The mating game

Laura Sirot teaches biology at the College of Wooster, but her passion is observing the intimate lives of insects - "I’ve spent a very good proportion of my life watching insects mate, I just find it so interesting.”  

While mosquitos in the wild don’t need any extra motivation to… get busy, she says in the lab, it’s important to set the mood…

The lighting, temperature, the humidity all have to be just right.  But music?  Not an incentive.  Apparently the vibrations bug mosquitoes.

Sirot uses a suction tube to place a single female into a cage filled with about forty amorous males. And in about the time it takes to describe the encounter, it’s over.

“Mosquitoes actually mate face to face and they sort of form a v-shape with the tips of their abdomens and you watch them and time them and count to about 15-20 seconds and it’s likely that the female’s actually been inseminated.”

Male proteins affect female behavior

And that magic moment provides what she’s looking for, mosquito semen, now inside the female, which Sirot sadly places inside a freezer. 

It turns out that the seminal fluid of mosquitoes is packed with chemicals that change the behavior of females.

Sirot is working is to identify those male mosquito proteins that, once inside the female, tell her to do things like - ‘stop mating’ or ‘go get a sip of blood to help the eggs grow.’ 

She says scientists are trying to figure out is how males are able to influence female feeding and reproduction -  "And if we can figure out how males are doing it, we’re hoping we can find new tools for us to do the same thing.”

Sirot and her colleagues are working to unravel the secrets of mosquitos’ sex life in order to develop control techniques that target only the harmful species and have little impact on the environment. 

Making sterile males more attractive

She says genetically modified male mosquitoes can be bred whose seminal proteins signal females to lay fewer eggs, or to mate only once --  a powerful tool when combined with another idea for controlling mosquitoes: releasing lab sterilized males into the wild.

She says if we can make those males we rear in the lab more competitive, then we might be able to increase the effectiveness of the sterile male technique.

Sirot’s work with the Asian tiger mosquito could help millions of people worldwide faced with dengue fever and other diseases carried by the pests. 

Asian tiger mosquitoes love discarded tires, and in the 1980’s eggs arrived in the Southern U.S. from used tires imported from Asia. They have found their way to Ohio, but so far the diseases they carry haven’t. 

Laura Sirot is a scientist on the front lines of pest control, but can’t suppress her admiration for insects’ love lives.

“These little beings that have tiny little nervous systems and yet they have very highly complex behavior.”

Understanding that behavior and the chemicals that control it could be the next breakthrough in our continual battle against the mosquito menace.

I’m Jeff St.Clair with this week’s Exploradio.