Dorcatoma substriata Hummel (Anobiidae) in Radnorshire, the 3rd known Welsh locality, with comments on its fungal associations

摘要

Dorcatoma substriata Hummel is primarily an English species within Britain and develops most commonly in the persistent dead dry fibrous brackets of annually fruiting bracket fungi, especially Inonotus species on living broadleaved trees, but also Phaeolus schweinitzii on conifers. The characteristic exit holes - larger than those of the other main inhabitants of the fungal brackets, Cis species - were recently seen in the caps of I. dryadeus brackets on an old oak on the southern boundary of Cwm Byddog Nature Reserve (S02144), Radnorshire (VC 43), 14 April 2014. A section of one bracket which had fallen away from the tree was retained to confirm the identification by rearing the adult beetle. Further emergence began in early May and continued for some weeks, generating 50 or so beetles which all proved to be D. substriata, as suspected. The species was added to the Welsh List by myself in 1993, from Chirk Park (SJ2638), Denbighshire (VC 50). It has subsequently been found by Adrian Fowles (pers. comm.) at Powis Castle Park (SJ2106), Montgomeryshire (VC 47) in 1996, making this discovery in Radnorshire the third known Welsh locality and the third Welsh county in which it has been discovered. The situation on the southern boundary of the Reserve may also be significant as it is the author's impression that I. dryadeus tends to fruit most prolifically on open-grown or semi-open-grown trees in warm sunny situations, so an open sunny situation may be a fungal choice as much as beetle choice. All three Welsh sites are very close to the English Border.