New findings on the courtship behaviour of Pardosa wagleri and P. saturatior, sibling species

Pardosa wagleri and P. saturatior are sibling species previously studied by Tongiorgi (1966) and Barthel & von Helversen (1990). Tongiorgi (1966) established the validity of the two species on the basis of differences in ecology, phenology, coloration and size. Barthel & von Helversen (1990) provided preliminary evidence for their separation by reproductive isolation mechanism and morphometric parameters. In this paper the courtship displays of the two species is described for the first time and compared by the examination of the sequence successions and optical flow, both based on video analysis. Intra-individual, intra- and inter-specific differences were tested with classical statistical analysis, including Anova, Nested-Anova and Paired t-test. The two displays are characterized by two units, the first (A) involving several parts of the spider body and the second (B) the male’s palps only. Main differences between P. wagleri and P. saturatior displays are found in unit A, which is characterized by two sub- units (A1 and A2) involving synchronic movements of palps, legs and abdomen. According to Nested Anova, unit B resulted identical for the two species. In conclusion our study deepens the work of Tongiorgi (1966) and Barthel & von Helversen (1990), providing new insight (description and contrast of the two displays) on the biology of the two species.