Our team, a collaboration of faculty mentors and undergraduates from Texas A&M-San Antonio and the University of New Mexico, conducted a study recently published in the Journal of Parasitology in which we evaluated the effect of Paragordius varius (a nematomorph) on the calling behaviour of male Acheta domesticus crickets 5. It has not been established however, whether other cricket behaviours are manipulated prior to nematomorph maturity and emergence. In fact, it is well established that horse-hair worms change the behaviours of their cricket hosts by causing them to jump into water, essentially committing suicide 4. Parasites in the phylum Nematomorpha, commonly called horse-hair worms, are parasites with a free-living stage that require an insect host, such as crickets, grasshoppers, cockroaches, or beetles, for development and as well as to deliver them to streams or lakes for their free-living reproductive stage 3. Parasites that have a free-living stage might alter host behaviours in ways that ensure delivery to the appropriate habitat for emergence keep the host alive long enough for parasite development (non-risky behaviour) or reserve energy for the developing parasite 2. If evolution is in play, parasites with complex life cycles would be predicted to alter behaviours in ways that increase the chance the parasite will reach the next host in their life cycle, such as inducing risky behaviour that increase predation rates by the next host. Parasites have been known to induce behavioural changes in their host 1 and of interest is whether these behavioural changes are a product of evolution benefiting the parasite or are merely side-effects of an intense infection.

It is well-established that parasites can affect the behaviour of their hosts, but can a parasitical worm really get a cricket to shut-up? Dr Megan Wise de Valdez thinks so, and here she tells us why

Download hair worms in crickets