Secondary predation: quantification of food chain errors in an aphid–spider–carabid system using monoclonal antibodies

Abstract

"Secondary predation" occurs when one predator feeds on a second predator, which has in turn eaten a target prey. Detection of prey remains within predators using monoclonal antibodies cannot distinguish between primary and secondary predation, potentially leading to quantitative and qualitative food chain errors. We report the first fully replicated experiments to measure secondary predation effects, using an aphid-spider-carabid system. Aphids, Sitobion avenae, were fed to spiders, Lepthyphantes tenuis, which were allowed to digest their prey for a range of time intervals. The spiders were then fed to carabids, Poecilus (=Pterostichus) cupreus, which were again allowed to digest their prey for set periods. The anti-aphid monoclonal antibody used to identify S. avenae remains in P. cupreus was one that detected an epitope that increased in availability over the first few hours of digestion, amplifying the signal, extending detection periods and thus increasing the chances of detecting secondary predation. Despite this, and the fact that spiders are known to digest their prey more slowly than many other predators, detection of secondary predation was only possible if the carabids were killed immediately after consuming at least two spiders which were, in turn, eaten immediately after consuming aphids. As this scenario is unlikely to occur frequently in the field it was concluded that secondary predation is unlikely to be a serious source of error during field studies.

Detecting arthropod intraguild predation in the field

“…Positive detection of a prey species in a predator does not necessarily indicate that the predator has directly eaten or killed and eaten the prey species. The detected prey species could have been eaten by another predator which in turn was consumed by the predator under investigation or the detected prey could be dead when consumed by the predator (Harwood et al 2001;Foltan et al 2005;. Using an aphid-spider-beetle model system, showed secondary predation by the beetle Pterostichus melanarius (Illiger) (Coleoptera: Carabidae) of the grain aphid Sitobion avenae (F.) (Hemiptera: Aphididae) which had been eaten by the spider Tenuiphantes tenuis (Blackwall) (Araneae: Linyphiidae).…”

Wing morphology is linked to stable isotope composition of nitrogen and carbon in ground beetles (Coleoptera: Carabidae)

“…In contrast to wing morphology, trophic levels are diffi cult to estimate in carabids and major compilations rely on feeding experiments, gut content analysis and field obser vations (Hengeveld, 1980;Harwood et al, 2001;Juen & Traugott, 2006). Stable isotope analysis promises a better Abstract.…”

Diversity and abundance of the coleopteran fauna from organic and conventional management systems in southern England

“…Carabid and staphylinid beetles are two of the most common taxa of above-ground, or epigeal, polyphagous predators in agroecosystems. Quantification of predation by carabids has been improved with the use of monoclonal antibodies, and recent studies have revealed the importance of earthworms and slugs as prey sources (Symondson & Liddell, 1993;Symondson et al, 2000;Harwood et al, 2001). Both carabids and staphylinids have been used as bioindicators of environmental changes in natural and modified ecosystems because of their relative ease of capture by pitfall trapping, responsiveness to environmental conditions, mobility and widespread distributions (Thiele, 1977;Dritschilo & Wanner, 1980;Good & Giller, 1991;Kennedy, 1992;Luff et al, 1992).…”