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Identification & Distribution:

The adult aptera of Aphis grossulariae (see first picture below) is dull green to dark green and is slightly to moderately wax powdered. The antennae are shorter than the body, and the hairs on the third antennal segment are straight or curved and at most 1-2 times the least width of that segment (cf. the very similar Aphis schneideri  which has the hairs on the third antennal segment fine and wavy and conspicuously erect, 1.8-4.0 times the basal diameter of that segment). The abdominal dorsum is entirely membranous or at most has narrow dusky bands across tergites 7 & 8. Aphis grossulariae has marginal tubercles present on at least some of abdominal tergites 2-6 (cf. Aphis epilobii  and Aphis epilobiaria  which have no marginal tubercles on abdominal tergites 2-6.) The siphunculi and legs are pale except for the tibial apices and tarsi which are dusky. The longest tibial hairs are greater than the least width of the hind tibia. The cauda is pale or slightly dusky. The body length of adult apterae is 1.2-2.1 mm.

The alate (see second picture above) has the head and thorax black, the abdomen green with dark stripes, the siphunculi and antennae dark and the cauda pale. Immature future alatae have paired pale white wax patches on the dorsum. The pictures below are micrographs showing (first) the marginal tubercles on the abdominal tergites, and (second) the hairs on the third antennal segment. In Europe there is evidence of natural hybridisation with Aphis schneideri (Rakauskas 2003 ).

The clarified slide mounts below are of adult viviparous female Aphis grossulariae : wingless, and winged.

Micrographs of clarified mounted  aptera & alate courtesy PaDIL.  Copyright Rebecca Graham (Department of Agriculture, Western Australia) under Commons Attribution 3.0 Australian License. 

The gooseberry - willowherb aphid host alternates between gooseberry (Ribes uva-crispa) where it curls the leaves and willowherb (Epilobium species). Certain members of the Onagaceae (Clarkia, Fuchsia, Oenothera) can also be used as secondary hosts. Sexual forms occur in autumn. Aphis grossulariae occurs throughout most of Europe to Russia and central Asia.

 

Biology & Ecology:

Life cycle
Primary host (gooseberry)

The eggs of Aphis grossulariae are laid on gooseberry in autumn. They hatch in March and early April the following year to give the fundatrices.

The fundatrices (see picture above) feed on the growing shoot and produce large numbers of apterous viviparae (see picture below).

These apterae then feed on the fruit buds and the tips of young shoots and produce large numbers of apterous and alate offspring.

Image above copyright Alan Outen,  all rights reserved.

As numbers build up, an increasing proportion of aphids develop to alatae. The species produces an especially large number of alatae from May onwards which leads to rapid dispersal to other host plants. Third and fourth instar developing alatae (first) and a mature alate (second) are shown below.

 

Some Aphis grossulariae remain on gooseberry all year round, but others migrate to the secondary hosts.

Secondary host (willowherb)

The main secondary hosts are the smaller willowherb species such as Epilobium montanum and Epilobium lanceolatum. The picture below shows a colony of Aphis grossulariae on Epilobium montanum.

It lives on the stem and flower heads of willowherb often forming mixed species colonies with Aphis epilobii. It can also be found in the summer on evening primrose (see picture below):

Ant attendance

Colonies of the gooseberry-willowherb aphid are often, but not always attended by ants.

The picture above shows the garden black ant (Lasius niger) attending Aphis grossulariae on currant. The picture below shows a red ant (Myrmica) attending the same species.

They are also sometimes ant-attended on the secondary host. The picture below shows a Lasius ant attending Aphis grossulariae on willowherb (Epilobium montanum)

Natural enemies

Despite the attentions of ants such as Lasius, Aphis grossulariae may be subject to high rates of parasitism especially by Lysiphlebus confusus (Starý & Havelka, 2008 ).

 

Lysiphlebus confusus appears to possess specific adaptations, chemical and behavioural, that negate the aggressive responses of various ant species (Völkl & Mackauer, 1993 ). Evidence of ant mimicry by the closely related Lysiphlebus fabarum which parasitizes Aphis fabae  was presented by Rasekh et al. (2010) . They showed that the parasitoid used ant-like antennation to reduce Aphis fabae defensive behaviour, and their attacks primed Aphis fabae to be more responsive to subsequent honeydew solicitation from both ants and the parasitoids themselves.

