Vanderbilt University biologists have unraveled an interesting behavior of mosquito sperm. The mosquito sperm can acknowledge smell and certain kind of chemical smell drives sperm to move forward and harder for reproduction.
As per the researchers, the mosquito’s sperm bear sensors similar to the one found on the mosquito’s antennae playing a part in the mosquito’s olfactory system. The specialized suite of chemical sensors found in the sperm is called odorant receptors (ORs) and are located on the tail of the sperm. These sensors upon sensing certain type of chemicals stimulate the tail to beat faster and thus control the sperm movement.
For the first time ORs has been seen to be operating in non sensory cells or tissue and therefore this discovery is very unique, says L.J. Zwiebel, the Cornelius Vanderbilt Chair in Biological Sciences who guided the study. This can also help in controlling the insects’ reproduction and preventing many mosquito carrying diseases.
Researchers believe that repeatedly during the process of evolution, structures are put to better uses after they have been emerged. Similarly, ORs were evolved in the reproductive system and later were included in a complex olfactory system of mosquito. If this is the case, use of sensory receptors in reproduction is more basic behavior than the olfactory system in the insect biology.
Female mosquitoes live for just one month and mate once during this short life span. The female stock (the sperms) donated by males in organ known as spermathecae. Upon mating, female stand in need of blood to get the fundamental elements in order to lay eggs. And this is the reason why females are known to bite and suck blood of humans and other creatures. The sperm stored in spermathecae of the female tract then fertilizes the eggs.
Research Assistant Professor Jason Pitts says that sperm require a chemical signal to get ready for fertilization. The sperm have been seen moving around in the spermathecae within a day after insemination. These movements need one or more stimulant and study suggests that the signals are collected by the odorant receptors.
Such odor receptors are also found in the sperm of the yellow fever mosquito Aedes aegypti, fruit fly Drosophila melanogaster, Asian tiger mosquito Aedes albopictus and the jewel wasp Nasonia vitripennis. This shows that the odorant receptors have a role to bring along eggs and sperm for reproduction, in many insect species.
Researchers are now trying to find a new option to regulate the mosquito populations. They are trying to find a chemical that can make males sterile and can be successfully employed in controlling the population using the sterile insect method. When these sterile males are released in the wild, they compete with the males for mating and thus keeping the population under check. This method in past proved successful, in eliminating the screwworm fly from parts of North America and have controlled the Mexican fruit fly and Medfly in Latin America. However, the method requires huge investment and the process to achieve the desire result is very complex.
Insect control is of major medical and economic importance. The spread of diseases such as malaria and dengue fever causing millions of deaths across the globe can be controlled by regulating the population. It is too early to say that to what extend this new discovery can help in regulating the pest population in the future but it looks promising as of now.