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Aphididae : Calaphidinae : Calaphidini : Euceraphis
 

 

Genus Euceraphis

Birch aphids

On this page: Euceraphis betulae gillettei papyrifericola punctipennis

Genus Euceraphis [Calaphidini]

Euceraphis are rather large active but fragile aphids with long thin legs. All adults, apart from oviparae, are winged insects. They secrete a bluish white wax, often in the form of tufts on their legs. The antennae are usually longer than the body. The birch-feeding species may have black dorsal abdominal markings. The cauda is knobbed and the anal plate is rounded. The oviparae are large, apterous, yellowish to dark brown with dark dorsal abdominal markings, and with the posterior abdominal segments extended into an ovipositor-like structure.

Euceraphis is a genus of 6 or more species living on the young shoots or the underside of birch and alder (Betulaceae). Adults may be found as accidentals on many plants besides their true hosts. They have a sexual stage in their life cycle, but do not host alternate and are not attended by ants. One species is considered a pest of ornamental birch varieties.

 

Euceraphis betulae (Silver birch aphid)

Adult winged viviparae of Euceraphis betulae have the head and thorax black above and below, and a pale green to pale yellow abdomen. They are covered with bluish-white wax. The dorsal abdomen may be unmarked, or have transverse black bands (common in spring and autumn) or black patches on abdominal tergites IV and V. The fundatrix in spring always has multiple dark cross bands (cf. Euceraphis punctipennis the fundatrix of which never has dark bands or patches on abdominal tergites IV & V). The base of antennal segment VI is usually 0.8-1.32 times longer than the second hind tarsal segment (cf. Euceraphis punctipennis which has the base of antennal segment VI usually 1.33-1.75 times longer than the second hind tarsal segment). The legs and antennae are usually quite dark. Note that recently moulted specimens may be pale and lack wax. The body length of Euceraphis betulae alates is 3.0-4.2 mm.

Immature Euceraphis betulae are green with conspicuous short black-tipped siphunculi.

The silver birch aphid lives on the undersides of leaves of silver birch (Betula pendula). Sexual forms occur from September to November. Euceraphis betulae occurs throughout Europe and has been introduced to North America and Australia.

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Euceraphis gillettei (American alder aphid)

All adult viviparae of Euceraphis gillettei are alate. Immatures (see first picture below) are pale green mottled with dark green, and have pale siphunculi. Adult alatae (see second and third pictures below) have a pale yellow head and prothorax, pale brown meso- and metathorax (=hind thorax), and a pale yellowish-green abdomen mottled with darker green. The base of antennal segment VI is 2.64-3.67 times longer than the apical rostral segment (RIV+V) (cf. Euceraphis quednaui on Betula occidentalis, which has the base of antennal segment VI 1.72-2.75 times longer than RIV+V). The hairs on antennal segment III are much shorter than the basal diameter of that segment (cf. Clethrobius comes, which has the hairs on that segment much longer than basal diameter of that segment). There are never any dark markings on the dorsal abdomen, and there is sparse bluish-white wax on the legs and antennae. The legs are pale with the apices of the tibiae and the entire tarsi black. The siphunculi are pale, short and flared. The cauda is pale and knoblike. The body length of adult Euceraphis gillettei alatae is 2.5-3.5 mm.

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

Euceraphis gillettei is an active species feeding on the leaves of alder (Alnus spp.). Oviparae and alate males occur in September-November. Euceraphis gillettei is found over much of Northern America, from British Columbia and Alasaka to Newfoundland, and from California to New Jersey.

