An extensive survey of the ectoparasites infesting bats in Paraguay provides information regarding the taxonomy and host distribution of streblid bat flies at a geographic interface between subtropical and temperate habitats. Five families of bats representing 45 species, including Molossidae (5 genera and 15 species), Natalidae (1 genus and 1 species), Phyllostomidae (11 genera and 15 species), Noctilionidae (1 genus and 2 species), and Vespertilionidae (4 genera and 12 species) were collected from 24 localities across Paraguay and sampled for ectoparasites. In total, 2,467 bat flies were collected, representing 11 genera and 31 nominal species of Streblidae, of which 6 genera and 24 species are new records for Paraguay. No streblids were collected from vespertilionid bats; 23 species infested phyllostomids, 6 species noctilionids, 1 species a natalid, and 1 species molossids. Streblid bat flies were highly specific to certain host groups and individual host species, and their geographic distributions closely followed those of their host bats. Of 31 streblid species surveyed, 27 were monoxenous (i.e., associated with a single host species), and 4 were stenoxenous (i.e., associated with a group of phylogenetically related hosts). The number of streblid species is greatly reduced in the Chaco region west of the Paraguay River, largely because of the lack of phyllostomid host bats. Streblid flies are obligate, blood-feeding ectoparasites of bats. In temperate North America, they primarily infest vespertilionid bats (Wenzel, 1970; Guerrero, 1994), and a few species over winter on hibernating bats (Zeve, 1958; Reisen et al., 1976). However, in Central and South America, the species richness of these flies is increased, primarily in association with phyl lostomid bats (Wenzel, 1970). The most important previous studies regarding the taxonomy and distribution of neotropical Streblidae were based on faunal surveys in Panama (Wenzel et al., 1966) and Venezuela (Wenzel, 1976). During those studies, 10 new genera and 94 new species were described, and the taxonomic foundation of New World Streblidae was estab lished. However, very little is known about the distribution and host associations of streblid flies infesting bats in the subtrop ical and temperate regions of South America. From 1991 to 1997, bats of the Yungas Forests in Argentina were surveyed for ectoparasites (Autino et al., 1999). Although 37 bat species are known from this region, which includes sites in the Argen tine provinces of Jujuy, Salta, Tucuman, and Catamarca, only 7 species of streblids were reported (Autino et al., 1999). In southern Brazil, 23 species are known from the state of Paran? (Graciolli and de Carvalho, 2001) and 11 species from the state of Rio Grande do Sul (Graciolli and Rui, 2001). An extensive, 5-yr survey of ectoparasites infesting bats in Paraguay provided the opportunity to increase our understanding about the distri bution of streblid bat flies across hosts and habitats at the in terface of subtropical and temperate zones. Parag...

ABSTRACT. Community structure, macrohabitat selection, and patterns of species co-occurrence were examined during a 14-month study of small mammals in the Cerrado Province of central Brazil. Data were collected from mark-recapture grids in brejo and gallery forest, and from live-trapping and specimen collection in all habitat types within cerrado (campo limpo, campo sujo, cerrado [s.s.], cerradao, brejo, valley-side wet campo, and gallery forest). Gallery forest supported the highest species richness, most complex vertical distribution of species, highest level of trophic diversity, and highest macroniche diversity. Degree of habitat selection varied widely. All habitat types supported both rodents and marsupials, although marsupials tended to be much less common in the grasslands (campos) than in woodlands (cerrado) and forests (cerradao, gallery forest). Some species, such as Didelphis albiventris, occurred in all habitat types, while others were much more restricted. Oryzomys bicolor, for example, ocurred only in gallery forest. No habitat type had a completely distinct fauna: overlap in species composition always occurred with at least one other habitat type. Because of the great variability of habitats, and the fact that subsets of the mammal fauna were frequently habitat specific, the overall species richness of any portion of mixed cerrado vegetation is remarkably high.

The results of a survey of spinturnicid mites (Gamasida: Spinturnicidae) infesting bats near Brasília, D.F., Brazil, are presented. One hundred twenty-five bats were collected, representing three families and 15 species. Seven species of spinturnicid mites (genus Periglischrus) were collected from nine species of bats (family Phyllostomidae). Each of the following six species of Periglischrus was associated with a single species of bat: Periglischrus acutisternus Machado-Allison and P. torrealbai Machado-Allison on Phyllostomus discolor Wagner; P. paravargasi Herrin and Tipton on Anoura caudifer (E. Geoffroy); P. caligus Kolenati on Glossophaga soricina (Pallas); P. ojasti Machado-Allison on Sturnira lilium (E. Geoffroy); P. herrerai Machado-Allison on Desmodus rotundus (E. Geoffroy). P. iheringi Oudemans was collected from four species of bats (Artibeus cinereus (Gervais), A. jamaicensis Leach, A. literatus (Olfers), and Vampyrops lineatus (E. Geoffroy]. No spinturnicids were found on Carollia perspecillata (L.) or on molossid or vespertilionid bats.

