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Aphis ochropus

Yellow teasel aphid

Identification & Distribution  Biology & Ecology 

Identification & Distribution:

Adult apterae of Aphis ochropus are yellow, yellowish-green or greenish yellow. The terminal process of antennal segment VI is 2.9-3.7 times the length of the base of that segment. The siphunculi are dark and are 2.00-2.86 times the length of the cauda. The cauda is pale (although in some of our specimens it appears dusky) with 7 hairs. The body length of the aptera of Aphis ochropus is 1.2-2.0 mm.

 

The fused terminal segments of the rostrum (RIV+V) are 1.4-1.8 times the length of the second hind tarsal segment (HTII). Alates of Aphis ochropus have 10-11 secondary rhinaria on the third antennal segment, and 2-3 rhinaria on the fourth segment.

 

Aphis ochropus feeds on the basal leaflets and subterranean parts of teasel (Dipsacus sylvestris). It is attended by ants usually Lasius species. The species was first recorded in Britain in south Wales in 2009. Our finding of this species in East Sussex in July 2015 was the first record of the species in England. It is otherwise known mainly from central and eastern Europe.

 

Biology & Ecology:

Baker (2009)  found the species in Britain for the first time in Wales in 2007. He thought it likely that plants growing at sites with free draining soils and high exposure to sunlight were favoured. In Sussex we found the species on teasel growing in similar habitats - namely on salt marsh (Rye Harbour) or shingle beach (Winchelsea Beach).

Their colour variability is well demonstrated in the picture below. Of the two apterae in the picture (centre left), one is yellow and the other is yellowish with a greenish suffusion over the thorax and anterior of the abdomen.

The picture above also shows two immature alates. They are greenish with conspicuous black-bordered wing buds.

We found Aphis ochropus usually attended by ants. The colony at Rye Harbour was attended by Lasius niger (see pictures below), and there was evidence of past attendance (soil tenting) at Winchelsea Beach.

 

Baker (2009)  thought that the species was most likely an obligate myrmecophile, since it has not been observed without ants. So far in Britain, Lasius niger is the only species of ant observed in attendance.

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. (2009). Aphis gentianae (Borner) and Aphis ochropus Koch (Aphidoidea) new to Britain. British Journal of Entomology & Natural History 22, 147-150. Abstract