Biology, images, analysis, design...
|"It has long been an axiom of mine that the little things are infinitely the most important" |
Identification & Distribution:In life Uroleucon campanulae are shiny reddish brown to black. Their body hairs are thick and placed upon well developed scleroites. The antesiphuncular sclerites are little developed in apterae but usually well developed in alates. The antennae, siphunculi, and cauda are black and the legs are bicoloured yellow and black. The body length of Uroleucon campanulae is 2.1 to 3.7 mm.
Uroleucon campanulae siphunculi have polygonal reticulation over more than 0.2 of their length. The siphunculi are 0.85-1.25 times the length of the cauda. The fused 4th and 5th rostral segment is 0.8-1.05 times the length of the second hind tarsal segment. Populations from different regions and hosts differ somewhat in morphology and there is possibly a complex of species in Europe.
The images above are micrographs of Uroleucon campanulae in alcohol.
The clarified slide mounts below are of adult viviparous female Uroleucon campanulae : wingless, and winged.
The Harebell aphid feeds on the upper parts of stems and flowers of Campanulaceae (Harebells) especially Campanula rotundifolia, Campanula rapunculus and Jasione montana, in Europe and Central Asia.
Biology & Ecology:
Uroleucon campanulae does not seem to be a common aphid and it has been little studied.
We have only found it once - in July at Dundreggan in northern Scotland. The host (harebell) was common, but Uroleucon campanulae was only found in one restricted location on about ten plants - just adjacent to a little used road.
Uroleucon campanulae spends its entire life cycle on bellflowers and does not host alternate. Sexual forms develop in autumn and the aphid overwinters in the egg stage.
Osiadacz, B. & Halaj, R. (2011) have looked at the diversity of aphid species on Campanulaceae (bellflowers). They noted that bellflowers have been colonized by only a limited number of aphids. Worldwide only a dozen or so aphid species are specifically associated with this family, whereas in Poland alone there are some 150 species associated with Asteraceae. Yet the Campanulaceae have about 2000 species worldwide. With the Asteraceae it seems there was coevolution of the aphid and plant species, but this has not happened with Campanulaceae. The plant family appears to have no notable defences and the sap is not toxic.
The low diversity seems to be because the vast majority of the Campanulaceae grow in very dry habitats, mainly xerothermic grasslands. Such habitats are 'challenging' for soft-bodied insects such as aphids. Also the degree of coverage by the plants is low - they grow separately rather than in dense aggregations.
Damage and control
Uroleucon campanulae is mentioned as a minor pest of decorative Campanula in Poland by Wilkaniec et al. (2008) .