Can Flower chafers be monitored with odour traps? (Coleoptera: Cetoniidae)

Monitoring is becoming an increasingly important for nature conservation. We tested odour traps for the monitoring of Flower chafers (Cetoniidae). These traps have been designed for eradication or monitoring the beetles in Mediterranean orchards where these beetles can be present in large numbers. Therefore, it is unclear whether these traps can be used to monitor these species in Northern Europe at sites where these species have relatively low population sizes. Odour traps for Cetonia aurata Linnaeus, 1761 and Protaetia cuprea Fabricius, 1775 were tested in five sites in Belgium and odour traps for Oxythyrea funesta Poda, 1761 and Tropinota hirta (Poda, 1761) at one site. In total 5 C. aurata, 17 Protaetia metallica (Herbst, 1782) and 2 O. funesta were captured. Furthermore, some more common Cetoniidae were found besides 909 non-Cetoniidae invertebrates. I conclude that the traps are not interesting to monitor C. aurata when the species is relatively rare. However, the traps seem to be useful to monitor P. metallica and to detect O. funesta even if it is present in low numbers. However, it is important to lower the high mortality rate of predominantly honeybee and bumblebees by adapting the trap design.