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Aphididae : Aphidinae : Macrosiphini : Macrosiphum
 

 

Genus Macrosiphum [Macrosiphini]

Macrosiphum are large spindle-shaped pink or green aphids, with long legs and antennae, the latter usually longer than the body. The adult viviparae may be winged or wingless. The antennal tubercles are rather high, smooth, and divergent. Siphunculi are long, flanged and not swollen, with a zone of regular polygonal reticulations covering the one-tenth to one-sixth near the end of the siphunculus. The cauda is always pale and very elongate.

Macrosiphum occur on rose (Rosaceae) and many other hosts including teasel (Dipsacaceae), Apiaceae, Valerianaceae and Ranunculaceae. They usually do not host alternate, although some species retain host alternation with rose as the primary host. Most species are not attended by ants, but there are a few exceptions to this.

 

Macrosiphum albifrons (Lupin aphid)

Macrosiphum albifrons apterae are large pale bluish grey-green oval-shaped aphids dusted with white wax (cf. Macrosiphum euphorbiae which is not dusted with wax). Their antennae and legs are pale or dusky with blackish apices. The siphunculi are light brown with dark tips, and are 0.21-0.32 times the body length, and 1.6-2.2 times the length of the cauda. The cauda is pale, slender and rather pointed. The body length of adult Macrosiphum albifrons apterae is 3.2-5.1 mm.

The alate (see second picture above) has a dusky head, brown thorax, a bluish green abdomen with small marginal spots and dusky siphunculi. The alate shown is a teneral - in other words it has just moulted and has yet to produce its wax covering. Mature alates are dusted with wax. Immatures (also in second picture above) have all dark siphunculi and are dusted with wax.

The lupin aphid does not host alternate but spends its entire life cycle on Lupin (Lupinus species). It lives mainly on the leaves, stems and flower spikes. It originates in North America where sexual forms with alate males develop in the autumn, and the aphid overwinters as eggs. In Europe Macrosiphum albifrons was first recorded in England in 1981 where it overwinters as viviparae. It is now widely distributed and considered an invasive pest species over much of Europe.

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Macrosiphum cholodkovskyi (Meadow Sweet aphid)

Macrosiphum cholodkovskyi apterae are yellow-green to dark blue-green (see first picture below of a green adult) or coral-pink to red (see second picture below of a pink immature), often with a darker longitudinal mid-dorsal band. The antennae are rather dark except at the bases, and are longer than the body. The femora and tibiae are dark distally. The siphunculi are mainly dusky, with a dark tip and a pale base, and are 1.7-2.2 times the length of the rather thick and blunt cauda. The body length of adult Macrosiphum cholodkovskyi apterae is 3.1-5.1 mm.

The alate Macrosiphum cholodkovskyi (see third picture above) has a brown head and thorax, and a motled green abdomen with rather pale marginal sclerites.

The meadowsweet aphid does not host alternate but spends its entire life cycle on meadow sweet (Filipendula ulmaria), and occasionally on valerians (Valeriana alliariifolia). Macrosiphum cholodkovskyi lives on the stem and among the flowers. It is found throughout Europe and parts of Asia.

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Macrosiphum coryli (American hazelnut aphid)

Adult apterae of Macrosiphum coryli (see first two pictures below) have a reddish-brown head and thorax. Their abdomen is greenish in the mid-dorsum, but is suffused with dark reddish-brown pigment laterally and posteriorly (cf. Macrosiphum pseudocoryli in North America, and Macrosiphum skurichinae in Siberia, which both have the abdomen wholly pale green). The antennae are mainly brown and 1.5 times the body length. Their dorsal body hairs are short, not capitate and not borne on tubercles (cf. Corylobium avellanae, which have long, thick and slightly capitate dorsal hairs arising from large tubercles). The dorsal cuticle of Macrosiphum coryli is smooth, and not sclerotic (cf. Macrosiphum vandenboschi in California, which has the dorsal cuticle very wrinkled and strongly sclerotized). The hind tibiae have a paler middle section (cf. Macrosiphum corylicola in Japan, which has the hind tibiae wholly black). The siphunculi are long and tapering, more than three times as long as the cauda, and with subapical polygonal reticulation. The siphunculi are entirely black, contrasting with the pale cauda (cf. Myzocallis coryli, which has very short pale siphunculi). The cauda is finger-shaped, and the anal plate is entire (=not divided). The body length of adult Macrosiphum coryli apterae is 1.6-2.2 mm.

