Ganglion-specific splicing of TRPV1 underlies infrared sensation in vampire bats.

Vampire bats (Desmodus rotundus) are obligate blood feeders that have evolved specialized systems to suit their sanguinary lifestyle. Chief among such adaptations is the ability to detect infrared radiation as a means of locating hotspots on warm-blooded prey. Among vertebrates, only vampire bats, boas, pythons and pit vipers are capable of detecting infrared radiation. In each case, infrared signals are detected by trigeminal nerve fibres that innervate specialized pit organs on the animal's face. Thus, vampire bats and snakes have taken thermosensation to the extreme by developing specialized systems for detecting infrared radiation. As such, these creatures provide a window into the molecular and genetic mechanisms underlying evolutionary tuning of thermoreceptors in a species-specific or cell-type-specific manner. Previously, we have shown that snakes co-opt a non-heat-sensitive channel, vertebrate TRPA1 (transient receptor potential cation channel A1), to produce an infrared detector. Here we show that vampire bats tune a channel that is already heat-sensitive, TRPV1, by lowering its thermal activation threshold to about 30 °C. This is achieved through alternative splicing of TRPV1 transcripts to produce a channel with a truncated carboxy-terminal cytoplasmic domain. These splicing events occur exclusively in trigeminal ganglia, and not in dorsal root ganglia, thereby maintaining a role for TRPV1 as a detector of noxious heat in somatic afferents. This reflects a unique organization of the bat Trpv1 gene that we show to be characteristic of Laurasiatheria mammals (cows, dogs and moles), supporting a close phylogenetic relationship with bats. These findings reveal a novel molecular mechanism for physiological tuning of thermosensory nerve fibres

Temporada reproductiva y sitios de nidificación del Canario de Tejado \u3cem\u3eSicalis flaveola\u3c/em\u3e en un área urbana de la ciudad de Mérida, Andes de Venezuela / Breeding Season and Nesting Sites of the Saffron Finch \u3cem\u3eSicalis flaveola\u3c/em\u3e in an Urban Area of the City of Mérida, Andes of Venezuela

El Canario de Tejado Sicalis flaveola se considera una especie relacionada a ambientes alterados. Con el propósito de determinar su temporada reproductiva, sitios de anidación y reutilización de nidos en la zona céntrica de la ciudad de Mérida, región andina de Venezuela, se realizaron recorridos una vez al mes desde marzo del 2020 hasta marzo de 2021 por ocho avenidas, sus calles trasversales y cinco plazas para buscar e identificar los nidos en diferentes estructuras de la ciudad a través de observaciones visuales directas. Una vez detectado, cada nido fue monitoreado durante ±10 minutos para caracterizarlo y determinar su estado de actividad (activo o abandonado). Se detectaron 103 nidos de los cuales 66 estaban abandonados y 37 fueron ocupados al menos una vez. Se identificaron cuatro tipos de cavidades artificiales y una natural para la construcción de los nidos: a, cajas metálicas pequeñas para cables de televisión (CM); b, cabezote o salida superior de tubería de cables eléctricos (TE); c, lámparas de iluminación vial (LAM); d, faroles de iluminación (FR); e, árboles (AR). La mayoría de los nidos (77%) se construyeron en CM y a su vez fueron el 62% de los nidos activos durante toda la temporada reproductiva. La actividad reproductiva del Canario de Tejado se presentó durante ocho meses consecutivos (desde abril hasta noviembre), con el mayor número de nidos activos al inicio de la temporada (abril–mayo) y fue disminuyendo progresivamente hasta el final de la misma. La mayoría de los nidos fueron utilizados una vez. Dadas las características de la especie de aprovechar los entornos urbanos para su beneficio, consideramos al Canario de Tejado como un “Explotador Urbano” en Venezuela. The Saffron Finch Sicalis flaveola is a bird species associated with disturbed environments. In order to improve the knowledge about its breeding season, nesting sites, and nest usage in downtown of Mérida city, Andes of Venezuela, a series of observation were carried out once a month from March 2020 to March 2021 in eight main avenues and their interconnected streets, as well as five public squares. Bird nests were located and identified in different structures. Once detected, each nest was observed by around 10 minutes in order to describe it and determine its activity status (active, abandoned). A total of 103 nests were found, 66 abandoned and 37 occupied at least once. Five cavity types were identified for nest construction, four artificial and one natural. These cavities corresponded to: a, small metal boxes for TV wiring (CM); b, upper outlet of electrical pipes (TE); c, street lighting poles (LAM); (d) street lighting bulbs (FR); and (e) natural trees (AR). Most nests (77%) were recorded in CMs and they represented 62% of the active nests during the breeding season. The Saffron Finch breeding season lasted eight consecutive months (from April to November) with the largest number of nests recorded in the beginning of the breeding season (April) with a decreasing number forward the end of it. Most of the nests were used only once. Given the species behavior, taking advantage of urban environments, we consider the Saffron Finch as an “Urban Exploiter” in Venezuela

Ganglion-specific splicing of TRPV1 underlies infrared sensation in vampire bats.

