How Certain Wasps React to Smells from Stink Bugs

Jim Crocker
4th August, 2024

How Certain Wasps React to Smells from Stink Bugs

Trissolcus oenone, one of the three scelionid egg parasitoids covered in the study (photograph separate from study).

Photo adapted from: Grey Smith / CC BY (Source)

Key Findings

  • The study by the University of Auckland focused on how chemical cues influence parasitoid wasps' host preferences
  • Researchers identified seven key volatile organic compounds (VOCs) that elicited strong antennal responses from three parasitoid species
  • Understanding these chemical cues helps predict how parasitoid wasps will interact with target and non-target species, improving biological control safety and effectiveness
The brown marmorated stink bug (Halyomorpha halys) has become a significant invasive pest in North America and Europe, causing extensive damage to crops. To combat this, scientists have been exploring the use of parasitoid wasps like Trissolcus japonicus as biological control agents. However, understanding the host-specificity of these parasitoids is crucial to ensure they do not negatively impact non-target species. A recent study by the University of Auckland[1] delves into how chemical cues influence parasitoid host preferences, providing valuable insights for pre-release risk assessments. Parasitoid wasps use their sense of smell to locate hosts. Chemical cues, or volatile organic compounds (VOCs), emitted by potential hosts play a significant role in this process. The study aimed to identify which VOCs are detected by parasitoid wasps and how these compounds affect their host preferences. Researchers used electrophysiological techniques like electroantennography (EAG) and gas chromatography coupled with electroantennographic detection (GC-EAD) to analyze the olfactory responses of three parasitoid species: Trissolcus japonicus, T. basalis, and T. oenone, to compounds associated with nine stink bug species. The study identified eight compounds that elicited antennal responses from all three parasitoid species. Of these, seven were identified: (E)-2-hexenal, (E)-4-oxo-2-hexenal, (E)-2-octenal, (E)-2-decenal, n-tridecane, n-dodecane, and (E)-2-decenyl acetate. Compounds like (E)-2-hexenal and (E)-2-decenal elicited stronger responses, indicating their potential importance in host-location behavior. These findings build on previous research that highlighted the role of chemical cues in parasitoid behavior. For example, a study on T. japonicus showed that this species exhibited stronger behavioral responses to kairomones (chemical signals) from its preferred host, H. halys, compared to a non-target host, Podisus maculiventris[2]. This suggests that chemical cues play a crucial role in host specificity, which is essential for the effectiveness and safety of biological control programs. Moreover, the study's focus on electrophysiological techniques provides a deeper understanding of how parasitoids detect and respond to these chemical cues. This approach complements traditional host range evaluations, which primarily focus on physiological compatibility[2]. By identifying specific compounds that influence parasitoid behavior, researchers can better predict how these wasps will interact with both target and non-target species in the field. The implications of this research are significant for biological control programs. Understanding the chemical ecology of parasitoid-host interactions helps refine risk assessments, ensuring that introduced biocontrol agents like T. japonicus will effectively target pests like H. halys without harming non-target species. This is particularly important given that previous studies have shown that T. japonicus can parasitize non-target species under certain conditions[3]. In conclusion, the study by the University of Auckland enhances our understanding of the chemical cues that mediate parasitoid host specificity. By identifying key VOCs and their effects on parasitoid behavior, this research provides valuable insights for developing safer and more effective biological control strategies. Integrating these findings with traditional host range evaluations can improve the precision of pre-release risk assessments, ultimately benefiting agricultural ecosystems by controlling invasive pests while preserving native species.

EnvironmentBiochemAnimal Science

References

Main Study

1) Electrophysiological Responses of Trissolcus japonicus, T. basalis, and T. oenone (Hymenoptera: Scelionidae) to Volatile Compounds Associated with New Zealand Stink Bugs (Hemiptera: Pentatomidae)

Published 3rd August, 2024

https://doi.org/10.1007/s10886-024-01533-7

Related Studies

2) Host Kairomones Influence Searching Behavior of Trissolcus japonicus (Hymenoptera: Scelionidae), a Parasitoid of Halyomorpha halys (Heteroptera: Pentatomidae).

https://doi.org/10.1093/ee/nvz155

3) Host-Acceptance Behavior of Trissolcus japonicus (Hymenoptera: Scelionidae) Reared on the Invasive Halyomorpha halys (Heteroptera: Pentatomidae) and Nontarget Species.

https://doi.org/10.1093/ee/nvy014


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