Abstract
We used a phylogenetic framework to examine the relationship between entomopathogenic nematode (EPN) vertical dispersal and infectivity when EPNs are exposed to a mixture of compounds found in late-stage EPN-infected insect cadavers. EPNs from five phylogenetically close and distant species ( Heterorhabditis bacteriophora , H. georgiana , H. megidis , H. indica and Steinernema feltiae ) were exposed to cadaver macerate produced by their own species’ infection and by H. bacteriophora infected hosts. We found that only three of the five species ( H. bacteriophora , H. indica and S. feltiae ) responded to exposure to their own macerate by increasing rates of dispersal. When we exposed all five species to a H. bacteriophora infected host macerate, we found that only H. bacteriophora responded by increasing dispersal, and that the most distantly related species ( S. feltiae ) essentially halted dispersal. These findings suggest that (1) responses to cadaver macerate vary, and (2) there may be a relationship between inherent dispersal rates and sensitivity to macerate exposure, as the most rapidly dispersing species ( H. megidis ) showed no response to macerate exposure.