What do krill kill?
Using molecular techniques to understand krill diet
Complex food webs could become easier to analyze with the advent of molecular techniques to identify the remains of prey items from part-digested stomach contents. However, a major stumbling block has been spotting the DNA of rare prey items against a background overwhelmed by the predator’s own DNA. Writing in Frontiers in Zoology, Hege Vestheim and Simon Jarman – biologists at the University of Oslo and the Australian Antarctic Division, respectively – describe a new method to block predator DNA from the identification process. As a result, their tests on Antarctic krill Euphausia superba were able to identify, for the first time, what one of the most abundant animals in the world eats to survive the winter. The method must assume krill don’t resort to cannibalism to make it through the toughest half of the year, but otherwise presents a neat way to find out what an animal has eaten: the study even, er, threw up several unknown species of algae. Source: Vestheim H & Jarman SN (2008) Blocking primers to enhance PCR amplification of rare sequences in mixed samples – a case study on prey DNA in Antarctic krill stomachs. Frontiers in Zoology DOI: 10.1186/1742-9994-5-12
Image: © NOAA
