A new study found that female guppies subjected to male harassment can swim faster and more efficiently to escape coercion. As female guppies become more exposed to such circumstances, physiological changes can develop and thus help in overall adaptation, just like female athletes who practice regularly to enhance their skills.
Over the last 100 years, the understanding of reproductive relationships between males and females has been modified from being a cooperative effort to something that sparks a conflict. Such change is probably because of the differences in the reproductive goals of each sex as they evolve. With this, quality male and female encounters become widely varied per sex and thus may result in the rise of different behaviors and coping mechanisms to benefit one's interest at the cost of the other.
Most often than not, male coercion of females occur as a result of the changes in reproductive goals. One example of this is sexual harassment whereby males continually court females in the hopes of finding a mating partner. Females, on the other hand, tend to escape from this act by expending high levels of energy to the point of injuring themselves. In order to prevent these events, females may potentially alter their behavior or functionality in such a way that it will enable them to decrease the impacts of coercion and totally escape from harassment.
The researchers from the University of Exeter and University of Glasgow investigated this adaptive behavior on female Trinidadian guppies (Poecilia reticulata) by subjecting them in varying degrees of male coercion for a period of months. This environment is said to be similar to what the species experience in the wild.
The findings of the observations, published in the journal Functional Ecology, show that after a period of five months, the female subjects that were made vulnerable to male harassment, developed more efficient swimming techniques while utilizing less energy at a given speed compared to those exposed to less male coercion.
"It seems that prolonged increases in high-intensity swimming in females, caused by male harassment, leads to changes in the physiology or swimming mechanics of individual fish," says Dr Safi Darden from the University of Exeter. This then results in decreased energy expenditures while swimming and may consequently reduce the negative impacts of the coercion.
In conclusion, Dr Shaun Killen from the University of Glasgow said that the swimming mechanics of the females served as a vital factor that influenced the study results. The researchers were able to observe that the highly-exposed females utilized less pectoral and fin-assisted technique. With this, it may be said that sexual harassment can lead to plastic modification in the usual routine energy exertion and functionality of females.
Photo: Roberto Verzo | Flickr