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

The alate of Macrosiphum coryli (not pictured) has a brown head and thorax, and a light green abdomen suffused with darker pigment around and posterior to the siphunculi. As with the aptera, the siphunculi of the alate are entirely black contrasting with the pale cauda. Very young immatures are mostly green, but third instars and above have some areas of reddish brown suffusion.

Macrosiphum coryli is not thought to host alternate, feeding only on the shoot tips and undersides of young leaves of the American hazelnut (Corylus americana) and beaked hazelnut (Corylus cornuta). This aphid prefers hazelnut growing in somewhat shaded situations; it is rather solitary in habit and not as gregarious as many species of the genus. It is assumed that sexuales develop in autumn, but they have yet to be described. Macrosiphum coryli is mainly found in the more northerly states of the USA and across Canada.

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Macrosiphum daphnidis (Daphne aphid)

Adult apterae of Macrosiphum daphnidis (see first picture below) are pale yellowish or whitish green with a slightly darker spinal stripe. Their antennae have the apex of each segment darkened, and the terminal process is 5.9-6.7 times as long as the base of antennal segment VI. The apterae have dark brown eyes (cf. Macrosiphum euphorbiae, which has red eyes). The apical rostral segment (RIV+V) is 0.8-0.9 times as long as the second hind tarsal segment (HTII). The longest hair on the vertex is 61-92 µm (cf. Macrosiphum euphorbiae. which has the longest hair on the vertex 28-48 µm). The longest hair on abdominal tergite III is 43-71 µm (cf. Macrosiphum euphorbiae, where the longest hair on that tergite is 21-37 µm). The femora of apterae are entirely pale, but the tibiae are dark apically. The siphunculi are slightly darker at the apices and have polygonal reticulation on the distal 0.1-0.2 of their length; the siphunculi are 1.8-2.3 times the caudal length. The cauda has 10-19 hairs. The body length of adult Macrosiphum daphnidis apterae is 2.4-4.2 mm.

The alate of Macrosiphum daphnidis (see second picture above) has the abdomen yellowish-green with faint dusky marginal sclerites on segments II-IV. The antennae are 1.2-1.5 times the body length, and have 26-47 secondary rhinaria on ANT III. The siphunculi are dusky and are 1.8-2.3 times the length of the cauda.

Macrosiphum daphnidis is thought to favour mezereon (Daphne mezereum), but is also found on other Daphne species including spurge laurel (Daphne laureola). It forms small, rather loose colonies on growing buds and shoots, and also scattered on the undersides of leaves where their colour can render them difficult to see. There is no host alternation, and sexual forms (oviparae and alate males) develop on Daphne in autumn. Macrosiphum daphnidis overwinters as eggs laid on the stems of the host plant. The daphne aphid is found over much of Europe, and has been introduced to north-western USA and Canada.

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Macrosiphum euphorbiae (Potato aphid)

Macrosiphum euphorbiae apterae are either green with a darker green longitudinal stripe or red (see pictures below), and often rather shiny. Their eyes are noticeably red, and the antennae are darker towards their tips. The fused apical rostral segment (RIV+V) is 0.83-1.02 times longer than the second hind tarsal segment (HTII) (cf. Macrosiphum tinctum for which RIV+V is 0.98-1.11 times longer than HTII and cf. Macrosiphum funestum for which RIV+V is 1.2-1.5 times longer than HTII). Their femora are brownish and rather pale with the apices not dark or only slightly so (cf. Macrosiphum hellebori, Macrosiphum gei, Macrosiphum cholodkovskyi and Macrosiphum euphorbiellum which all have dark apices to the femora). The siphunculi are pale sometimes with the tips darker, but not as dark as the tips of the tibiae (cf. Macrosiphum rosae which has the siphunculi entirely black). The siphunculi are reticulated on the apical 13-20% and are 1.7-2.2 times the length of the cauda. The cauda is rather pointed and not constricted. The body length of Macrosiphum euphorbiae apterae is 2.0-4.0 mm.