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Euceraphis papyrifericola (Paper birch aphid)

All adult viviparae of Euceraphis papyrifericola are alate. Immatures (see first picture below) are green with dusky siphunculi. Adult alatae (see second picture below) have a light brown thorax and a pale green abdomen, and are frequently covered with bluish-white wax which may form tranverse segmental bands on the dorsal abdomen. In spring and summer they usually have no dorsal abdominal pigmentation, but in autumn the sexuparae often have dark sclerites in the centre of tergites IV & V. Discrimination from other Euceraphis species depends on antennal characteristics. The base of antennal segment VI has only 1 hair (cf. Euceraphis lineata, Euceraphis mucida & Euceraphis quednaui, all of which usually have more than 1 (2-12) hairs on that segment). The second hind tarsal segment (HTII) is usually 0.7-1.28 times the length of antennal segment I, and usually shorter (0.7-1.1 times) than the terminal process (cf. Euceraphis betulae & Euceraphis punctipennis, both of which usually have HTII 1.24-1.75 times the length of antennal segment I, and usually longer (0.9-2.3 times) than the terminal process.) The siphunculi and cauda are both pale.

Note: Euceraphis papyrifericola is very similar to, and closely related to, the Japanese species Euceraphis betulijaponica, and it could be regarded as a subspecies thereof.

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

The main host of Euceraphis papyrifericola is paper birch (Betula papyrifera), but it may also be found on gray birch (Betula populifolia) and mountain paper birch (Betula cordifolia). The paper birch aphid feeds on the undersides of leaves (and small twigs?) and, like other Euceraphis, is very active. Sexuales - oviparae and males - occur in late August to October. Euceraphis papyrifericola is found in north-east USA and across Canada.

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Euceraphis punctipennis (Downy birch aphid)

Adult winged forms of Euceraphis punctipennis have a pale green abdomen and are covered with bluish-white wax. Their head and thorax are dark brown. Dorsal black patches when present are usually confined to abdominal tergites IV and V. Dark cross bands are never present on fundatrices in spring (distinguishes specimens from Euceraphis betulae, at least in spring!). The base of antennal segment VI is usually 1.33-1.75 times longer than the second hind tarsal segment (cf. Euceraphis betulae which has the base of antennal segment VI usually 0.8-1.32 times longer than the second hind tarsal segment). The body length of Euceraphis punctipennis adult alates is 3.0-4.8 mm.

Immature Euceraphis punctipennis are green with conspicuous short black-tipped siphunculi.

The downy birch aphid lives on the undersides of leaves of downy birch (Betula pubescens). Sexual forms occur in October and November. Euceraphis punctipennis occurs throughout Europe.

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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).

Useful weblinks

References

  • Stroyan, H.L.G. (1977). Homoptera: Aphidoidea (Part) - Chaitophoridae and Callaphidae. Handbooks for the identification of British insects. 2 (4a) Royal Entomological Society of London. Full text

 

Identification requests

David Fenwick, 22 August 2013, Euceraphis

Wondered what you thought of this Euceraphis, was on Silver Birch but there was Downy all around too. I'm thinking possibly Euceraphis punctipennis.

Goss Moor, Mid-Cornwall. 21.08.13.

Images copyright www.aphotofauna.com all rights reserved.

   

Bob, Influentialpoints:

  • With black bands on abdominal segments IV & V, these could be either Euceraphis betulae or E. punctipennis.

    In the autumn the only way to tell the difference between these 2 species is to examine the ratio of the length of the base of the 6th antennal segment VI, to the length of 2nd hind tarsal segment. This ratio is larger in E. punctipennis than E. betulae.

    Unfortunately these photos really don't have enough detail for such measurements.

 


 

Sally Luker 19/10/2014

I'm in the process of sorting data from this year's fieldwork, and today is aphid ID time. Attached are a couple of pics of aphids found on an ornamental birch in Morrab Gardens, Penzance. Although the aphids look very familiar, I'm struggling to come up with an ID for them - it's probably really obvious but any help would be much appreciated!

Images copyright Sally Luker, all rights reserved.

 

Bob, Influentialpoints:

  • These are certainly Euceraphis, but there is insufficient detail in the photos to tell whether they are E. punctipennis or E.betulae.

    You would need to be able to compare the length of the base of the 6th antennal segment to the length of the 2nd hind tarsal segment. Bit tricky from photos! The problem, in part comes down to depth-of-focus...

Sally Luker 19/10/2014

I'm happy with Euceraphis sp. (I talked myself out of even getting to that stage!). Thanks for the ID advice also. Right, back to the remaining mysteries...