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Calaphis betulicola

Black-tipped dark-veined birch aphid

Identification & Distribution  Other aphids on the same host 

Identification & Distribution:

In life Calaphis betulicola apterae (see first picture below) are pale green or yellowish, with dark apices to antennal segments, femoro-tibial joints, tibial apices and tarsi. The head and thorax are pale. Calaphis betulicola antennae are longer than the body, and the terminal process is clearly longer than the base of the last antennal segment. Winged individuals (see second picture below) have characteristically darkened wing veins.

 

The siphunculi are pale but with dark brown tips (see first picture below) - this characteristic usually distinguishes the species from Calaphis flava which has the siphunculi pale or a little dusky at the flange. Most secondary rhinaria on antennal segment III are placed towards the middle of the segment (see second picture below), rather than being near the base. This provides a more reliable means to distinguish C. betulicola from C. flava. The body length of Calaphis betulicola is 2.0 to 2.3 mm.

 

Calaphis betulicola is found on the undersides of leaves of Betula spp., especially on Betula pubescens, usually on seedlings and small trees less than 1 meter high. It has been recorded as living on Betula nana in Scotland and Sweden. It is distributed from northern Europe across Russia to China and Japan, as well as in the USA and Canada.

 

Other aphids on same host:

Blackman & Eastop list about 72 species of aphids  as feeding on birches worldwide, and provides formal identification keys for aphids on Betula. Of those, only 18 species occur on silver birch (Betula pendula) and/or downy birch (Betula pubescens) in Europe.

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 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).

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