Summary details for Wabasso replicatus (Holm, 1950)

Distribution

The species was discovered in Britain on the Insh Marshes RSPB reserve in the Spey Valley, Scotland in July 1999, and was found there again in July 2000 and July 2002. A closely related species was described by Chamberlin (1948) from eastern Canada under the name Eulaira quaestio, while Holm (1950) described Diplocentria replicata from Sweden. These two taxa were synonymised by Millidge (1984) and transferred by him into a new genus Wabasso. However, the differences between New and Old World populations are consistent, thus justifying their taxonomic separation as W. quaestio and W. replicatus respectively (Merrett & Dawson, 2005). W. replicatus has also been found in Greenland, Iceland, Norway, Finland and Russia east of the Urals, but seems never to be common.

Habitat and ecology

Little appears to be known about its requirements, the species occupying both wet and dry habitats in its northern range. The two males found in 1999 were sieved from wet flood debris on an open part of Insh Fen, with further immatures shaken from dry Molinia tussocks on the fen in July 2000, and both sexes in 2002. The vegetation here is relatively acidic with Molinia dominant, and in the wetter areas frequent Eriophorum. Insh Marshes form part of the natural flood plain of the Spey Valley and are regularly inundated during the winter, the water often lying well into the spring or even summer in wet years, such as 1999. In summer there is low intensity grazing on the fen by sheep. The period of maturity may be short, with adults elsewhere found between June and August. As Scotland lies farther south Wabasso may perhaps mature earlier here.

Status

A species discovered new to Britain in 1999 and known only from one location where any changes in management regime could pose a threat to the continued survival of the population. It may have been overlooked in the past, as females in particular are potentially confusable with Diplocentria bidentata, but is likely to be rare.

Threats

Only known from a single site, any changes in management of Insh Marshes could pose a threat to this species.

Management and conservation

Maintain the current management regime at Insh Marshes until more is known of its ecological requirements. Text based on Dawson, I.K., Harvey, P.R., Merrett, P. & Russell-Smith, A.R. (in prep.).