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Invasion success of ladybirds

Foto: Roman Bucher

Despite the growing scientific literature on detrimental effects of invasive species, we often lack a mechanistic understanding why some species become invasive while others remain benign. Non-native predators bearing a unique set of cues might have the double advantage of naïve prey and naïve predators and thus outcompete native predators. Due to the strong trophic interdependence and the availability of similar and novel non-native lady beetle species, the ant-lady beetle-aphid system is particularly well suited to test for predator-prey naïveté.
Here, we will compare the aggression of ants towards lady beetles, the avoidance behavior of aphids, and the consumption of aphids by lady beetles currently occurring in Europe and in North America. This intercontinental approach is crucial to evaluate the importance of predator-prey naiveté for the invasion success of a non-native species. In addition, we will analyze lady beetle cues to quantify cue similarity between native and non-native species. The combination of behavioral experiments with chemical analyses will not only shed light on the semiochemicals that mediate these interactions but also improve our ability to explain and predict high-impact invasions of insect predators.

PI: Roman Bucher

Team: Ayse Gül Ünlü and Roman Bucher

Cooperation partner: Florian Menzel (University of Mainz), John J. Obrycki (University of Kentucky)

Project funding: DFG