Abstract
1. Pachycrepoideus vindemiae and Trichopria drosophilae are cosmopolitan
pupal parasitoids of Drosophilidae that attack the invasive Drosophila
suzukii. This study investigated one aspect of their phenotypic
plasticity – host acceptance and offspring fitness on 25 Drosophila
species in a phylogenetic framework. Each parasitoid’s key biological
and ecological traits were compared among the different host species. 2.
Results demonstrate that both parasitoids successfully parasitized and
developed from all tested host species. Although the parasitoids’
efficiency and offspring fitness varied among host species, effects on
life-history characteristics or ecological traits appeared to be
unrelated to the phylogenetic position of tested host species. 3. Both
parasitoids benefited from attacking larger hosts, with body size of
emerging progeny positively correlated to host size and an increased
fecundity (mature egg load) of female wasps. Achieving larger body size
came at no significant costs in immature development time. 4. The
results show remarkable levels of phenotypic plasticity in the
parasitoids’ body growth and development, which is discussed with
respect to their potential for host range expansion.