Which Ants Farm Aphids?
WouterVarious ant species obtain facultative benefits from tending aphids. These include the ability to aerate soil, decompose organic matter, and control large aphid populations. However, inter-species relationships are not well understood.
Many farming mutualisms are highly diverse. Some have evolved to be highly specific, while others are coadapted to benefit both species. Some have vertical symbiont transmission while others have horizontal symbiont acquisition.
Foraging work organization is simplified in autumn in red wood ants Formica. Colony size affects organization of honeydew collection. Ant colonies typically interact with single aphid clonal lineages. In addition to foraging, ants guard aphid eggs and larvae. They also regurgitate honeydew to feed their queen.
The social structure of ants increases with colony size. However, horizontal dispersal between mounds is limited in salt march habitats. Walking may account for this limited dispersal.
Lasius flavus ants appear to have adapted to life styles as livestock. Their husbandry system is highly similar to human cultural practices. They live in fixed plant structures and actively engineer nest mound habitats.
The density of Lasius ants is one of the highest known for ants. The density appears sustainable. However, the system appears to be obligate interdependent. This may suggest that ants replace aphid-producing livestock when the adult aphids reach maturity.
The overall composition of aphid MLGs in the nest mound changed significantly between 2008 and 2009. In the earlier year, the MLGs were likely missed. However, the population-wide frequency of MLGs was 0.044.
