The Geographical and Ecological Distribution of Arboreal Psocoptera

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Annu. Rev. Entomol. 1985.30:175-196. Downloaded from arjournals.annualreviews.org by Mr. Bas van Berkum on 10/10/07. For personal use only. Annual Reviews www.annualreviews.org/aronline 180 THORNTON three-segmented tarsi, is unique in the family; it is primitive in several respects but has apomorphous characters in common with Elipsocidae. These recent discoveries are of biogeographical and phylogenetic interest and underscore the incompleteness of knowledge, even of such a well-investigated are, a. Recent work on European Elipsocidae (29) has shown that Hemineura dispar occurs in Scandinavia, Estonia, and Germany and at high altitudes in Switzerland and France and in Moravia. Badonnel regarded the species as a postglacial relict; its southern limit is in the mountains of southern France where two congeneric species also occur, H. bigoti and H. hispanica, the latter also known from Spain,. Whereas dispar evidently has two generations per year, at least in Moravia, the two Mediterranean species are univoltine winter species. Both are parthenogenetic, with apterous females, but they differ from one another in aspects of biology and behavior. It is possible that all three species are glacial relicts, since dispar alone has survived in the north and extended to high locations in the south of its range; the other two persist only in the northwest Mediterranean area where they have a long resting stage in the egg and a short active generation in winter. The Atlantic islands have also recently received considerable attention (35, 37). The Canary Islands, which are nearest to the mainland, have 28 species (10 endemic), followed by Madeira, with 19 (4 endemic). The Azores have species (4 endemic), and only 3 species (2 endemic) are known from the Verde Islands. Atlantopsocus (Psocidae), a genus that occurs in the Atlantic islands, comprises three species and is known from Ireland, Morocco, the Canaries, Madeira, and the Azores. Its closest relative appears to be Camelopsocus (54), of which five species are known from western North America. Mesopsocus, which is well represented in northwest Africa, extends only to the Canaries, where one species is endemic; this genus, in which most species have flightless females, is also absent from Madagascar (below). Twelve psocopteran species (four endemic) are known from Saint Helena (7); three of these cosmopolitan and four occur in Northwest Africa and the Atlantic islands mentioned above, possibly introduced by Portuguese maritime activity. Of the endemics, three have closely similar counterparts in West and Central Africa, and one is evidently an older endemic of unknown affinities. Ethiopian Region Coverage of Africa has been patchy; almost 80% of the species are known only from the type locality. The known fauna totals 493 species, and its relationships with those of Madagascar and the Mascarene islands have recently been considered. In West Africa 160 species are known, in East Africa 155 (20, 21), and in southern Africa 239 species are recorded from Angola (9) and 90 from other areas. Africa is rich in a number of families while others that are well represented elsewhere, such as Lachesillidae and Philotarsidae, are absent or have only few species.
Annu. Rev. Entomol. 1985.30:175-196. Downloaded from arjournals.annualreviews.org by Mr. Bas van Berkum on 10/10/07. For personal use only. Annual Reviews www.annualreviews.org/aronline DISTRIBUTION OF ARBOREAL PSOCOPTERA 181 The family Mesopsocidae appears to have its center of diversity in Africa; it is absent from Neotropical and Australian regions and Madagascar and only weakly represented in the Nearctic and Oriental regions (21). The genera Hexacyrtoma and Labocoria are African, and Psoculus occurs in Europe and Africa. The largest genus, Mesopsocus (40 species, 29 described), has species in the Ethiopian region, 14 in the Palaearctic (three also occurring in the Nearctic), and one in the Oriental region. Of three East African mountain massifs, Mount Kenya, the Aberdares, and the Empakaai region, the first two, which are closest to one another, were found to have the most similar psocopteran faunas and each had 19% endemicity, whereas the endemicity of the more isolated Empakaai region was 41%. There is a parallel here with geographical archipelagos (80). A closely related group of four species of Mesopsocus, all with apterous females, occurs at high elevations on mounts Kenya and Kilimanjaro (one species), Mount Kenya and the Aberdares (one), and Empakaai (two). A fifth species with apterous females is evidently restricted to the shores of Lake Naivasha, and a sixth is found on Mount Kenya, the Aberdares, and Empakaai. In the last case, the differentiation of an Empakaai species appears to have been impeded by the presence (unusual in Mesopsocus) of winged females (21). In West Africa the psocid fauna of the 250 km wide Togo-Benin gap, which separates the rain forests to the west from those of Nigeria and Central Africa to the east, has affinities with eastern rather than western regions (101). Six of the 28 species collected from the gap link it with the eastern regions; no Ivory Coast or Guinea species occurred in the collections. Of the 12 new species found in the Gap, only 2 have affinities with western species, and both are widespread; the most similar counterparts of the other 10 species occur to the east. More collecting to the west is needed to confirm the isolation of the western forest bloc species from those of the main body of equatorial rain forest, a finding which would lend support to the hypothesis that the lowland forest isolate to the west was confined to refugia during arid glacial periods. The Madagascar fauna has all the features of insularity; 166 of the 197 species are endemic (84%) as are 6 of 37 genera (16%) (3, 6). Endemic species complexes exist in eight genera. The species flocks of Thylacella, Amphientomum, Ctenopsocus, and Blastopsocidus are each thought to derive from a single founder, whereas those of Myopsocus and Ptycta represent two lines (3). Explosive speciation is also evident in Caecilius (26 species, 24 endemic) and Amphipsocus (29 species, all endemic). Radiation is greatest in the amphipsocid subtribe Amphipsocina, which has three endemic genera. Notable absences of groups well represented in Africa include the genera Belapha, Fulleborniella, Ectopsocopsis, Myopsocus, the families Elipsocidae and Mesopsocidae, and the subfamily Cerastipsocinae of the Psocidae. Nevertheless, links with Africa are evident. The genera Paracaecilius, Epipsocopsis, Harpezoneura, and Blastopsocidus are only known from Africa and Madagascar, and there are
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The Geographical and Ecological Distribution of Arboreal Psocoptera

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