The alate (see third picture above) has pale greenish to yellow-brown thoracic lobes, with only the antennae and siphunculi noticeably darker than in the apterae.

The potato aphid is a common and highly polyphagous species. It is often a pest on various crops such as potato (Solanum tuberosum), lettuce (Lactuca sativa) and beets (Beta vulgaris) as well as on numerous garden ornamentals. Macrosiphum euphorbiae is a vector of about one hundred plant viruses. The species originates from the north-eastern USA where it produces sexual forms and host alternates with rose (Rosa) as its primary host. Elsewhere it usually overwinters as viviparae. Aphid numbers increase rapidly from early spring, and alates spread infestations to other plants. It is an especial problem in unheated greenhouses. Macrosiphum euphorbiae was introduced to Europe about 1917 and is now cosmopolitan.

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Macrosiphum euphorbiellum =Macrosiphum amygdaloides (Euphorbia aphid)

Macrosiphum euphorbiellum adult apterae (see first picture below) are usually green, sometimes with a darker green longitudinal stripe, but may also be pink, magenta or wine red. Their eyes are reddish and the antennae are dusky. The antennal terminal process is 4.2-5.2 times longer than the base of the sixth antennal segment. The apical parts of the femora are black (cf. Macrosiphum euphorbiae which has the apical parts of the femora pale or only slightly dusky). The siphunculi are pale with the tips darker. The cauda is rather pointed and not constricted. The body length of Macrosiphum euphorbiellum apterae is 2.0-4.0 mm.

The alate (see second picture above) is similarly coloured to the aptera.

The euphorbia aphid does not host alternate, but spends its entire life cycle on spurge, especially wood spurge (Euphorbia amygdaloides) and red spurge (Euphorbia characias). It feeds on the stems and in the flowerheads. Red oviparous females and red winged males have been found in autumn in Switzerland. Macrosiphum euphorbiellum is found in southern England, southern Ireland and much of central and southern Europe. There is also a single American record from Washington, USA in 2017.

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Macrosiphum funestum (Blackberry aphid)

The adult apterae of Macrosiphum funestum (see first picture below) are a rather dull green or red. Their antennae are dark or dusky with darker tips to each segment, and are longer than the body. Antennal hairs are long enough to be conspicuous (cf. Sitobion fragariae which has short and blunt antennal hairs less than half the width of the base of antennal segment III). The tips of the tibiae and the ends of the femora are dark. The abdomen is unsclerotized apart from small marginal and antesiphuncular sclerites (cf. Sitobion fragariae which has the dorsum sclerotized). The siphunculi are dusky but not black, and have paler bases (cf. Macrosiphum rosae which has siphunculi entirely black). The siphunculi are about 0.33 times the body length, 2.5-3.5 times the length of the cauda (cf. Sitobion fragariae which has siphunculi 1.7-2.7 times the length of the cauda). The siphunculi are reticulated on the apical 12-15%. The body length of Macrosiphum funestum apterae is 3.0-4.3 mm.

The alate viviparous female (see third picture above) has the abdomen green or red with rather distinct black marginal and antesiphuncular sclerites. The antennae are up to 1.5 times the body length, with segment III bearing 15-33 rhinaria along one side.

The blackberry aphid does not host alternate but spends its entire life cycle on blackberry (Rubus fruticosus agg.). Macrosiphum funestum lives mostly on the young shoots and leaves. Sexual forms are produced in autumn and the aphid overwinters as eggs on the blackberry stems. The species is found throughout Europe into Turkey and Iran, and has been introduced into Canada.

