Flying bats use serial sampling to locate odour sources

Olfactory tracking generally sacrifices speed for sensitivity, but some fast-moving animals appear surprisingly efficient at foraging by smell. Here, we analysed the olfactory tracking strategies of flying bats foraging for fruit. Fruit- and nectar-feeding bats use odour cues to find food despite the sensory challenges derived from fast flight speeds and echolocation. We trained Jamaican fruit-eating bats ( Artibeus jamaicensis ) to locate an odour reward and reconstructed their flight paths in three-dimensional space. Results confirmed that bats relied upon olfactory cues to locate a reward. Flight paths revealed a combination of odour- and memory-guided search strategies. During ‘inspection flights’, bats significantly reduced flight speeds and flew within approximately 6 cm of possible targets to evaluate the presence or absence of the odour cue. This behaviour combined with echolocation explains how bats maximize foraging efficiency while compensating for trade-offs associated with olfactory detection and locomotion.

Natural infection with Trypanosoma cruzi in bats captured in Campeche and Yucatán, México

Introduction: Bats have been reported as hosts of the Trypanosoma cruzi protozoan, the etiologic agent of American trypanosomiasis, an endemic zoonotic disease in México.Objective: To describe T. cruzi infection in bats from the states of Campeche and Yucatán, México.Materials and methods: Captures were made from March to November, 2017, at three sites in Yucatán and one in Campeche. Up to four mist nets on two consecutive nights were used for the capture. The bats’ species were identified and euthanasia was performed to collect kidney and heart samples for total DNA extraction. Trypanosoma cruzi infection was detected by conventional PCR with the amplification of a fragment belonging to the T. cruzi DNA nuclear.Results: Eighty-six bats belonging to five families (Vespertilionidae, Noctilionidae, Mormoopidae, Phyllostomidae, and Molossidae) and 13 species (Rhogeessa aeneus, Noctilio leporinus, Pteronotus davyi, P. parnellii, Artibeus jamaicensis, A. lituratus, A. phaeotis, Glossophaga soricina, Carollia sowelli, Chiroderma villosum, Uroderma bilobatum, Sturnira parvidens, and Molossus rufus) were captured. Infection frequency by PCR was 30,2% (26/86) detected only in the renal tissue. The infected species were P. parnellii, G. soricina, A. lituratus, A. jamaicensis, S. parvidens, C. villosum, and R. aeneus.Conclusions: Our results confirmed the participation of several bat species as hosts in the T. cruzi transmission cycle in the region. Further studies are necessary to establish the importance of these animals in the zoonotic transmission of T. cruzi.

Unraveling molecular mechanisms of immunity and cancer-resistance using the genomes of the Neotropical bats Artibeus jamaicensis and Pteronotus mesoamericanus

Bats are exceptional among mammals for harbouring diverse pathogens and for their robust immune systems. In addition, bats are unusually long-lived and show low rates of cancer. Contiguous and complete reference genomes are needed to determine the genetic basis of these adaptations and establish bats as models for research into mammalian health. Here we sequenced and analysed the genomes of the Jamaican fruit bat (Artibeus jamaicensis) and the Mesoamerican mustached bat (Pteronotus mesoamericanus). We sequenced these two species using a mix of Illumina and Oxford Nanopore Technologies (ONT), assembling draft genomes with some of the highest contig N50s (28-29Mb) of bat genomes to date. Work is in progress to increase the base-level accuracies of these genomes. We conducted gene annotation and identified a set of 10,928 orthologs from bats and mammalian outgroups including humans, rodents, horses, pigs, and dogs. To detect positively selected genes as well as lineage-specific gene gains and losses, we carried out comprehensive branch-site likelihood ratio tests and gene family size analyses. Our analysis found signatures of rapid evolution in the innate immune response genes of bats, and evidence of past infections with diverse viral clades in Artibeus jamaicensis and Pteronotus mesoamericanus. We additionally found evidence of positive selection of tumor suppressors, which may play a role in the low cancer rates, in the most recent common ancestor of bats. These new genomic resources enable insights into the extraordinary adaptations of bats, with implications for mammalian evolutionary studies and public health.

