A really cool new paper about just how ants keep aphids as “cattle”:
Ant semiochemicals limit apterous aphid dispersal. Proceedings of the Royal Society B: Biological Sciences. Thomas H Oliver, et al.
Aphid poop is actually a concentrated sugar solution–it’s called “honeydew“. Some species of ants tend aphids, and “milk” them for their sugary poop by stroking with their antennae. Ants will aggressively protect their aphids, and even pick them up and move them to safety when they are in danger.
The ant benefits by receiving honeydew from the aphid, while the aphid benefits by being protected by the ant. This kind of symbiosis is called mutualism– both animals benefit from the association.
But all is not so happy fuzzy–it appears that the Ants are DRUGGING their aphids to keep them docile! From the Abstract:
“Here, we show that the walking movement of mutualistic aphids is also reduced by ant semiochemicals. Aphids walk slower and their dispersal from an unsuitable patch is hampered by ants. If aphid walking dispersal has evolved as a means of natural enemy escape, then ant chemicals may act as a signal indicating protection; hence, reduced dispersal could be adaptive for aphids. If, however, dispersal is primarily a means to reduce competition or to maintain persistent metapopulations, then manipulation by ants could be detrimental. “
The paper speculates that the presence of ants may even inhibit the development of alate (winged) forms of aphids that help dispersal.
Nature is so awesomely devious :)
Image from ViaMoi