Defense expression in the aphid Myzocallis asclepiadis.By McMartin, K.A. & S.B. Malcolm.
Pierce Cedar Creek Institute, Hastings, MI. 15 pp., 2008
McMartin, K.A. & S.B. Malcolm. 2008. Defense expression in the aphid Myzocallis asclepiadis
. Final Report. Pierce Cedar Creek Institute, Hastings, MI. 15 pp.
The aphid Myzocallis asclepiadisis
a relatively unknown species that feeds on the common milkweed Asclepias syriaca. This aphid is very mobile and mobility appears to be the primary defense against predators. However, over the course of the summer, the aphid changes color, from a pale yellow-green to having orange spots. This aphid could be a model to answer the question of how aposematism evolves. In this study, a natural, unmanipulated population of My. asclepiadisis
was monitored, and experiments manipulating development and density to determine the nature of the color change were conducted. However, it does not appear that development and density are cues for color change. Photographic analysis of color and HPLC analysis are underway to determine the extent of color change and whether that change corresponds to an increase in cardenolide sequestration.
Ants defend aphids against lethal disease.By Nielsen, C., A.A. Agrawal, and A.E. Hajek.
Biology Letters DOI: 10.1098/rsbl.2009.0743, 2009
Nielsen, C., A.A. Agrawal, and A.E. Hajek. 2009. Ants defend aphids against lethal disease. Biology Letters DOI: 10.1098/rsbl.2009.0743
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
Coexistence of three specialist aphids on common milkweed, Asclepias syriaca.By Smith, R.A., K.A. Mooney, A.A. Agrawal.
Ecology. 89(8): 2187-2196., 2008
Smith, R.A., K.A. Mooney, A.A. Agrawal. 2008. Coexistence of three specialist aphids on common milkweed, Asclepias syriaca. Ecology. 89(8): 2187-2196.
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.