Mouthparts

The mouthparts are formed from appendages of head segments 3-6. In omnivorous insects, such as cockroaches, crickets, and earwigs, the mouthparts are of a biting and chewing type (mandibulate) and resemble the probable basic design of ancestral pterygote insects more closely than the mouthparts of the majority of modern insects. Extreme modifications of basic mouth-part structure, correlated with feeding specializations, occur in most Lepidoptera, Diptera, Hymenoptera, Hemiptera, and a number of the smaller orders. Here we first discuss basic mandibulate mouthparts, as exemplified by the European earwig, Forficula auricularia (Dermaptera: Forficulidae) (Fig. 2.10), and then describe some of the more common modifications associated with more specialized diets.

There are five basic components of the mouthparts:

1 labium, or "upper lip", with a ventral surface called the epipharynx;

2 hypopharynx, a tongue-like structure;

3 mandibles, or jaws;

4 maxillae (singular: maxilla);

The labrum forms the roof of the preoral cavity and mouth (Fig. 3.14) and covers the base of the mandibles. Until recently, the labrum generally was considered to be associated with head segment 1. However recent studies of the embryology, gene expression, and nerve supply to the labrum show that it is innervated by the tritocerebrum of the brain (the fused ganglia of the third head segment) and is formed from fusion of parts of a pair of ancestral appendages on head segment 3. Projecting forwards from the back of the preoral cavity is the hypopharynx, a lobe of uncertain origin, but perhaps associated with the mandibular segment; in apterygotes, earwigs, and nymphal mayflies the hypopharynx bears a pair of lateral lobes, the super-linguae (singular: superlingua) (Fig. 2.10). It divides the cavity into a dorsal food pouch, or cibarium, and a ventral salivarium into which the salivary duct opens (Fig. 3.14). The mandibles, maxillae, and labium are the paired appendages of segments 4-6 and are highly variable in structure among insect orders; their serial homology with walking legs is more apparent than for the labrum and hypopharynx.

The mandibles cut and crush food and may be used for defense; generally they have an apical cutting edge and the more basal molar area grinds the food. They can be extremely hard (approximately 3 on Moh's scale of mineral hardness, or an indentation hardness of about 30 kg mm-2) and thus many termites and beetles have no physical difficulty in boring through foils made from such common metals as copper, lead, tin, and zinc. Behind the mandibles lie the maxillae,

coronal suture epicranial suture (an ecdysial line)

frontal suture

Beekeeping for Beginners

Beekeeping for Beginners

The information in this book is useful to anyone wanting to start beekeeping as a hobby or a business. It was written for beginners. Those who have never looked into beekeeping, may not understand the meaning of the terminology used by people in the industry. We have tried to overcome the problem by giving explanations. We want you to be able to use this book as a guide in to beekeeping.

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