Common name:

Root-eating beetles

Number of species:


Size Range:



4-4-4. Lobed or not.


  • Monotoma bicolor
  • Monotoma brevicollis
  • Monotoma spinicollis
  • Monotoma testacea
  • Cyanostolus aeneus
  • Rhizophagus fenestralis
  • Rhizophagus picipes


Despite their common name, the 23 British species of Monotomidae (formerly Rhizophagidae) are predatory, rather than root-feeding.  1.5-6mm long, elongate and parallel-sided, they have truncate elytral apices and are usually found in and around decaying organic matter.  Compost heaps, dung, birds’ nests and beneath bark are all typical habitats and two species, Rhizophagus parallelocollis Gyllenhal and R. perforatus Erichson are subterranean and can be found in coffins. 

Two species (Monotoma conicicollis Guérin-Méneville and M. angusticollis (Gyllenhal)) are myrmecophilous and the predatory R. grandis Gyllenhal is a biocontrol species introduced as a predator of the scolytid Dendroctonus micans (Kugelann) in spruce plantations.