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)

Search this site

Aphididae : Aphidinae : Macrosiphini : Uroleucon
 

 

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) Europe, North America

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) Europe, Asia, South America

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 ambrosiae (New England aster aphid) North America

Adult apterae of Uroleucon ambrosiae are red-brown to dark brown or dull red (see two pictures below), with black siphunculi and a pale cauda. The antennae are dusky to black, but paler on antennal segments I, II and the base of III, with 14-27 secondary rhinaria on segment III, and a terminal process which is 5.5-6.5 times the base of antennal segment VI (cf. Uroleucon leonardi, which has a terminal process 6.3-7.2 times the base of segment VI). The rostrum fully reaches the third pair of coxae, with the apical rostral segment (RIV+V) longer than the base of antennal segment VI. There are dusky scleroites on the dorsum of the abdomen. Abdominal marginal tubercles are absent (cf. Macrosiphum nigrotuberculatum, which has small black marginal abdominal tubercles). The hind tibia usually has a pale or dusky basal section, but this not as pale as the cauda for more than 0.5 of its length (Uroleucon ivae on Ambrosia & Iva, which has the tibia as pale as the cauda for more than 0.7 of its length). The second hind tarsal segment (HTII) is 0.9-1.1 times the length of RIV+V (cf. Uroleucon pseudoambrosiae, which has HTII 0.7-0.85 times RIV+V). The siphunculi are 1.1-1.3 times the length of the cauda, have a third of their length with polygonal reticulation, and are uniformly dark (cf. Uroleucon rudbeckiae, whose siphunculi are much paler at the base). The pale cauda tapers to a rather acute point, and bears 7-8 hairs on each side. The Uroleucon ambrosiae aptera body length is 2.5-3.5 mm.

Images above, copyright Jesse Rorabaugh, no rights reserved.

The Uroleucon ambrosiae alate vivipara is coloured similarly to the aptera, apart from having dark brown thoracic lobes and a dark blotch on tergite VI posterior to the base of each siphunculus. The antennae are entirely black, with 31-45 secondary rhinaria on antennal segment III. The rostrum hardly reaches the third pair of coxae. The dusky abdominal scleroites are often reduced or lacking.

In eastern and northern USA, and Canada, Uroleucon ambrosiae is mainly found on Ambrosia and Iva. However, populations in south-western USA, and Central and South America are far less specific, having been found feeding on the leaves and flower-stems of many additional genera in the Asteraceae including Achillea, Aster, Cichorium, Eupatorium, Lactuca, Rudbeckia and Senecio. The more polyphagous form is sometimes regarded in South America as a subspecies, Uroleucon ambrosiae ssp. lizerianum. The species is monoecious holocyclic in temperate North America with alate males, but it is usually anholocyclic in southern USA, and Central and South America.

Read more...

 

Uroleucon anomalae (New England aster aphid) North America

Adult Uroleucon anomalae apterae (see first picture below of aphid giving birth) are pale green to yellow-green. Antennal segment III bears 28-46 secondary rhinaria. The apical rostral segment (R IV+V) is 1.4-1.85 times as long as the second hind tarsal segment (HT II), and bears more than 14 accessory hairs (cf. Uroleucon erigeronense, usually on Erigeron, which has RIV+V less than 1.4 times the length of HT II). Dorsal abdominal tubercles are absent. The coxae are pale, as are the trochanters and basal halves of the femora. The tibiae are mainly light brown (cf. Uroleucon paucosensoriatum in eastern USA and Canada, which has entirely dark tibiae). The siphunculi are dark apically, but pale basally (cf. Uroleucon astronomus in eastern USA and Canada, mainly found on Eurybia macrophylla, which has the siphunculi uniformly pigmented, as does Uroleucon paucosensoriatum). The siphunculi are 0.21-0.55 times the body length and 1.1-1.4 times the length of the (pale) cauda. The body length of adult Uroleucon anomalae apterae is about 1.9-2.0 mm.

Images above by permission, copyright Claude Pilon, all rights reserved.

Immature Uroleucon anomalae (see second picture above) are also pale green, but with pale siphunculi and a distinct orange hue on the head and between their siphunculi. The alate (not pictured) has a light green, head, thorax, abdomen and cauda; the siphunculi are dark apart from near the base. Antennal segment III bears 35-51 secondary rhinaria.

Uroleucon anomalae feeds on the flower stems of the New England aster (Symphyotrichum novae-angliae, see picture above). This aphid species is apparently restricted to this glandular-hirsute Aster species and possesses a correspondingly elongated apical rostral segment (at about 1.5 times length of its second hind tarsal segment). Uroleucon leontodontis in Europe has a similar elongated apical rostral segment for feeding on the glandular-hirsute rough hawkbit ( Leontodon hispidus). Uroleucon anomalae is distributed through the eastern USA into Canada.