Vampire bats (Desmodus rotundus) are obligate blood feeders that have evolved specialized systems to suit their sanguinary lifestyle. Chief among such adaptations is the ability to detect infrared radiation as a means of locating hotspots on warm-blooded prey. Among vertebrates, only vampire bats, boas, pythons and pit vipers are capable of detecting infrared radiation. In each case, infrared signals are detected by trigeminal nerve fibres that innervate specialized pit organs on the animal's face. Thus, vampire bats and snakes have taken thermosensation to the extreme by developing specialized systems for detecting infrared radiation. As such, these creatures provide a window into the molecular and genetic mechanisms underlying evolutionary tuning of thermoreceptors in a species-specific or cell-type-specific manner. Previously, we have shown that snakes co-opt a non-heat-sensitive channel, vertebrate TRPA1 (transient receptor potential cation channel A1), to produce an infrared detector. Here we show that vampire bats tune a channel that is already heat-sensitive, TRPV1, by lowering its thermal activation threshold to about 30 °C. This is achieved through alternative splicing of TRPV1 transcripts to produce a channel with a truncated carboxy-terminal cytoplasmic domain. These splicing events occur exclusively in trigeminal ganglia, and not in dorsal root ganglia, thereby maintaining a role for TRPV1 as a detector of noxious heat in somatic afferents. This reflects a unique organization of the bat Trpv1 gene that we show to be characteristic of Laurasiatheria mammals (cows, dogs and moles), supporting a close phylogenetic relationship with bats. These findings reveal a novel molecular mechanism for physiological tuning of thermosensory nerve fibres

Phyllostomid bat occurence in successional stages of neotropical dry forests

Tropical dry forests (TDFs) are highly endangered tropical ecosystems being replaced by a complex mosaic of patches of different successional stages, agricultural fields and pasturelands. In this context, it is urgent to understand how taxa playing critical ecosystem roles respond to habitat modification. Because Phyllostomid bats provide important ecosystem services (e.g. facilitate gene flow among plant populations and promote forest regeneration), in this study we aimed to identify potential patterns on their response to TDF transformation in sites representing four different successional stages (initial, early, intermediate and late) in three Neotropical regions: México, Venezuela and Brazil. We evaluated bat occurrence at the species, ensemble (abundance) and assemblage level (species richness and composition, guild composition). We also evaluated how bat occurrence was modulated by the marked seasonality of TDFs. In general, we found high seasonal and regional specificities in phyllostomid occurrence, driven by specificities at species and guild levels. For example, highest frugivore abundance occurred in the early stage of the moistest TDF, while highest nectarivore abundance occurred in the same stage of the driest TDF. The high regional specificity of phyllostomid responses could arise from: (1) the distinctive environmental conditions of each region, (2) the specific behavior and ecological requirements of the regional bat species, (3) the composition, structure and phenological patterns of plant assemblages in the different stages, and (4) the regional landscape composition and configuration. We conclude that, in tropical seasonal environments, it is imperative to perform long-term studies considering seasonal variations in environmental conditions and plant phenology, as well as the role of landscape attributes. This approach will allow us to identify potential patterns in bat responses to habitat modification, which constitute an invaluable tool for not only bat biodiversity conservation but also for the conservation of the key ecological processes they provide

Summary of the tests evaluating seasonal variation at the assemblage level.

<p>Study sites are the same as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084572#pone-0084572-g001" target="_blank">Fig. 1</a>. For tests based on randomizations (composition and abundance) the standardized effect size is provided (Z = (Observed value – Expected value)/StDev of expected values). The Z-score quantifies, in units of standard deviation, the position of the observed metric within the simulated distribution. Significant relationships (p-value ≤0.05) appear in bold and marginally significant relationships (0.05). Structure: result of the Kolmogorov-Smirnov test evaluating seasonal changes in bat assemblages regarding their structure (species rank distribution). Detailed information about these analyses are presented in the method section.</p

Species richness estimated with the first-order jackknife estimator, per site and per season.

<p>Study regions: Chamela Cuixmala Biosphere Reserve in Mexico (A), Unidad de Producción Socialista Agropecuaria Piñero in Venezuela (B), and Mata Seca State Park in Brazil (C). Sampling sites representing different successional stages are: pastures (from P1 to P3), early (from E1 to E3), intermediate (from I1 to I3) and late stage (from L1 to L3). Seasons: rainy season (triangles) and dry season (circles). Error bars represent the ±95% confidence intervals.</p