Effect of local and exotic origin of Asteraceae seeds on their consumption by ground beetles (Coleoptera: Carabidae)

Prior familiarity of carabid beetle populations with seeds of a plant species might result in a preference for locally available species, either due to evolutionary adaptation or learning. Rejection of exotic species might favor the survival of the exotic species due to enemy release. In adults of two Carabidae species, Pseudoophonus rufipes (DeGeer) and Harpalus affinis (Schrank), we investigated the consumption of seeds of the local (growing inside the distribution range of experimental carabid individuals) Asteraceae species Taraxacum officinale and Crepis biennis, and the exotic (growing outside this area) Asteraceae species Adenostyles alliariae and Homogyne alpina. We assumed that the seeds of the exotic species would be consumed less than the seeds of the local species because the seeds of exotic species are not typically found within the range of the tested carabid populations and therefore may be preferred less than the seeds of local species. The seeds of both exotic species were consumed less than the seeds of the preferred local species, T. officinale, but were consumed more than the seeds of the rejected local species, C. biennis. Both carabid species preferred A. alliariae seeds over H. alpina seeds. No difference was observed between the preferences of the mobile and well-flying species P. rufipes and the sedentary and rarely flying H. affinis. The study did not demonstrate the hypothesized preference of the two tested beetle species for the seeds of locally available plant species.