Do parasites impair the fight-or-flight reactions of their hosts? Experimental investigations of beetles infected with nematodes

Temporary stressors are a part of life in the animal kingdom, whether they be encounters with predators, transient anthropogenic disturbances or severe weather events. All animals must therefore be capable of dealing with such stressors to ensure their survival, which is the ‘fight-or-flight reaction’. A number of recent research studies, across a range of animal taxa, have found that certain parasites can affect how their hosts deal with these stressors.

In the Davis lab, students have recently conducted a variety of experiments using a common beetle species, the horned passalus (pictured), which is host to a nematode called Chondronema passali. Recent work has shown parasitized beetles have reduced physical strength, cannot fight as well as non-parasitized individuals, and importantly, their stress reactions appear to be affected.

In summer 2019, a project is planned where an REU student will conduct a series of benchtop lab experiments that will all attempt to identify how parasites influence the ability of their hosts to deal with an acute stressor. This will involve field-collection of beetles (from the surrounding area), bringing them to the lab and performing behavioral experiments with them over the summer. The experiments will primarily focus on monitoring changes in stress levels of beetles before and after application of non-lethal stressors.

The ideal student for these projects will be someone who is comfortable handling insects and performing icky dissections, and who can work well in the tick- and chigger-infected field (forest habitats).

Host laboratory: Andy Davis
Type of project: Empirical/Laboratory-based