title: Can multiple-copy sequences of prey DNA be detected amongst the gut contents of invertebrate predators?
abstract: The first experiments to clearly demonstrate that DNA techniques might be used to detect predator-prey interactions between arthropods are reported. The accurate modelling of such interactions has depended until now upon a mixture of laboratory experiments, population monitoring and biochemical tests. The latter involve gut-content analyses, and have most recently depended upon the development of prey-specific monoclonal antibodies. Although these are excellent for detecting predation on a target prey, they are impractical for analysing the prey range of a particular predator. Molecular detection depends upon the ability of DNA to resist digestion in the predator gut and of the polymerase chain reaction (PCR) to amplify prey-specific DNA from semidigested material. As a first step, experiments using carabid beetles, Pterostichus cupreus L., as predators and mosquitoes as prey are reported. The target sequences were fully characterized multiple-copy esterase genes from two laboratory strains of Culex quinquefasciatus Say. Although DNA was extracted from homogenates of whole beetles (minus appendages), a 146 bp product could be amplified from both mosquito strains digested in the beetle gut for 28 h. The larger, 263 bp product was detectable for 28 h in one mosquito strain, but could not be amplified after 5 h from the other. Whether the beetles had eaten one mosquito or six, digested for zero or 28 h, the prey were equally detectable. Having demonstrated that shorter, multiple-copy sequences survive digestion for a considerable period in the gut of a predator, the opportunity exists to develop new detection systems for studying predation in the field.
authors.affiliation: Cardiff School of Biosciences, Cardiff University, UK.
authors.forename: R H
authors.initials: RH
authors.lastname: Zaidi
authors.forename: Z
authors.initials: Z
authors.lastname: Jaal
authors.forename: N J
authors.initials: NJ
authors.lastname: Hawkes
authors.forename: J
authors.initials: J
authors.lastname: Hemingway
authors.forename: W O
authors.initials: WO
authors.lastname: Symondson
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D003465:Culex / Q000187:drug effects / Q000235:genetics*; D004247:DNA / Q000032:analysis*; D004351:Drug Resistance / Q000235:genetics; D004950:Esterases / Q000235:genetics; D020387:Food Chain; D018628:Gene Dosage; D007306:Insecticides / Q000494:pharmacology; D007408:Intestinal Absorption / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods*; D015203:Reproducibility of Results
chemical_list: D007306:Insecticides; D004247:DNA; D004950:Esterases