Geographical and Seasonal Patterns of Spleen Mass and Acarine Load in Tropical and Subtropical Leaf-Nosed Bats

DNA barcoding and new records of Ornithodoros yumatensis from Central Mexico

Bats represent the second order of mammals with the highest number of species worldwide with over 1,616 species, and almost 10% of them are recorded in Mexico. These mammals have a great diversity of ectoparasites, in particular soft ticks of the genus Ornithodoros. Desmodus rotundus is one of the bat species that has scarcely been studied in terms of tick species richness in Mexico, with three tick species reported in five of the 32 Mexican states. For this reason, the aim of the present work was to identify ticks associated with D. rotundus from Central Mexico. Fieldwork was undertaken in the municipality El Marqués, Ejido Atongo A, Querétaro, Mexico. Bats were captured using mist nets and were visually inspected for tick presence. The ectoparasites were identified morphologically and molecularly with the use of mitochondrial markers 16SrDNA and cytochrome oxidase subunit I (COI). A total of 30 D. rotundus (1 female, 29 males) were captured, from which 20 larvae identified as Ornithodoros yumatensis were recovered. Molecular analysis confirmed the presence of this species with identity values of 99-100% with sequences of this species from the southwestern US, and the Yucatán Peninsula, Mexico. This is the first report of ticks associated with bats for the state of Querétaro, providing the first sequences of the COI gene from Mexican populations of O. yumatensis and shows an increase in the distribution of this soft tick across Central Mexico.

Ornithodoros dyeri (Parasitiformes: Ixodida: Argasidae) parasitizing Leptonycteris yerbabuenae (Chiroptera: Phyllostomidae) in Mexico

Parasites are a selective force that shape communities and ecosystems. Hosts represent a food source, habitat, and a way to disperse. In recent years, investigations dealing with bats and their role as hosts to numerous parasitic organisms, including metazoan ectoparasites and endoparasites have increased, and soft ticks (Parasitiformes: Ixodida: Argasidae) are among the best known. In Mexico, 16 species of soft ticks associated with bats have been reported up to now, but there are no specific records of soft ticks parasitizing Leptonycteris yerbabuenae in the country. Herein, we record for the first time the presence of Ornithodoros dyeri parasitizing L. yerbabuenae and report an extension of its geographic distribution. The same tick species was also recorded from the California leaf-nosed bat (Macrotus californicus). Data on prevalence, mean intensity, mean abundance, tick identification, and possible scenarios of life cycle associations for O. dyeri and one of its hosts, L. yerbabuenae, are discussed.

Macroimmunology: The drivers and consequences of spatial patterns in wildlife immune defence

The prevalence and intensity of parasites in wild hosts varies across space and is a key determinant of infection risk in humans, domestic animals and threatened wildlife. Because the immune system serves as the primary barrier to infection, replication and transmission following exposure, we here consider the environmental drivers of immunity. Spatial variation in parasite pressure, abiotic and biotic conditions, and anthropogenic factors can all shape immunity across spatial scales. Identifying the most important spatial drivers of immunity could help pre-empt infectious disease risks, especially in the context of how large-scale factors such as urbanization affect defence by changing environmental conditions. We provide a synthesis of how to apply macroecological approaches to the study of ecoimmunology (i.e. macroimmunology). We first review spatial factors that could generate spatial variation in defence, highlighting the need for large-scale studies that can differentiate competing environmental predictors of immunity and detailing contexts where this approach might be favoured over small-scale experimental studies. We next conduct a systematic review of the literature to assess the frequency of spatial studies and to classify them according to taxa, immune measures, spatial replication and extent, and statistical methods. We review 210 ecoimmunology studies sampling multiple host populations. We show that whereas spatial approaches are relatively common, spatial replication is generally low and unlikely to provide sufficient environmental variation or power to differentiate competing spatial hypotheses. We also highlight statistical biases in macroimmunology, in that few studies characterize and account for spatial dependence statistically, potentially affecting inferences for the relationships between environmental conditions and immune defence. We use these findings to describe tools from geostatistics and spatial modelling that can improve inference about the associations between environmental and immunological variation. In particular, we emphasize exploratory tools that can guide spatial sampling and highlight the need for greater use of mixed-effects models that account for spatial variability while also allowing researchers to account for both individual- and habitat-level covariates. We finally discuss future research priorities for macroimmunology, including focusing on latitudinal gradients, range expansions and urbanization as being especially amenable to large-scale spatial approaches. Methodologically, we highlight critical opportunities posed by assessing spatial variation in host tolerance, using metagenomics to quantify spatial variation in parasite pressure, coupling large-scale field studies with small-scale field experiments and longitudinal approaches, and applying statistical tools from macroecology and meta-analysis to identify generalizable spatial patterns. Such work will facilitate scaling ecoimmunology from individual- to habitat-level insights about the drivers of immune defence and help predict where environmental change may most alter infectious disease risk.

Epizoic Fauna Survey on Phyllostomid Bats (Chiroptera: Phyllostomidae) in a Shaded Coffee Plantation of Southeastern Chiapas, Mexico

This is the first complete assessment of the ectoparasite fauna on phyllostomid bats in a shaded coffee plantation in Mexico. The study was carried out at Finca San Carlos, in the municipality of Tapachula, southeastern Chiapas, Mexico. The bats were captured over three consecutive nights every month, from December 2005 to November 2006, using four mist nets. We captured 192 phyllostomid bats, representing 18 species, upon which 1,971 ectoparasites, belonging to 11 families and 65 species, were found. We found that 160 of the 192 captured bats were hosts to ectoparasites, giving an infestation prevalence of 83.3%. Of the 65 ectoparasitic species, 14 were classified as monoxenous and 17 as stenoxenous. More ectoparasites were recorded in the dry season (n = 1,439) than the wet season (n = 532), and we recorded some families of ectoparasite on particular areas of the bat body. An ordination of bat species, based on their ectoparasitic species community structure, formed groups at the subfamily level or lower taxonomic categories. We suggest that the close ectoparasite-host relationships could be examined as an additional tool to elucidate the taxonomic relationships between the hosts.