Host specificity is a characteristic property of parasite-host associations and often is high among those involving obligate or permanent parasites. While many parasites are highly host-specific under natural conditions, specificity may break down in the absence of dispersal barriers. We tested the host specificity of obligate and permanent blood-feeding bat parasites (Hemiptera: Polyctenidae) under experimental conditions where parasite dispersal barriers had been removed. Under these conditions, parasites not only readily accepted a secondary host species but also remained there when a primary host was immediately available. Experiments with bat bugs and observations of streblid bat flies suggest that specificity may at least temporarily break down when dispersal barriers are removed. To affect long-term coevolutionary patterns, such transfers would necessarily entail the establishment of viable parasite populations on secondary host species.

A multivariate analysis of morphometric data suggests that the nominally pleioxenous ectoparasite, Androlaelaps rotundus, includes at least three distinct host-associated populations in Paraguay. Where multiple akodontine hosts occur sympatrically, each host species is accompanied by a morphologically distinct mite population. These host-mite associations were consistent across all localities, implying that A. rotundus is a complex of unrecognized species.Key words: ectoparasites, laelapidae, Androlaelaps, Eubrachylaelaps, akodontini, Akodon, Bolomys, Paraguay. RESUMO Androlaelaps rotundus Fonseca (Acari: Laelapidae) associada com roedores akodontinos noParaguay: um exame morfométrico do ectoparasito pleoxeno Uma análise multivariada de dados morfométricos sugere que o ectoparasito pleixeno Androlaelaps rotundus, composto por distintas populações hospedeiro-associadas, no Paraguai. Quando múltiplos hospedeiros akodontinos ocorrem simpatricamente, cada espécie de mamífero é acompanhada por uma população morfologicamente distinta de ácaro. Estas associações hospedeiro-ácaro repetiram-se nos estudos realizados em diferentes localidades, mostrando que A. rotundus é um complexo de espécies críticas indistinguíveis.

Colicus spinosus Goff & Gettinger, n. sp., is described from Marmosa agilis. Quadraseta brasiliensis Goff & Gettinger, n. sp., is described from Marmosa agilis, Monodelphis americana, and Oryzomys capito. All specimens were collected in central Brazil. The diagnosis of the genus Arisocerus Brennan, 1970, is corrected to describe the setation of the palpal tarsus as 7BS rather than 6BS as listed in the original description.

An extensive survey of ectoparasitic nycteribiid flies infesting bats in Paraguay provides information about their taxonomy and hosts at a geographic interface between subtropical and temperate habitats. During the study, 2,931 bats representing five families, 22 genera, and 45 species were captured and sampled for ectoparasites. Of these, 86 individuals belonging to six species of vespertilionid bats, and one individual of a molossid bat, harbored 150 fly specimens. We identified five species of Basilia Miranda-Ribeiro, with one, Basilia juquiensis Guimarães, representing a new record for Paraguay. In total, six species of Basilia have been reported to occur in Paraguay.

A study of associations between small mammals and ectoparasites in two adjacent nature reserves near Brasilia, Federal District, Brazil, revealed that ectoparasitic mites of the genus Laelaps Koch are host specific. Data on the prevalence and intensity of mite infestations were combined with measures of the reproductive activity of mite populations to estimate the association of each host-mite pair. Twelve morphologically distinct species of Laelaps occurred in monoxenous and oligoxenous associations with the cricetid rodent genera Oryzomys, Nectomys, Rhipidomys, and Calomys. Nine were referred to species recognized at the time of the study; three were described as new species in a recent publication. When mites initially assigned as the same species infested more than one host species, an examination of the morphological variation within and among mite specimens supported the hypothesis that mites infesting different hosts were reproductively isolated populations. Dispersal pathways apparently were restricted, occurring primarily between conspecific individuals. In one instance, two morphologically similar groups of Laelaps paulistanensis Fonseca were associated with two closely related rodent species, Oryzomys fornesi Massoia and O. nigripes (Olfers). Although the data presented here indicate that these two groups of mites are conspecific, further study is warranted.