Ontogeny

Does aphid/ant mutualism vary depending on the age of either species? Do different developmental stages of aphids evoke different behavior in ants?


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Effect of aphid age on honeydew production and ant attendance

Honeydew production is not consistent throughout an aphids lifetime. First and second instar larvae of M. fuscoviride produce only half of the amount of honeydew as older larvae or adults (fig.2)(Fischer et al). The concentration of sugars in the honeydew does not change with age. The concentration of amino acids, however, increases with aphid age. The increase in production of honeydew is an attractant to attending ants as there is a greater reason to invest in protection due to the increase in available nutrients. The intensity of ant-attendance is significantly lower in colonies of first and second instar larvae than in colonies of older age classes (fig.1)(Fischer et al).


Fig. 1. (a) Intensity of ant attendance (mean number of ants per aphid
and hour ± SE)(Fischer et al)


Fig. 2. Total sugar concentrations (in μg sugar per μl honeydew)
(mean ± SE) in the honeydew of various age classes of the aphid M.
fuscoviride on T. vulgare. No means differ significantly at p< 0.05
(Kruskal–Wallis ANOVA)((Fischer et al).