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Aphis crepidis

Hawk's-beard root aphid

On this page: Identification & Distribution  Biology & Ecology 

Identification & Distribution:

Aphis crepidis apterae are dark bluish-green to yellow-green, and are not wax powdered (see first picture below). The dorsum of Aphis crepidis is membranous apart from a rather faint short dusky spinal bar on tergite 8, and marginal tubercles are prominent (see second picture below showing three marginal tubercles).

The femora and proximal tibial hairs are shorter than the least width of the tibia. The siphunculi are dark and the cauda is dusky. The body length of Aphis crepidis is 1.2-2.0 mm.

Aphis crepidis is very closely related to, and apparently morphologically indistinguishable from, Aphis taraxacicola  (which feeds on dandelion not hawk's-beard).

The hawk's-beard root aphid lives in ant shelters at the base of Crepis biennis and Crepis capillaris. It does not host alternate and sexual forms have been found in September. Stroyan (1984),  reports that Aphis crepidis is very little known in Britain (only Cambridge and Derby), but comments that the species is perhaps overlooked, a common problem for all the root feeders. It has recently been reported from Wales (Baker (2009) ) and now (our own observations) from Rye Harbour in East Sussex. Aphis crepidis is found throughout Europe, apart from the north, and extends into Iran.

 

Biology & Ecology:

The host plants of Aphis crepis, smooth hawk's-beard (Crepis capillaris) (see picture below) and beaked hawk's-beard (Crepis vesicaria), are common at Rye Harbour in East Sussex, especially on old shingle ridges and near the edge of salt marsh areas.

We have found Aphis crepidis in ant shelters at the base of such plants (see picture below).

All the colonies we have found have been attended by the common black ant Lasius niger (see picture below).

Baker (2009)  found Aphis crepidis feeding sheltered and attended by the ant Lasius niger on basal and subterranean parts of Crepis capillaris growing on amenity grassland at Cardiff Bay, Wales. He also found the same species on subterranean and rarely the upper parts of a Crepis species growing beside a pebble beach at Barry, Wales.

Immatures of Aphis crepidis (see pictures above and below) are a markedly paler green than the adults.

Baker (pers. comm.) has recorded Lysiphlebus fabarum as a parasitoid of Aphis crepidis in Wales. Barahoei (2014)  has recorded Aphidius matricariae as a parasitoid of Aphis crepidis in Iran.

Acknowledgements

We especially thank Rye Harbour Nature Reserve  for their kind assistance, and permission to sample.

We have made provisional identifications from high resolution photos of living specimens, along with host plant identity. In the great majority of cases, identifications have been confirmed by microscopic examination of preserved specimens. We have used the keys and species accounts of Blackman & Eastop (1994)  and Blackman & Eastop (2006)  supplemented with Blackman (1974) , Stroyan (1977) , Stroyan (1984) , Blackman & Eastop (1984) , Heie (1980-1995) , Dixon & Thieme (2007)  and Blackman (2010) . We fully acknowledge these authors as the source for the (summarized) taxonomic information we have presented. Any errors in identification or information are ours alone, and we would be very grateful for any corrections. For assistance on the terms used for aphid morphology we suggest the figure  provided by Blackman & Eastop (2006).

Useful weblinks 

References

  •  Baker, E.A. (2009). Observations of aphids (Aphidoidea) new to Wales. British Journal of Entomology and Natural History 22, 235-246. Abstract 

  •  Barahoei, H. et al. (2014). Checklist of Aphidiinae parasitoids (Hymenoptera: Braconidae) and their host associations in Iran. Journal of Crop Protection 3(2), 199-232. Full text