Do Heteropterans Have Longer Molecular Prey Detectability Half-Lives Than Other Predators? A Test With Geocoris punctipes (Heteroptera: Geocoridae) and Orius insidiosus (Heteroptera: Anthocoridae)
2015
Simmons, Alvin M. | Webe, Donald C. | Payton, Mark E. | Hu, Jing S. | Greenstone, Matthew H.
Molecular gut-content analysis has revolutionized the study of predator-prey interactions and yielded important insights into arthropod community processes. However, the raw data produced by most gut-content assays cannot be used to assess the relative impact of different predator taxa on prey population dynamics. They must first be weighted by the detectability half-lives for molecular prey remains for each predator-prey combination. Otherwise, interpretations of predator impact will be biased toward those with the longest detectabilities. Molecular ecologists have noted taxonomic trends in the length of the half-life, in particular that they tend to be longer in spiders, staphylinids, and true bugs. We compare new data from feeding trials of two previously untested true bugs, Geocoris punctipes (Say) (Lygaeidae) and Orius insidiosus (Say) (Anthocoridae), with those from four other heteropterans and three coleopterans, in order to test the hypothesis that half-lives tend to be longer in predatory Heteroptera than in predators of other groups. At 18.4 hand 21.8 h, respectively, the new half-lives are statistically longer than those of the adult beetles, statistically indistinguishable from that of larval Coleomegilla maculata (DeGeer), and statistically shorter than three of the four previously published heteropteran half-lives. If only adults are considered, heteropterans and coleopterans are separable, but the range is still so large that there are multiple statistical differences among the half-lives, making generalization at the order level unsupportable. The hypothesis is rejected.
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