Insect Diversity

suggests their closest relatives may be Grylloblattodea or Phasmida (Klass et al., 2002).

The Paraneoptera (hemipteroid orders) share a number of features. They possess suctorial mouthparts, and the clypeal region of the head is enlarged to accommodate the cibaria1 sucking pump (see Figure 3.17). Their tarsi have three or fewer segments, the ganglia in the nerve cord are fused, there are six or fewer Malpighian tubules, and cerci are absent (at least in extant species). The anal lobe of the hind wing is reduced, never having more than five veins, and when the hind wing is drawn over the abdomen, it folds once along the anal or jugal fold, not between the anal veins as in the pliconeopterans. The wing venation of hemipteroids is much reduced as a result of fusion of primary veins and almost complete loss of crossveins and, when both fore and hind wings are present, is basically similar in each. Included in the hemipteroid assemblage are four extant orders and a few entirely fossil groups, though the number of these will surely increase as the Protorthoptera are reworked. As noted earlier, the Miomoptera and Caloneurodea are considered hemipteroid by some authors, but are included in the endopterygote or pliconeopteran groups by others. The Glosselytrodea (Permian-Jurassic) are considered hemipteroid by Hamilton (1972) and Kukalova-Peck (1991) on the basis of limited wing-venational features, though most authorities consider them endopterygotes close to the neuropteroids (Carpenter, 1977, 1992), based on different interpretation of the homologies of the wing venation. Unfortunately, the mouthparts and immature stages are not known. Hemiptera (true bugs) (Figure 2.7B), Psocoptera (psocids), and Thysanoptera (thrips) are known from as early as the Lower Permian period. The rich fossil record of the hemipterans indicates that the three major groups (Sternorrhyncha, Auchenorrhyncha, and Heteroptera) were already separated in the Permian (Wootton, 1981; Kukalova-Peck, 1991). Psocopterans may be the closest to the hemipteroid stem group, though their simplified wing venation and stubby, triangular mouthparts are derived features. The thrips are poorly represented in the Paleozoic fossil record, though interestingly the earliest specimens still have symmetrical mouthparts, unlike the extant forms in which the right mandible has been lost. Phthiraptera (chewing and sucking lice) are barely known as fossils; Saurodectes, a chewing louse from the Lower Cretaceous, may have parasitized pterosaurs. However, the many similarities between them and Psocoptera, notably the specialized preoral water-uptake mechanism, ovipositor structure, polytrophic ovarioles, hypopharynx (in primitive chewing lice), and nuclear rDNA sequences, suggest that the two are sister groups (Wheeler et al., 2001). Indeed, some authorities include them in a single order Psocodea.

The main feature that unites members of the Oligoneoptera (endopterygotes) is the presence of the pupal stage between the larval and adult stages in the life history. Other probable synapomorphies include the absence of compound eyes in the immature stages (instead, stemmata occur), development of the wing rudiments in pouches beneath the larval integument, and the absence of external genitalia in immature stages. Despite these features, early investigators experienced some difficulty in deciding whether the group had a monophyletic or polyphyletic origin. The difficulty arose because, whereas the orders Mecoptera, Lepi-doptera, Trichoptera, Diptera, and Siphonaptera show obvious affinities with each other and form the so-called panorpoid complex (Hinton, 1958), the remaining groups (neuropteroids, Coleoptera, Hymenoptera, and Strepsiptera) appear quite distinct, each apparently bearing little similarity to any other endopterygote group. The modern consensus, supported by both morphological and molecular data, is that the Oligoneoptera is a monophyletic taxon with the major subgroups forming at a very early date. However, opinions differ with respect

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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