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Mercury (Hg) endangers human and wildlife health globally, primarily due to its release from artisanal small-scale gold mining (ASGM). During gold extraction, Hg is emitted into the environment and converted to highly toxic methylmercury by microorganisms. In Madre de Dios (MDD), Peru, ASGM dominates the economy and has transformed rainforests into expansive deforested areas punctuated by abandoned mining ponds. The aim of this study was to evaluate the use of bats as bioindicators for mercury pollution intensity in tropical terrestrial ecosystems impacted by ASGM. We collected 290 bat fur samples from three post-ASGM sites and one control site in Madre de Dios. Our results showed a wide Hg distribution in bats (0.001 to 117.71 mg/kg) strongly influenced by feeding habits. Insectivorous and piscivorous bats from ASGM sites presented elevated levels of Hg surpassing the mercury small mammal threshold for small mammals (10 mg/kg). We observed the highest reported fur mercury concentrations for insectivorous Neotropical bats reported to date (Rhynchonycteris naso, 117 mg/kg). Our findings further confirm that Hg emissions from ASGM are entering local food webs and exposing wildlife species at several trophic levels to higher levels of Hg than in areas not impacted by mining. We also found that three bat genera consistently showed increased Hg levels in ASGM sites relative to controls indicating potential usefulness as bioindicators of mercury loading in terrestrial ecosystems impacted by artisanal and small-scale gold mining.

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Innovative techniques, such as environmental DNA (eDNA) metabarcoding, are now promoting broader biodiversity monitoring at unprecedented scales, because of the reduction in time, presumably lower cost, and methodological efficiency. Our goal was to assess the efficiency of established inventory techniques (live-trapping grids, pitfall traps, camera trapping, mist netting) as well as eDNA for detecting Amazonian mammals. For terrestrial small mammals, we used 32 live-trapping grids based on Sherman and Tomahawk traps (total effort of 10,368 trap-nights); in addition to 16 pitfall traps (1,408 trap-nights). For bats, we used mist nets at 8 sites (4,800 net hours). For medium and large mammals, we used 72 camera trap stations (5,208 camera-days). We identified vertebrate and mammal taxa based on eDNA analysis (12S region, with V05 and Mamm01 markers) from water samples, including a total of 11 3-km transects for stagnant water sampling and seven small streams for running water sampling. A total of 106 mammal species were recorded. Building on sample-based rarefaction and extrapolation curves, both trapping grids and pitfall were successful, recording 91.16% and 82.1% of the expected species for these techniques (~22 and ~9 species), and 16.98% and 6.60% of the total recorded mammal species, respectively. Mist nets recorded 83.2% of the expected bat species (~48), and 34.91% of the total recorded species. Camera trapping recorded 99.2% of the predicted large- and medium-sized species (~31), and 33.02% of the total recorded species. eDNA recorded 75.4% of the expected mammal species for this technique (~68), and 47.0% of the total recorded species. eDNA resulted in a useful tool that saves on effort and reduces sampling costs. This study is among the first to show the large potential of eDNA metabarcoding for assessing Amazonian mammal communities, providing, in combination with conventional techniques, a rapid overview of mammal diversity with broad applications to monitoring, management and conservation. By including appropriate genetic markers and updated reference databases, eDNA metabarcoding method can be extended to the whole vertebrate community.

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Resumen En el Perú se registran al menos 180 especies de murciélagos. Sin embargo, son pocos los estudios acerca de sus ectoparásitos, dentro de los cuales destacan las denominadas moscas de murciélagos (Diptera: Streblidae y Nycteribiidae), en los cuales se estima un total de 158 especies en la región Neotropical. En el Perú, una de las regiones con menos información es la costa. En este estudio actualizamos el conocimiento de las asociaciones ectoparásito-hospedero en murciélagos de la costa peruana, una de las regiones ecologicas con más degradación y pérdida de hábitat. Se evaluaron cinco localidades en las regiones de Piura, Lima y Tacna. Se capturaron 85 murciélagos pertenecientes a 7 especies; 4 de Phyllostomidae, 2 de Molossidae y 1 de Vespertilionidae. Se encontraron seis especies de dípteros (Diptera: Streblidae) y un hemíptero (Hemiptera: Polyctenidae) y se reporta por primera vez algunas de estas asociaciones en las regiones de Lima y Piura. Se reporta también a Anoura peruana como hospedero de Anastrebla modestini (Streblidae) en una colonia reproductiva compartida con Platalina genovensium, y por primera vez para la región de Piura, el co-parasitismo de los estréblidos Megistopoda aranea, Aspidoptera phyllostomatis y Metelasmus pseudopterus en un mismo individuo de Artibeus fraterculus.

Abstract There are at least 180 species of bats in Peru. However, there are few studies about ectoparasites of bats, among which the so-called bat flies (Diptera: Streblidae and Nycteribiidae) stand out, with a total of 158 species estimated for the Neotropical region. In Peru, one of the ecological regions with the least information is the coast. In this study we updated the knowledge of the ectoparasite-host associations in bats from the Peruvian coast, one of the regions of the country with the most degradation and loss of habitat. Five locations in the Piura, Lima and Tacna regions were evaluated. 85 bats belonging to 7 species were captured: 4 from Phyllostomidae, 2 from Molossidae and 1 from Vespertilionidae. Six dipterous species (Diptera: Streblidae) and one Hemiptera species (Hemiptera: Polyctenidae) were found and some of these associations are reported for the first time in the Lima and Piura regions. Anoura peruana is also reported as the host of Anastrebla modestini (Streblidae) in a reproductive colony shared with Platalina genovensium, and for the first time for the Piura region, the co-parasitism of the Megistopoda aranea, Aspidoptera phyllostomatis and Metelasmus pseudopterus in a same individual of Artibeus fraterculus.