Scientists used to think that hermaphrodites, due to their low position in the evolutionary scale, did not have sufficiently developed sensory systems to assess the “quality” of their mates.
A new work has shown, however, that earthworms are able to detect the competition by fertilising the eggs that is going to find its sperm, tripling its volume when there is rivalry. This ability is even more refined as they are able to transfer more sperm to more fertile partners.
Hermaphrodites, organisms that have both female and male reproductive organs, such as earthworms, are denied the right to choose their partner. However, a study by researchers at the University of Vigo has shown that worms are capable of telling whether another worm is a virgin or not, and triple the volume of sperm transferred during copulation if they detect a fertilisation competition risk.