Preferences of carabid beetles (Coleoptera: Carabidae) for herbaceous seeds

Abstract

Preferences of seed predators may be an important factor that introduces bias in the results of seed predation studies. In this paper, we report on the experimentally established preferences of carabid beetles for seeds of herbaceous plants. The standard arrangement of 28 species of seeds from 13 families was offered to 37 species of carabids belonging to 5 tribes. The overall consumption was affected by the body mass more than by the body length and showed a quadratic relationship with the dry body mass of the carabid. The number of preferred species of seeds varied from 1 to 16, and in unspecialized species the ordered standardized consumptions formed an almost straight line with negative slope, while in specialized to highly specialized species the standardized consumption exponentially declined with increasing order of species. The most preferred seeds were Taraxacum officinale, Capsella bursa-pastoris, Tripleurospermum inodorum and Descurainia sophia, which were preferred by 28, 20, 19 and 19 species of carabids, respectively, while Consolida regalis, Arctia lappa and Bidens tripartita were not preferred by any of the studied carabids. We pinpoint that choice for a model seed species for a seed predation experiment in the field shall reflect the attractiveness of the seed for predators as seed identity may bring bias in the results.