Abstract
Positive associations between parasitic infections and developmental instability are often reported in the literature. In some cases, developmentally unstable individuals are of lower genetic quality and more prone to infection, whereas in other cases, parasites appear to directly cause developmental instability. We determined whether parasitism correlated with fluctuating asymmetry in femur length, a measure of developmental instability, in two species of cockroaches harbouring benign nematodes, and four species of grasshoppers infected with harmful gregarine protozoans. We found no evidence that the more asymmetrical individuals were more heavily parasitized, in either of the six insect species. These results provide several exceptions to the pattern generally reported in the recent literature, and suggest that, at least among insects, fluctuating asymmetry and parasitism are not always associated.