Biology, images, analysis, design...
|"It has long been an axiom of mine that the little things are infinitely the most important" |
Uroleucon cichorii = Uroleucon cichorii cichorii
Large chicory aphidIdentification & Distribution Biology & Ecology
Identification & Distribution:Adult apterae of Uroleucon cichorii are shining metallic grey-brown with black antennae and siphunculi. The femora are yellow basally and black on the distal half. The key distinguishing characer is that the Uroleucon cichorii tibiae are entirely black (cf. Uroleucon grossum and Uroleucon obscurum which have much of the basal half of the tibiae yellow-brown rather than black). The apical segment of the rostrum is 1.04-1.33 times the length of the second hind tarsal segment.The antennal terminal process is 5.4-8.4 times longer than the base of antennal segment 6. The siphunculi are 1.1-1.7 (normally 1.4-1.6) times the length of the cauda. The body length of the adult Uroleucon cichorii aptera is 2.8-4.9 mm.
The large chicory aphid does not host alternate, but lives all year on the upper parts of stems of chicory (Cichorium spp.). It is also frequently recorded from other related composite genera, including Crepis, Hieracium, Hypochaeris and Lapsana, suggesting it is less host-specific other Uroleucon species. Sexual forms appear in September, and the species overwinters in the egg stage. Uroleucon cichorii is distributed throughout Europe and into Asia.
Biology & Ecology:
We have only found this species once, in late summer on smooth hawk's-beard (Crepis capillaris) in Bedfordhire in September.
Like other Uroleucon species, Uroleucon cichorii can build up to large numbers in late summer.
The hind tibiae are conspicuously black, enabling us to confidently assign this colony to Uroleucon cichorii (=Uroleucon cichorii cichorii rather than to the closely related Crepis specialist, Uroleucon grossum (=Uroleucon cichorii grossum).
The picture above shows a number of immature Uroleucon cichorii comprising both females and males. Very young immature female viviparae (and probably oviparae) are a deep reddish-brown. As they mature most of the dorsum becomes metallic grey leaving the posterior area near the siphunculi reddish- brown. Young alate males are green - quite different from the developing females.
Several authors have recorded the parasitoids occurring on Uroleucon cichorii. Tomanovic et al. (2003) recorded Ephedrus niger, Praon volucre, Praon yomeneae, Aphidius funebris and Binodoxys centaureae in his review of aphidiines parasitizing Uroleucon cichorii in the West Palaearctic. Kos et al. (2012) recorded Ephedrus plagiator, Praon volucre, Praon yomenae, Aphidius funebris and Aphidius matricariae parasitizing Uroleucon cichorii in Slovenia.
Other aphids on chicory (Cichorium intybus):
Blackman & Eastop list 31 species of aphid as feeding on Cichorium intybus and/or Cichorium intybus worldwide, and provide formal identification keys. Baker (2015) lists 20 of these species as occurring in Britain: Aphis craccivora, Aphis fabae, Aphis gossypii, Aulacorthum solani, Brachycaudus helichrysi, Hyperomyzus lactucae, Hyperomyzus picridis, Macrosiphum euphorbiae, Myzus ornatus, Myzus persicae, Nasonovia ribisnigri, Pemphigus bursarius, Protrama flavescens, Protrama radicis, Trama caudata, Trama troglodytes, Uroleucon cichorii, Uroleucon picridis and Uroleucon sonchi.
Note: Bell et al. (2015) (Appendix S2) have also published an "annotated checklist of aphids present in the UK". We discuss some of the reasons for the differences between Baker's and Bell's lists in our rare aphids page.