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Genus BrachycaudusShort-tailed aphidsOn this page: Brachycaudus aconiti amygdalinus bicolor cardui helichrysi lateralis linariae lucifugus lychnidis malvae napelli persicae prunicola prunifex schwartzi tragopogonisGenus Brachycaudus [Macrosiphini]Brachycaudus are rather small to medium-sized aphids which are green, dark green or ochreous-reddish. They have very low antennal tubercles and their antennae are shorter than the body. The terminal process of the last antennal segment is 3 or more times the basal part. The abdominal dorsum in apterous Brachycaudus is variably sclerotized, but frequently has an extensive dark sclerotic shield. Marginal tubercles are small or absent, and never on abdominal tergite 7. The siphunculi are short to moderate in length, nearly smooth, cylindrical or tapering, and distinctly flanged. The cauda is semicircular or helmet-shaped, shorter than its width, and with a slight basal constriction. Brachycaudus is a genus of 50 species found mainly in the Palearctic. About 14 species have plum (Prunus spp.) as the primary host. There are species groups associated with different secondary hosts - two of the most common species use daisies (Asteraceae). Other species do not host alternate, living year round on a variety of plant species. Some Brachycaudus species still have a sexual stage in their life cycle, but most do not. Brachycaudus aphids may be attended by ants. Some are important crop or fruit tree pests. Brachycaudus aconiti (Black monkshood aphid) Southern Europe, Central Asia and SiberiaAdult apterae of Brachycaudus aconiti (see picture below) have a light brown head and a shining black sclerotic abdominal dorsum, with the underside of the abdomen and the antennae, legs and siphunculi also black (cf. Brachycaudus napelli, which has an extensive black sclerotic shield over most of the dorsum, but the posterior, and much of the underside, are dark crimson). Antennal tubercles are low. The antennae are about 0.6 times body length with the terminal process about 3.1-3.5 times the base of antennal segment VI. There are 0-8 (but more on alatiform specimens) secondary rhinaria on antennal segment III (cf. Brachycaudus napelli, which has 10-25 rhinaria on segment III). The longest hair on antennal segment III is 0.8-1.2 times the maximum diameter of that segment. The rostrum reaches to the hind coxae or nearly so. The apical rostral segment (RIV+V) is 1.1-1.3 (1.6) times as long as the second hind tarsal segment (HTII) with 7-9 accessory hairs (cf. Brachycaudus napelli, which has RIV+V 0.9-1.2 times the length of HTII). There are marginal tubercles on the prothorax and some abdominal segments. The siphunculi are about 0.11-0.12 times the body length and 2.3-2.6 times the caudal length. The cauda is short, rounded, pentagonal with 10-13 hairs. The body length of adult Brachycaudus aconiti apterae is 2.7-2.9 mm.
Image above copyright Brbol under a creative common licence. There is no description available of the alatae Brachycaudus aconiti, but they are likely similar to the closely related Brachycaudus napelli. They bear 7-13 secondary rhinaria on antennal segment III. Immatures are green with a light brown head. Brachycaudus aconiti is monoecious on Aconitum spp. and Delphinium spp. It mainly feeds on the flower stems and leaf petioles, and rarely on the undersides of leaves. The species is holocyclic, with apterous males and oviparae. Brachycaudus aconiti is found in central, south and south-east Europe, Central Asia and Siberia. Brachycaudus amygdalinus (Short-tailed almond aphid) Europe, Middle East, North & South Africa, AsiaIn spring Brachycaudus amygdalinus colonies cause rolling of young almond or peach leaves, and stunting of new growth, to produce pseudogalls (see first picture below). Each leaf is rolled somewhat obliquely with respect to its mid-rib.On their primary host the apterae (see second picture below) of Brachycaudus amygdalinus are squat-bodied and green with rather short pale legs and antennae. The adults have a variably fragmented black dorsal patch with dorsal bars anteriorly and posteriorly (cf. Brachycaudus helichrysi, which is yellow-green with no dark dorsal patch; Brachcaudus schwartzi, which is shiny yellow brown to dark brown with an extensive black dorsal patch; and cf. Brachycaudus persicae, which is shiny dark brown to black). The antennae are 6-segmented. The apical rostral segment (R IV+V) is only about 0.8 times as long as the second hind tarsal segment (HT II) and bears 4 accessory hairs (cf. other Brachycaudus, spp. on Prunus which have RIV+V at least 0.9 times the length of HTII and bearing at least 5 accessory hairs). Abdominal tergite VII (or VII and VIII) has spinal tubercles. The siphunculi are pale with dusky tips (cf. Brachycaudus schwartzi, which has black siphunculi). The cauda is very broadly rounded, with its length less than half its basal width (cf. Brachycaudus helichrysi, which has a cauda about as long as its basal width). The body length of adult Brachycaudus amygdalinus apterae is 1.6-2.1 mm.
