Prociphilus caryae

Identification & Distribution

There are three subspecies of Prociphilus caryae, all in America. Their primary hosts are species in the apple subtribe (Malinae). In spring the fundatrix and her offspring form pseudogalls by rolling half of the leaf up on itself (see first picture below). This leaf roll is usually discoloured yellowish. In western America, Prociphilus caryae caryae gall the leaves of serviceberry (Amelanchier laevis). Again in western America, Prociphilus caryae arbutifoliae gall the leaves of toyon (Photinia arbutifolia =Heteromeles salicifolia). In eastern America Prociphilus caryae fitchii gall Saskatoon berry (Amelanchier alnifolia, see first picture below) and apples (Malus domestica, Malus angustifolia).

Images above by permission, copyright Claude Pilon, all rights reserved.

The Prociphilus caryae fundatrix (second picture above) and the immature alatae (see picture below) are both densely wax-coated.

Image above by permission, copyright Claude Pilon, all rights reserved.

In June the offspring of the fundatrix develop wings to give the emigrant alatae (not pictured). The emigrant alate has a dark head bearing two pairs of very pale and clearly-defined wax pore plates. One pair is on the frons and the other on the vertex. Their antennae are dark with 14-22 secondary rhinaria on segment III, 1-6 on segment IV, 0-5 on segment V, and 0-1 on segment VI. Antennal segment I is shorter than its basal width. The thorax is dark with oval wax plates on the mesothorax. The wings are dusky, especially towards the distal end. The wing veins are distinctly bordered, and the forewing media vein is unbranched. The abdomen is pale with large marginal wax plates increasing in size towards the caudal end. Siphunculi are absent, and the cauda bears 2-6 hairs.

Emigrant alatae of the three subspecies can be distinguished as follows (for more details see Smith, 1969):

• Prociphilus caryae caryae (=P. c. alnifoliae) have secondary rhinaria on antennal segments III-VI usually 18-4-1-0. The rhinaria are not in a single row, and are narrow to oval oblong, often less than 0.5 times the diameter of the segment. The head has large wax plates. Rostral segments RIV+V usually bear 2 accessory setae. The cauda has 3-7 setae.
• Prociphilus caryae arbutifoliae have secondary rhinaria on segments III-VI, usually 26-7-3-0. The rhinaria are variable, some are narrow, some oblong and relatively broad. RIV+V has 2-6 accessory setae. Denticulation is sparse on rhinaria of antennal segment III. The cauda bears 3-7 setae. The body length of emigrant alatae of ssp. arbutifoliae is 2.9-4.1 mm.
• Prociphilus caryae fitchii (=P. c. pyri) have secondary rhinaria on segments III-VI (18-4-3-0). The rhinaria are denticulate, in a single row, and usually longer than the segment diameter. There are two pairs of distinct wax plates on head. RIV+V has 4 accessory setae, the cauda has 2-6 setae. The body length of emigrant alatae of ssp. fitchii is 1.8-3.3 mm.

Emigrant alatae of subspecies fitchii and subspecies caryae migrate to secondary hosts, the roots of pine (Pinus species). Alatae of subspecies arbutifoliae migrate to an unknown secondary host, probably pine roots. Through the summer the aphid populations on the roots of their secondary host are tended by ants. In October-November sexuparae develop, and these return to the primary hosts where they deposit sexuales in bark crevices near the base of the tree or in nearby leaf litter. Instead of host-alternating, some parthenogenetic populations persist throughout the year on pine roots. Prociphilus caryae fitchii is widely distributed in eastern North America.

Other aphids on the same host

Primary hosts

• Prociphilus caryae subspecies have been recorded from 2 species of June berries (Amelanchier): Prociphilus caryae caryae on Amelanchier laevis; Prociphilus caryae fitchii on Amelanchier alnifolia.

  Blackman & Eastop list 5 species of aphid as feeding on serviceberry (Amelanchier laevis) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 1 as occurring in Britain (Show British list).

  Blackman & Eastop list 5 species of aphid as feeding on saskatoon berry (Amelanchier alnifolia) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 1 as occurring in Britain (Show British list).

• Prociphilus caryae fitchii has been recorded on 2 species of the apple genus (Malus angustifolia, Malus domestica).

  Blackman & Eastop list more than 49 species of aphid which feed on apples (Malus domestica, which includes Malus pumila & Malus sylvestris) worldwide (Show World list). Of those aphid species, Baker (2015) lists 21 as occurring in Britain (Show British list).

Secondary hosts

Prociphilus caryae caryae has not been recorded from pine roots in the field, but Smith (1969) readily established laboratory colonies on eastern white pine (=Weymouth Pine, Pinus strobus), and Blackman reports sexuparae in British Columbia from western white pine (Pinus monticola) appear to be them. Prociphilus caryae ?arbutifoliae has been recorded from whitebark pine (Pinus albicaulis) and Sugar Pine (Pinus lambertiana). Prociphilus caryae fitchii has been recorded on Pinus strobus roots.

• Blackman & Eastop list 18 aphid species of aphid as feeding on Pinus strobus worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 5 as occurring in Britain (Show British list).

• Blackman & Eastop list 18 aphid species of aphid as feeding on Pinus albicaulis worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 5 as occurring in Britain (Show British list).

Acknowledgements We are especially grateful to Claude Pilon for pictures of Prociphilus caryae. Identification of specimens photographed by Claude Pilon was confirmed by Eric Maw by microscopic examination and DNA analysis of preserved specimens. For taxonomic details we have used the keys and species accounts of Smith (1969) together with information from Roger Blackman & Victor Eastop in Aphids on Worlds Plants. 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 Smith, C.F. (1969). Pemphiginae associated with the roots of conifers in North America Annals of the Entomological Society of America 62(5), 1128-1152. Abstract