Phylogeny and Classification

Modern Psocoptera are but the remnants of an order that had already undergone an extensive evolution by the end of the Permian period. Of the four hemipteroid orders, the Psocoptera are generally considered to be closest to the ancestral stock. The earliest fossil Psocoptera (from the Lower Permian of Kansas [U.S.A.] and Moravia [Czech Republic]) differ from modern species with regard to wing venation and mouthpart characters and are placed in a distinct suborder Permopsocina. However, many of the numerous Oligocene fossils, and even some Cretaceous species, can be assigned to extant families (some even to extant genera) indicating that the order has undergone relatively little change since the Mesozoic. Living Psocoptera are divisible into three well defined suborders: Trogiomorpha, Troctomorpha, and Psocomorpha (Eupsocida). The Trogiomorpha contains the most primitive and the Psocomorpha the most advanced Psocoptera. The Psocomorpha has been the dominant suborder since the Late Cretaceous. Unfortunately, insufficient systematic work has been done to permit firm conclusions to be reached with respect to the relationships of the many families. This is especially true for the Psocomorpha, to which at least 75% of the recent species belong. The classification of Badonnel (1951), which is used here, continues to be accepted as the one that most accurately reflects phylogenetic relationships within the order (Smithers, 1991; Mockford, 1993).

Suborder Trogiomorpha

Distinguishing characters of Trogiomorpha include antennae with more than 20 segments, never secondarily annulated; tarsi three-segmented; labial palps two-segmented; pterostigma not thickened, or absent; and paraprocts with strong posterior spine.

In this suborder the major families are the LEPIDOPSOCIDAE, TROGIIDAE, PSO-QUILLIDAE, and PSYLLIPSOCIDAE. Lepidopsocidae (165 species) form a primarily tropical group ofbark- and leaflitter-inhabiting forms recognized by their somewhat mothlike appearance produced by the scales on their body and wings. Though a small family (about 20 species), the Trogiidae is a cosmopolitan group that includes several species found in buildings. Examples are Trogium pulsatorium (Figure 8.1A), a common book-louse that feeds on paper, vegetable matter, and cereal products, and Lepinotus inquilinus that is found especially in granaries and warehouses. Psoquillidae and Psyllipsocidae are both small (about 20 species in each), widely distributed families. Psoquillids are found on bark, in bird nests, and litter. Psyllipsocids occur in caves and termite nests. Both families include some species found indoors.

Suborder Troctomorpha

Features of Troctomorpha are 12- to 17-segmented antennae, with some flagellar segments secondarily annulated; 2- or 3-segmented tarsi; 2-segmented labial palps; pterostigma not thickened; and paraprocts without a strong posterior spine.

The largest families in this suborder are the LIPOSCELIDAE (140 species), AMPHIENTOMIDAE (40 species), and PACHYTROCTIDAE (60 species). The

FIGURE 8.1. Psocoptera. (A) Trogium pulsatorium (Trogiidae) (distal antennal segments omitted); (B) Li-poscelis sp. (Liposcelidae); and (C) Ectopsocus californicus (Ectopsocidae). [A, from P.-P. Grasse (ed.), 1951, Traite de Zoologie, Vol. X. By permission of Masson, Paris. B, C, from L. A. Swan and C. S. Papp, 1972, The Common Insects of North America. Copyright 1972 by L. A. Swan and C. S. Papp. Reprinted by permission of Harper & Row, Publishers, Inc.]

FIGURE 8.1. Psocoptera. (A) Trogium pulsatorium (Trogiidae) (distal antennal segments omitted); (B) Li-poscelis sp. (Liposcelidae); and (C) Ectopsocus californicus (Ectopsocidae). [A, from P.-P. Grasse (ed.), 1951, Traite de Zoologie, Vol. X. By permission of Masson, Paris. B, C, from L. A. Swan and C. S. Papp, 1972, The Common Insects of North America. Copyright 1972 by L. A. Swan and C. S. Papp. Reprinted by permission of Harper & Row, Publishers, Inc.]

Liposcelidae is a cosmopolitan group whose members are recognized by their greatly enlarged hind femora. The family includes a number of common booklice (Liposcelis spp.) (Figure 8.1B) found in houses, warehouses, and ship holds. Outdoor species typically occur in litter and under bark. However, occasionally they have been taken in the nests of vertebrates, in the fur of mammals, and on birds' feathers, these associations possibly aiding dispersal of the psocopterans. Amphientomids are predominantly found in tropical regions of the Old World. They occur under bark and in litter. Pachytroctidae are also mainly tropical, occurring in both the Old and the New World. Typically, they are found under bark or in litter, occasionally in buildings.

Suborder Psocomorpha

Features of Psocomorpha include antennae almost always 13-segmented, with flagellar segments not secondarily annulated; tarsi 2- or 3-segmented; labial palps unsegmented; pterostigma not thickened; and paraprocts with strong posterior spine.

Judging by their common features, this very large suborder, containing more than 20 families, is probably derived from or had a common ancestry with the Troctomorpha. Most members of the suborder are found outdoors, on growing vegetation, in leaflitter, or on bark. The AMPHIPSOCIDAE (140 species) is a cosmopolitan family that includes some of the largest Psocoptera. They are generally found on broad-leaved foliage. ARCHIPSOCIDAE (60 species) form a tropical family, largely from South America and Africa, some species of which live in massive aggregations under sheets of webbing that may cover an entire tree. The CAECILIIDAE is a very large family (370 species mostly in the genus Caecilius) of worldwide distribution. Most species are foliage dwellers. ECTOPSOCIDAE (120 species), which form a cosmopolitan group, are typically found in dry foliage and leaf litter though a few species are found elsewhere; for example, Ectopsocus californicus (Figure 8.1C) is a common booklouse and E. pumilis is a cosmopolitan species found in granaries and warehouses. PERIPSOCIDAE (120 species) are bark dwellers with a cosmopolitan distribution. Members of the ELIPSOCIDAE and EPIPSOCIDAE (each with about 100 species) are

Beekeeping for Beginners

Beekeeping for Beginners

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