Read more...

 

Uroleucon breviscriptum (Nondescript daisy aphid) North America

Adult apterae of Uroleucon breviscriptum (see first picture below) have the head and body medium green. The antennae have segments I-II and the base of III green, but the remainder of the segments are brown to dark brown. The apical rostral segment (RIV+V) is brown, and is 0.8-1.0 times the second hind tarsal segment. The proximal two thirds of the femora are green but the distal third, and the tibiae and tarsi, are brown. The siphunculi are mainly dark but with a pale basal section, and are 1.4-2.0 times as long as the cauda (cf. Uroleucon erigeronense, which has siphunculi 2.1-2.8 as long as the cauda; and cf. Uroleucon macgillivrayae, which has siphunculi 0.9-1.4 times the cauda). The cauda of Uroleucon breviscriptum is green, bears 7-12 hairs, and tapers to a slender point.

Images above by permission, copyright Claude Pilon, all rights reserved.

The alate (not pictured) has the head, prothorax and abdomen yellowish green and the meso- and metathorax yellowish brown. The siphunculi are dark apart from the base and the cauda is green.

Uroleucon breviscriptum has been recorded from smooth aster (Symphyotrichum laeve) and New York aster (Symphyotrichum novi-belgii). It does not deform or curl the leaves. Oviparae of this species have been found in October. Uroleucon breviscriptum has previously been described as being found in western North America, albeit those pictured here are from the east (Quebec).

Read more...

 

Uroleucon caligatum (Northern green goldenrod aphid) North America

Adult apterae of Uroleucon caligatum are green with mostly-black antennae and legs. The siphunculi are also mostly black, but with pale bases, and the cauda is pale with a dusky tip. The antennal tubercles are well developed. The longest hairs on antennal segments III-VI are equal to the basal diameter of segment III. The apical rostral segment (RIV+V) is greater than 1.3 times the hind tarsal segment (HT II) (cf. Uroleucon tissoti, which has RIV+V less than 1.3 times HT II). Paired spinal tubercles are usually present on most or all of abdominal segments II-VII (cf. Uroleucon luteolum, which has no spinal tubercles present). Abdominal tergite VIII has 4 hairs. The second hind tarsal segment (HTII) is 0.125-0.17 mm, and longer than the maximum width of the hind femur. The siphunculi have a pale section at the base, and a distal zone of reticulation of at least 2-3 rows of closed polygonal cells. The siphunculi are attenuated distally, and are 1.1-1.3 times as long as the cauda (cf. Uroleucon erigeronense, which has siphunculi which are 1.8-2.3 times the length of the cauda). The body length of adult Uroleucon caligatum apterae is 3.2-4.0 mm.

Images above by permission, copyright Claude Pilon, all rights reserved.

Alatae (see second picture above) are very similar in colour to apterae, but with a slightly browner thorax and red pigment spots around the ocelli. Antennal segment III has 24-50 secondary rhinaria distributed over the whole length of the segment on one side. Immature Uroleucon caligatum (see pictures below) also resemble the adult apterae, but with mainly brown rather than black siphunculi, with pale bases.

Uroleucon caligatum feeds on goldenrod (Solidago species). Moran (1984) notes that Solidago canadensis, Solidago altissima, Solidago gigantea, Solidago rugosa are the hosts most colonized in nature, but Solidago altissima supports faster development than Solidago canadensis or Solidago gigantea (Moran, 1981). The species is common in north-eastern USA and Canada.

Read more...

 

Uroleucon campanulae (Harebell aphid) Europe, Central Asia

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) Europe, Asia

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) Europe, North America

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 erigeronense (Large fleabane daisy aphid aphid) North, Central & South America, Europe, Asia, Australia

Adult apterae of Uroleucon erigeronense are uniformly pale green or yellowish green, usually with a darker spinal stripe (see first picture below). The antennae are dark except for antennal segments I & II, which are pale. The terminal process is 3.1-4.7 times the length of the base of antennal segment VI. The apical rostral segment (RIV+V) is 0.9-1.1 times as long as the second hind tarsal segment (HTII). The dorsum is membranous, and the body hairs are not placed on scleroites. The siphunculi are mainly dark but have a pale basal section and are 1.8-2.4 times the length of the cauda. The cauda is pale or dusky and has 6-10 hairs, the most distal of which are shorter than the more proximal hairs. The body length of adult Uroleucon erigeronense apterae is 2.3-2.8 mm.

