Threatened or harmful? Opportunism across spatial scales apparently leads to success during extralimital colonisation
2016
Horák, Jakub
Various parts of the world face invasion of alien organisms. Nevertheless, the evidence for expansion of species that were close to extinction is close to zero. This story of the rose chafer beetle Oxythyrea funesta appears to be somewhat reminiscent of how in mythology the Phoenix rose from the ashes. Regarding this interesting situation, I struggled to find the drivers that were responsible for the abundance of this beetle across three spatial scales. This study, perhaps, reveals why a formerly relictual and threatened animal is able to colonise and increase its abundance in present landscapes. The study of the vegetation structure of the O. funesta microhabitat showed that it visited high plants in preference. Visitations of O. funesta took place on 20 plant species from ten families with four blossom colours with no specific preference. No difference was found among categories of adult behaviour at the patch level. Only rising flowering intensity of plants promoted species abundance at the regional level. Furthermore, the species was associated with generalist insects and reached higher abundance than some of them. Therefore, the studied beetle appeared to be a habitat opportunist rather than generalist and this made it an unexpected winner that thrives from present land use. Its visitation of flowering patches can be considered as a use of stepping stones. Unfortunately, rising amounts of flower damage by this species appears to be problematic for its conservation. Furthermore, the presence of this species on legally protected species lists highlights the need to determine its actual situation.
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