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 182 THORNTON seven cases of species pairs with a member of each occurring in Africa and Madagascar; other species pairs appear to represent a more recent disjunction within Madagascar itself. The Mascarene Islands, Reunion and Mauritius, together have a fauna of 44 species, half of which is endemic to the group. The islands have know faunas of 34 (12 endemic) and 16 (6 endemic) species respectively, with 6 species common (4 endemic) (2, 10, 94). Three genera endemic--lsophanopsis (Caeciliidae) on Reunion and Mockfordiella (Caeciliidae) and Mascaropsocus (Peripsocidae) on both islands. The fauna has remarkably little affinity with that of Madagascar. For example, the relationships of the Reunion endemics with Madagascar are few and probably represent very old phylogenetic events; present conditions are unfavorable for faunal exchange. North America and the Neotropics About a score of North American species have Holarctic distributions. Some may be true relicts, but about half are probably the result of recent introductions (49, 50). Lachesilla, one of the largest genera in the order with almost 300 recognized species (27; A. N. Garcia-Aldrete personal communication), has its chief representation in North America (over 120 species endemic). Of the 18 species groups recognized, all are represented in the Americas and all but two in North and Central America. Only three groups extend beyond the New World to Africa (all), Europe (one), and Madagascar (one). Systematic studies of the cerastipsocine Psocidae suggest an early New World radiation with African and Oriental groups as derivatives (51). example of a monophyletic group confined to Central and North America is Kaestneriella (Peripsocidae) (56). Recent work on the North American fauna has concentrated on detailed continental distributions of species (25), species pairs (48), and species groups (14, 40, 41, 43-45, 53). Many of these distributions may be related to the effects of glacial changes (disruptions of previously continuous ranges, Pleistocene refugia, and early Tertiary invasions from the south). In view of the massive representation of Lachesilla on the continent it is remarkable that only four species occur in Cuba, only one of which is unknown elsewhere. Of the 68 psocids known from Cuba (8, 46), 35 (51%) are presumed endemics. About half have close relatives in the Caribbean area or the adjacent mainland, and in the Psocidae the genera Blaste and Indiopsocus have closely related groups of species that are probably autochthonous. There is no endemic genus. Most of the widespread tropical species occur also in Africa and were possibly introduced to the American tropics during the slave trade. Jamaica has also been surveyed (93), and 83 species are known./kgain, there
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 183 are no endemic genera, and again remarkably few species (three, two endemic) of Lachesilla occur there. Several genera have speciated in the highlands, and 55 species (66%) are presumed endemics. Fourteen species are neotropical, five African, and nine cosmopolitan or tropicopolitan. There are few species in common with Cuba. In both Cuba and Jamaica there are rather few affinities with Mexico, and whereas links with the Floridean paxt of North America have been detected in the case of Cuba, South America has been suggested as a main source area for Jamaica. The very weak representation of Lachesilla and weak affinities with Central America argue against a land connection to the west, and the hurricane patterns in the Caribbean are in accord with the Floridean and South American affinities suggested. A further 40-50 species are known from other Caribbean islands (11, 24, 42, 43), over half of which are endemic to individual islands; they include 6 of the 10 species of the Caribbean genus Spurostigma, 3 of the endemic genus Troctopsocopsis, and a largely Caribbean group of Caecilius. Additional collections, both in the Caribbean and mainland areas to the south, are needed before hypotheses of Caribbean psocid biogeography can be formulated. Groups well represented in the neotropics include the families Pachytroctidae, Archipsocidae, Epipsocidae, and Liposcelidae and the amphipsocid genus Polypsocus. The Neurostigmatidae, Spurostigmatidae, Thyrosophorinae (Psocidae), and the genera Steleops and Dasydemella are confined to the region while the Troctopsocidae, Dolabellopsocidae, and Ptiloneuridae each have but a single species outside South America (in Europe, India-China, and Africa respectively). Endemic genera include Spurostigma, Isthmopsocus, and Dolabellopsocus. Some otherwise rather widespread families are absent (Psilopsocidae, Mesopsocidae) and others are relatively weakly represented (Lepidopsocidae, Amphientomidae, Ectopsocidae, Elipsocidae, Myopsocidae, Philotarsidae, and Stenopsocidae). It is thus possible to characterize the neotropical psocopteran fauna in these general terms. The known Galapagos fauna (90) comprises 40 species, and where affinities can be determined they appear to be largely with the above region. Two species of Indiopsocus are of particular interest. I. dentatus is related to species from the Caribbean, the gulf coast of Mexico, and southern Florida (E. L. Mockford, personal communication); it occurs at low and high altitudes and is on almost all Galapagos islands. I. acraeus appears to be most closely related to I. expansus, known from the Colombian Andes at 2750 m. In contrast to I. dentatus it is a high altitude stenotope, found only on high islands at elevations above 500 m. In both species, differences between island populations and between isolates on volcanoes of a single island have been recognized, and peripheral isolates are more differentiated than those on more centrally located, less isolated islands or volcanoes (I. W. B. Thornton, unpublished). Correla-
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The Geographical and Ecological Distribution of Arboreal Psocoptera

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