Images above copyright Dr László Érsek, all rights reserved. Alatae of Brachycaudus amygdalinus (see third picture above) have a dark central abdominal patch. Spring migrant alatae have secondary rhinaria on their antennae; with 12-21 on segment III, and 0-1 on segment IV. Brachycaudus amygdalinus apterae, on their secondary host, are smaller and somewhat more elongate. They are brown to dark green in colour with dusky siphunculi and 5-segmented antennae. Brachycaudus amygdalinus host alternates from Prunus species (especially almond, Prunus dulcis, or peach, Prunus persica) to various Polygonaceae (especially horsetail knotweed, Polygonum equisetiforme), prostrate knotweed, Polygonum aviculare, redshank, Persicaria maculosa, and tall buckwheat, Fagopyrum cymosum). It may also be anholocyclic on Polygonaceae (the knotweed or smartweed-buckwheat family). Brachycaudus amygdalinus is found in Europe, especially southern Europe, the Middle East, North Africa Central Asia, Pakistan, and has been introduced into South Africa. Brachycaudus bicolor (Hound's tongue aphid) Europe, Middle East, AsiaBrachycaudus bicolor apterae (see first picture below) are shining yellowish tinged with pink, to pale green, with separate cross bars on thoracic segments, a variably developed black patch situated dorsally on the abdomen and 2 or 3 black stripes at the tip. The hairs on abdominal tergite 8 are 30-113 μm long, much longer than the dorsal hairs on more anterior segments. Brachycaudus bicolor has conspicuous flat marginal tubercles present on all segments from the pronotum to abdominal tergite 7, and spinal tubercles on the pronotum and abdominal tergites 7 and 8 (see). Their siphunculi may be pale, dusky or quite dark. The body length of apterous Brachycaudus bicolor is 2.1-2.4 mm.
The alate (see second picture above) also has a variably developed black patch on the abdomen, and especially conspicuous marginal tubercles. She has 28-52 secondary rhinaria on antennal segment III, and 3-8 on segment IV. In Britain Brachycaudus bicolor is usually found in ant-attended colonies on root collars or at the bases of leaves of hound's tongue (Cynoglossum officinale). No sexual morphs have been recorded, and the species overwinters as parthenogenetic forms. Brachycaudus bicolor has been found in Britain, southern Europe, Egypt and parts of Asia. Brachycaudus cardui (Plum - thistle aphid) Europe, Asia, North Africa, North AmericaBrachycaudus cardui apterae (see first picture below) are brownish-yellow, pale green or brown, with separate cross bars on thoracic segments, a large shining black spot situated dorsally on the abdomen and 2 or 3 black stripes at the tip. The Brachycaudus cardui rostrum is long and reaches the hind coxae. The longest hairs on abdominal tergite 8 are 85-110 μm long, and the longest hairs on the hind femur are 40-80 μm long. (cf. the short-haired Brachycaudus lateralis. for which the longest hairs on abdominal tergite 8 are 20-61 μm long, and the longest hairs on the hind femur are 10-25 μm long. ) Their siphunculi are black, thick and cylindrical and 1.7-3.4 times the length of their cauda. The body length of apterae is 1.8-2.4 mm.
