Influence of the Rearing Host on Biological Parameters of Trichopria drosophilae, a Potential Biological Control Agent of Drosophila suzukii

Abstract

<i>Trichopria drosophilae</i> is a pupal parasitoid that can develop in a large number of drosophilid host species including the invasive pest <i>Drosophila suzukii</i>, and is considered a biological control agent. We investigated the influence of the rearing host on the preference and performance of the parasitoid, using two different strains of <i>T. drosophilae</i>, reared on <i>D. melanogaster</i> or <i>D. suzukii</i> for approximately 30 generations. Host switching was employed to assess the impact of host adaptation on <i>T. drosophilae</i> performance. In a no-choice experimental setup, <i>T. drosophilae</i> produced more and larger offspring on the <i>D. suzukii</i> host. When given a choice, <i>T. drosophilae</i> showed a preference towards <i>D. suzukii</i>, and an increased female ratio on this host compared to <i>D. melanogaster</i> and <i>D. immigrans</i>. The preference was independent from the rearing host and was confirmed in behavioral assays. However, the preference towards <i>D. suzukii</i> increased further after a host switch from <i>D. melanogaster</i> to <i>D. suzukii</i> in just one generation. Our data indicate that rearing <i>T. drosophilae</i> for several years on <i>D. melanogaster</i> does not compromise its performance on <i>D. suzukii</i> in the laboratory. However, producing a final generation on <i>D. suzukii</i> prior to release could increase its efficacy towards the pest.