Head Appendages

3.2.1. Antennae

A pair of antennae are found on the head of the pterygote insects and the aptery-gote groups with the exception of the Protura. However, in the larvae of many higher Hymenoptera and Diptera they are reduced to a slight swelling or disc.

In a typical antenna (Figure 3.6) there are three principal components: the basal scape by which the antenna is attached to the head, the pedicel containing Johnston's organ (Chapter 12, Section 3.1), and the flagellum, which is usually long and annulated. According to Kukalova-Peck (1992), the scape, pedicel, and flagellum are homologous with the subcoxa, coxa, and remaining segments, respectively, of the ancestral leg (Figure 3.21A). The annuli on the flagellum do not correspond with the ancestral leg joints; that is, the annuli are constrictions, not sutures. The scape is set in a membranous socket and surrounded by the antennal sclerite on which a single articulation may occur. In the majority of insects movement of the whole antenna is effected by muscles inserted on the scape and attached to the cranium or tentorium. However, in Collembola there is no Johnston's organ and each antennal segment is moved by a muscle inserted in the previous segment.

Although retaining the basic structure outlined above, the antennae take on a wide variety of forms (Figure 3.7) related to their varied functions. Generally, it is the flagellum that is modified. For example, in some male moths and beetles the flagellum is plumose and flabellate, respectively, providing a large surface area for the numerous chemosensilla that give these insects their remarkable sense of smell (see Chapter 12, Section 4). By contrast, the plumose nature of the antennae of male mosquitoes makes them highly sensitive to the sounds generated by the beating of the female's wings (Chapter 12, Section 3.1). Other functions of antennae include touching, temperature and humidity perception, grasping prey, and holding on to the female during mating (Schneider, 1964; Zacharuk, 1985). For taxonomists, this variety of form may be an important diagnostic feature.

3.2.2. Mouthparts

The mouthparts consist of the labrum, a pair of mandibles, a pair of maxillae, the labium, and the hypopharynx. In Collembola, Protura, and Diplura the mouthparts are

: 1 111 1 : 1 -i-i*:- FIGURE 3.6. Structure of an antenna. [From R. E.

Snodgrass, Principles of Insect Morphology. Copyright 1935 by McGraw-Hill, Inc. Used with permission of McGraw-Hill Book Company.]

FIGURE 3.7. Types of antennae. [After A. D. Imms, 1957, A General Textbook of Entomology, 9th ed. (revised by O. W. Richards and R. G. Davies), Methuen and Co.]

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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