Age-dependent Variation in Longevity, Fecundity and Fertility of Gamma Irradiated Bagrada hilaris (Hemiptera: Pentatomidae): Insights for a Sustainable SIT Program

Authors: PAOLINI, ALESSANDRA - Bbca-Onlus, Italy; MUSMECI, SERGIO - Enea Casaccia Research Center; MAINARDI, CHIARA - University Of Rome; PECCERILLO, CHIARA - University Of Trento, Italy; CEMMI, ALESSIA - Enea Casaccia Research Center; DI SARCINA, ILARIA - Enea Casaccia Research Center; MARINI, FRANCESCA - Bbca-Onlus, Italy; SFORZA, RENE - European Biological Control Laboratory (EBCL); CRISTOFARO, MASSIMO - Bbca-Onlus, Italy

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2025
Publication Date: 4/13/2025
Citation: Paolini, A., Musmeci, S., Mainardi, C.E., Peccerillo, C., Cemmi, A., Di Sarcina, I., Marini, F., Sforza, R., Cristofaro, M. 2025. Age-dependent Variation in Longevity, Fecundity and Fertility of Gamma Irradiated Bagrada hilaris (Hemiptera: Pentatomidae): Insights for a Sustainable SIT Program. Insects. 16(4):408. https://doi.org/10.3390/insects16040408.
DOI: https://doi.org/10.3390/insects16040408

Interpretive Summary: Controlling alien insect pests in cropping systems without chemicals is challenging. Here, we evaluate the use of irradiation to determine the feasibility of the sterile insect technique (SIT) approach to controlling the bagrada bug, Bagrada hilaris. This work complements previous investigations carried out on two of the major pentatomid pests, e.g., the brown marmorated stinkbug and the bagrada bug. Due to the evidence of a gregarious phase during the autumn, we tested the possibility of making massive collections of wild-type bagrada bugs, irradiating and releasing them for small scale SIT programs. This study documented how irradiation doses of gamma rays impact the physiological parameters, such as fertility, fecundity, and longevity, of two-weeks old bagrada adults and fifth-instar nymphs. Our results warrant further research to test the feasibility of SIT directly on bagrada bug populations in confined-field conditions alone or in combination with a classical biological control program.

Technical Abstract: Bagrada hilaris is an invasive stink bug causing important yield losses in Brassica crops. It originates from India, Southeast Asia, Middle East and South Africa, and is reported as invasive in several southwestern US states, Hawaii, Mexico, Chile and in the Mediter-ranean islands of Malta and Pantelleria (Italy). In the context of an integrated pest management (IPM) strategy, classical biological control is regularly combined with SIT (sterile insect technique) obtaining successful results. In this study we tested the effects of gamma rays on longevity, fecundity and fertility of bagrada bugs. We irradiated them at two different stages of their life cycle (fifth-instar nymphs and two-weeks old adults). Irradiation at the nymphal stage had a strong impact on female fecundity, with eggs number approaching zero at a dose of 80 Gy. Similarly, a full suppression of female fertility was achieved at 80 Gy when they were mated with males irradiated as nymphs or as mature adults. For longevity, gamma rays had only a slight impact on adult male and female life span. Due to the evidence of a gregarious phase during the autumn, these results suggest that SIT applications by massive collections of bagrada bugs at various stages of development during autumn, followed by irradiation and reintroduction to the field, might be a safe and economically sound approach of control. Research is currently underway to evaluate the fitness of sterile males and mating patterns. Further studies in confined-field conditions will be needed.