The alate Brachycaudus cardui (see second picture above) has a large black patch on the dorsal abdomen. Immatures are greenish or reddish. In continental Europe Brachycaudus cardui host alternates between various Prunus species, mainly cherry, plum and apricot, and various wild and cultivated daisies (Asteraceae) especially thistle (Carduus and Cirsium spp.) and borage (Boraginaceae). In Britain it seems to live all year round on Asteraceae. Infested leaves undergo severe curling. Dense colonies occur at the base of flower heads and on the leaves. A return migration to primary hosts occurs in autumn. The plum-thistle aphid is found throughout Britain and Europe as well as in Asia, north Africa and North America. Brachycaudus helichrysi (Leaf-curling plum aphid) CosmopolitanFeeding by Brachycaudus helichrysi in spring induces pseudogall formation on their host Prunus, with the leaves rolling up tightly perpendicular to their mid-rib and laterally (see first picture below). The adult aptera of Brachycaudus helichrysi (see second picture below) is variable in colour, ranging from yellow to green to pink to white, often shiny with a slight wax dusting. Their antennae are shorter than the body with dusky tips. The dorsum of the abdomen is without a black shield. Their siphunculi are pale, tapered and short - 0.8-2.0 times the length of the cauda. The cauda is pale, short and blunt. The body length of Brachycaudus helichrysi apterae is 0.9 - 2.0mm.
The alate Brachycaudus helichrysi (see third picture above) has a dark dorsal abdominal patch, with 13-46 secondary rhinaria on the third antennal segment and 0-18 on the fourth. The leaf-curling plum aphid host alternates between various plum (Prunus) species (especially domestic plum and blackthorn, Prunus spinosa) and a wide range of Asteraceae such as asters, chrysanthemums, yarrow and groundsel. Brachycaudus helichrysi populations on red clover (Trifolium pratense) have been called var warei, but are not thought sufficiently distinct to warrant subspecific status. Anholocyclic populations occur in warmer regions and in glasshouses, and are sometimes found on new growth of various trees. This aphid is a serious pest on fruit trees and sunflowers. The distribution of Brachycaudus helichrysi sensu lato is cosmopolitan, but recent molecular studies have shown they comprise at least three sibling species which evolved in geographically isolated populations. Brachycaudus lateralis (Short-haired thistle aphid) EuropeBrachycaudus lateralis apterae (see first picture below) are green or reddish, with separate cross bars on thoracic segments, a large shining black spot situated dorsally on the abdomen and 2 or 3 black stripes at the tip. The rostrum is long and reaches the hind coxae. The longest hairs on abdominal tergite 8 are 20-61 µm long, and the longest hairs on the hind femur are 10-25 μm long (cf. the closely related Brachycaudus cardui for which the longest hairs on abdominal tergite 8 are 85-110 μm long, and the longest hairs on the hind femur are 40-80 μm long). Their siphunculi are black, thick and cylindrical and 2.3-3.4 times the length of the cauda. The body length of apterae of Brachycaudus lateralis is 1.6-2.6 mm. Note: the results of recent DNA studies suggest that Brachycaudus lateralis should only be accorded subspecific status to Brachycaudus cardui.
The alate female (not pictured) has a dorsal patch irregularly bordered, and partly broken into crossbars and smaller sclerites. There are 18-35 secondary rhinaria on antennal segment III, and none on segment IV. Immatures (see second picture above) often have reddish patches on a greenish background. The pictures below are micrographs of Brachycaudus lateralis in alcohol. The first is an adult aptera whilst the second shows the very short hairs on the femur. Brachycaudus lateralis is usually found close to the ground on the stems and leaves of numerous Asteraceae, including chamomile (Anthemis), thistles ( Carduus, Cirsium) and ragworts and groundsels (Senecio), where they are usually attended by ants which tent over the colony with soil particles. It usually remains on Asteraceae all year, although it has been recorded host alternating to plum (Prunus). Brachycaudus lateralis is found over most of Europe. Brachycaudus linariae (Toadflax aphid) EuropeAdult apterae of Brachycaudus linariae are deep blackish shiny green. The last two fused rostral segments range in length from 0.135 to 0.160 mm. There are medium to large flat marginal tubercles on the pronotum and on some or all of abdominal tergites 1-5. The body length of adult Brachycaudus linariae apterae is 1.4-1.9 mm.