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Macrosiphum gaurae (Beeblossom aphid)

Adult apterae of Macrosiphum gaurae are variable in colour from green (see first picture below) to orange-red (see second picture below) to pink (see third picture below). Their antennae have segments I, II, and III light brown, segment IV dark brown, and the more distal segments dark brown to black (cf. Macrosiphum euphorbiae, whose antennae are mainly pale). The fused apical rostral segment (RIV+V) is 1.1-1.25 times as long as the second hind tarsal segment (HTII). Their legs are mostly light brown, but the tarsi and the distal parts of the femora and tibiae are dark brown to black. The siphunculi usually have the basal third pale and the distal two thirds dark brown to black (cf. Macrosiphum euphorbiae, which has mainly pale siphunculi with dusky tips). However, there is some evidence that the degree of darkening of the Macrosiphum gaurae siphunculi may vary across the continent (Jansen in Aphidtrek), if so the antennal coloration may be a more reliable discriminant from Macrosiphum euphorbiae. The cauda is dusky, but the same colour as the body (whether green or pink). The body length of adult Macrosiphum gaurae apterae is 2.7-3.9 mm.

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

Immature Macrosiphum gaurae resemble the adult apterae, but with paler siphunculi and much shorter caudas. The alate Macrosiphum gaurae (see third picture above) has a reddish brown head and thorax and a pale abdomen with the same abdominal colour variations as the apterae. The legs have the femora dark brown distally and paler basally, and the distal part of the tibiae and the tarsi dark brown to black. There are often light brown marginal sclerites on abdominal segments II-V. The siphunculi are dark distally but paler basally. The cauda is dusky and concolorous with the body.

Macrosiphum gaurae feeds on the stems and leaves of beeblossoms (Gaurae spp.) and evening primroses (Oenothera spp.). They do not host alternate, but remain all year on Gaurae / Oenothera. Oviparae have been collected on Gaura in Oregon in October. The beeblosom aphid is widely distributed in he United States and Canada.

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Macrosiphum gei (Herb Bennet aphid)

Macrosiphum gei apterae are spindle-shaped, usually mid-green to bluish green (see first picture below) or wine red (see second picture below), occasionally mauve with green mottling. The femora and siphunculi are somewhat darker at the apices. Their antennae are pale at the bases but darker towards the apices. The terminal process of antennal segment VI is 4.5-6 times the length of its base. The hairs on the dorsum of Macrosiphum gei are noticeably long (see first picture below) with the longest hair on abdominal tergite III usually more than 55 μm (cf. Macrosiphum euphorbiae for which the longest hair on abdominal tergite III is usually less than 38 µm). The siphunculi are 1.7-2.1 times the length of the cauda with reticulation on the apical 11-17%. The cauda is rather pointed and not constricted.

The Macrosiphum gei alate (see third picture above) has the head and thorax brown with indistinct marginal sclerites and dark antennae and siphunculi; there are 8-26 secondary rhinaria on the third antennal segment. Immatures (see second picture below) are green or red and may be lightly dusted with wax.

Macrosiphum gei is found in dense colonies on the upper parts of the flower stem of Geum urbanum (herb Bennet, wood avens). It can also occur on the undersides of the leaves of some Apiaceae, especially Anthriscus. Records of this species as a pest of potatoes result from misidentification of Macrosiphum euphorbiae as Macrosiphum gei. It is found in Europe and west Siberia and has been introduced to North America.

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Macrosiphum hellebori (Hellebore aphid)

Macrosiphum hellebori apterae (see first picture below) are yellowish green with darker marbling, with dark apices to the antennal segments, femora, tibiae and siphunculi (cf. Macrosiphum euphorbiae in which the femora are entirely pale or slightly dusky distally). The terminal process of antennal segment VI is 6.4-7.9 times the length of its base. The fused apical segment of the rostrum (RIV+V) is 0.8 times the length of the second hind tarsal segment. The siphunculi are 2.2-2.8 times the length of the rather thick and blunt cauda.

The alate (see second picture above) has the head and thorax brown with rather faint marginal sclerites. The siphunculi are mainly dusky or dark, apart from the base which is pale.

Macrosiphum hellebori lives in sometimes large colonies on the undersides of leaves of Helleborus spp. On mainland Europe it overwinters in the egg stage and oviparae and alate males are found in autumn. In Britain it overwinters mainly as viviparae. Macrosiphum hellebori is found in Europe and has been introduced to New Zealand, Australia and North America.

