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Genus Ctenocallis

Hedgehog aphids

On this page: Ctenocallis  Ctenocallis setosa 

Genus Ctenocallis [Panaphidini]

Ctenocallis are small to medium size aphids, with the body of the aptera bearing long finger-like marginal backwardly directing processes. The siphunculi are short truncate and are situated at the base of the marginal processes on abdominal tergites VI. The Ctenocallis genus contains only three species, each with its own distribution in Europe and North Africa (Atlantic, Pannonian and Mediterranean).

 

Ctenocallis setosa (Broom hedgehog aphid)

Identification: Ctenocallis setosa apterae are unmistakable given their numerous long finger-like papillae (small rounded protuberances) protruding from the dorsum. Adult apterae (see first picture below) are yellowish, but with the yellow ground colour of the dorsum more or less obscured by brownish segmental bars which extend from near the mid-line to the body margins. There is a complete segmental series of long, finger-like papillae on the spinal and marginal regions of the body segments. The marginal series is complete from the pronotum to the seventh abdominal tergite, with one papilla on each side per segment. That of the sixth abdominal segment is shorter than the rest and the siphuncular pore opens at its base anteriorly. The spinal series is complete from the head to the eighth abdominal segment inclusive. The cauda has a slightly elongate knob, bearing about 14 hairs, and the subanal plate is fairly deeply cleft. The body length of the adult aptera is only 1-5-1.6 mm.

The alate (see second picture above) has the papillae much reduced in size and the siphuncular pores are more or less apical on short, blunt spinulose processes. The wing membrane is rather densely and finely spinulose-imbricate, and the radial sector is absent, its support function being performed by the strongly recurved first branch of the median vein.

Ctenocallis setosa feeds flattened against the midribs on the upper sides of leaves of broom Cytisus scoparius. Its colour, small size and irregular profile make it very difficult to see - especially on the older, often blotchy leaves. It is has an Atlantic distribution in Europe, and has been introduced to North America, but is generally rare.

Our observations are the second record of Ctenocallis setosa in UK to date.
First observedby: H.L.G. Stroyan1954 & 1958at: West Byfleet, Essex
Secondby: Influential Points25 August 2017at: Bedgebury pinetum, Kent

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Acknowledgements

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 sp 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).

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References

  •  Blackman, R.L. & Eastop, V.F. (2006). Aphids on the world's herbaceous plants and shrubs. Vols 1 and 2. John Wiley & Sons.