Brachycaudus linariae alatae have 11-33 secondary rhinaria on the third antennal segment, 6-9 on the fourth segment and 0-2 on the fifth segment. Immatures are a somewhat paler green. Toadflax aphids live on the basal parts of toadflax, especially yellow toadflax (Linaria vulgaris). Sexual morphs of the toadflax aphid have not yet been found in UK, but have been recorded in Slovakia. Brachycaudus linariae is found in parts of western and northern Europe and most of eastern Europe. Brachycaudus lucifugus (Short-tailed plantain aphid) EuropeAdult apterae of Brachycaudus lucifugus are yellowish-green with dark cross bars on the pronotum and mesonotum, a transverse row of sclerites on the metanotum, and a shiny dark brown to black dorsal patch on abdominal segments 1-5. The patch frequently has pale windows or is broken into cross-bands. Abdominal tergite 8 bears 4 very short (less than 10 μm) hairs in a single row, like the dorsal hairs on more anterior segments. The black siphunculi are about double the length of the cauda. The cauda is rounded, as long as it is wide, with 6-9 hairs. The body length of adult apterae is 1.4-2.0 mm.
The alate of Brachycaudus lucifugus does not have broad cross bands or a large dark patch on the dorsal abdomen, but has transverse bars on tergites 7 and 8 with rarely a few sclerotic spots forming lines on tergites 4-6 only. The short-tailed plantain aphid lives on roots, and root collar, and at the leaf bases of ribwort plantain (Plantago lanceolata). There is no host alternation. Brachycaudus lucifugus is usually ant attended, as in the second picture above. Oviparae and small apterous males can be found in autumn. In England it is restricted to southern counties. Elsewhere in Europe Brachycaudus lucifugus is known from Germany, Hungary, Italy, Poland and Switzerland. Brachycaudus lychnidis sp. grp. (Campion aphids) Europe, West AsiaThe dorsal abdomens of adult apterae of Brachycaudus lychnidis sp. grp. (Brachycaudus klugkisti and Brachycaudus lychnidis ss.) have an extensive solid shiny black shield (see first picture below) with the underside red-brown. Their median frontal tubercle is about as high as the antennal tubercles. Their antennae are 0.6-0.8 of the body length. Their legs have the fore femora pale with dorsally dark apex; the hind femora are dusky with a pale base and the tibiae are pale with the apex and base dark. Their siphunculi are dark truncated conical, and are 1.2-2.3 times the length of the cauda. The cauda is rounded or semi-oval. They often have a wax ring around the terminal abdominal segments - this is not mentioned in the literature, presumably because such deposits are not apparent in prepared slide specimens.
Alatae (see second picture above) have a large dark dorsal patch covering tergites 3-8, fused with the marginal sclerites. Immatures are often suffused with dark red between and around the siphunculi. The ovipara has the hind tibia distinctly thickened in the middle, and the male is apterous The two members of the species pair can be distinguished by the number and length of hairs on the third antennal segment, and by the shape of the cauda:
The campion aphids Brachycaudus lychnidis and Brachycaudus klugkisti both live all year on red campion (Silene dioica) and related species. A further aphid species, Brachycaudus lychnicola, also has the same host, but lives at the base of the plant. All the aphids we have found on campions have been living on the upper parts of the plant. Oviparae and apterous males are produced in October. Both Brachycaudus lychnidis and Brachycaudus klugkisti are found in Britain and over most of Europe, with the former species extending eastwards to western Siberia. Brachycaudus malvae (Mallow aphid) Europe, AsiaAdult apterae of Brachycaudus malvae are pale green with separate black cross bars on thoracic segments, and an extensive shining black sclerotic shield on the dorsum (cf. Brachycaudus helichrysi which has no dark sclerotization on the dorsum). The hairs on the third antennal segment are very short, only 0.2-0.25 times the basal diameter of that segment. The last two fused apical rostral segments (RIV + V) are 0.165-0.190 mm in length. Marginal tubercles are often absent; if present they are usually only on the prothorax and abdominal tergites 2-4. Abdominal tergite 8 bears 10-14 short hairs, not in a single row. The siphunculi are black and cylindrical. The body length of Brachycaudus malvae apterae is 1.8-2.3 mm.
