InfluentialPoints.com
Biology, images, analysis, design...
Aphids Find them How to ID AphidBlog
"It has long been an axiom of mine that the little things are infinitely the most important" (Sherlock Holmes)

 

 

Genus Uroleucon [Macrosiphini]

Uroleucon are medium-sized to rather large aphids which may be shiny red, reddish brown or blackish brown. The antennal tubercles are well developed, smooth with diverging sides. The antennae are about as long as the body. Dorsal abdominal hairs are not capitate and are placed on scleroites which are normally dark. Antesiphuncular sclerites may be present or absent; postsiphuncular scleroites are normally present. The siphunculi are black and long with a zone of polygonal reticulation occupying the subapical 0.15-0.4 of their length. The cauda is yellow, dusky or black, finger shaped, long and rather pointed.

Uroleucon is a large genus, with 226 species distributed worldwide associated almost entirely with the daisy (Asteraceae) and bellflower (Campanulaceae) families. They either feed on one species, or on a few, related species. They do not host alternate. They usually have a sexual stage in their life cycle and overwinter as eggs. Uroleucon are not usually attended by ants.

 

Uroleucon achilleae (Red yarrow aphid)

Apterae of Uroleucon achilleae (see first picture below) are red or brownish red with rows of black dorsal spots (cf. most Macrosiphini on Achillea are green or greenish mottled with red). Their antennae are pale with darker segments I, II and the tips of segments of the flagellum. Marginal sclerites and antesiphuncular sclerites are absent. Abdominal hairs are long and placed on rather large scleroites. The legs are yellow with the apical one third of femora and the bases and tips of tibiae black. The siphunculi are black, and cauda is yellow. The body length of Uroleucon achilleae is 2.4-2.6 mm.

The alate (see second picture above) is similar to the apterous adult, but has marginal and antesiphuncular sclerites and cross bars on abdominal segments VII and VIII. The ovipara has the basal half of the hind tibia dark and swollen.

Uroleucon achilleae feeds on the lower leaves of yarrow (Achillea spp.) where it can cause withering. It does not host alternate. Oviparae and alate males occur in October (sometimes earlier). It is found throughout most of Europe and has been introduced to California and Oregon in the USA.

Read more... 

 

Uroleucon aeneum (Dark-tailed thistle aphid)

Uroleucon aeneum apterae (see two pictures below) are shiny metallic bronze-black. The third antennal segment has rhinaria extending over 0.37-0.52 of the length. The apical rostral segment (RIV+V) is 0.23-0.26 mm long. Antesiphuncular sclerites are absent. The tibiae are dark but with a paler dusky middle section, and the hind femur is dark on the distal 0.4-0.5 (cf. Uroleucon cirsii  which has mainly pale legs that are only darkened towards the apices of the segments, and Uroleucon jaceae  which has tibiae totally black). The siphunculi of Uroleucon aeneum have reticulation on the distal 0.15-0.20, and are 1.4-1.8 times the length of the cauda. The cauda is wholly dark (cf. Uroleucon cirsii  which has a slightly dusky yellow cauda). The body length of the adult Uroleucon aeneum apterae is 3.0-4.3 mm.

Both images above copyright Brian Eversham,  all rights reserved.

The alate viviparous Uroleucon aeneum female is much like the apterous viviparous female, but has well developed antesiphuncular sclerites. Antennal segment III has 50-68 secondary rhinaria. The apterous ovipara is similar to the apterous viviparous female, and the alate male has a dark green body with black spots.

Uroleucon aeneum lives in sometimes very large colonies on the upper parts of stems of thistles, mainly Carduus species, but also on some Cirsium species. The dark-tailed thistle aphid does not host alternate, but remains all year round on thistle. Oviparae and alate males appear in September. Uroleucon aeneum is found throughout Europe to Turkey, Armenia, Kazakhstan and Siberia, and has been introduced to Argentina and Chile.

Read more... 

 

Uroleucon campanulae (Harebell aphid)

In life the adult aptera of Uroleucon campanulae (see first picture below) is shiny reddish brown to black. The fused apical rostral segments (RIV+V) are 0.8-1.05 times the length of the second hind tarsal segment (HTII). Their body hairs are thick and placed upon well developed scleroites. The legs are bicoloured yellow and black, and the antennae, siphunculi, and cauda are black. 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 body length of Uroleucon campanulae is 2.1 to 3.7 mm.

Antesiphuncular sclerites are little developed in apterae, but usually well developed in alates (see second picture above).

The Harebell aphid feeds on the upper parts of stems and flowers of Campanulaceae (Harebells) especially Campanula rotundifolia, Campanula rapunculus and Jasione montana. Populations from different regions and hosts differ somewhat in morphology and there is possibly a complex of species in Europe. Uroleucon campanulae is found in Europe and Central Asia.

