube-like mouth called a proboscis. The legs and wings are attached to the thorax. Some insect larvae – cater- pillars, for example – have additional legs on the abdomen. The abdomen houses the fat reserves, the heart and, in adults, the reproductive organs (eggs or sperm). The insect life cycle consists of several stages: egg, larvae and adult. The number of larval stages, usually 4 to 6, varies among species. Although each insect species has its specific life cycle, there are generally two types (Figure 2). In the first type, complete metamorphosis, the larva and the adult are quite different. The transition from larva to adult is a phase called pupating. The pupa is inactive and does not have functional mandibles. After a certain length of time, a mature adult emerges. In the second type of life cycle, incomplete metamorphosis, the larva or nymph hatches from the egg and resembles the adult, except that it is smaller and may have a different colour. Its way of life and diet are similar to those of the adult. The nymph does not pupate, but rather it ‘changes instar’ (moves to its next developmental stage) as it moults. Coleoptera is one of the largest insect orders. Commonly, these insects are known as beetles. They represent 40% of all insect species. Many economi- cally important pests of both crops and stored products are beetles. Damage can be caused by the adult insect or the larva, or both. Fortunately, though, many beetle species are edible. The adult beetle has two sets of wings. The elytra acts as a protective shell; it is not used for flying (Figure 3). The elytra must be raised in order to make space for the hidden wings to expand and allow the beetle to fly. After flight the rear wings are refolded under the elytra. The mouth parts and legs differ with each beetle species, as they are adapted to each specific environment and diet. Claws, called tarsi, are found at the end of the last leg segment. These claws allow the beetle to climb. The beetle undergoes complete metamorphosis: its larval stage does not re- semble its adult stage. The female beetle lays its eggs near the food source. The larvae emerge and grow through different instars (larval stages). A beetle larva has short legs, and often its head is darker than the rest of its body. The larva pupates for a certain period of time before becoming an adult. Here we’ll discuss three different beetle species, their preferred habitats and the best way of collecting or rearing them. These serve as examples for other edible beetle species. Palm trees harbour various insects, including several edible beetle species. Here we discuss two species. The first of these two, the larvae of the palm beetle Rhynchophorus phoe- nicis , is a delicacy in many parts of Nigeria and other countries in Africa (Figure 4). Various ethnic groups have different names for the larvae. Locally, the larvae are valued for their high nutritious potential as well as a certain pharmaceutical potential. It is common to see the larvae being sold in many cities in the western, southern and middle belt of Nigeria. They are referred to as edible worms, larvae, grubs or maggots. The Urobhos and Ibibios in the Delta and Akwa Ibom states of Nigeria are very fond of the larvae. Palm trees under stress (for any reason) and fallen palms serve as breeding sites for this insect and can support hundreds of larvae. The palm weevil is diurnal: active during the day. The female weevil lays her eggs in palm holes and crevices made by humans or by other insects. She searches ac- tively for cut petioles (stalks that attach leaves to stems) to serve as oviposi- tor (egg-positioning) sites. Each female lays about 200 – 500 eggs which hatch after about three days. The larva is yellowish white or creamy in colour. It has no legs (is apodous) and moves by a wave of contraction and relaxation of the segmented body. The larva is about 7 – 10 cm long and oval in shape. At maturity it has a reddish-brown head capsule. The larval stage usually lasts 8 – 9 weeks. Pupation takes place in a cocoon of broken plant fibres. Developing from an egg to an adult insect may take from 5 to 9 months, depending on cir- cumstances such as temperature. Palm weevil larvae are of economic importance because they produce both beneficial and harmful effects. They cause harm as serious pests to oil, coconut and Raphia palm trees. They destroy the host plant and cause low produce yields. The larvae are voracious feeders. With their hard mouth parts, they penetrate and damage the plant tissues, causing the leaves to die. Decay follows with the formation of galleries with a moist mass of fragmented fibres and a characteristic sour odour. The trunk later becomes tunnelled and weakened and then breaks. The beneficial aspect, on the other hand, is that the larva are edible. This is a benefit for the various populations living where the larvae are found. The larvae are generally referred to as edible worms or grubs. How this food is prepared for eating differs from one locality to another. Some tribes (Urhobos and Isokos, both in Delta state) strongly recommend it for their pregnant women, probably as a source of essential nutrients. The adult insects are also eaten occasionally, when they are caught. Children usually love them. Freshly infected young palm trees are difficult to localize. The area around the trees is wet, so it is arduous for the collector to move about. Also, the infested young palms may look very ...