The Correlation between Volatile Compounds Emitted from Sitophilus granarius (L.) and Its Electrophysiological and Behavioral Responses

Simple Summary Postharvest loss has become a crucial issue for the grain supply chain. Storage of grain without losses in quality is a critically important aspect of global food security. The monitoring and detection of insect infestations in stored grain is essential to inform pest management decisions. Insect olfaction is a principal sensory modality for sensing semiochemicals from their external environment and regulates their behaviors. Some semiochemicals function as attractants or repellents, which could be used for insect surveillance and pest control. In this study, the granary weevil Sitophilus granarius (L.), was used as an example to evaluate volatile compounds released from the weevils' and their initiated electrophysiological and behavioral responses. An improved understanding of S. granarius chemical ecology will lead to developing more efficient and environmentally friendly pest control strategies and technologies. The granary weevil Sitophilus granarius (L.) is one of the most serious primary insect pests of stored products. When S. granarius present in grains, various volatile organic compounds are released as chemical signals which can be used to detect the insects. In this study, volatile chemical compounds released from S. granarius were analyzed using the headspace solid phase micro-extraction (HS-SPME) coupled with gas chromatography (GC)-mass spectrometry (MS) techniques. Two key compounds, 3-hydroxy-2-butanone and 1-pentadecene, were identified from mixed gender of S. granarius adults at high density. Moreover, both male and female adults showed dose-dependent electroantennography (EAG) responses to 3-hydroxy-2-butanone. In behavioral assays, S. granarius was attracted to 3-hydroxy-2-butanone at 0.001 mu g/10 mu L but repelled at 10 mu g/10 mu L or higher. S. granarius was consistently repelled by 1-pentadecene at concentrations at 0.001 and 1000 mu g/10 mu L. 3-hydroxy-2-butanone and 1-pentadecene have considerable potential to offer in the development of new approaches for the monitoring and management of this destructive stored grain insect pest.

Automated summary

This study analyzed volatile chemical compounds released from the granary weevil Sitophilus granarius and identified two key compounds, 3-hydroxy-2-butanone and 1-pentadecene, which played important roles in the electrophysiological and behavioral responses of this insect. These compounds have potential in developing new approaches for monitoring and managing insect pests in stored grain, reducing postharvest loss.