ADAMO, S.A.; Dalhousie University: A good male is hard to find – problems in identifying an ‘immunocompetent’ male

Immune systems are composed of a number of separate physiological mechanisms. Therefore, different pathogens can induce different immune responses. In the cricket Gryllus texensis we found that lysozyme-like activity correlated with resistance to the bacterium Bacillus cereus (n=102). However, phenoloxidase activity did not correlate with resistance to B. cereus (n=124). Phenoloxidase activity did correlate slightly with resistance to the fungus Beauveria bassiana (n=63). Preliminary data suggest that phenoloxidase activity, lysozyme-like activity and bead encapsulation did not correlate significantly with one another within individuals (Kendall W=0.13, p<0.1, n-32). These results suggest that most males will be better at resisting some pathogens than they are at resisting others. Few, if any, males will be resistant to all pathogens. Therefore, before we (or female conspecifics) can find an �immunocompetent� male, we must decide which pathogens the male should be able to resist.