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Aphidinae : Macrosiphini : Macrosiphum tuberculaceps
 

 

Macrosiphum tuberculaceps

Sweet-after-death aphid

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

Identification & Distribution

Adult apterae of Macrosiphum tuberculaceps are large, robust, yellowish aphids with mainly pale appendages, except for the antennae and siphunculi, which are dark apically. The frontal tubercles are large and prominent. The ventral surface of the head has many spinules scattered from the antennal tubercles to mouthparts and posteriorly on each side. Antennal segment III has 1-4 circular secondary rhinaria near the base. The rostrum is short, extending to the second pair of coxae. The pronotum often has spinal tubercles. The abdomen has small, pointed hairs, with the dorsum finely reticulated and wrinkled. Hairs on the coxae and anal plate are long and fine, but those on apical parts of the tibiae are spine-like. Tarsal segment I has 4 hairs, 2 of which are lateral with 2 "sense pegs" between them (cf. Macrosiphum vancouveriae also feeding on Berberidaceae, which has only 3 hairs on tarsal segment I). The siphunculi are somewhat swollen distally, finely imbricated, and almost twice the caudal length. The cauda is large, paddle-shaped, rounded apically, only slightly constricted before the middle, and has up to 16 hairs. The adult Macrosiphum tuberculaceps aptera body length is 3.5-4.3 mm.

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

The colour of the live alate Macrosiphum tuberculaceps does not appear to have been described, but the abdomen is most probably yellow green. There are interrupted dusky crossbars on each abdominal segment. The head has a pair of spinal tubercles, and the antennal tubercles are prominent. The basal half of antennal segment III has 7-8 round secondary rhinaria, arranged in a row. The siphunculi are swollen on the distal half.

This species is monoecious holocyclic on its sole known host, sweet after death (Achlys triphylla, Berberidaceae). Jensen (2000) briefly describes its life cycle in Oregon. Egg hatch occurs in March and fundatrices mature in April. Alatae are rarely produced. Oviparae and the rarer (alate) males can be found in October and November. Populations are dispersed, with few aphids on any given plant. The aphid is rare and difficult to find at times. Adults are apt to drop when plants are disturbed. Macrosiphum tuberculaceps is so far known only from Oregon and Washington, and probably British Columbia. The host plant is known from western British Columbia to northwestern California, and from the Cascade Mountains to the coast, so the aphid may well have a wider distribution than currently recognised.

 

Other aphids on the same host

Macrosiphum tuberculaceps has so far only been recorded on 1 plant species: Achlys triphylla.

  • Blackman & Eastop list 1 species of aphid Macrosiphum tuberculaceps as feeding on sweet after death (Achlys triphylla) worldwide. This species is not listed by Baker (2015) as occurring in Britain.

Acknowledgements

We are grateful to Andrew Jensen and Walter Siegmund for making their images of Macrosiphum tuberculaceps & Achlys triphylla respectively, available for use under a creative commons licence.

We have used the species accounts given by Essig (1942), and MacGillivray (1958), (as Amphorophora tuberculaceps) together with information from Jensen (2000), and 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

  • Jensen, A.S. (2000). Eight new species of Macrosiphum from Western North America, with notes on four other poorly known species. Proceedings of the Entomological Society of Washington 102(2), 427-472. Full text

  • Essig, E. (1942). New species of the genus Amphorophora (Hemiptera: Aphididae). Annals Entomological Society of America 35, 1-16. Full text

  • MacGillivray, M.E. (1958). A study of the genus Masonaphis Hille Ris Lambers, 1939 (Homoptera, Aphididae). Temminckia 10, 1-131. (p. 124)