Parasitism and Suitability of <i>Aprostocetus brevipedicellus</i> on Chinese Oak Silkworm, <i>Antheraea pernyi</i>, a Dominant Factitious Host

• Main Authors: Jing Wang, Yong-Ming Chen, Xiang-Bing Yang, Rui-E Lv, Nicolas Desneux, Lian-Sheng Zang
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Insects
• Subjects: egg parasitoids; parasitism; factitious host; fertilization; <i>Aprostocetus brevipedicellus</i>; <i>Antheraea pernyi</i>
• Online Access: https://www.mdpi.com/2075-4450/12/8/694

<i>Aprostocetus brevipedicellus</i>, a eulophid gregarious egg parasitoid of lepidopterous pests, is a potential biological control agent for the control of many forest pests. A dominant factitious host, <i>Antheraea pernyi</i>, has been widely used for mass rearing several parasitoids in China. However, whether <i>A. pernyi</i> eggs are suitable for <i>A. brevipedicellus</i> rearing remains unclear. Here we evaluated <i>A. brevipedicellus</i> parasitism and fitness of their offspring on <i>A. pernyi</i> eggs with five different treatments, including manually-extracted, unfertilized and washed eggs (MUW), naturally-laid, unfertilized and washed eggs (NUW), naturally-laid, unfertilized, and unwashed (NUUW) eggs, naturally-laid, fertilized and washed eggs (NFW), and naturally-laid, fertilized and unwashed eggs (NFUW). The results showed that <i>A. brevipedicellus</i> could parasitize host eggs in all treatments but significantly preferred MUW eggs to other treatments. Moreover, <i>A. brevipedicellus</i> preferred unfertilized eggs to fertilized eggs and parasitized more washed eggs than unwashed. The pre-emergence time of parasitoid offspring emerging from fertilized eggs was shorter than that from unfertilized eggs. More parasitoid offspring emerged from unwashed eggs than that from washed eggs. The offspring emergence rate was high (>95%) and also female-biased (>85%) among all egg treatments. The egg load of female parasitoid offspring emerging from MUW and NUW eggs was 30–60% higher than the remaining treatments. Overall, MUW eggs of <i>A. pernyi</i> are the most suitable for the mass production of <i>A. brevipedicellus</i>.