Data from: Sugar provisioning maximizes the biocontrol service of parasitoids

There is increasing interest in the use of food supplements in agriculture
to enhance the performance of parasitoids as part of conservation
biological control. Nevertheless, there is limited evidence demonstrating
the effectiveness of this approach, and this shortage of successful
examples raises doubt regarding the validity of this approach. The use of
sugar sources relies on tiered premises that: (i) parasitoids are sugar
limited and (ii) this limitation is alleviated through the provision of
sugar sources, thereby increasing both (iii) parasitoid fitness and (iv)
the population density, which together lead to (v) an increase in
parasitism. In the present study, we address these five premises through
experiments examining the release of the parasitoid Aphytis melinus DeBach
(Hymenoptera: Aphelinidae) into the citrus agroecosystem with and without
sugars. The results demonstrated that A. melinus is sugar limited when
honeydew producers are scarce in the field. The provision of sugars did
not increase the sugar contents in A. melinus females but rather increased
the realized fecundity in these parasitoids, suggesting that females use
energy for foraging and oviposition. Sugar sources increased the
parasitoid population density twofold, and this increase most likely
reflects the enhanced parasitoid longevity. Higher population densities
and the increased realized fecundity of A. melinus obtained from trees
with sugars were reflected in a twofold increase of parasitized hosts.
Synthesis and applications: this study provides the first evidence
supporting the five premises underlying sugar provisioning for parasitoids
and demonstrates the potential value of sugar provisioning to enhance
natural pest control in agricultural systems.