Location: Fruit and Tree Nut ResearchTitle: Chemotaxis of Steinernema carpocapsae to Galleria mellonella (L.) larvae infected by con- or hetero-specific entomopathogenic nematodes
|FU, YA-QI - Nankai University|
|WANG, WEN-WU - Nankai University|
|CHEN, CHAO-YING - Nankai University|
|SHAN, SHAO-JIE - Nankai University|
|Shapiro Ilan, David|
|LIU, YAO-HUA - Nankai University|
|CHENG, WEI-MIN - Agro-Environmental Protection Institute|
|GU, XIN-HUI - China National Tobacco Corporation Nanjing Compamy|
|RUAN, WEIBIN - Nankai University|
Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/14/2020
Publication Date: 12/11/2020
Citation: Fu, Y., Wang, W., Chen, C., Shan, S., Shapiro Ilan, D.I., Liu, Y., Cheng, W., Gu, X., Ruan, W. 2020. Chemotaxis of Steinernema carpocapsae to Galleria mellonella (L.) larvae infected by con- or hetero-specific entomopathogenic nematodes. Biocontrol Science and Technology. 31/299-313. https://doi.org/10.1080/09583157.2020.1853049.
Interpretive Summary: Due to environmental concerns, alternatives to broad spectrum chemical insecticides are being investigated. Entomopathogenic nematodes (also known as beneficial nematodes) are small round worms that are natural bio-insecticides and are safe to humans and the environment. We are working to understand how these nematodes navigate in the soil to find insects to attack, and how they determine if an insect is worthy of infecting. We found that the nematodes respond to chemical cues in the soil that are emitted from insects. Once an insect is already infected the nematode is less likely to attack because nutrition inside the host is diminished and the chance of finding mates is reduced. Elucidating the infection behavior of beneficial nematodes will help us use them more efficiently in sustainable crop protection approaches.
Technical Abstract: Entomopathogenic nematodes (EPN) infect insects and reproduce within the host cadaver. The nematodes are presumed to find hosts via chemotaxis. However, the chemotaxis of nematode species in response to insects previously infected by con- and hetero-specific EPN in soil conditions has not be elucidated. Our aim was to address the response of Steinernema carpocapsae All (Sc) to Galleria mellonella cadavers infected by con- or hetero-specific EPN (Heterorhabditis bacteriophora HB1, S. feltiae SN, S. rarum 17 C&E) in soil via chemotaxis assays. Additionally, the effects of different time points post-infection were also evaluated. Results indicated that live and previously infected G. mellonella larvae repel infection juveniles of Sc (p<0.05) regardless of the time point post-infection and EPN species (con- or hetero-specific). Moreover, it was found that insects infected by different EPN species released dimethyl disulfide identified by Solid Phase Microextraction -GC-MS. We found that dimethyl disulfide acted as a repellent to Sc infective juveniles even at 100 times dilution of the expected concentration. Our results suggest that in a soil context, infective juveniles were repelled by live and epn-infected G. mellonella larvae independent of nematode species (con- and hetero-specific) and time post-infection.