The Life-Cycle, Abundance and Seasonal Movement of the Wolf Spider, Lycosa (Pardosa) lugubris, in Central Scotland

Abstract

Wolf spiders belong to the family Lycosidae, a group of ground-dwelling spiders which are among the largest and most conspicuous members of the terrestrial invertebrate fauna of temperate regions. Adult females of the European representatives of the genus Lycosa are about 6 mm in length. Lycosids have relatively good eyesight, by spider standards (Homann 1931) they are good sprinters and they do not make use of silk to catch their prey. They are said to chase and catch their prey (Savory 1928; Nielsen 1932; Bristowe 1958) although this has been questioned (Edgar 1969). The egg mass is wrapped in a layer of silk and this cocoon or egg sac is carried by the female, attached to her spinnerets. Their large size, conspicuousness and high density in favourable habitats, makes them very suitable for population studies. The wolf spider, Lycosa lugubris (Walckenaer), occurs over the whole of Western Europe, from Finland in the north to Spain and Italy in the south. It is found in Asiatic as well as European Russia (Bristowe 1939), and has also been recorded in Japan (Yaginuma 1962). Most authors describe its habitat as being in or near woods (Dahl 1908; Norgaard 1945; Locket & Millidge 1951; Wiebes 1959; Hallander 1967a). Locket & Millidge say 'it never seems to occur far from woods' while Wiebes says it is 'very common in clearings in woods'. All the specimens of L. lugubris which I have taken in Scotland have been collected in or near deciduous woodland. This paper, which is part of a 4-year study on the ecology of L. lugubris, attempts to elucidate the close association of this spider with woodlands. This has been done by studying the life-cycle, and the habitats occupied by the spider at different stages in its life-cycle. Most of the field work was carried out in an oak woodland (Quercus petraea (Matt.)) near Glasgow University Field Station on the Ross Peninsula on the east bank of Loch Lomond. The average height of the trees was between 40 and 50 ft and they were 70-100 years old. Clearings had been made in a number of areas to allow for the planting of conifers. Vaccinium myrtillus L. is the dominant plant over large areas of the Peninsula while Pteridium aquilinum (L.) is dominant in places. In this paper frequent reference is made to whether the sampling areas are shaded or whether they are situated in clearings. Reference is made to eight sampling areas. Areas I and 2 were partly shaded, areas 3-6 were shaded and areas 7 and 8 were in clearings.