Interactions between interactions: predator-prey, parasite-host, and mutualistic interactions.
ABSTRACT Ecological interactions such as those between predators and prey, parasites and hosts, and pollinators and plants are usually studied on their own while neglecting that one category of interactions can have dramatic effects on another. Such interactions between interactions will have both ecological and evolutionary effects because the actions of one party will influence interactions among other parties, thereby eventually causing feedback on the first party. Examples of such interactions include the effects of predators and parasites on the evolution of host sexual selection, the effects of parasites and predators on the evolution of virulence, and the effects of parasites and predators on the evolution of pollinator mutualisms. Such interactions among interactions will generally prevent simple cases of coevolution, because any single case of interaction between two parties may be affected by an entire range of additional interacting factors. These phenomena will have implications not only for how ecologists and evolutionary biologists empirically study interactions but also on how such interactions are modeled.
Full-textDOI: · Available from: Anders Pape Moller, Aug 25, 2014
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ABSTRACT: Many parasites apparently change the behavior of their hosts in a way that seemingly increase the probability of successful reproduction and transmission, suggesting that parasites somehow are able to manipulate the behavior of hosts to their own advantage. Such adaptive manipulation implies that  different roles are played by manipulated and manipulator individuals;  manipulation reduces the fitness of the manipulated individual;  the manipulator gains a fitness advantage; and  this order of events should hold up when analyzed in a phylogenetic context. While some ex-amples of parasite-host interactions are consistent with some of these criteria, there is little strict evidence consistent with all four criteria. Parasite manipulation of vertebrate hosts may differ from that of invertebrates because of differences in cognitive ability, and complexity of the parasite community. Literature on avian brood parasites and their hosts suggests that hosts may be fully aware of their parasitism status. Using studies of the great spotted cuckoo and its magpie host I ar-gue that parasitized hosts probably are doing the best they can, given their status, and that their fitness pay-offs would be even worse if they produced higher levels of resistance. Next, I argue that hosts in general may be aware of their infection status, and that each host individual interacts with so many different parasites, each with their 'own' evolutionary inter-ests, that hosts are unlikely to behave only in response to any single parasite. Rather, host behavior could be considered to reflect a compromise between the evolutionary interests of all the inhabitants of a given host individual. Therefore, it might be difficult to argue that hosts are manipulated by parasites, and I suggest that we may learn more about parasite-host interactions by quantifying the evolutionary interests of hosts and their multitude of parasites, amensals and commen-sals, and that host behavior may more readily be understood from the point of view of the participants involved in these different interspecific interactions.The Open Ornithology Journal 01/2009; 2(1):29-36. DOI:10.2174/1874453201003010086
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ABSTRACT: Both above- and below-ground interspecific interactions contribute to ecosystem functioning in terrestrial systems, and the integration of below- and above-ground interactions is crucial for deepening our knowledge of nutrient cycling and community dynamics in terrestrial ecosystems. The present study explored the effects of plant–microbe interactions on aphid honeydew quality and quantity and important factors mediating ant–aphid mutualisms and below-ground nutrient dynamics. Soybean aphids (Aphis glycines) were inoculated onto two closely related strains of soybean plants: a nodulating strain that associates with rhizobia and a non-nodulating strain that does not harbor any nitrogen-fixing bacteria. As expected, prior to aphid inoculation, nodulating plants were significantly taller and had more leaves than non-nodulating plants. Aphids feeding on nodulating strains were found to reach slightly larger colony sizes and produce honeydew with significantly different sugar profiles than those feeding on non-nodulating plants. The honeydew collected from aphid colonies feeding on nodulating plants contained 160 % more total sugars than honeydew collected from colonies feeding on non-nodulating plants, but there was no difference in total amino acid-N content in honeydew from colonies feeding on the different plant strains. We discuss the implications of honeydew composition for nutrient cycling and community dynamics and suggest areas of future research to elucidate the consequences of altered aphid honeydew composition on ecosystem properties.Arthropod-Plant Interactions 06/2014; 8(3):213-220. DOI:10.1007/s11829-014-9304-5 · 1.18 Impact Factor
PLoS Pathogens 07/2014; 10(7):e1004093. DOI:10.1371/journal.ppat.1004093 · 8.06 Impact Factor