Both images above copyright Andy Jensen under a Attribution-NoDerivs-NonCommercial 1.0 Generic license

The alate Uroleucon erigeronense (see second picture above) is green, like the aptera, and has an unmarked dorsum and a dusky cauda. The ovipara is similar to the apterous viviparous female, but has dorsal hairs placed on distinct but unpigmented scleroites and the basal half of the hind tibia is dark and swollen. The alate male has the anterior membranous parts of the body reddish brown, and the abdomen green.

The 'typical' hosts of Uroleucon erigeronense are fleabane daisies (Erigeron and Conyza, but not Pulicaria, fleabane) where it feeds on the upper parts of the stems. In its native North America Uroleucon erigeronense is also found on several other genera in the Asteraceae, as it is in Central and South America where it is invasive. It has also been introduced to Europe where it is restricted to fleabanes, from where it has spread to most of the western Palaearctic as well as Korea and Australia. In northern temperate climates Uroleucon erigeronense produces oviparae and alate males in September-October.

Read more...

 

Uroleucon eupatorifoliae (Varicolored snakeroot aphid) North America

Adult apterae of Uroleucon eupatorifoliae are dark dull green and/or red-brown (see note below). The head has large diverging antennal tubercles which bear several rather long, hyaline hairs. Their antennae are longer than the body. The first two antennal segments are greenish-brown, the remaining segments are very dark brown or black. Many of hairs on antennal segment III are longer than the basal diameter of that segment. Marginal tubercles on the abdomen are usually absent, and brown scleroites are usually present around dorsal abdominal setae. The legs have the femoral bases pale greenish, and the apical portion dark brown; the tibiae are dark brown. The siphunculi are dark brown to black, widest at the base, and tapering slightly toward the apex. The apical one-third is reticulated, with the portion below the reticulations heavily imbricated. The cauda is dark, long and narrow with a definite constriction below the middle (cf. Uroleucon nigrotuberculatum, Uroleucon eupatoricolens and Uroleucon ambrosiae, all of which have a mostly pale cauda). The cauda bears four long slightly curved hairs on each side, and two or three shorter dorsal ones.

Both images above by permission, copyright Claude Pilon, all rights reserved.

The alate of the reddish-brown form is shown above. The antennae are slightly longer than the body, with the segments I-II very dark brown, and remaining segments black. Antennal segment III has approximately 30 secondary rhinaria scattered over more than half the surface of the segment.

Uroleucon eupatorifoliae was first described from Eupatorium incarnatum (= Fleischmannia incarnata) in Florida. It has also been recorded from the same host in more northerly states in eastern USA and (these observations) from Eupatorium ageratoides (= Ageratina altissima) in Canada. Sexual morphs have been collected in December in Florida.

Read more...

 

Uroleucon formosanum (Oriental lettuce aphid) East Asia

Adult apterae of Uroleucon formosanum (see first and third pictures below) are red, with a broad black or blackish red 'saddle' across the metathorax and abdominal tergites I-II. The eyes, antennae and siphunculi are also black, but the cauda is yellow, much paler than the siphunculi (cf. Uroleucon compositae, which has the cauda almost as dark as the siphunculi). The antennal tubercles are well developed, diverging and smooth; the median frontal tubercle is undeveloped. The antennae are longer than the body, and segment III bears 96-135 strongly protuberant circular secondary rhinaria scattered over the whole length (cf. Uroleucon sonchellum in North America, which has 49-93 secondary rhinaria on that segment, which do not protrude strongly). The terminal process is 4.8-6.3 times the base of antennal segment VI. The rostrum reaches beyond the middle legs. The legs are pale brown with the apical halves of the femora, apices of the tibiae, and the tarsi black. The siphunculi are cylindrical, but slightly expanded towards the base, about 1.5 times as long as the cauda, and reticulated on the distal third. The cauda is large, sword-shaped, and provided with about 8 pairs of long lateral bristles. The body length of adult Uroleucon formosanum apterae is 2.3-3.4 mm. Immatures are normally red, with short black siphunculi, but may occasionally be blackish red (see first picture below).

First image above copyright Onidira, second image copyright Licheng Shih,
both under a Creative Commons License.

Alatae of Uroleucon formosanum (see second picture above) are dark red with the head and thorax blackish red, the antennae and siphunculi black and the abdomen dark red, except the basal part of the dorsum and the underside which are black. The cauda is yellow. The rostrum reaches the second pair of coxae. The wings are hyaline, the pterostigma pale yellow, and the veins yellowish brown. The legs are pale brown, with the apical halves of the femora, apices of the tibiae, and the tarsi black. The siphunculi are reticulated on the distal 0.4 of their length. In other respects the alate vivipara is similar to the apterous vivipara.

