Rola pająków w zmniejszaniu szkód powodowanych przez szarańczaki (Acridoidea) na łące - badania eksperymentalne

Bibliographical references (page 763)

Strony 755-764 : ilustracje ; 24 cm

Streszczenie w języku polskim

Bibliografia na stronie 763

Pages 755-764 : illustrations ; 24 cm

Abstract in Polish

The results of experiments concerning the elimination of Acridoidea by spiders of the species Araneus quadratus Clerck are described. It was established that their elimination due to spiders depends on the initial density of the prey population - the percentage of the insects caught in the webs rises with the increase of the density of the insects in the environment. The elimination also increases if the spiders are already stabilized in the environment at the moment of introduction of the prey and when they deal with a population new to the given environment, not adapted to the new conditions. The losses in the yield of vascular plants caused by grasshoppers were two times smaller in the experiments in which spiders were present as compared with those occuring in an environment with the same initial number of insects in the absence of spiders.