Read more... 

 

Uroleucon cichorii (Large chicory aphid)

Adult apterae of Uroleucon cichorii (see first picture below) are shining metallic grey-brown with black antennae and siphunculi. The antennal terminal process is 5.4-8.4 times longer than the base of antennal segment VI. The apical segment of the rostrum (RIV+V) is 1.04-1.33 times the length of the second hind tarsal segment (HTII). Nearly all dorsal hairs arise from dark scleroites (cf. Uroleucon sonchi  where dorsal scleroites on abdominal tergites 1-5 are either absent, or very small). The femora are yellow basally and black on the distal half. The tibiae of Uroleucon cichorii 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 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 alate (not pictured) has the last rostral segment (RIV+V) 1.05-1.4 times longer than the second hind tarsal segment (HTII). Immatures (see second picture above) are more reddish than the adults.

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 than 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.

Read more... 

 

Uroleucon cirsii (Large thistle aphid)

Uroleucon cirsii apterae (see first picture below) are bronzy or reddish brown with pale legs that are darkened towards the apices of the segments. Abdominal hairs are placed on pigmented scleroites. Spinal scleroites are fused into larger sclerites, each normally with three hairs. Crescent shaped antesiphuncular sclerites are present (cf. Uroleucon aeneum  and Uroleucon jaceicola  which do not have antesiphuncular sclerites). The siphunculi are 0.25-0.34 times the body length, and 1.6-2.2 times the length of the cauda, with polygonal reticulation on less than the distal 0.25 of their length. The slightly dusky yellow cauda has 20-33 hairs (cf. Uroleucon aeneum  which has a black cauda). Uroleucon cirsii is a rather large aphid with a body length of 3.2-5.2 mm.

The alate (see second picture above) is bronzy or reddish brown much like the aptera with a pale cauda and pale legs that are darkened towards the apices of the segments.

The large thistle aphid is one of several species of aphids that lives on the leaves and stems of the creeping thistle (Cirsium arvense) and related species. Oviparae and dark green males appear in late September to October, and eggs are laid on the undersides of the radical leaves. Uroleucon cirsii is found throughout Europe and has been introduced to North America.

Read more... 

 

Uroleucon grossum (Large hawksbeard aphid) = Uroleucon cichorii grossum

Apterae of Uroleucon grossum are shining metallic brown with black antennae and siphunculi, and a pale yellow cauda. Uroleucon grossum antennae are about as long as body, with the antennal terminal process 5.4-8.4 times longer than the base of the sixth antennal segment (cf. Uroleucon obscurum  which has the antennal terminal process 3.8-5.3 times longer than the base of the sixth antennal segment.) The last two (fused) segments of the rostrum are 1.04 to 1.33 as long as the second tarsal segment (see micrographs below). Uroleucon grossum body hairs are placed on distinct scleroites, and there are crescent-shaped antesiphuncular sclerites (see first picture below). Their legs are mostly black, but the basal parts of the femora are pale and the middle parts of the tibiae are brown (cf. Uroleucon cichorii  which have the tibiae entirely dark). The siphunculi are 1.3 to 1.7 times the length of the cauda. The caudal hairs number 19 to 33. Their body length ranges from 2.7 to 4.4 mm.

The alate female Uroleucon grossum has rather large marginal sclerites.

Uroleucon grossum does not host alternate but lives all year on the upper parts of stems of Crepis species. Sexual forms appear in late summer, and the species overwinters in the egg stage. Uroleucon grossum is distributed throughout Europe to Siberia and Mongolia.

Read more... 

 

Uroleucon hypochoeridis (Large cat's ear aphid)

Uroleucon hypochoeridis is a large pinkish-grey aphid with pale legs that are darkened towards the apices of the segments. The apical segment of the rostrum (RIV+V) is usually shorter than, or similar in length to, the second segment of the hind tarsus (HTII) (cf. Uroleucon cichorii  which has RIV+V longer than HTII). Abdominal hairs are placed on scleroites and the crescent-shaped antesiphuncular sclerites are prominent. The coxae are dusky or dark, darker than the basal parts of femora. The cauda is pale usually with about 17 hairs.

Alate Uroleucon hypochoeridis (see second picture above) are similarly coloured to the apterae. Immatures are grey with a reddish-pink suffusion around the bases of the siphunculi.

The large cat's ear aphid lives on the stems of cat's ear (Hypochoeris radicata), autumn hawkbit (Leontodon autumnalis) and related species. Oviparae and alate males occur from late August to October. It is found throughout Europe.

Read more... 