Alatae have a large black dorsal patch may be broken up to a greater or lesser degree into transverse bars. Their antennae each bear 21-30 secondary rhinaria on segment III and 0-3 on segment IV. Brachycaudus malvae is closely related to Brachycaudus cardui and Brachycaudus lateralis in the subgenus Acaudus. Brachycaudus malvae lives all year feeding on mallow (Malva) species with no host alternation. Aphid colonies are usually attended by ants. Sexual morphs have apparently not been described. The species is found in much of Europe (Britain, Spain, Italy, southern Russia, Ukraine) and China - an odd distribution suggesting the species has been overlooked in many countries. Brachycaudus napelli (Crimson-tipped monkshood aphid) EuropeAdult apterae of Brachycaudus napelli have an extensive black sclerotic shield over most of the dorsum, but the posterior, and much of the underside, are dark crimson (cf. Delphinobium junackianum, which has no dark sclerotic shield and is coloured uniformly dark blue-green). Their antennae are 0.6-0.7 times as long as the body, and the terminal process is 2.7-4.3 times the length of the base of antennal segment VI. All the apterae are alatiform, and antennal segment III bears 10-25 secondary rhinaria (cf. Brachycaudus aconiti, which has 0-8 secondary rhinaria in the aptera). The apical rostral segment (RIV+V) is 0.9-1.2 times the length of second hind tarsal segment (HTII) (cf. Brachycaudus aconiti, which has RIV+V 1.2-1.6 times the length of HTII). The first hind tarsal segment (HTI) has only 2 hairs (cf. Brachycaudus aconiti in southern Europe, and Brachycaudus rociadae in the USA, which both have 3 hairs on HTI). The siphunculi have a very well developed flange, and are 1.7-2.4 times the caudal length. The siphunculi are 0.31-0.55 times the length of antennal segment III (cf. Brachycaudus aconiti, which has siphunculi 0.57-1.0 times the length of antennal segment III). The cauda is helmet-shaped, shorter than its basal width and with about 10 hairs. The body length of adult Brachycaudus napelli apterae is 2.0-2.9 mm. Note: Brachycaudus napelli is in subgenus Acaudus along with Brachycaudus aconiti,, to which it is closely related. Brachycaudus aconiti occurs in central and southern Europe, and parts of Asia.
Images above copyright Renze Borkent, all rights reserved. Alatae of Brachycaudus napelli (not pictured) have similar characteristics to the apterae except their antennae are about 0.8 times the body length, and the antennal terminal process is about 5 times the base of antennal segment VI. Alatae bear 17-37 secondary rhinaria on antennal segment III and 0-4 on segment IV. Brachycaudus napelli mainly feeds on monkshood (Aconitum spp.), forming colonies on the stems, flowers and fruits, and sometimes on the leaves. It is also found on delphinium (Delphinium spp.). Both Aconitum and Delphinium species are normally toxic to animals. The aphid does not host alternate, and sexuales (oviparae and apterous males) develop in the autumn. The crimson-tipped monkshood aphid is found in west and north-west Europe, south to Spain, and has also been recorded from Austria and the Czech Republic. Brachycaudus persicae (Black peach aphid) Europe, Asia, southern Africa, Australia, North & South AmericaAdult apterae of Brachycaudus persicae have a shiny sclerotized dark brown or black dorsum (see dark individual in first picture below). The fused apical rostral segments of the aptera are shorter than 0.175 mm in length. First tarsal segments are each with 2-3 hairs (cf. Brachycaudus schwartzi, which has the first tarsal segments each with 4 hairs). The flanged siphunculi are black (cf. Myzus persicae which have pale siphunculi with darkened tips) and are more than 0.1 times the body length, clearly more than twice the length of the cauda and longer than the hind tarsi (cf. Brachycaudus schwartzi, which has markedly shorter siphunculi). The cauda is dark, short and broad. The body length of adult apterae is 1.5-2.2 mm.
