Post-exposure learned avoidance of the rice weevil, Sitophilus oryzae, to three entomopathogenic nematodes, Heterorhabditis bacteriophora isolates, and their efficacy and penetration rates on this insect
JOURNAL OF ASIA-PACIFIC ENTOMOLOGY, cilt.29, sa.3, ss.1-8, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 29 Sayı: 3
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.aspen.2026.102620
- Dergi Adı: JOURNAL OF ASIA-PACIFIC ENTOMOLOGY
- Derginin Tarandığı İndeksler: Scopus, Science Citation Index Expanded (SCI-EXPANDED), BIOSIS, Zoological Record
- Sayfa Sayıları: ss.1-8
- Bursa Uludağ Üniversitesi Adresli: Evet
Özet
Entomopathogenic nematodes (EPNs) have gained considerable attention for their potential use in sustainable insect pest control strategies. The rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) is one of the most economically important stored-product pests worldwide. This study aimed to evaluate the penetration and insecticidal efficacy of three Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae) isolates (HB1138, HB4, and HBNL) against adult S. oryzae, and to assess the behavioural responses of surviving adults following EPN exposure. We hypothesized that prior exposure to EPNs would influence the subsequent orientation behaviour of surviving adults. Infective juveniles (IJs) of the isolates were applied to S. oryzae adults at eight concentrations (3–400 IJs/adult). Behavioural responses of adults surviving exposure to 400 IJs/adult were assessed using a three-chamber choice assay, in which previously exposed and non-exposed individuals were given simultaneous access to EPN-treated and untreated wheat. Adult mortality increased significantly with increasing IJ concentration, whereas no significant differences were detected among isolates. The highest mortality (66.67%) was recorded for HB1138 at 400 IJs/adult, and this isolate also exhibited the highest mean penetration rate (31.33 IJs/adult). Non-exposed individuals showed no preference between EPN-treated and untreated wheat, whereas previously exposed adults showed isolate-dependent behavioural responses. Insects previously exposed to HB4 showed a significantly higher probability of choosing EPN-treated wheat, whereas HB1138- and HBNL-exposed individuals consistently avoided EPN-treated wheat. Overall, H. bacteriophora isolates affected S. oryzae through both direct mortality and post-exposure behavioural responses, underscoring the need to consider sublethal effects in EPN-based biocontrol.