Image above copyright ahan88 under a Creative Commons License.

Uroleucon formosanum feed on various Lactuca and Sonchus species. The feeding site is the stems, and along the midrib on the undersides of leaves. In more temperate climates, such as Korea and Japan, it is monoecious holocyclic, but in tropical areas populations are anholocyclic. Thus Takahashi (1921) notes that near Tokyo in Japan, the sexual forms make their appearance in November, but in Taiwan sexual forms do not occur. The species is one of the most common aphids in Japan, with winged forms also being common. The species is found in Japan, Korea, China, Taiwan, the Mariana Islands and east Siberia, and questionably in India.

Read more...

 

Uroleucon grossum (Large hawksbeard aphid) = Uroleucon cichorii grossum Europe, North Asia

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) Europe

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 impatiensicolens (Rufous jewelweed aphid) North-eastern North America

Adult apterae of Uroleucon impatiensicolens (not pictured) are reddish brown to bronze-brown with black siphunculi and a pale cauda. Their antennae are about as long or somewhat longer than the body. The longest hairs on segment III are less than the basal diameter of that segment. The last rostral segment and the second hind tarsal segment are much shorter than antennal segment I. Uroleucon impatiensicolens appears rather hairy in life. Hairs on abdomen are in in transverse rows, each hair having a small dorsal tubercle at its base. The hind femora have the basal half light colored, contrasting with the dark apical half. The first tarsal segment has 5 hairs. The siphunculi are 1.2-1.4 times as long as the cauda, with the distal 0.3-0.4 reticulated (cf. Macrosiphum euphorbiae, Macrosiphum pallidum and Macrosiphum impatientis, which all have siphunculi 1.4-2.2 times the length of the cauda, with the distal 0.13-0.23 reticulated). The cauda is elongate, with 13-21 hairs. The body length of adult Uroleucon impatiensicolens apterae is 2.5-3.6 mm.

Both images above by permission, copyright Claude Pilon, all rights reserved.

Alatae of Uroleucon impatiensicolens (see two pictures above) are similarly coloured to the apterae. They have dark brown, distinct marginal sclerites on abdominal segments II-IV and the postsiphuncular sclerites are entire. The cauda is pale to dusky. Immatures (see picture below) are also similar to the adult apterae, but have paler legs and siphunculi.

Uroleucon impatiensicolens is found on jewelweeds (Impatiens) species in north-eastern North America (Canada, USA).

Read more...

 

Uroleucon jaceae (Large knapweed aphid) Europe, Middle East, Central & South Asia

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) Europe, West & Central Asia

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 leontodontis (Large hawkbit aphid) Europe

Adult apterae of Uroleucon leontodontis are shining brown with black antennae and siphunculi and a yellow cauda. The antennae have a terminal process 5.1-6.7 times longer than the base of antennal segment VI (cf. Uroleucon picridis which has a terminal process 4.4-5.8 times longer than the base of antennal segment VI ). The apical rostral segment (RIV+V) is long and slender, and 1.32-1.57 times the length of the second hind tarsal segment (HTII) (cf. Uroleucon cichorii and Uroleucon grossum where RIV+V is 1.04-1.35 times the length of HTII). The hind coxae are dusky to dark, like the distal parts of the femora (cf. Uroleucon picridis which has the hind coxae much paler than the distal parts of the femora). The siphunculi are 1.3-1.8 times the length of the cauda, with reticulation on the apical 24-30%. The cauda has 17-24 hairs. The body length of the adult aptera is 3.2-4.3 mm.

The alate of the species (see second picture above) has only been described fairly recently by Depa & Mróz (2012). The body is shiny dark brown, and the antennae are dark. The legs are black except for the basal parts of the femora, the siphunculi are black and the cauda is yellow. The apical rostral segment (RIV+V) is long and slender, and 1.3-1.6 times the length of the second hind tarsal segment (HTII).

Uroleucon leontodontis is often recorded as occurring on all hawkbits (including Scorzoneroides autumnalis ), although given its evolved adaptation of an extra long apical rostral segment (see below), it seems more likely that it is largely restricted to bristly hawkbit (Leontodon hispidus), lesser hawkbit (Leontodon taraxacoides), hairy hawkbit (Leontodon hirtus) and Leontodon crispus, all of which have trichomes on their stems. Oviparae and alate males occur in September & October. It is found in Britain and continental Europe.

Read more...