MURCIÉLAGOS (CHIROPTERA) EN ÁREAS VERDES URBANAS DE LA CIUDAD DE TEPIC, NAYARIT, MÉXICO

ResumenLos murciélagos desempeñan un papel fundamental en los ecosistemas, ya que efectúan múltiples interacciones bióticas como la dispersión de semillas, polinización y el control de plagas, además de que poseen hábitos alimenticios muy variados. En Nayarit se han registrado 67 especies de quirópteros, pero ningún estudio se ha enfocado en las zonas urbanas del estado. Nuestro objetivo fue evaluar la diversidad y abundancia de murciélagos en las áreas verdes de la zona urbana de Tepic, Nayarit. Se realizó un muestro en nueve sitios empleando una red de 12 metros, colocada de 18:00 h a 23:00 h., durante el periodo de noviembre del 2015 a noviembre del 2016, en el cual se acumuló un total de 45 horas/red. Se muestrearon tres tipos de hábitat urbanos: plazas, zanjones y parques. Con los datos recabados se estimó el índice de diversidad alfa de Shannon y se realizó una prueba de t modificada por Hutchenson para comparar los distintos ecosistemas. Se registraron tres especies de murciélagos (Artibeus lituratus, Artibeus jamaicensis y Artibeus hirsutus). Los parques resultaron el ecosistema que registró la mayor diversidad y abundancia de murciélagos, mientras que la especie que se documentó con mayor frecuencia fue A. lituratus.Palabras clave: ambientes antropizados, parques urbanos, quirópteros.AbstractThe bats play a fundamental role in the ecological processes of ecosystems, they carry out multiple biotic interactions such as seed dispersers, pollination, and pest control, they also have very varied feeding habits. In the Mexican state of Nayarit have been registered 67 bat species, but no one research has focused on the urban areas. Our objective was to research the species present in the green areas of the city of Tepic, Nayarit. Nine sites were sampled using a 12-meter network, which was placed from 6:00 p.m. to 11:00 p.m. The samplings were carried out from November 2015 to November 2016, for a total of 45 hours/network. Three types of habitat were covered: plazas, zanjon, and parks. We performed the Shannon alpha index to assess diversity and a t-test was used to compare between the different habitats. Three species were registered (Artibeus lituratus, Artibeus jamaicensis and Artibeus hirsutus). The urban ecosystem with the greatest diversity and abundance was the parks and the species that presented the highest frequency in the urban area was A. lituratus.Key words: Anthropized areas, bats, green spaces.

MURCIÉLAGOS ASOCIADOS A LOS MANGLARES EN EL GOLFO DE CHIRIQUÍ, PANAMÁ

Este estudio informa sobre las especies de murciélagos registrados en dos zonas de manglar en el Golfo de Chiriquí, República de Panamá. Las capturas de murciélagos se hicieron durante la estación lluviosa de 2016 y en la lluviosa y seca de 2017. El objetivo del estudio fue caracterizar la fauna de quirópteros en los manglares para estimar el papel que estos animales juegan en ese tipo de bosques. Los murciélagos fueron capturados mediante redes de niebla de 2.5 m de alto por 12 m de largo. Se capturaron 455 ejemplares, pertenecientes a 25 especies y cinco familias, donde Phyllostomidae abarcó19 especies (88% de las especies). Otras familias observadas fueron Emballonuridae (una especie), Noctilionidae (una especie), Mormoopidae (una especie) y Vespertilionidae, con tres especies. Las especies más abundantes fueron Artibeus jamaicensis, Desmodus rotundus, Carollia perspicillata y Glossophaga soricina, que abarcaron el 80.33% de las capturas.

Hematologic Values of Jamaican Fruit Bats (Artibeus jamaicensis) and the Effects of Isoflurane Anesthesia

Jamaican fruit bats (Artibeus jamaicensis) are used as an animal model for several viruses, including Middle East respiratory syndrome virus, dengue virus, Zika virus, and Tacaribe virus. However, despite ongoing studies regarding these pathogens, little is known regarding the bats' normal physiology. In this study, phlebotomy of the propetagial (cephalic) vein was performed to establish baseline hematologic parameters in an apparently healthy, captive population of Jamaican fruit bats. Furthermore, we compared results from physically restrained and isoflurane-anesthetized bats. Our findings indicate significant increases in WBC count, lymphocytes, and monocytes in the anesthetized bats. However, RBC and platelet parameters were not different between the 2 groups. This information on the normal hematologic parameters of Jamaican fruit bats, adds to our overall understanding of the normal physiology of this species, and expands our knowledge on bat species in general.

Leptospira patógenas en murciélagos de Campeche y Yucatán, México

Objetivo. Reportar la infección con Leptospira en riñones de murciélagos de Campeche y Yucatán, México, a través de la amplificación por PCR de dos fragmentos distintos del gen 16S RNA ribosomal. Materiales y métodos. Se realizaron capturas en un sitio de Campeche y dos de Yucatán. A los murciélagos capturados se les aplicó la eutanasia y se les realizó una necropsia para recolectar tejido renal que se usó en la extracción de ADN total. Se realizaron dos PCR convencionales para la amplificación de los fragmentos de 16S RNA ribosomal. Se obtuvieron las secuencias de algunos productos positivos y se analizaron con herramientas bioinformáticas para identificar la especie infectante de Leptospira. Resultados. Se capturaron 69 murciélagos pertenecientes a cuatro familias y a ocho especies distintas. La familia con mayor diversidad fue Phyllostomidae con cinco especies. La especie con mayor frecuencia de captura fue Artibeus jamaicensis (59.4%). Las PCR arrojaron una frecuencia de infección global de 21.7%. Las especies infectadas fueron A. jamaicensis, Pteronotus parnellii y Chiroderma villosum. El análisis bioinformático arrojó un 99.0% de identidad para Leptospira noguchii, Leptospira borgpetersenii y Leptospira santarosai. Conclusiones. Algunas especies de murciélagos de Yucatán y Campeche son portadores renales de leptospiras patógenas, por lo que pueden participar en el ciclo silvestre de transmisión en la región. La frecuencia de infección encontrada en los riñones de los murciélagos utilizados es mayor en comparación con aquellas obtenidas en otros reservorios de Yucatán y Campeche. Nuevas especies de murciélagos son reportadas como portadores de Leptospira para México.