Ecology of fear: Ontogeny-mediated non-consumptive effects in a parasite-host system

Non-consumptive effects (NCEs) arise in the presence of parasites even
when the infection does not occur and can include changes to host
behaviour, physiology, or morphology. Using the Drosophila nigrospiracula
– Macrocheles subbadius fly-mite system, we investigated the impact of
parasite exposure (sans infection) during the pupal and adult
pre-reproductive stages. First, we exposed fly pupae to mites—either
indirectly (caged mites) or directly (free-roaming mites) to test the
effects of parasite exposure on pupation success. Second, we tested how
exposing adult female flies to mites prior to reproduction affects
fecundity during the post-exposure reproductive period. We found that
direct exposure to mites significantly decreased the rate of successful
eclosion (development from pupa to adult) compared to unexposed pupae;
however, the duration of pupation was not significantly affected. The
indirect exposure did not have a significant effect on either successful
eclosion or duration of pupation. We also found that indirectly exposed
(caged mites) females had a significant decrease in the number of
offspring produced, but only for the first few days post-eclosion,
suggesting the effect was reversible after mite removal. NCEs arise after
mite exposure during the pupal and pre-reproductive life stage of
Drosophila, in the form of decreased eclosion success and fecundity.
Investigating the NCEs associated with parasite exposure at various life
stages of the host is important in understanding the ecology of fear and
its total impact on hosts throughout their entire lifespan, with
consequences for host ontogeny and population growth.