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Aphidinae : Macrosiphini : Illinoia menziesiae
 

 

Illinoia menziesiae

Rusty menziesia aphid

On this page: Identification & Distribution Other aphids on the same host

Identification & Distribution

Adult apterae of Illinoia menziesiae (see first picture below) are grey-green to salmon pink, with pinkish legs and antennae. The head is smooth, with a distinct median frontal tubercle and moderately prominent, divergent antennal tubercles. The antennae are somewhat shorter than the body length, pale but with the distal half of antennal segment IV, and all of segments V and VI dark. Antennal segment III bears 0-1 secondary rhinaria. The rostrum reaches to the middle coxae, with 10-12 hairs on the apical rostral segment in addition to the usual 3 pairs at the apex. Marginal tubercles are present on prothorax, and occasionally there are also small marginal tubercles on some of abdominal segments I-V. There are 5 hairs on the first tarsal segment (HTI), and both first and second tarsal segments have distinct spinules on the imbrications (cf. Macrosiphum opportunisticum and Macrosiphum parvifolii, which both have 3-4 hairs on HTI and no spinules). The siphunculi are cylindrical, about 1.75 times the length of the cauda, and with 2-3 rows of weak reticulations at the apex (cf. Ericaphis wakibae, which has no subapical polygonal reticulation on its siphunculi). The cauda bears 7 hairs. The body length is 2.0-2.5 mm. Illinoia menziesiae alatae are undescribed.

Note: Blackman comments that the specimens from which the description given above was made (from Robinson, 1969) were probably fundatrices. The siphunculi are unusual for this genus in having little or no distal swelling.

First image above copyright Andrew Jensen, second image above copyright Walter Siegmund,
both under a creative common licence.

Illinoia menziesia feeds on the undersides of leaves of rusty menziesia (Rhodendron ferruginea, see second picture above) causing a discoloring on the top side of the leaves of the host plant, where it causes a yellowing and downward curling of apical portions of leaves. The species is monoecious holocyclic, with oviparae and apterous males in early September-October. It is found in western USA and Canada.

 

Other aphids on the same host

Blackman & Eastop list 4 species of aphid as feeding on Rhododendron ferruginea (=Menziesia ferruginea) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 1 as occurring in Britain (Show British list).

Acknowledgements

We are grateful to Andrew Jensen and Walter Siegmund for making their images available for use under a creative commons licence.

We have used species account given by Robinson (1969) (as Masonaphis menziesiae), together with information from Roger Blackman & Victor Eastop in Aphids on Worlds Plants. We fully acknowledge these authors and those listed in the reference sections as the source for the (summarized) taxonomic information we have presented. Any errors in 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

  • Robinson, A.G. (1969). Four new species of aphids (Homoptera: Aphididae) from Western Canada. The Canadian Entomologist 101, 1115-1120. Abstract