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Genus Anoecia

Dogwood - grass aphids

On this page: Genus Anoecia  Anoecia corni 

Genus Anoecia [Anoeciinae]

Anoecia are medium-sized aphids which may be winged or wingless. Wingless adults are greenish-gray or gray with a dark sclerotic dorsal abdominal plate. The winged form has a characteristic dark posteriodorsal abdominal patch and a large black pterostigmal spot on the forewing. Young nymphs are white or cream in colour.

There are about 24 species of Anoecia in North America, Europe and eastern Asia. Some host alternate from dogwood (Cornaceae) to roots of grasses (Poaceae), with the oviparae laying their eggs on the bark of the trunk. Other Anoecia species live year-round on the roots of grasses (Poaceae) or sedges (Cyperaceae).

 

Anoecia corni (Common dogwood-grass aphid)

Fundatrices of Anoecia corni in spring on dogwood (Cornus) are dark brown or blackish. They have reduced eyes and 5-segmented antennae, whereas subsequent generations have large compound eyes and 6-segmented antennae. The siphunculi of all Anoecia corni forms are reduced to inconspicuous pores. Winged forms, both spring migrants and the sexuparae returning to Cornus in autumn, have a large black pterostigmal spot on the forewing, a white band around the top of the abdomen and a dark patch on the abdomen covering tergites 3-6. The body length of winged forms is quite variable ranging from 1.9-3.0 mm.

 

The first picture above shows two mature apterous Anoecia corni fundatrices (wingless stem mothers) with several developing nymphs. The siphunculi are reduced to pores and the antennae have only 5-segments (not visible in the picture). The winged form (shown in the second picture) above has two clear distinguishing features - a large black pterostigmal spot on the forewing, and a dark patch on the abdomen covering the posterior tergites 3-6 bordered by a white band.

In Europe Anoecia corni host alternates between dogwood (Cornus spp.) and roots of grasses (Poaceae). In eastern Asia and in areas where introduced (South Africa and North America), the dogwood-grass aphid remains all year round on grasses and some cereals.

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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).

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