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Macrosiphum impatientis (Green jewelweed aphid)

Adult apterae of Macrosiphum impatientis are shining green to dark green with strikingly black siphunculi. The antennae are mostly light brown, but antennal segment III is dark brown around the secondary rhinaria, as are the apices of segments III-V (cf. Macrosiphum pallidum, which has antennal segment III black except at the base). The tibiae of Macrosiphum impatientis are mainly light brown although somewhat darker towards the apices (cf. Macrosiphum pallidum, which has black tibiae). Abdominal tergites VII & VIII are usually without spinal tubercles (cf. Macrosiphum pallidum, which has abdominal tergites VII & VIII each with a pair of spinal tubercles). The siphunculi of Macrosiphum impatientis are mostly black, but with their extreme base paler (cf. Macrosiphum euphorbiae, which has the siphunculi either pale or only dusky at the apices, and cf. Macrosiphum rosae on rose, which has the siphunculi entirely black). The siphunculi taper very gradually from base to apex with 4-8 rows of rather large polygonal reticulations. If our images are representative, the cauda of the adult is conspicuously yellow. The body length of adult Macrosiphum impatientis apterae is 1.7-3.8 mm.

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

Alatae of Macrosiphum impatientis (see first picture below of IV instar alatoid & second picture of adult alate) are dark green with the thorax tinged with brown, and have dark brown to black siphunculi and antennae. The wing veins are dusky with brown bordering only the base of the radial sector. The marginal sclerites on abdominal segments II-V are sometimes dusky to light brown.

Macrosiphum impatientis host alternates from roses (Rosa spp., its primary hosts) to jewelweeds or touch-me-nots (Impatiens spp., its secondary hosts). The population overwinters in the egg stage. Sexual forms develop on rose in autumn - but since oviparae have been found on Impatiens, it seems Macrosiphum impatientis may also sometimes overwinter on its secondary host. The known distribution of Macrosiphum impatientis extends from Canada to the north-east (Pennsylvania and Virginia) and midwest (Illinois and Nebraska) of the United States. It has been considered to be a rare species in the United States, but that situation may be changing. It has been found to be common on orange jewelweed (Impatiens capensis) in Maryland on both Carolina rose (Rosa carolina) and the increasingly widespread invasive multiflora rose (Rosa multiflora) growing near Impatiens plants.

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Macrosiphum pseudocoryli (American hophornbeam aphid)

Adult apterae of Macrosiphum pseudocoryli are green with mostly black siphunculi. Their antennae are markedly longer than the body (1.29-1.73 times). Antennal segment III has 2-7 secondary rhinaria in a row, and the longest hairs on antennal segment III are 0.5-0.7 times the basal diameter of the segment. The apical rostral segment (RIV+V) is 1.4-1.8 times as long as the second hind tarsal segment (HTII) and bears 14-18 accessory hairs. There are no dark markings on the dorsum (cf. Macrosiphum coryli, which has the abdomen green, but suffused with dark reddish-brown pigment laterally and posteriorly). Spinal and marginal tubercles are present on some segments. The bases of the femora are pale, the distal part of the femora and central parts of the tibiae are brown, and the apices of tibiae & tarsi are dark brown to black. The tarsal segments have 3 hairs. The siphunculi are black except for the base which is pale (cf. Macrosiphum coryli, which has the siphunculi wholly black), and they are not swollen (cf. Illinoia corylina & Illinoia macgillivrae, which both have slightly but distinctly swollen siphunculi). The siphunculi have a subapical zone of polygonal reticulation, and are usually more than twice the length of the cauda. The body length of adult Macrosiphum pseudocoryli apterae is 2.4-3.6 mm.

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

The alate Macrosiphum pseudocoryli has a brown head and thorax, but is otherwise similarly-colored to the aptera. Antennal segment III bears 12-19 secondary rhinaria in a row along one side on the basal 0.8-0.9 of the segment. Immatures are similarly colored to adults, but are usually somewhat paler and have dusky siphunculi (note young immatures of Macrosiphum coryli are also green, but without the dark reddish brown pigment of the adults, and so may be confused with immature Macrosiphum pseudocoryli).