 

Uroleucon jaceae (Large knapweed aphid)

Uroleucon jaceae is a large blackish brown or reddish brown aphid, with rows of black spots on the dorsal abdomen (the spots are not very clear in life) (see first picture below). Abdominal tergites 2-4 often have small marginal tubercles about the size of hair bases. The femora have the basal half pale and distal half dark, with a rather sharp transition between them. The tibiae are totally black (cf. Uroleucon aeneum  which has the tibiae brownish in the middle; also cf. Uroleucon jaceicola  which has the legs mainly yellow with 'knees', tibial apices and tarsi black). The siphunculi are reticulated over the distal 0.16-0.27 of their length and are 1.3-1.8 times the length of the cauda. The cauda is black (cf. Uroleucon jaceicola which has a yellow cauda) and bears 18-30 hairs. The body length of Uroleucon jaceae apterae is 3.0-4.5 mm long.

The alate Uroleucon jaceae (see second picture above) has rather small marginal sclerites and 45-80 secondary rhinaria on antennal segment III.

The large knapweed aphid lives on various knapweeds (Centaurea species) and a few other species of Asteraceae. Oviparae and alate males can be found from late September. Uroleucon jaceae is found throughout Europe, the Middle East, Central Asia and Pakistan.

Read more... 

 

Uroleucon jaceicola (Yellow-legged knapweed aphid)

Apterae of Uroleucon jaceicola are dark bronze-brown. They have strong body hairs, pointed and placed on rather large scleroites. Their coxae are dark, but the legs are yellow apart from black knees and black apices to the tibiae (cf. Uroleucon jaceae  which has wholly dark tibiae). The siphunculi of Uroleucon jaceicola are black, although they may be paler in summer than in spring. The siphunculi are 2.0-3.0 times the length of the cauda. The cauda is pale yellow with a dusky tip, and bears 9-18 hairs (cf. Uroleucon jaceae  which has a black cauda). The body length of Uroleucon jaceicola apterae is 2.9-3.3 mm.

The alate Uroleucon jaceicola has several clear abdominal marginal sclerites and long thin siphunculi.

Uroleucon jaceicola lives on the stems of common knapweed (Centaurea nigra). In spring the yellow-legged knapweed aphid is found mainly low on stem, but moves to the upper parts later on. Oviparae and very dark apterous males of Uroleucon jaceicola have been found on the petioles of radical leaves in October. Uroleucon jaceicola is found in Europe, west Siberia and Central Asia.

Read more... 

 

Uroleucon obscurum (Large hawkweed aphid)

Adult apterae of Uroleucon obscurum are reddish brown to bronze with black antennae and siphunculi and a yellow cauda. The antennal terminal process is 3.8-6.2 times longer than the base of antennal segment 6. The apical segment of the rostrum (RIV+V) is 1.06-1.29 times the length of the second hind tarsal segment (HTII). The body hairs are rather long, and placed on distinct scleroites. The femora are yellow basally and black on the distal half. The tibiae have the basal half yellowish brown. The siphunculi are 1.1-1.6 times the length of the cauda. The body length of an adult Uroleucon obscurum aptera is rather less than for most species at 1.8-3.7 mm.

The large hawkweed aphid does not host alternate. It can be found on the upper parts of stems of hawkweed (Hieracium spp.). Sexual forms appear in September, and the species overwinters in the egg stage. Uroleucon obscurum is distributed throughout Europe and into Asia.

Read more... 

 

Uroleucon picridis (Large oxtongue aphid)

Adult apterae of Uroleucon picridis (see first picture below) are dark shiny reddish brown, with black antennae and siphunculi. The fused terminal segments of the rostrum (RIV+V) are 1.45-1.84 times the length of the second hind tarsal segment (HT2) (cf. Uroleucon cichorii  where RIV+V is much shorter at 1.17-1.33 times HT2). The dorsal hairs are borne on distinct scleroites, and there are also antesiphuncular sclerites and rather small marginal sclerites. The legs are black with the basal half of the femora and middle part of tibiae light brown. The hind coxae are much paler than the distal parts of the femora. The siphunculi are 1.4 to 1.7 times the length of the yellow cauda. The body length of the Uroleucon picridis adult is 2.6-3.7 mm.

The large oxtongue aphid lives on its host ox-tongue (Picris) all year round. Apterous oviparae and slender dark green males can be found in October and November. Uroleucon picridis is found in most of Europe and across Asia, but not in the Scandinavian countries nor Denmark. In Britain it is restricted to the southern counties.

Read more... 

