| plant genotype shapes ant-aphid interactions: implications for community structure and indirect plant defense. | little is known about the mechanisms by which plant genotype shapes arthropod community structure. in a field experiment, we measured the effects of milkweed (asclepias syriaca) genotype and ants on milkweed arthropods. populations of the ant-tended aphid aphis asclepiadis and the untended aphid myzocallis asclepiadis varied eight- to 18-fold among milkweed genotypes, depending on aphid species and whether ants were present. there was no milkweed effect on predatory arthropods. ants increased ap ... | 2008 | 18419551 |
| coexistence of three specialist aphids on common milkweed, asclepias syriaca. | coexistence of host-specific herbivores on plants is believed to be governed by interspecific interactions, but few empirical studies have systematically unraveled these dynamics. we investigated the role of several factors in promoting coexistence among the aphids aphis nerii, aphis asclepiadis, and myzocallis asclepiadis that all specialize on common milkweed (asclepias syriaca). competitive exclusion is thought to occur when interspecific competition is stronger than intraspecific competition ... | 2008 | 18724729 |
| ants defend aphids against lethal disease. | social insects defend their own colonies and some species also protect their mutualist partners. in mutualisms with aphids, ants typically feed on honeydew produced by aphids and, in turn guard and shelter aphid colonies from insect natural enemies. here we report that formica podzolica ants tending milkweed aphids, aphis asclepiadis, protect aphid colonies from lethal fungal infections caused by an obligate aphid pathogen, pandora neoaphidis. in field experiments, bodies of fungal-killed aphids ... | 2010 | 19923138 |
| multifaceted determinants of host specificity in an aphid parasitoid. | the host specificity of insect parasitoids and herbivores is thought to be shaped by a suite of traits that mediate host acceptance and host suitability. we conducted laboratory experiments to identify mechanisms shaping the host specificity of the aphid parasitoid binodoxys communis. twenty species of aphids were exposed to b. communis females in microcosms, and detailed observations and rearing studies of 15 of these species were done to determine whether patterns of host use resulted from var ... | 2009 | 19219460 |
| plant chemical defense indirectly mediates aphid performance via interactions with tending ants. | the benefits of mutualistic interactions are often highly context dependent. we studied the interaction between the milkweed aphid aphis asclepiadis and a tending ant, formica podzolica. although this interaction is generally considered beneficial, variation in plant genotype may alter it from mutualistic to antagonistic. here we link the shift in strength and relative benefit of the ant-aphid interaction to plant genotypic variation in the production of cardenolides, a class of toxic defensive ... | 2017 | 28060424 |