When bugs reveal biodiversity

Abstract

One of the fundamental challenges of conservation biology is gathering data on species distribution and abundance. And unless conservationists know where a species is found and in which numbers, it is very difficult to apply effective conservation efforts. In today's age of increasingly powerful monitoring tools, instant communication and online databases, one might be forgiven for thinking that such knowledge is easy to come by. However, of the approximately 5,400 terrestrial mammals on the IUCN Red List, no fewer than 789 (ca. 14%) are listed as ‘Data Deficient’ (IUCN 2012) – IUCN's term for ‘haven't got a clue’. Until recently, the only way to gather information of numbers and distribution of terrestrial mammals (and many other vertebrates) was through observational‐based approaches such as visual records, the presence of tracks or spoor or even identification from bushmeat or hunters' trophies pinned to the walls in local villages. While recent technological developments have considerably improved the efficacy of such approaches, for example, using remote‐sensing devices such as audio‐ or camera‐traps or even remote drones (Koh & Wich 2012), there has been a growing realization of the power of molecular methods that identify mammals based on trace evidence. Suitable substrates include the obvious, such as faecal and hair samples (e.g. Vigilant et al. 2009), to the less obvious, including environmental DNA extracted from sediments, soil or water samples (e.g. Taberlet et al. 2012), and as recently demonstrated, the dietary content of blood‐sucking invertebrates (Gariepy et al. 2012; Schnell et al. 2012). In this issue of Molecular Ecology, Calvignac‐Spencer et al. (2013) present a potentially powerful development in this regard; diet analysis of carrion flies. With their near global distribution, and as most field biologists know, irritatingly high frequency in most terrestrial areas of conservation concern (which directly translates into ease of sampling them), the authors present extremely encouraging results that indicate how carnivorous flies may soon represent a strong weapon in the conservation arsenal.

Identifying conservation priorities in a defaunated tropical biodiversity hotspot

“…Advances in non‐invasive survey methods and statistical modelling techniques provide ways to address these challenges. Two non‐invasive methods have revolutionized surveys for tropical mammals: camera‐traps (Tobler, Carrillo‐Percastegui, Pitman, Mares, & Powell, ) and high‐throughput sequencing of environmental DNA (eDNA) (Bohmann, Schnell, & Gilbert, ). Camera‐trapping is a well‐established method and has been used to gather data on even the rarest of tropical mammal species (Ganas & Lindsell, ; Raloff, ; Whitfield, ).…”

“…Large-and medium-sized mammals tend to be particularly vulnerable to hunting because they often occur at lower average population densities and have lower intrinsic rates of increase and longer generation times (Bodmer, Eisenberg, & Redford, 1997;Cardillo et al, 2005;Davidson, Hamilton, Boyer, Brown, & Ceballos, 2009). Indeed, the "empty forest syndrome" that Redford (1992) warned about almost three decades ago is now a commonplace phenomenon and, given the ever-increasing demand for wildlife products in the world's tropical regions (Rosa et al, 2016;Ripple et al, 2016), this trend is unlikely to slow in the coming years.…”

Viral Metagenomics on Blood-Feeding Arthropods as a Tool for Human Disease Surveillance

“…This combines VEM with invertebrate-derived DNA (iDNA), a term designating the genetic material ingested by invertebrates feeding on vertebrates [77]. Several studies have shown that iDNA from a variety of vertebrate species can be identified from field-caught animals, including mosquitoes [78,79], carrion flies [59,60,80], biting midges [81], leeches [71,82] and ticks [83]. For the identification of host DNA from arthropod blood meals, PCR-based or serological techniques are traditionally used [84,85,86,87,88].…”

Targeted detection of mammalian species using carrion fly‐derived DNA

“…) or contained by invertebrates feeding on vertebrates (iDNA; Bohmann et al . ; Calvignac‐Spencer et al . ,b; Schnell et al .…”

“…Novel sources of DNA allowing for a broad screening of local mammalian biodiversity with reduced costs and effort have recently been identified. Specifically, great potential is seen in the use of DNA gathered from the environment (eDNA; Taberlet et al 2012) or contained by invertebrates feeding on vertebrates (iDNA; Bohmann et al 2013;Calvignac-Spencer et al 2013a,b;Schnell et al 2012). In one of the latter proof of principle studies, Calvignac-Spencer and coworkers focused on blow and flesh flies (families Calliphoridae and Sarcophagidae; later collectively referred to as 'carrion flies'), which are globally distributed and are known to feed on various mammalian-borne materials (carcasses, open wounds and faeces; Norris 1965).…”