Multiple Cues for Winged Morph Production in an Aphid Metacommunity

Abstract

Environmental factors can lead individuals down different developmental pathways giving rise to distinct phenotypes (phenotypic plasticity). The production of winged or unwinged morphs in aphids is an example of two alternative developmental pathways. Dispersal is paramount in aphids that often have a metapopulation structure, where local subpopulations frequently go extinct, such as the specialized aphids on tansy (Tanacetum vulgare). We conducted various experiments to further understand the cues involved in the production of winged dispersal morphs by the two dominant species of the tansy aphid metacommunity, Metopeurum fuscoviride and Macrosiphoniella tanacetaria. We found that the ant-tended M. fuscoviride produced winged individuals predominantly at the beginning of the season while the untended M. tanacetaria produced winged individuals throughout the season. Winged mothers of both species produced winged offspring, although in both species winged offspring were mainly produced by unwinged females. Crowding and the presence of predators, effects already known to influence wing production in other aphid species, increased the percentage of winged offspring in M. tanacetaria, but not in M. fuscoviride. We find there are also other factors (i.e. temporal effects) inducing the production of winged offspring for natural aphid populations. Our results show that the responses of each aphid species are due to multiple wing induction cues.

Chemotypic variation in terpenes emitted from storage pools influences early aphid colonisation on tansy

“…In the tansy aphid life-cycle, the main dispersal period occurs at the end of May/early June (early aphid colonisation) when winged morphs first appear and most plants are unoccupied, i.e. aphids are free to choose among host plants2636. Winged aphids are only produced for a few weeks, after which new colonisations of empty plant patches occurs by walking unwinged aphids (late colonisation, from late June).…”

“…These aphids exhibit a metapopulation structure on tansy, with dispersal among plants limited to the few generations (or weeks) when winged aphids are present26. The aphids interact with their tending ant species, with other specialised tansy aphid species and the myriad of natural enemies to form a metacommunity.…”

Habitat variation, mutualism and predation shape the spatio‐temporal dynamics of tansy aphids

“…These different clusters vary in size and can be easily distinguished in the field. Further, winged offspring are predominantly produced only during generations three to four at the start of the season (Mehrparvar et al, 2013). It is host to several specialised aphids such as Metopeurum fuscoviride Stroyan (Aphididae) that have been shown to exhibit metapopulation structuring, with aphid populations genetically structured more at the individual plant level than at the site level (Loxdale et al, 2011).…”

The interactive effects of competition and predation risk on dispersal in an insect

“…[6]), most previous studies have manipulated single factors. However, any one factor may interact with either internal or external cues in their effects on dispersal.…”