 

Uroleucon pilosellae (Mouse-ear hawkweed aphid)

In life Uroleucon pilosellae apterae are dark reddish grey-brown with black siphunculi and a yellow cauda (see first two pictures below). The antennae are about as long as the body. The fused apical segments of the rostrum (RIV+V) are about 1.2 times the length of the second tarsal segment (HTII). Well developed antesiphuncular sclerites are present. The tibiae have a paler middle section and the coxae are dark (see micrographs below). The first tarsal segment has only 3 hairs (see micrograph below) (cf. Uroleucon cichorii  and Uroleucon obscurum  which both have 5 hairs on the first tarsal segment). The siphunculi are 1.6 to 1.9 times the length of the cauda (cf. Uroleucon obscurum  which has the siphunculi 1.0-1.4 times the length of the cauda). The number of caudal hairs is 12 to 18. The body length of an adult aptera of Uroleucon pilosellae is 2.2-2.5 mm.

Uroleucon pilosellae is found on the flower stems of Hieracium pilosella and possibly other Hieracium throughout Europe. Laamari et al. (2013)  have recently recorded it on Leontodon hispidus.

Our observations appear to be the first, and only, record of Uroleucon pilosellae in UK on its host to date.
First observedby: Influential Points25 July 2013at: Dundreggan estate, Scotland

Read more... 

 

Uroleucon solidaginis (Goldenrod aphid)

Uroleucon solidaginis apterae are shining reddish brown, with rows of dark hair-bearing scleroites. Their antennae are longer than the body and the third antennal segment is as dark as the rest of the antennae. Uroleucon solidaginis antennae and legs are mainly yellowish brown with the apical parts of the femora, knees and tips of tibiae dark. There are no antesiphuncular sclerites. Both the siphunculi and cauda are black, and their siphunculi are 1.6-2.1 times as long as the cauda. The distal 25% of the siphunculi is reticulated. Uroleucon solidaginis body length ranges from 2.3 to 4.1 mm.

Immatures are bright red. The alate males are green - see picture of colony of Uroleucon solidaginis with males by Jarmo Holopainen. 

The goldenrod aphid is found on the upper parts of goldenrod (Solidago virgaurea). It does not host alternate. Oviparae and alate males can be found from mid-July to October. Uroleucon solidaginis is found in Europe, Asia, north Africa and North America.

Read more... 

 

Uroleucon sonchi (Large sowthistle aphid)

Uroleucon sonchi is a large smooth dark brownish or pinkish-brown aphid with a glossy shine. Dorsal scleroites on abdominal tergites 1-5 are either absent, or very small (cf. Uroleucon cichorii which has dorsal hairs arising from dark scleroites). Antesiphuncular sclerites are usually rudimentary or absent. The siphunculi are less than twice as long as the cauda. The coxae of Uroleucon sonchi are dark.

The large sowthistle aphid lives on sowthistle (Sonchus species) especially common sowthistle (Sonchus oleraceus) and prickly sowthistle (Sonchus asper). It has a very wide distribution being found over most of the world.

Read more... 

 

Uroleucon tanacetii (Crimson tansy aphid)

Apterae of Uroleucon tanaceti are red, reddish brown or crimson, with yellowish antennae and black apices. Body hairs are long and placed on small, discrete scleroites. Antesiphuncular and marginal sclerites are absent. The legs are (usually) yellow with the apices of the tibiae black. The siphunculi are brown or black, often with the middle part paler brown giving a characteristic bicoloured appearance. The cauda is yellow. The body length of Uroleucon tanaceti is 2.2 to 3.4 mm.

The crimson tansy aphid is found on tansy (Tanacetum spp.), especially on the lower yellowing leaves. It also occurs on cultivated Chrysanthemum species. Winged males and wingless female oviparae occur in October. Uroleucon tanaceti is distributed throughout Europe to Siberia and Central Asia, and North America.

Read more... 

 

Uroleucon taraxaci (Bronze-brown dandelion aphid)

Adult apterae of Uroleucon taraxaci are shining dark bronze-brown. The antennae and legs (except for the femoral bases) are black. Dorsal abdominal hairs are mostly placed on dark scleroites, which are black and numerous and sometimes merged together. Antesiphuncular and post-siphuncular sclerites are either absent or very small. The rather short and thick cauda is black like the siphunculi, and bears 8-12 hairs. The body length of the adult Uroleucon taraxaci aptera is 2.5-3.8 mm.

The bronze-brown dandelion aphid is seldom seen as, unlike most members of the genus, it is light-averse. It lives on leaf undersides and basal leaf parts of of dandelion (Taraxacum spp.) near ground level. Uroleucon taraxaci is found in Britain, throughout continental Europe, parts of Asia, and has been introduced to North America.

Read more... 

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).

Useful weblinks 

References

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

  • Heie, O.E. (1980-1995). The Aphidoidea, Hemiptera, of Fennoscandia and Denmark. (Fauna Entomologica Scandinavica) E.J. Brill, London