Winged spring migrants have similar coloration to the apterae, and have 23-51 secondary rhinaria on the third antennal segment, 9-21on the fourth, and 1-6 on the fifth. Immature stages of Brachycaudus persicae are yellowish to dark brown. Brachycaudus persicae is most commonly found in large spring colonies on young stems of peach (Prunus persica) or apricot (Prunus armeniaca), often persisting into the summer on root suckers. In Europe there is some evidence of host alternation from Prunus to Orobanchaceae, but Brachycaudus persicae may remain all year on Prunus. Aphids apparently of this species are also widely distributed on peach outside Europe, including the Middle East, southern Africa, Australia, New Zealand, and North and South America. Brachycaudus prunicola (Black-barred plum aphid) Europe, AsiaAdult apterae of Brachycaudus prunicola are olive-green to chestnut reddish brown with shiny black broad cross bands on each abdominal segment. The dorsal crossbands are often not completely fused intersegmentally and/or have a spinal gap, and are not connected to the marginal sclerites, at least on abdominal tergites II-III (see two pictures below showing, first, a lightly marked aptera and, second, a heavily marked aptera) (cf. Brachycaudus prunifex, which has the dorsal cross bands usually fused into a solid patch on abdominal tergites II-V that connects on each side with the marginal sclerites). The longest hair on the inner side of antennal segment II is 0.4-1.0 times longer than the basal diameter of antennal segment III (cf. Brachycaudus prunifex where that hair is 0.8-1.6 times longer than the basal diameter of antennal segment III). The apical rostral segment (RIV+V) is 0.88-1.05 times the length of the second hind tarsal segment (HTII). There is often a chestnut-reddish suffusion around the siphuncular bases and on the dorsum of the prothorax. The black siphunculi are rather short, less than twice as long as the cauda. The body length of adult apterae is 1.4-2.4 mm. Immature Brachycaudus prunicola are grey green with chestnut-reddish areas of suffusion.
First image above copyright Marko Šćiban, all rights reserved. The Brachycaudus prunicola alate (see third picture above) is olive green to brownish with a median sclerotized dorsal shield on tergites III-VI, and transverse bars on tergites VII-VIII. Brachycaudus prunicola feeds on the young growth of blackthorn (Prunus spinosa), domestic plum (Prunus domestica) and damson (Prunus insititia) causing severe leaf curl and discoloration. Some populations remain all year on Prunus but some may host alternate to salsify (Tragopogon). Brachycaudus prunicola is found throughout continental Europe (but apparently not in Britain) into Russia, Kazakhstan and Pakistan. Brachycaudus prunifex (Black-backed sloe aphid) Western EuropeIn spring Brachycaudus prunifex induce curled leaf pseudogalls on new growth of blackthorn (Prunus spinosa, see first picture below) (cf. Brachycaudus helichrysi, which produce very similar pseudogalls on blackthorn). Most adult Brachycaudus prunifex apterae are shiny blackish-brown (see second picture below). They have separate cross bars on thoracic segments, but the cross bars on their abdomen are usually fused to give a solid patch on abdominal tergites II-V (cf. Brachycaudus prunicola, which often have the dorsal cross bands not completely fused intersegmentally and/or with a spinal gap).
