Mouse competition affects sexual effort
The common male house mouse calculates exactly when and which form of exertion in sex is worthwhile, according to Brian Preston and Paula Stockley of the University of Liverpool. The researchers observed rodents during copulation and evaluated whether male animals change their copulation mechanics in the presence of possible competitors for the female.
This is clearly the case, according to the researchers after extensive analysis of the impact frequency and frequency, total duration and number of sperm released per act. In fact, the males reduced their efforts - more precisely, which calculated from the measured parameters, the female was receptive making "copulation stimulant" - before the first ejaculation, as soon as they smell, see or hear a male rival.
Apparently, the animals accelerated the coitus process in order to be able to safely get a chance in the presence of rival females, the scientists suspect. Another result of their study fits in with this, according to which the ejaculation is brought forward in time, especially in weaker animals in male company. Stronger males, on the other hand, could still assert themselves in the face of intensified competition, the researchers suspect, and therefore invest more resources in the quality of intercourse. As is already known, repeated phases of copulation interrupted by short pauses in female rodents increase the release of a neurohormone that increases the probability of pregnancy.