Various predators attack Aphis grossulariae on gooseberry including cecidomyiid larvae (see picture below).

We have not yet observed any predators on the secondary host, but Gilbert (2005)  notes that Aphis grossulariae is a preferred prey of the larvae of Episyrphus balteatus on willowherb.

 

Damage and Control

The dense colonies of the gooseberry-willowherb aphid at the growing tips of gooseberry cause severe deformation and clumping of young leaves (see picture below). This can result in stunting of growth.

In commercial crops of gooseberry an insecticide spray is often applied in spring just before flowering. Since Aphis grossulariae overwinter in the egg stage and hatch soon after bud burst, this approach usually gives good control (Gratwick, 1992 ). Foliar sprays may be needed subsequently to control winged aphids on the tips of the young shoots. A winter wash may also be applied to kill the overwintering eggs.

 

Other aphids on same host:

Primary host

Blackman & Eastop list 21 species of aphid  as feeding on gooseberries (Ribes uva-crispa) worldwide, and provide formal identification keys.

Of those aphid species, Baker (2015)  lists 16 as occurring in Britain: Aphis fabae,  Aphis grossulariae, Aphis oenotherae, Aphis schneideri,  Aphis triglochinis, Aulacorthum solani,  Cryptomyzus galeopsidis,  Cryptomyzus korschelti,  Cryptomyzus ribis,  Eriosoma grossulariae, Eriosoma ulmi,  Hyperomyzus lactucae,  Hyperomyzus pallidus,  Hyperomyzus picridis,  Hyperomyzus rhinanthi  and Nasonovia ribisnigri. 

Secondary hosts

Blackman & Eastop list about 33 species of aphids  as feeding on willowherbs worldwide, and provides formal identification keys for aphids feeding on various Epilobium species.

Of those aphid species, Baker (2015)  lists 16 as occurring in Britain: Aphis epilobiaria,  Aphis epilobii,  Aphis fabae,  Aphis frangulae,  Aphis gossypii,  Aphis grossulariae, Aphis mirifica, Aphis praeterita,  Aphis salicariae,  Brachycaudus cardui,  Macrosiphum euphorbiae,  Macrosiphum tinctum,  Myzus ascalonicus,  Myzus lythri, Myzus ornatus  and Myzus persicae. 

Acknowledgements

We especially thank Alan Outen Bedfordshire Invertebrate Group  for one of the images above.

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. (2006). Aphids on the World's Herbaceous Plants and Shrubs. Vols 1 & 2. J. Wiley & Sons, Chichester, UK. Full text 

  • Gilbert, F. (2005). Syrphid aphidophagous predators in a food-web context. European Journal of Entomology 102, 325-333..Full text 

  • Gratwick, M. (1992). Crop pests in the UK. Collected edition of MAFF leaflets. Full text 

  • Rakauskas, R. (2003). Natural hybridisation between Aphis grossulariae and Aphis schneideri: morphological evidence (Sternorrhyncha: Aphididae). European Journal of Entomology 100, 429-434.Full text 

  • Rasekh, A. et al. (2010). Ant mimicry by an aphid parasitoid, Lysiphlebus fabarum. Journal of Insect Science 10: 126. Full text 

  • Starý, P. & Havelka, J. (2008). Fauna and associations of aphid parasitoids in an up-dated farmland area (Czech Republic). Bulletin of Insectology 61 (2), 251-276. Full text 

  • Stroyan, H.L.G. (1984). Aphids - Pterocommatinae and Aphidinae (Aphidini). Handbooks for the identification of British insects. 2 (6) Royal Entomological Society of London.

  • Völkl W & Mackauer M. (1993). Interactions between ants and parasitoid wasps foraging for Aphis fabae ssp. cirsiiacanthoidis on thistles. Journal of Insect Behavior 6, 301-312. Full text