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Body Size Distribution of Spider Species in Various Forest Habitats

Stańska M., Stański T.

Polish Journal of Ecology

2017

Vol. 65, nr 4

359--370

The body size is one of the main attributes of living organisms. The knowledge of body size patterns of co-occurring species and the related factors can contribute to the understanding of many ecological processes. The aim of the study was the analysis of the distribution of the spider species of different size in heterogeneous forest habitats: ground, herbaceous vegetation, tree trunks and leaves. The research was conducted in deciduous stands of the Białowieża Forest (eastern Poland). Spiders were collected by: a) pitfall traps and sieving the litter through an entomological sieve for the ground layer; b) sweep-netting for herbaceous vegetation; c) bark traps for tree trunks and d) shaking the branches of trees and shrubs for leaves. In total, 247 spider species belonging to 22 families were recorded: 195 species in the ground layer, 122 in herbaceous vegetation, 60 on trunks, and 48 on leaves. The analysis revealed that ground layer was inhabited by the small sized species (mean 5.2 ± 0.11 mm) while larger species inhabited herbaceous vegetation (mean 6.6 ± 0.26 mm), trunks (7.2 ± 0.20 mm) and leaves (6.8 ± 0.41 mm). Moreover, the mean species body size decreased with the increasing number of collected species. Several potential mechanisms are discussed as those determining the preference of various sized spider species in particular habitats like different microclimatic conditions, the nutritional quality of prey and predation. Moreover, the very likely reason of differences in the size of spider species between the ground layer and other habitats is the most complex structure of the former habitat.

Long-term variation in laying date and clutch size of Pied Flycatchers Ficedula hypoleuca in Central Poland

Skwarska J., Kaliński A., Wawrzyniak J., Markowski M., Mikus W., Bańbura M., Bańbura J., Glądalski M., Zieliński P.

Polish Journal of Ecology

2012

Vol. 60, nr 1

187-192

Long-term annual variation in the timing of egg laying, clutch size and relationship between clutch size and the progress of the season was analysed for the Pied Flycatcher Ficedula hypoleuca nesting in a mature deciduous woodland in central Poland in 2002-2010. The earliest mean egg laying date was 8 May (2005) and the latest 18 May (2008), resulting in the maximum difference of 10 days between averages for years. No long- term trend was found. The total average of annual mean laying dates was 12 May. For all nine years the average of annual mean clutch sizes was 6.54 [plus or minus] 0.28 (SE) eggs; for individual seasons mean clutch size ranged from 6.0 to 7.1 eggs but differences among years were not significant. Clutch size clearly tended to decline with the progress of the breeding season within years, with some variation between years; correlation for pooled standardized data was -0.49. This supports the idea that in long-distance single-brooded passerine birds clutch size should decrease with the course of the breeding season due to progressively deteriorating food conditions.