Brush-Thighed Seed-Eater Beetle (Harpalus froelichii) - Species Action Plan

Ref 2/S23 Species Action Plan 23
Plan Author: Norfolk County Council (H. Thompson)
Plan Co-ordinator: Heathland BAP Topic Group
Plan Leader: Natural England
Final Draft February 2007

Current Status

National Status

  • Harpalus froelichii is found on sandy soils at the margins of agricultural fields and on coastal sand dunes. It requires dry, bare ground with partial plant cover. Its life history is unknown and it has either an annual or, possibly, biennial life cycle. Larvae, and possibly also adults, feed largely on seeds of herbaceous weeds. The adults fly readily and have been caught at light traps. It is active only at dusk and after dark and is readily caught in pitfall traps.
  • Although at one time found in the vicinity of the Dorset heaths and in east Suffolk and Norfolk, Harpalus froelichii has not been recorded from Dorset since the 1920s nor the East Anglian coast since the 1930s. All of the more recent records are from the Norfolk and Suffolk Brecks. It is often abundant where found. In Europe, it has an eastern distribution within a rather narrow latitudinal range: Britain and northern France are the western limit of its distribution.
  • In Great Britain, this species is classified as Vulnerable.

Norfolk Status

  • In Norfolk, Harpalus froelichii is confined to the Brecks, with records from Cranwich Camp, Barnhamcross Common, Santon Downham and Brettenham Heath. In addition, the species has twice been caught in a light trap in a private garden in Thetford.
  • Harpalus froelichii is a seed-eating beetle feeding predominantly on fat hen (Chenopodium album). This plant is a common species of sandy disturbed ground. Given how abundant and widespread this species is in Norfolk, it is a mystery why Harpalus froelichii only occurs in a tiny proportion of the dry sandy fields and Breck grasslands within its geographical range. The beetle flies readily and has been taken in light traps. Indeed, moth traps are recommended as a survey technique in July and August, so distribution would not seem to be a problem.
  • Conservation action for this species should benefit an assemblage of invertebrates, which includes many of the Breckland specialities.

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Current factors causing loss or decline in Norfolk

  • Loss of ruderal communities on disturbed sand, including field margins.
  • Modern treatment of arable weeds through herbicide and seed cleaning.

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Current Action in Norfolk

  • The limited records would not seem to be for want of looking. Mark Telfer's report "Action for Harpalus froelichii in 2001/2 and 2002/3" published 2003, gives an extensive review of the literature on this species, and collates all the most recent records from the author's considerable survey efforts, and those of the Norfolk coleopterist Martin Collier. With the exception of the private address in Thetford, all the sites in Norfolk where this species has been recorded are protected by conservation designations, as follows:
Site Designation Date of Record
Cranwich Camp SSSI, SAC 1987
Brettenham Heath SSSI, SAC, NNR 1961
Barnham Cross Common SSSI, SAC, LNR 2001

The Barnham Cross Common record is from a moth trap only and diurnal searches have failed to find any beetles. Telfer considers the habitat unsuitable for this species.

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Action Plan Objectives and Targets

The following targets are the current targets following the 2001 targets review.

National

  • Maintain populations at all known sites.
  • Enhance populations at all known sites by 2010.
  • Ensure the maintenance of five viable populations across the historic range by 2010.

Norfolk

  • Ensure populations still exist at 2003 levels at Brettenham Heath, Santon Downham and Cranwich Camp by 2010.

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