Evaluating BG-Sentinel trap setting as an effective surveillance tool for mosquito vectors in the Republic of Cyprus

Effective surveillance of invasive Aedes mosquitoes, particularly Ae. aegypti and Ae. albopictus, is essential for early detection, risk assessment, and optimization of control strategies such as the Sterile Insect Technique (SIT). Although BG-Sentinel 2 traps are widely used in Europe, their performance under eastern Mediterranean conditions remains insufficiently evaluated. We assessed the attractiveness of BG-Sentinel 2 traps baited with BG-Lure, dry ice (CO₂), their combination, and unbaited controls using a Latin square field design in Larnaca and Nicosia, Cyprus. A total of 1,649 mosquitoes were collected. In Larnaca, Ae. aegypti occurred at low densities. Male captures were consistently low and unaffected by attractants, while female captures increased significantly only when BG-Lure and CO₂ were combined (RR = 2.7, 95% CI: 1.6-4.5). In Nicosia, Ae. albopictus was abundant, but responses were sex-specific. Male captures were significantly reduced by CO₂ alone (RR = 0.297, 95% CI: 0.175-0.467), with a weaker reduction when combined with BG-Lure, while female captures were not significantly affected by any treatment. For Culex pipiens, CO₂ strongly increased female captures (RR ≈ 16), irrespective of BG-Lure, whereas males showed only a modest response to BG-Lure alone. Overall, attractant efficacy was highly species- and sex-specific. Standard baiting strategies did not consistently enhance detection of invasive Aedes mosquitoes and, in some cases, reduced male captures, with implications for SIT programs. These findings emphasize the need for local validation of surveillance protocols particularly at points of entry.