Plaguicidas organoclorados en murciélagos (Chiroptera) asociados al bosque húmedo tropical en Córdoba, Colombia

Investigaciones sobre toxicidad ambiental por pesticidas se han realizado principalmente en mamíferos terrestres, pero existe poca información sobre plaguicidas organoclorados en murciélagos. Teniendo en cuenta el papel funcional de este grupo en varios procesos ecosistémicos como insectívoros, frugívoros y polinizadores, su afectación puede estar causando un impacto negativo en la salud de los ecosistemas naturales. En Colombia, no hay estudios que documenten esta problemática; por tanto, el objetivo fue determinar la presencia de plaguicidas organoclorados en el ensamblaje de murciélagos del bosque húmedo tropical (bh-T) en Córdoba, Colombia. Se evaluó la presencia de organoclorados en hígado y músculo de murciélagos del sector Manso-Tigre, un área protegida con ocupación campesina. La concentración de plaguicidas organoclorados como Aldrin, Dieldrin, Endrin, Heptacloro epóxido, α-BCH, βBCH, γ-BCH, 2,4-DDD, 2,4-DDT, 4,4-DDE y 4,4-DDT, se determinó por cromatografía de gases. Niveles de organoclorados en hígado y músculo presentaron diferencias significativas (P<0,05). Se detectó mayor contenido de organoclorados en hígado en las especies Trachops cirrhosus (α–BCH, γ-BCH, Endrin, pp-DDE), Desmodus rotundus (β-BCH), Micronycteris microtis (Aldrin), Platyrrhinus helleri (Heptacloro) y Phyllostomus hastatus (pp-DDT). En tejido muscular, la concentración de organoclorados fue mayor en Trachops cirrhosus (α-BCH, γ-BCH, Endrin, pp-DDE), Artibeus planirostris (β-BCH), Micronycteris microtis (Aldrin, Heptacloro) y Phyllostomus hastatus (pp-DDT). La contaminación por organoclorados en murciélagos posiblemente está relacionada con el uso de agroquímicos, insecticidas y compuestos fosfatados para uso agrícola. Los resultados permiten reconocer a los murciélagos como bioindicadores de contaminación ambiental al indicar procesos de cambios o disturbios en los hábitats.

Sensory ecology of the frog-eating bat, Trachops cirrhosus, from DNA metabarcoding and behavior

Metabarcoding of prey DNA from fecal samples can be used to design behavioral experiments to study the foraging behavior and sensory ecology of predators. The frog-eating bat, Trachops cirrhosus, eavesdrops on the mating calls of its anuran prey. We captured wild T. cirrhosus and identified prey remains in the bats’ fecal samples using DNA metabarcoding of two gene regions (CO1 and 16S). Bats were preying on frogs previously unknown in their diet, such as species in the genus Pristimantis, which occurred in 29% of T. cirrhosus samples. Twenty-three percent of samples also contained DNA of Anolis lizards. We additionally report apparently rare predation events on hummingbirds and heterospecific bats. We used results from metabarcoding to design acoustic and 3D model stimuli to present to bats in behavioral experiments. We show predatory responses by T. cirrhosus to the calls of the frog Pristimantis taeniatus and to the rustling sounds of anoles moving through leaf-litter, as well as attacks on a stuffed hummingbird and a plastic anole model. The combination of species-specific dietary information from metabarcoding analyses with behavioral responses to prey cues provides a unique window into the foraging ecology of predators that are difficult to observe in the wild.

Social structure and relatedness in the fringe-lipped bat ( Trachops cirrhosus )

General insights into the causes and effects of social structure can be gained from comparative analyses across socially and ecologically diverse taxa, such as bats, but long-term data are lacking for most species. In the neotropical fringe-lipped bat, Trachops cirrhosus , social transmission of foraging behaviour is clearly demonstrated in captivity, yet its social structure in the wild remains unclear. Here, we used microsatellite-based estimates of relatedness and records of 157 individually marked adults from 106 roost captures over 6 years, to infer whether male and female T. cirrhosus have preferred co-roosting associations and whether such associations were influenced by relatedness. Using a null model that controlled for year and roosting location, we found that both male and female T. cirrhosus have preferred roosting partners, but that only females demonstrate kin-biased association. Most roosting groups (67%) contained multiple females with one or two reproductive males. Relatedness patterns and recapture records corroborate genetic evidence for female philopatry and male dispersal. Our study adds to growing evidence that many bats demonstrate preferred roosting associations, which has the potential to influence social information transfer.

First record of pigmentation disorder in the Fringe-lipped Bat Trachops cirrhosus (Spix, 1823) (Chiroptera: Phyllostomidae) from southeast Brazil

Piebaldism is a genetic pigmentation disorder, which is caused by absence of melanocytes in parts of the skin and/or hair follicles, with eyes and claws normally pigmented. The occurrence of piebaldism in natural populations is rare and the effects on fitness are still unknown. This article reports the first case of pigmentation disorders in the Fringe-lipped Bat Trachops cirrhosus (Spix, 1823) (Chiroptera: Phyllostomidae) caught in Barra do Triunfo, city of João Neiva, northeastern state of Espírito Santo, southeast Brazil.

The role of male forearm crust odour in fringe-lipped bats (Trachops cirrhosus)

Chemical signals can play important roles in communication, and this is especially true for social mammals such as bats. Male fringe-lipped bats (Trachops cirrhosus) produce an odorous substance on their forearm, called forearm crust. Only adult males with descended testes produce forearm crust. This is thus a sexually dimorphic odour, which suggests that it is a sexually selected trait. Since males lack a specific gland on their forearm we sought to identify the source of the forearm crust. Our second aim was to test female and male preference for this trait. Based on gas chromatography and mass spectrometry analyses we tentatively identified several compounds that were exclusive to the forearm crust. We found that the chemical composition of the forearm crust was not mainly composed of chest gland secretions or urine. We conducted a y-maze odour preference experiment to test whether adult females and reproductive males preferred the odour of a male with forearm crust compared to the odour of a male without forearm crust. Contrary to our prediction we found that females did not approach the scent of a male with forearm crust more frequently than the scent of male without forearm crust. We found that males with forearm crust, however, preferred the odour of males without forearm crust. Overall our results suggest that in this Neotropical bat species, reproductive males could use odorous signals in the forearm crust to mediate interactions between reproductive males and potentially avoid costly competition for mates or aggression. In sum, our results shed light on the role that chemical mediated signals can play in mammalian social behaviour.