Some individuals of Brachycaudus prunifex may instead be reddish or greenish with reduced dark pigmentation on the dorsum. Brachycaudus prunifex can only be satisfactorily separated from Brachycaudus prunicola by examining the length of antennal or body hairs. The longest hair on the inner side of antennal segment II is 0.8-1.6 times the basal diameter of antennal segment III (cf Brachycaudus prunicola which has longest hair on the inner side of antennal segment II 0.4-1.0 times that diameter). The dark siphunculi are quite short, and of similar length to the dark cauda. The body length of adult apterae is 1.4-2.4 mm. Brachycaudus prunifex does not host alternate but lives all-year-round on blackthorn (Prunus spinosa). It had been suggested that the species host-alternates to Tragopogon, but this has not been substantiated. Sexuales are most likely produced in autumn, but so far only males have been found. Brachycaudus prunifex is found in England, Wales, and Ireland, where the closely related Brachycaudus prunicola does not occur. Brachycaudus prunifex has also been found in northern France. In the rest of Europe its niche is occupied by Brachycaudus prunicola. Brachycaudus schwartzi (Peach curl aphid) Europe, West & South Asia, North Africa, South America, North AmericaAdult apterae of Brachycaudus schwartzi are shiny yellowish-green to greenish-brown to dark brown (see pictures below), usually with some orange-pink suffusion especially around their siphunculi, and with broad dark segmental stripes. The antennae are shorter than the body length, with the terminal process 2.3-4.8 times as long as the base of antennal segment VI. The rostrum generally reaches beyond the middle coxae with the apical rostral segment 0.9-1.1 times as long as the second hind tarsal segment. The dorsal cuticle is extensively sclerotized, but is partly segmentally divided especially on the anterior tergites, and does not extend laterally to the spiracles (cf. Brachycaudus persicae, where sclerotization of the dorsal abdomen is almost complete, extending laterally to the spiracles and not segmentally divided). Marginal abdominal tubercles (=circular membranous areas, which are clearly visible on marginal sclerites just anterior to the siphunculi on the yellow form) on abdominal tergites II-IV are mostly greater than 18 μm, and are often as large as or larger than spiracles (cf. Brachycaudus prunifex and Brachycaudus prunicola, which have marginal abdominal tubercles on abdominal tergites II-IV, if present, mostly less than 18 μm, and smaller than the spiracles). The siphunculi are dark and short. The cauda is short and rounded, shorter than its basal width and pigmented. Immatures are greenish with dark scleroites, with an orange-pink suffusion over their posterior tergites.
First image above copyright Zdenëk Hyan, second image copyright Mihajlo Tomić The alate Brachycaudus schwartzi (not pictured) is orange-yellow with a discontinuous black dorsal abdominal patch. The antennae are shorter than the body, and bear 25-37 secondary rhinaria on segment III, 7-14 on IV and 0-1 on V. The siphunculi are cylindrical, short and dark. The cauda is short and rounded. Brachycaudus schwartzi is monoecious holocyclic on peach (Prunus persica). In spring colonies of this species cause severe curling and distortion of peach leaves. Sexuales develop in autumn. Brachycaudus schwartzi is found in Europe, West & South Asia, North Africa, South America and southern states of North America. Brachycaudus tragopogonis (Goats-beard aphid) Europe, South AmericaAdult apterae of Brachycaudus tragopogonis (see first picture below) are shining grey-brown to dark brown, although a dense colony appears black. The cross bands are often divided spinally as well as intersegmentally into paired pleural patches. The siphunculi are 0.05-0.06 times as long as the body length and 1.2-1.5 times as long as the cauda. The cauda is helmet-shaped. The body length of Brachycaudus tragopogonis apterae is 1.4-2.3 mm.
The alate viviparous female (see second picture above) has some membranous intersegmental stripes or windows in the dorsal sclerotic area, and abdominal segment 4 has paired ventral spots much smaller than those on segments 5 and 6. The extent of dorsal abdominal sclerotization on both the aptera and the alate is variable. Some are rather heavily sclerotized, whilst others are less so - especially anteriorly. Brachycaudus tragopogonis lives all year round on the stem and leaves of Tragopogon (goatsbeard) species with no host alternation. Oviparae and winged males appear in autumn. The species is found in southern Britain and over much of Europe, and has been introduced to South America.
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