Environmental DNA (eDNA) and invertebrate-derived DNA (iDNA) have been increasingly recognized as a powerful tool for biodiversity assessment and conservation management. However, because of uncertainties on the efficiency of eDNA/iDNA approach in comparison to conventional methods, its use to assess the vertebrate diversity is still rare. Here we assessed the efficiency of eDNA/iDNA in comparison to conventional methods to survey vertebrate diversity across several type of samplers, vertebrate groups, and location (tropical vs temperate zones), as well as its efficiency to be used as a proxy for relative abundance or biomass across different molecular methods (qPCR and metabarcoding) and types of experiments (in the lab or in the field). The metanalysis showed that, in general, there is no difference in the number of species detected or number of sites that a target species was detected when using eDNA/iDNA or conventional methods, suggesting that eDNA/iDNA and conventional methods were equally efficient in characterizing the biodiversity. However, for water sampler and fish, separately, the risk of not finding a species was greater using conventional method than eDNA, suggesting that eDNA/iDNA was more efficient in finding the target species. Abundance and biomass showed similar correlation patterns, and there was a positive correlation between eDNA/iDNA and abundance/biomass data, suggesting that eDNA/iDNA can be used as a proxy for abundance and biomass. Therefore, eDNA/iDNA has proved to be an efficient tool to assess vertebrate diversity in terms of both diversity of species and abundance or biomass.

Ingested-derived DNA (iDNA) from insects can represent a powerful tool for assessing vertebrate diversity because insects are easy to sample, have a varied diet, and are widely distributed. Despite these advantages, the use of iDNA for mammalian detection is still little explored, especially in the neotropical region. Here we aimed to compare the effectiveness of mosquitoes and flies to detect mammals in a semi-controlled area of a Zoo that houses native and non-native species. We evaluated the number of mammal species detected by the iDNA samplers and verified the distance range of each sampler group for detecting the mammal species. To capture mosquitoes and flies we used CDC (Center for Disease Control) and fish-baited plastic bottle traps, respectively, distributed in eight sampling points during five days. Using two mini-barcodes (12SrRNA and 16SrRNA) and the metabarcoding approach, we identified 45 Operational Taxonomic Units from 10 orders. There was no difference between the number of species recovered per individual insect, although the number of flies captured was higher, resulting in more mammal species recovered by this insect group. Eight species were recorded exclusively by mosquitoes and 20 by flies, suggesting that using both samplers allowed a more comprehensive screening of the biodiversity. The maximum distance recorded was 337 m for flies and 289 m for mosquitoes, but the average range distance did not differ between insect groups. Our essay proved to be quite efficient for the mammal detection, considering the high number of species detected with a reduced sampling effort. Thus, combining iDNA from different samplers and metabarcoding can be a powerful tool for mammal survey and monitoring in the neotropics.