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Euceraphis gillettei

American alder aphid

On this page: Identification & Distribution Biology & Ecology Other aphids on the same host Damage & Control

Identification & Distribution

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.

Note: Given the variation in their karyotype (=chromosome count & gross structure), the name Euceraphis gillettei may currently denote more than one species.

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.

 

Biology & Ecology

Natural enemies

Mackauer & Foottit (2012) report on a cecidomyiid Endaphis sp. which is a locally common endoparasite of the aphid Euceraphis gillettei on alder in coastal British Columbia. The picture below shows the cecidomyiid Endaphis fugitivora which is a parasitoid on Pentalonia nigronervosa (banana aphid).

Image above copyright CBG Photography Group under a Creative Commons License.

The midge parasitizing Euceraphis gillettei represents the first known parasitoid of aphids that may develop gregariously inside the host. Mackauer & Foottit present field and laboratory observations on the parasitoid's life history and host instar preference. They also discuss the mechanisms enabling the partitioning of the available "host space" between the Endaphis sp. and an aphidiid Praon parasitoid.

 

Other aphids on the same host

Euceraphis gillettei occurs on 5 species of Alnus (Alnus rhombifolia, Alnus rubra, Alnus rugosa, Alnus sieboldiana, Alnus tenuifolia). Note: early workers including Palmer (1952), refer to Euceraphis gillettei as also occurring on Betula but this is due to confusion with Euceraphis quednaui which feeds on Betula occidentalis (see Blackman & de Boise, 2002).

Acknowledgements

We are especially grateful to Claude Pilon for pictures of Euceraphis gillettei (for more of her excellent pictures see).

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), Blackman & de Boise (2002) and Blackman & Eastop (2006) 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. & De Boise, E. (2002). Morphometric correlates of karyotype and host plant in genus Euceraphis (Hemiptera: Aphididae). Systematic Entomology 27, 323-335. Abstract

  • Mackauer, M. and Foottit, R. (2012). A gall midge, Endaphis sp. (Diptera: Cecidomyiidae), as a gregarious aphid parasite. The Canadian Entomologist 111(5), 615-620. Abstract

  • Palmer, M.A. (1952). Aphids of the Rocky Mountain Region: including primarily Colorado and Utah, but also bordering area composed of southern Wyoming, southeastern Idaho and northern New Mexico. Full text