 

Uroleucon montanivorum (Mountain cornflower aphid) Europe

Adult apterae of Uroleucon montanivorum (see first picture below) are spindle-shaped and coloured glossy reddish brown to black. The antennae of the adult aptera are 1.2-1.4 times as long as the body, with their terminal process 6.9-7.5 times longer than the base of segment VI. The apical rostral segment (RIV+V) is 1.6-1.9 times as long as the second hind tarsal segment (HTII) (cf. Uroleucon compositae, which has RIV+V 1.1-1.4 times the length of HTII, and Uroleucon aeneum, which has RIV+V 1.2-1.3 times the length of HTII). The hair-bearing sclerites of the abdominal tergites are discernible as transverse rows of black flecks. Postsiphuncular sclerites are very distinctly developed, but antesiphuncular sclerites are lacking or rudimentary in Uroleucon montanivorum. Their femora have the basal 0.67-0.75 yellowish white, abruptly grading into matt-black distally (cf. Uroleucon compositae, whose mainly dark femora are only pale on the basal 0.2-0.3 of their length). The tibiae are dark basally and distally but otherwise rather pale (cf. Uroleucon jaceae, which has wholly dark tibiae). The siphunculi are black, tapering towards the apical end, and about twice as long as the cauda. The cauda is dark, sabre-shaped, slender, and with 20-29 hairs (cf. Uroleucon jaceicola, which has a pale yellow cauda with 9-18 hairs). The body length of adult Uroleucon montanivorum apterae is 3.6-4.4 mm.

First image above copyright Alan Orange, all rights reserved.
Second image above copyright Christophe Quintin under a CC BY-NC 2.0 licence.

The alate Uroleucon montanivorum (not pictured) is similar to the aptera, but abdominal sclerotization is stronger. Their antennae are 1.2 - 1.5 times as long as the body. Antennal segment III has 59-80 secondary rhinaria distributed over the entire length.

Uroleucon montanivorum feeds on the apical leaves and shoots of the mountain cornflower (Centaurea montanum). Oviparae and alate males have been found from late summer to autumn. It has previously only been recorded from southern Germany, France and Switzerland, but has now been found present in a garden in Wales.

Read more...

 

Uroleucon nigrotibium (Dark-legged goldenrod aphid) North America

Adult apterae of Uroleucon nigrotibium have the entire body red-brown (cf. Uroleucon cadens, Uroleucon caligatum, Uroleucon erigeronense and Uroleucon gravicorne, which have the body green). Their antennae are mainly dark with 7-16 secondary rhinaria on antennal segment III (cf. Uroleucon atripes, which has 13-47 secondary rhinaria on that segment). Marginal sclerites are dusky and broken, and scleroites are dusky and larger than those of alate viviparae. The second hind tarsal segment (HTII) is shorter than the apical rostral segment (RIV+V), and shorter than antennal segment I. The legs have the proximal half of the femora pale, and the distal half dark dusky to dark. The tibiae are almost uniformly dark (cf. Uroleucon solidaginis, which has tibiae with a pale section in the middle). The first hind tarsal segment (HTI) has 3 hairs (cf. Uroleucon atripes, which usually has 5 hairs on HT I). Abdominal tergite VIII usually has 2 hairs (cf. Uroleucon atripes, which usually has 4 hairs on abdominal tergite VIII). The siphunculi are entirely dark and the cauda is pale.

Both images above by permission, copyright Claude Pilon, all rights reserved.

Alate Uroleucon nigrotibium viviparae are similarly coloured to the apterae. They have 14-39 secondary rhinaria on antennal segment III. There are dusky marginal sclerites on abdominal segments II, III, and IV, all bearing small transparent marginal tubercles. The antesiphuncular sclerites are broken, but postsiphuncular sclerites are large and entire.

Uroleucon nigrotibium appears to be restricted to a few species of goldenrod, especially grey goldenrod (Solidago nemoralis) and sweet goldenrod (Solidago odora). These aphids fall readily from their host when disturbed, much like Uroleucon cadens and Uroleucon crepusisiphon. All three species produce few winged morphs, but apterae walk frequently between plants, thus initiating new colonies nearby (Moran, 1985). The species is known from the eastern states of the USA (Michigan, North Carolina) and from Canada (Quebec).

Read more...