Macrosiphum pseudocoryli is found on young growth and undersides of leaves of American hophornbeam (Ostrya virginiana) and hazel (Corylus species). Oviparae have been collected in Virginia in late September, so the population is assumed to overwinter in the egg stage. The species is found in north-eastern USA and across southern Canada.

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Macrosiphum ptericolens (Bracken aphid)

Adult apterae of Macrosiphum ptericolens (see first picture below) are pale yellowish green to a darker shiny green. Their antennae are longer than the body, with the terminal process 5.1-6.5 times the length of the base of antennal segment VI, and 1-15 secondary rhinaria in an irregular row on the basal two fifths of antennal segment III. The abdominal dorsum is pale and smooth, being entirely but lightly sclerotized. The siphunculi are strongly tapering, and have 5-10 rows of distinct reticulations, with the reticulated area sometimes distinctly constricted. The siphunculi are pale with dark tips (cf. Macrosiphum funestum which has dusky to dark siphunculi with pale bases), and are 2.7-3.5 times the length of the rather short, tapering cauda (cf. Macrosiphum euphorbiae which has siphunculi 1.7-2.2 times the length of the cauda). The body length of Macrosiphum ptericolens apterae is 2.3-3.3 mm.

The alate Macrosiphum ptericolens (see second picture above) is similarly coloured to the apterous viviparous female, but with 38-62 secondary rhinaria on antennal segment III.

The bracken aphid does not host alternate, but spends its entire life cycle on bracken (Pteridium spp.). Macrosiphum ptericolens is indigenous to eastern North America, but has been introduced into England, central Europe and South America.

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Macrosiphum rosae (Rose aphid)

Adult Macrosiphum rosae apterae are green or deep pink to red-brown. The antennae and sometimes the head are dark, as are the ends of the tibiae and femora. The abdomen may or may not have small marginal sclerites and antesiphuncular sclerites. The siphunculi are black and bent outwards and are reticulated on the apical 10-17%. They are about 0.27-0.41 times the body length and 1.9-2.4 times the length of the cauda. The cauda is pale yellow. The adult aptera of Macrosiphum rosae is 1.7-3.6 mm long.

Macrosiphum rosae alatae have conspicuous black sclerites along the sides of the abdomen (see third picture above). They also have green and red colour forms. Immatures are similar in appearance to the adult apterae, but the cauda is not developed and the siphunculi are dusky, not black.

The rose aphid usually overwinters in the egg stage on rose bushes (its primary host), although in mild winters some adults may continue to reproduce parthenogenetically. In spring they colonise the young growth of rose, and produce large numbers of alates. These mostly migrate to their secondary hosts, teasels (Dipsaceae) and valerians (Valerianaceae). However, colonies can be found all summer on rose and the species is an important horticultural pest. Macrosiphum rosae has a worldwide distribution.

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Macrosiphum stellariae (Green willowherb aphid)

Adult apterae of Macrosiphum stellariae are yellowish green, green or red. The antennae have the apices of the segments dark with the terminal process 5.3-6.7 times as long as the base of antennal segment VI. Antennal segment III has 2-9 secondary rhinaria, concentrated near the base of the segment. The fused apical segment of the rostrum (RIV+V) is 0.8-1.0 times the length of the second hind tarsal segment (HTII). The legs are mainly pale but the distal tips of the femora and tibiae are dark (cf. Macrosiphum euphorbiae which has the apical parts of the femora pale or only slightly dusky). The siphunculi are mostly pale, but their apices are frequently as dark or darker than the tips of the tibiae (cf. Macrosiphum euphorbiae which never has the apices of the siphunculi as dark or darker than the tips of the tibiae). The siphunculi are about 0.25 times body length (cf. Macrosiphum penfroense, on Silene maritima, which has the siphunculi 0.3 times the body length); they are 1.8-2.1 times the length of the cauda, with reticulation on the apical 13-18%. The cauda is rather blunt and slightly constricted, with 8-15 hairs. The body length of adult Macrosiphum stellariae apterae is 1.8-4.4 mm. The immatures in the colony we found were heavily wax-dusted (see second picture below, showing an alatoid fourth instar nymph).

