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Identifying inter- and intra-guild feeding activity of an arthropod predator assemblage†
Version of Record online: 26 MAR 2013
Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
Volume 38, Issue 3, pages 258–271, June 2013
How to Cite
HAGLER, J. R. and BLACKMER, F. (2013), Identifying inter- and intra-guild feeding activity of an arthropod predator assemblage. Ecological Entomology, 38: 258–271. doi: 10.1111/een.12014
This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or a recommendation by the USDA for its use.
- Issue online: 6 MAY 2013
- Version of Record online: 26 MAR 2013
- Manuscript Accepted: 2 JAN 2013
- Manuscript Revised: 12 DEC 2012
- Manuscript Received: 7 SEP 2012
- arthropod sampling;
- biological control;
- food chain;
- Predator gut analysis;
- trophic interactions
Understanding predator–prey interactions of the arthropod community in any given ecosystem is essential in pinpointing the biological control services provided by natural enemies.
Hence, four prey-specific polymerase chain reaction (PCR) assays were developed to analyse the gut contents of the cotton predator community. The four targeted prey included a herbivore/pest, omnivore/pest, omnivore/beneficial, and carnivore/beneficial.
First, prey retention tests were conducted to determine how long a prey item of each target species could be detected in a predator after ingestion. The assays yielded highly variable inter-assay and intra-assay prey detection efficiencies.
Then, a multifaceted field study was conducted to quantify the population dynamics of the cotton predator assemblage and to assess the frequencies of predation that each predator species exhibited on the targeted prey. In total, 1794 predators, representing 17 arthropod families, were collected over two seasons using both sweep net and whole plant sampling procedures.
The predator gut assays showed that there was substantial inter-guild predation occurring on the herbivore/pest, Bemisia tabaci (Gennadius); moderate intra-guild predation on the omnivore/pest, Lygus spp. (Lygus lineolaris (Palisot de Beauvois), L. hesperus Knight, and L. elisus Van Duzee) and the omnivore/beneficial, Geocoris spp. (Geocoris punctipes (Say), and G. pallens Stål); and very little intra-guild predation on the carnivore/beneficial, Collops vittatus (Say).
The gut assays also revealed that DNA of the targeted pests, B. tabaci and Lygus spp., were found more frequently in insect predators than spiders; whereas there were no significant differences in predation between the predatory insects and spiders for the beneficial insects, Geocoris spp. and C. vittatus.
Finally, there was a significantly higher frequency of predation events recorded for B. tabaci, Lygus spp., and Geocoris spp. in the sweep net samples. This indicates that the method of collection might influence the interpretation of the gut assay results.