Phylogeny and Classification

The Thysanoptera appear to be most closely related to the Hemiptera, with which they may have had a common ancestor in the Upper Carboniferous or Lower Permian period. An earlier suggestion (Grinfel'd, 1959, cited in Stannard, 1968) that the order arose as a pollen-feeding group is no longer tenable in light of recent comparative morphological and ontogenetical studies of the mouthparts (Heming, 1993). This author suggested that thrips arose from a litter-dwelling, fungivorous ancestor, with the gradual loss of the left mandible perhaps resulting from selection pressure for small body size, a single structure being quite adequate for making a hole in the tissue. Subsequently, numerous small but significant changes in mouthpart structure enabled thrips (especially Tubulifera) to radiate into the numerous, cryptic microhabitats that they now occupy. Unfortunately, this radiation cannot be traced in the relatively poor, early fossil record for this order; indeed, some supposed early fossils (e.g., Permothrips) are now thought to belong to other hemipteroid orders (Mound et al., 1980). From the Cretaceous period on, fossils become much more abundant, but most of these can be assigned to modem families. Recent Thysanoptera can be arranged in two suborders and nine families. Of the two suborders, the Terebrantia, whose members retain wing veins and, in females, a well-developed ovipositor, are undoubtedly more primitive than the Tubulifera, whose species have veinless wings and a greatly reduced ovipositor. A proposed phylogeny of the extant families is shown in Figure 8.25.

Suborder Terebrantia

Uzelothrips scabrosus, collected in Brazil and Singapore on dead twigs and litter, is the sole species in the family UZELOTHRIPIDAE. Its relationship with other Terebrantia remains conjectural but, on the basis of its fully developed tentorium, Mound et al. (1980) suggested that it might be a relict form. The MEROTHRIPIDAE form a small Neotropical group whose 15 species occur in leaf litter or on dead twigs. The family has several characters that suggest it may be the most primitive of the extant Thysanoptera. Most of the 260 species of AEOLOTHRIPIDAE live in temperate regions in both the Northern and the Southern

FIGURE 8.25. A proposed phylogeny of the Thysanoptera. [After B, S. Heming, 1993, Structure, function, ontogeny, and evolution of feeding in thrips, in: Functional Morphology of Insect Feeding (C. W. Schaefer and R. A. B. Leschen, eds.), Thomas Say Publications in Entomology: Proceedings. By permission of the Entomological Society of America.]

FIGURE 8.25. A proposed phylogeny of the Thysanoptera. [After B, S. Heming, 1993, Structure, function, ontogeny, and evolution of feeding in thrips, in: Functional Morphology of Insect Feeding (C. W. Schaefer and R. A. B. Leschen, eds.), Thomas Say Publications in Entomology: Proceedings. By permission of the Entomological Society of America.]

Hemisphere. They mostly feed on other arthropods though some species eat pollen or the tissues of vascular plants. The HETEROTHRIPIDAE (70 species) (as defined by Mound et al., 1980) is a strictly New World group of pollen-feeding thrips found on trees and flowers. The FAURIELLIDAE and ADIHETEROTHRIPIDAE, with four and five species of pollen feeders, respectively, were originally included in the previous family. The fauriellids include two genera from southern Africa and one from southern Europe, the adiheterothripids one genus from western North America and a second that ranges from the eastern Mediterranean to India. By far the largest and most specialized group in the suborder is the cosmopolitan family THRIPIDAE (1710 species). Though some thripids are predaceous, pollenophagous, or fungivorous, the great majority feed on sap obtained from the epidermis or mesophyll of vascular plants. Most pest thrips belong to this family and cause damage either directly by generally weakening their hosts or indirectly by serving as vectors of disease-causing viruses. Several pest species have been transported through trade to many parts of the world. Taeniothrips inconsequens, the pear thrips (Figure 8.26A), is a European species now widespread through North America where it is a major pest of sugar maple. Taeniothrips simplex, the gladiolus thrips, is another widespread species. Thrips tabaci, the onion thrips, is a cosmopolitan species, which, although preferring onions, is known to feed also on many other plants, including tomatoes, tobacco, cotton, and beans. This, and other species of Thrips and Frankliniella, are known to transmit the virus that causes spotted wilt of tomatoes. Species of Limothrips (grain thrips) are important pests of cereal crops in various parts of the world.

Suborder Tubulifera

All but one species (Lonchothrips linearis; LONCHOTHRIPIDAE) in this suborder of about 3100 species are placed in the cosmopolitan family PHLAEOTHRIPIDAE

FIGURE 8.26. Thysanoptera. (A) The pear thrips, Taeniothrips inconsequens (Thripidae); and (B) Liothrips citricornis (Phlaeothripidae). [A, from P.-P. Grasse (ed.), 1951, Traité de Zoologie, Vol. X. By permission of Masson, Paris. B, from L. J. Stannard, Jr., 1968, The thrips, or Thysanoptera, of Illinois, Bull. Ill. Nat. Hist. Surv. 29(4):215-552. By permission of the Illinois Natural History Survey.]

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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