 

Uroleucon nigrotuberculatum (Red goldenrod aphid) North America, East Asia

Adult apterae of Uroleucon nigrotuberculatum (see first picture below) are bright to dull orange-red with dark antennae, legs and siphunculi, and a pale cauda (cf. Uroleucon nigrotibium, which is dark brown with dark appendages and pale cauda). Antennal tubercles are well developed. The longest hairs on antennal segment III are about as long as the basal diameter of that segment. The apical rostral segment (RIV+V) is roughly equal to or slightly longer than the second hind tarsal segment (HTII). The aptera has small black marginal tubercles on the abdomen (cf. Uroleucon rudbeckiae and Uroleucon ambrosiae, which have no such tubercles). The proximal half of the femora is pale, the distal half dark. The tibiae are dark brown or black for their entire length (cf. Uroleucon pieloui and Uroleucon gigantiphagum, which have the tibiae of apterae lighter basally). Each first tarsal segment usually has 4 hairs. The siphunculi are uniformly black (cf. Uroleucon rudbeckiae, which has siphunculi with pale bases). The cauda bears 23-32 hairs. The body length of adult Uroleucon nigrotuberculatum apterae is 2.4-4.3 mm.

First image above copyright Stephen Luk, second image above copyright Kevin.
Both under a Creative Commons Attribution-NonCommercial license.

The alate Uroleucon nigrotuberculatum (see second picture above) has the body dull orange-red, with dark antennae and legs. Antennal segment III has 29 - 53 secondary rhinaria. The legs have the proximal half of the femora pale, and remaining portions dark. There are dusky marginal sclerites on abdominal segments II, III, and IV and dusky scleroites scattered over the abdomen. Some or all marginal sclerites bear small, dark, and elongate or cone-shaped tubercles. The siphunculi are uniformly black and the cauda is pale, usually with a dusky tip, and bearing 22-28 hairs. Immature Uroleucon nigrotuberculatum are similarly coloured to the adults.

In their native North America, Uroleucon nigrotuberculatum feed on goldenrods (Solidago spp.). When introduced into Japan, the species was initially found feeding on other genera in the Asteraceae (Callistephus, Chrysanthemum, Helianthus, Rudbeckia) and on Oenothera. Sugimoto & Matsumoto (2000) report they later they became more specific to an introduced goldenrod species (Solidago altissima). Different hosts (Eupatorium and Montanoa spp.) have also been reported at high altitudes in Mexico. Sexuales are produced in autumn. Uroleucon nigrotuberculatum are distributed across North America, and are now found in Japan.

Read more...

 

Uroleucon obscuricaudatum (Dusky-tailed sunflower aphid) North America

Adult apterae of Uroleucon obscuricaudatum are red-brown to reddish, with dark antennae & siphunculi, and a dusky cauda (see first picture below). Antennal segment III has 5-14 secondary rhinaria, and bears hairs of length 0.04-0.05 mm. The rostrum reaches or slightly surpasses the third pair of coxae, with the apical rostral segment (RIV+V) 0.75-0.95 times the base of antennal segment VI (cf. Uroleucon parvotuberculatus, which has RIV+V 1.0-1.2 times the base of antennal segment VI). Marginal tubercles are absent (cf. Uroleucon parvotuberculatus, where small pale marginal tubercles are sometimes present on abdominal tergites II-IV). The coxae are pale (cf. Uroleucon compositae which has dark coxae). Antesiphuncular sclerites are present, but fragmented (cf. Uroleucon helianthicola where crescent-shaped antesiphuncular sclerites are present and intact). The siphunculi are reticulated over the apical 0.33-0.4. The cauda is dusky, darkest at its apex, but always paler than the siphunculi (cf. Uroleucon helianthicola, which has a dark cauda; and Uroleucon ambrosiae, which has a pale cauda). The body length of adult Uroleucon obscuricaudatum apterae is 2.7-3.4 mm.

Note: Uroleucon obscuricaudatum belongs to the "ambrosiae complex" of the genus Uroleucon. The most diagnostic feature of this species is the smoky cauda.

First image above copyright Tom Murray, second image above copyright Beatriz Moisset,
both under a Creative Commons Attribution License.

Uroleucon obscuricaudatum is monoecious holocyclic on sunflowers (Helianthus spp.) and false sunflowers (Heliopsis spp.). Note that several of the apterae in the picture above are hanging from the branch held only by the rostrum. We have noted this 'behaviour' by stem feeders several times on willow (e.g. Tuberolachnus salignus and Pterocomma pilosum). On one occasion several were dead, but sometimes all are alive. The dusky-tailed sunflower aphid is found in the USA and Canada.

Read more...

 

Uroleucon obscurum (Large hawkweed aphid) Europe, Asia

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) Europe, Asia

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) Europe

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.

Read more...

