Phylogeny and Classification

It is generally accepted that the Phthiraptera are derived from a free-living Psocopter-alike ancestor, based on a number of synapomorphies (Chapter 2, Section 3.2). There is virtually no fossil record: the Early Cretaceous chewing louse Saurodectes vrsanskyi may have parasitized pterosaur reptiles, and a sucking louse, Neohaematopinus relictus has been found on a rodent, Citellus, from the Pleistocene of Siberia. However, this has not prevented some authors from speculating that the order may be quite ancient, possibly originating as early as the Upper Carboniferous/Lower Permian. Kim and Ludwig (1982) proposed this very early origin for the order to be consistent with their hypothesis that the group arose from an ancestor within the psocopteran suborder Permopsocida, an idea rejected by Lyal (1985). Rather, Lyal (1985) proposed, the lice may have evolved from liposcelidlike Pso-coptera that, as noted in the previous section, have occasionally been found in the nests and on the body of birds and mammals. Initially, this association perhaps aided dispersal of the insects, but in time they may have begun to feed on flakes of dead skin, bits of feathers, etc. At this stage, the association between the ancestral louse and its host presumably would have been facultatively parasitic and much less host-specific than is the case with modern Phthiraptera. The virtual absence of fossils has meant that proposals with respect to the origin and phylogeny of the order have come largely from examination of the host associations of lice, and the phylogeny and zoogeography of their mammalian and avian hosts. Such studies suggest that ancestral lice did not arise until the Cretaceous, with either birds or mammals as hosts. The earliest lice were chewing forms, and from these arose the modern Amblycera on the one hand, and a line leading to the remaining groups on the other. The latter itself split, giving rise to the Ischnocera, whose ancestor retained chewing mouthparts and had either a bird or a mammal as host, and the common ancestor of the Rhyncoph-thirina and Anoplura which, like all modern members of these two groups, presumably fed on mammals. While the Rhyncophthirina retained chewing mouthparts, the Anoplura evolved suctorial mouthparts in conjunction with their blood-feeding habit. Though this scheme may be a reasonable explanation of the evolution of Phthiraptera, Barker (1994)

FIGURE 8.2. A suggested phylogeny of the Phthiraptera. The relationship of the Trimenopodidae to other Amblyceran families is uncertain.

has stressed that the coevolution of lice and their vertebrate hosts has not always occurred, and that host-switching by lice is fairly common. Thus, a phylogeny based on lice characters rather than characters of the host is preferable.

Some authors place the chewing lice and sucking lice in separate orders, the Mallophaga and Anoplura, respectively, the great differences in mouthpart structure and feeding habits being taken as sufficient justification for this separation. Generally, however, all lice are included in the order, Phthiraptera, divisible into four suborders, Amblycera, Ischnocera, Rhyncophthirina, and Anoplura. Thus, the Mallophaga, which comprises the first three suborders, is a paraphyletic group in this scheme, leading some authorities (e.g., Barker et al., 2003) to urge that the term be abandoned. A suggested phylogeny of the Phthiraptera is presented in Figure 8.2.

Suborder Amblycera

Members of the suborder Amblycera have the following characteristics: capitate, four-segmented antennae, lying in grooves; mandibles horizontal, maxillary palps present; and mesothorax and metathorax usually separate.

Generally six families are recognized in this suborder, a group of about 850 species that is considered to contain the more primitive lice. Of the six families, three are restricted to avian hosts, two to marsupials, and one to placental mammals. The MENOPONIDAE form the largest family (650 species) and have a cosmopolitan distribution. Its members infest birds, and several species are important pests of poultry, for example, Menacanthus stramineus (the chicken body louse) and Menopon gallinae (the shaft louse) (Figure 8.3A). The LAEMOBOTHRIIDAE are a small family containing the single genus Laemobothrion,

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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