Factors affecting detectability of prey DNA in the gut contents of invertebrate predators: a polymerase chain reaction‐based method

Abstract

This study aimed to determine factors that influence the detection of DNA of Plutella xylostella L. (Lepidoptera: Plutellidae) in the gut contents of arthropod predators when the polymerase chain reaction is used to amplify a diagnostic fragment of the gene coding for cytochrome oxidase subunit I. The effects of temperature, time since feeding, subsequent food intake, sex, weight, and species of predator on prey detectability were studied in the laboratory. Three types of predator were studied: the spider Venator spenceri Hogg. (Araneae: Lycosidae), a bug with sucking mouthparts, Nabis kinbergii (Reuter) (Heteroptera: Nabidae), and a coccinellid with chewing mouthparts, Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae). In all experiments, the detectability of prey DNA was negatively correlated with time post‐feeding. The duration of detectability differed among the predator species. The time calculated for median detection success at 20 °C ranged from 49.6 h in V. spenceri to 36.1 h in N. kinbergii and 17.1 h in H. variegata. In H. variegata, but not in V. spenceri, the rate of detection decreased with increasing temperature. Subsequent food intake did not affect the detectability of DNA of P. xylostella in V. spenceri. In H. variegata, sex and weight of the predator did not influence detection of prey DNA. In addition, this study uncovered potential sources of error caused by detection of prey DNA following secondary cannibalistic and intraguild predation. The results provide essential information for the interpretation of prey detection data from field‐collected predators’ gut contents.

Molecular analysis of the gut contents of Harmonia axyridis (Coleoptera: Coccinellidae) as a method for detecting intra-guild predation by this species on aphidophagous predators other than coccinellids

“…This is in agreement with similar studies on different predator groups (e.g. Agusti et al, 2003;Hosseini et al, 2008). The half-life of the period for which prey DNA could be detected for each predator-prey combination ranged from 8.9 to 52.4 h; the long half-life for fourth instar H. axyridis feeding on C. carnea indicates it is possible to detect relatively rare predation events (Gagnon et al, 2011a).…”

“…In addition to the factors investigated in this study, temperature, time for which the predators are starved and what they eat subsequently are reported to affect the level at which prey can be detected (Hosseini et al, 2008;Weber & Lundgren, 2009). Furthermore, this technique cannot discriminate primary and secondary predation , scavenging behaviour (Juen & Traugott, 2005) or prey DNA obtained via cannibalism (Sheppard & Harwood, 2005).…”

“…Factors known to influence the level at which the DNA of prey can be detected (Hosseini et al, 2008) were investigated, including digestion time, meal size and H. axyridis developmental stage, weight, sex and morpho-type.…”

Food Relationships

“…variegata , but not in the spider, although sex and weight of Hip. variegata did not infl uence detection of prey DNA (Hosseini et al 2008 ). PCR can only be used to detect prey DNA in the gut if the predator was captured shortly before testing.…”

Molecular-genetic methods of the investigation of trophic relations hips in the agrocoenosis

“…на скорость переваривания пищи в кишечнике хищников и, соответственно, на качество определения случаев хищничества (Berg et al, 2008a(Berg et al, , 2008bHosseini et al, 2008).…”