 

Uroleucon pseudambrosiae (Wild lettuce aphid) Canada, Eastern USA, Poland

Adult apterae of Uroleucon pseudambrosiae (see first picture below) are red to red-brown or dark brown, with black antennae and siphunculi, and a pale or dusky cauda much paler than the siphunculi (cf. the Asian species Uroleucon compositae & Uroleucon lactucicola which have the cauda almost as dark as the siphunculi). The legs have the coxae and the basal two thirds of the femora pale, the distal part of the femora black, and the tibiae yellowish-brown with dark apices. The antennae have 16-39 secondary rhinaria on segment III (cf. Uroleucon sonchellum, which has 49-93 secondary rhinaria on segment III). The hairs on that segment are 0.025-0.035 mm in length. The rostrum reaches the third pair of coxae. The second hind tarsal segment (HTII) is long and thin, being about the same length (0.9-1.1 times) as the apical rostral segment (RIV+V) (cf. Uroleucon ambrosiae, which has HTII shorter, only 0.75-0.85 times the length of RIV+V). There are no antesiphuncular sclerites present (cf. Uroleucon picridis, which has antesiphuncular sclerites). The siphunculi are rather thick, their apical third is reticulated, and they are 1.1-1.5 times the caudal length (cf. Uroleucon bicolor and Uroleucon murale, which have long, thin siphunculi, 1.5-2.0 times the length of the cauda). The cauda has 20-32 hairs. The body length of adult Uroleucon pseudambrosiae apterae is 2.2-3.4 mm.

Images above copyright David Cappaert, Bugwood
under a creative commons licence.

Alate Uroleucon pseudambrosiae (see second picture above) are similarly coloured to the apterous forms, except that late in the season alate forms on dying Lactuca often have a greenish cast. The alate vivipara has 36-53 secondary rhinaria on antennal segment III. The longest hairs on antennal segment III are 0.025-0.03 mm. The rostrum surpasses the second pair of coxae. Marginal tubercles are absent. The siphunculi have the apical third reticulated, and the cauda has 13-27 hairs.

The most common host for Uroleucon pseudambrosiae is wild lettuce (Lactuca spp.), although it has also been recorded from many other genera in the Asteraceae. The species is monoecious holocyclic and produces oviparae and alate males in autumn. The wild lettuce aphid is found in Canada, and eastern USA south to Florida, and has been introduced to Europe (Poland).

Read more...

 

Uroleucon pulicariae (Large fleabane aphid) Europe, Central & East Asia

Adult apterae of Uroleucon pulicariae (see pictures below) are dark reddish-brown with black siphunculi and a pale yellow cauda. The femora are pale on the basal half and dark on the distal half. The tibiae are mainly pale, and are dark only at the base and apex. The body length of adult apterae is 2.8-3.1 mm.

Images above copyright Slobodan Stevčić, all rights reserved.

Uroleucon pulicariae feeds on the stems of fleabanes (Inula and Pulicaria species). It is found across continental Europe (but not in Britain) and into Central Asia, and it is also recorded from North Korea.

Read more...

 

Uroleucon rudbeckiae (Goldenglow aphid) North America

Adult apterae of Uroleucon rudbeckiae (see first picture below) are shiny bright vermillion red with mainly yellowish-brown legs and blackish antennae. Postsiphuncular sclerites and scleroites at the bases of dorsal hairs are pale and inconspicuous. Their femora are pale or dusky, sometimes with a darker patch at the apices. The siphunculi become gradually darker distally, so are much paler at the base than at the apex (cf. Uroleucon ambrosiae, Uroleucon leonardi and Uroleucon nigrotuberculatum, which all have entirely black siphunculi). The siphunculi are rather thick, less than 1.6 times as long as the cauda, with reticulation of small polygonal cells on at least the distal quarter of their length. The cauda is pale yellowish or sometimes dusky. The body length of adult Uroleucon rudbeckiae apterae is 2.4-3.2 mm.

Images above by permission, copyright Claude Pilon, all rights reserved.

Alatae of Uroleucon rudbeckiae (see second picture above) are coloured much the same as the apterae. The antennae are much longer than the body with a paler area near the base; they are sited on large antennal tubercles. The siphunculi are dark over a slightly greater extent than in the apterae, but the base is still pale. The cauda is yellowish red, constricted above the middle, with many lateral hairs on each side, upcurved and acute.

Uroleucon rudbeckiae live, usually in large colonies, on the stems of coneflowers (Rudbeckia spp.). Blackman in Aphids on Worlds Plants suggests that records from other Asteraceae genera are likely to be misidentifications. There is no host alternation, with the entire life cycle taking place on Rudbeckia. Sexuales develop in autumn, and eggs are laid on the foodplant stems. Uroleucon rudbeckiae is widely distributed in North America from Canada to Mexico.

