Spatial-pattern analysis in a territorial spider: evidence for multi-scale effects

Authors

  • Klaus Birkhofer,

  • Joh R. Henschel,

  • Stefan Scheu


K. Birkhofer (birkhofer@bio.tu-darmstadt.de) and S. Scheu, Univ. of Technology Darmstadt, Inst. of Zoology, Schnittspahnstrasse 3, DE-64287 Darmstadt, Germany. – J. R. Henschel, Gobabeb Training and Research Centre, P.O. Box 953, Walvis Bay, Namibia.

Abstract

Territorial animals maintain a certain distance to neighbouring conspecifics, presumably leading to a regular spatial pattern through social spacing. Nevertheless, most animal populations are assumed to show aggregation at certain distance ranges, reflecting the scale dependency of spatial patterns. Leucorchestris arenicola (Araneae: Sparassidae) is a burrow-living spider species that shows territorial behaviour against conspecifics. A multi-scale approach in spatial analysis revealed that territory owners had fewer neighbours than expected under spatial randomness at distances up to 6 m. Behavioural field experiments showed that territory owners were able to perceive and react to burrow constructing neighbours up to at least 4 m distance from their own burrow. At larger distances individuals were often more aggregated than expected under spatial randomness. Analysing adult and immature relationships showed attraction between different development stages at small distances and avoidance at larger distances. The analysis reveals diverse spatial patterns in a territorial and cannibalistic species, showing that both behaviour and environment affect pattern development at different distances. The study outlines the importance of multi-scale approaches for spatial analysis and the need for accompanying experiments to facilitate the interpretation of results.

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