Invertebrates for vertebrate biodiversity monitoring: comparisons using
three insect taxa as iDNA samplers
Abstract
Metabarcoding of environmental DNA (eDNA) is now widely used to build
diversity profiles from DNA that has been shed by species into the
environment. There is substantial interest in the expansion of eDNA
approaches for improved detection of terrestrial vertebrates using
invertebrate-derived DNA (iDNA) in which hematophagous, sarcophagous,
and coprophagous invertebrates sample vertebrate blood, carrion, or
feces. Here, we use metabarcoding and multiple iDNA samplers (carrion
flies, sandflies, and mosquitos) to profile gamma and alpha diversity in
a dry, tropical forest in the southern Amazon. Our main objectives were
to (1) compare diversity found with iDNA to camera trapping, which is
the conventional method of vertebrate diversity surveillance and (2)
compare each of the iDNA samplers to assess the effectiveness,
efficiency, and potential biases associated with each sampler. Carrion
flies were the most effective sampler, despite the least amount of
sampling effort and the fewest number of individuals captured for
metabarcoding, in describing vertebrate biodiversity followed by
sandflies. Camera traps had the highest median species richness at the
site-level but showed strong bias towards carnivore and ungulate species
and missed much of the diversity described by iDNA methods. Mosquitos
showed a strong feeding preference for humans as did sandflies for
armadillos, thus presenting potential utility to further study related
to host-vector interactions.