Read more...

 

Uroleucon russellae (Pearly everlasting aphid) North America

Adult apterae of Uroleucon russellae are bronzy black with dark antennae. The antennal terminal process is about 4.5-6 times as long as the base of antennal segment VI. The apical rostral segment (RIV+V) is 1.8-2.3 times the length of the second hind tarsal segment (HTII) (cf. Uroleucon idahoensis, a pale green species also found on Anaphalis, which has RIV+V 0.8-1.7 times HTII). The dorsal abdomen has some hairs arising from dark scleroites. Antesiphuncular sclerites are totally absent, postsiphuncular sclerites are well developed. The coxae and the basal half of the femora are pale, the distal half of the femora is blackish. The distal half and the very base of the tibiae are black, with the basal half from brownish yellow to blackish brown. The siphunculi are black and reticulated over the distal 0.15-0.37. The cauda is usually darkish, sometimes almost black, and bears 12-23 hairs. The body length of adult Uroleucon russellae apterae is 2.5-3.3 mm.

Images above by permission, copyright Claude Pilon, all rights reserved.

The alate Uroleucon russellae is much like the aptera, but has the head and thorax blackish brown sclerotic. Antennal segment III has about 35-57 secondary rhinaria over very nearly its wholelength. The abdomen has dark marginal sclerites, and there is a more or less complete sclerotic band across tergite VIII. The siphunculi are less enlarged at base and thinner throughout than on the aptera, with the distal 0.2-0.67 reticulated. The wings have rather pale brownish veins.

Uroleucon russellae is found on the stems and leaves, and in inflorescences, of pearly everlasting (Anaphalis margaritacea) and catsfoot (Antennaria neodioica). Moran (1985) notes that the aphid's unusually long apical rostral segment is most likely an adaptation to the hairiness of its host. Sexuales develop in autumn with alate males, and the species overwinters in the egg stage. Hille Ris Lambers (1960) notes this species is rather common in Eastern Canada in the inflorescences of Anaphalis margaritacea. Similarly Jensen, in AphidTrek, notes that it is one of the few native Uroleucon species that is somewhat common in western North America. Uroleucon russellae is widespread in western and northern USA and across Canada.

Read more...

 

Uroleucon solidaginis (Goldenrod aphid) Europe, Asia, North Afriva, North America

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) Cosmopolitan

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) Europe, Asia, North America

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) Europe, Asia, North America

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...

 

Uroleucon verbesinae (Bicolored frostweed aphid) North America

Adult apterae of Uroleucon verbesinae are either shiny black or bright shiny red (cf. Uroleucon rurale, which is greenish-brown). Their antennae are slightly longer than the body and are uniformly black. The apical rostral segment (RIV+V) is very long and thin, 1.6-1.9 times as long as the second hind tarsal segment, and more than 4 times longer than its basal width (cf. Uroleucon rurale, which has RIV+V 1.2-1.56 times the length of the second hind tarsal segment, and less than 4 times its basal width). The bases of the femora are pale yellow; the rest of the femora and all the tibiae & tarsi are black. The dorsal hairs are without dark basal scleroites. Dusky antesiphuncular sclerites are present, which on the live insect only show up on the red apterae. The siphunculi are long and black, more than 1.5 times the length of the cauda which is also black (cf. Uroleucon ambrosiae, which has siphunculi less than 1.5 times as long as the cauda, which is pale). The siphunculi have reticulation on the distal 0.23-0.35 of length, comprising numerous small polygonal cells. Immatures of the red form are a slightly paler red than the adults, whilst immatures of the black form are dark reddish brown.

First image copyright C.A. Ivy, second image copyright Miriam Vaughn, both under a CC BY-NC 3.0 license.

Like the adult apterae, alatae of Uroleucon verbesinae (not pictured) are either shining black or bright red. Alatae have 25-36 secondary rhinaria scattered along all of antennal segment III (cf. Uroleucon rurale alatae, which have 13-27 secondary rhinaria, mostly on the basal two thirds of segment III).

Uroleucon verbesinae appears to be restricted to feeding on frostweed (Verbesina virginica) in the USA, but in Honduras it has been found on Verbesina myriocephala. It usually feeds under the leaves, moving to the stems when crowded on the leaves (cf. Uroleucon rurale, which feeds preferably on the stem). As far as is known, Uroleucon verbesinae is monoecious holocyclic. Uroleucon rurale, the only other Uroleucon so far known to feed on Verbesina virginica, has a more northerly distribution being found in the eastern USA from South Carolina northwards.

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