Young aphids may ride on the backs of adult aphids to get back to the safety of a host plant quicker, according to an article published in Frontiers in Zoology.
Researchers at the University of Haifa, Israel, observed large groups of aphids dropping to the ground from the plants they were attached to as a defence against animals grazing on the plants. Following the escape, the authors noticed young aphids mounting the backs of adult aphids and "catching a ride," which allowed them to reach the safety of a new plant faster.
Dr Moshe Gish, corresponding author of the study, said: "Since the ground is a hostile environment for an aphid, the faster it returns to a host plant, the higher the aphid's chances of survival. Young aphids have difficulty travelling over cracks, stones and twigs, so riding on a back of a fast-walking adult can shorten the time a young aphid needs to spend off the plant. Since young aphids cannot survive very long on the ground, this behavior may improve their chances of survival.
Dr Gish said: "We were surprised to find that the adults do not seem to like young aphids climbing on their back."
The researchers observed the adult aphids frequently attempting to remove the young aphids from their backs and the young aphids trying to withstand the removal attempts. This behavior was found to slow the adults down, but the adults were not always successful at removing the young aphids.
The authors caution that these behaviors were observed in a laboratory, therefore care should be taken when generalising outside of this setting.
Read more about this study at Science Daily.