Parasites face an interesting tradeoff. They exploit their hosts for their livelihood, yet over-exploitation can result in host death before the parasite is transmitted. The research team will test the hypothesis that, when hosts are subject to multiple infections by genetically diverse parasites, competition among the parasites selects for more aggressive host exploitation and greater virulence than when the parasites within a host are genetically related. The researchers are experimentally manipulating the dispersal rate of parasites among hosts, thereby altering the relatedness of parasites within hosts. After 20 generations of selection, the researchers will examine whether parasites from the low-relatedness treatment have become more aggressive than parasites from the high-relatedness treatment. The parasite, Steinernema carpocapsae, is an insect-infecting nematode, which has been used for biological control. The team will also examine variation in the anti-bacterial properties of a symbiotic bacteria of the nematodes.
This work will benefit society in general by testing key theory incorporating evolutionary analysis into combating infectious disease. Additionally, it will increase our knowledge of an agriculturally, and potentially pharmaceutically, important system. This work will also provide salary for one full-time post-doctoral researcher and internships for four undergraduates each year for three years.
