Obserwacje nad reemigracją pająka Araneus quadratus Cl. na teren łąk

Kajak, Anna

doi:ISSN 0424-7205

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Title: Obserwacje nad reemigracją pająka Araneus quadratus Cl. na teren łąk

Abstract:

The phenomenon of influx of young A. quadratus individuals was noted on the territory of the “Artificial A” meadow; from which following to very scrupulous hay barvest they vanished in the precedent vegetative season (fig. 1). During the period from hay making until end of September there were found at application of both methods (scoop and squares method) 2 individuals only on the meadow explored. Rapid disappearance of A. quadratus occurred already before sexual maturity of separate individuals (tab. l) and so no cocoons were laid at all. Approximate number of nests per 8 stripes about 75 m long and 1 m wide had been examined in June 1955. On the meadow in question no nest was found. It is only from 16th of June that young individuals were catched there. The number of same proved to be in June much smaller than on the compared ,,Bagienko” meadow, nevertheless already in the month of July those numbers take similar figures (tab. II, fig. 2). On the “Artificial A” meadow quantity of A. quadratus proves to be in July 8 times higher than in the year 1953. On other meadows likewise there was recorded in 1955 the increase of number (three times bigber on "Bagienko"). Thus there had to be noted the same tendency to the increase of number than on other meadows, in spite of the fact that the whole population which settled on above meadow had to migrate from neighbouring territories. The phenomenon is probably to be explained by dispersal of young forms by air flight. In the literature on the subject of spiders this way of the youngsters’ migration frotn their nests is mentioned also (S a v o r y 1928, G e r t s c h 1949, B r i s t o w e 1929). The ,,Artificial A” meadow was occupied very fast. Young individuals could be found there simultaneously as on other meadows on which there were nests, although their original number was evidently lower (tab. II). Individuals leaving the nests situated close to the “Artificial A” meadow were compelled to pass the distance of about 300 m to reach the opposite edge of the meadow. In spite of the fact that the whole population which settled on the “Artificial A” meadow is of an immigrating character, changes of number run equally as on the compared meadow (fig. 2) in both vegetational seasons 1954 and 1953.

References:

l. Bristowe, W. S. 1939 - The comity of Spiders - London.
2. Gertsch, W. J. 1949 - American spiders - Toronto.
3. Savory, T. H. 1928 - The biology of spiders - London.