The alate Macrosiphum stellariae (not pictured) is similar to the aptera except the head capsule is brown, antennal segments I and II are dusky green-brown, the base of segment II is colourless to green and the rest of the antenna is dark brown or black. Also the prothorax is green, and the mesothorax is green with dark brown sclerites. The femur has the distal quarter dark brown to black, and the siphunculi are dark distally with a black tip.

Macrosiphum stellariae forms small colonies on the young shoots of various members of the pink family (Caryophyllaceae) especially species of Dianthus, Silene and Stellaria, and rarely on some other plants. Sexual forms develop in autumn, although in some countries overwintering is thought to be by parthenogenetic forms. Macrosiphum stellariae is found throughout northern and central Europe, and has been introduced to Canada and New Zealand.

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Macrosiphum tinctum (Green willowherb aphid)

Macrosiphum tinctum apterae are mid to blue green with a darker spinal stripe (see first picture below), or less commonly pink-red (see second picture below). The antennal terminal process is.6-7.1 times the base of the sixth antennal segment. The fused last two segments of the rostrum (RIV+V) are 0.98-1.1 times longer than the second segment of the hind tarsus (cf. Macrosiphum euphorbiae in which (RIV+V) are 0.83-1.02 times longer than the second segment of the hind tarsus). The femora of Macrosiphum tinctum are entirely pale. The dark apical sections of the tibiae are usually markedly swollen to 1.5 or more times their least diameter (cf. Macrosiphum euphorbiae which does not have the apical sections of the tibiae so swollen). The siphunculi are dusky at their apices and are 0.30-0.37 times the body length.

The alate viviparous female (not pictured) has a green (or rarely red) abdomen and, as with the aptera, the dark apical sections of the tibiae are often markedly swollen.

The green willowherb aphid does not host alternate. Macrosiphum tinctum is found on willowherbs (Epilobium species), mainly Epilobium angustifolium (rosebay willowherb) and Epilobium montanum (broad-leaved willowherb). The species is widely distributed in Europe.

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Macrosiphum weberi (Devils bit aphid)

Adult apterae of Macrosiphum weberi are plump oval to elliptical in shape (cf. Macrosiphum rosae, which are spindle-shaped). They are usually coloured dark violet-red, but Holman (1972) reports occasional green or yellow individuals and a green form is present in Scotland (see Stroyan, 1955, and images presented here). Antennal segments I & II are black, III & IV are mainly pale, segment V is similar but darker and segment VI is black apart from the tip of the terminal process which may be whitish. The abdomen often has moderate to quite large black marginal sclerites on segments I-IV and VII, as well as large black ante- and post-siphuncular sclerites. Spino-pleural sclerites are also sometimes present, most often on abdominal segments VII & VIII. The femora have their distal thirds black. The siphunculi are entirely black (cf. Macrosiphum euphorbiae, which has pale siphunculi which may be brownish distally). The siphunculi are less than 0.33 times the body length, abruptly tapering near the base and quite slender, about equal in thickness to the hind tibiae at midlength (cf. Macrosiphum rosae, whose siphunculi are usually longer than 0.33 times the body length, and thicker than the hind tibiae at midlength). The cauda is yellowish-white and at least 0.5 times the siphuncular length, without any basal constriction.

Both images above copyright Alan Watson Featherstone all rights reserved.

The alate Macrosiphum weberi is similar to the aptera except that the head and thorax are black, antennal segment III is dark due to secondary rhinaria along most of its length, and the femora have their distal halves black. The alate abdomen has large dark grey to black lateral sclerites, narrow spinal sclerites and ante- and postsiphuncular sclerites.

The principal host of Macrosiphum weberi is devil's-bit scabious, Succisa pratensis, but it has also been recorded on two species of Scabiosa. There is no host alternation, and sexuales with alate males develop in autumn. Colonies of Macrosiphum weberi are usually attended by ants. The devil's bit aphid has been recorded from much of Europe, but mainly seems to frequent alpine areas.

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Acknowledgements

Whilst we make every effort to ensure that identifications are correct, we cannot absolutely warranty their accuracy. We have mostly made 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).

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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