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Obscure dark-tipped aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution
Adult apterae of Abstrusomyzus phloxae are pale apple-green with faint orange patches around their siphuncular bases. The head is ornamented with numerous spicules, and the antennal tubercles are moderately developed with prominent converging scabrous processes extending from the antennal bases. The dorsal abdomen is without dark markings, but does have hexagonal reticulation which is faint due to the pale, unsclerotized tergum (cf. Abstrusomyzus reticulatus, Abstrusomyzus valuliae & Abstrusomyzus leucocrini, which all have the dorsum of the abdomen dark pigmented, usually black). The siphunculi are mostly pale but with a dark tip (cf. Aphis asclepiadis, Aphis fabae, Aphis gossypii, Aphis plantaginis, Aphis frangulae, Aphis spiraecola & Protaphis middletonii, all of which have dark siphunculi). The siphunculi are slightly swollen subapically over about the distal quarter (cf. Aulacorthum solani, Myzus ornatus & Neomyzus circumflexus, which have the distal half of the siphunculi tapering or cylindrical, and Rhopalosiphoninus latysiphon and Rhopalosiphoninus staphyleae, which have the siphunculi markedly swollen). The body length of adult Abstrusomyzus phloxae apterae is 1.2-1.8 mm.
Note: Aphid species chosen for comparisons above are just some of those found on Plantago and Apocynum, which are the most frequent hosts of Abstrusomyzus phloxae.
Image above copyright Andrew Jensen under a cc by-nc-sa licence.
The dorsal abdomen of the alate Abstrusomyzus phloxae (see second picture below) has dark lateral sclerites, with interrupted cross bands on some segments which often have hexagonal reticulation similar to the tergum of apterous vivipara.
Both images above copyright Gregory Parks, AphID, Bugwood.org under a cc by-nc-sa licence.
Abstrusomyzus phloxae is a polyphagous species, having been recorded from several Asteraceae (Achillea, Agoseris, Centaurea) and from a number of unrelated genera including Apocynum, Capsella, Carex, Cerastium, Galium, Phacelia, Phlox, Plantago, Polygonum, Ranunculus, Stellaria, Trifolium, Viola. In the eastern USA Abstrusomyzus phloxae is most common on Plantago, and in the western USA it is common on Apocynum. Note that Abstrusomyzus on strawberries (Fragaria spp.) are more likely to be Abstrusomyzus valuliae and on Oxalis spp. are more likely to be Abstrusomyzus reticulatus (Jensen & Stoetzel, 1999). Usually Abstrusomyzus phloxae colonizes the basal or rosette leaves of low-growing plants where colonies are often ant-tented. On Apocynum it feeds on the undersides of leaves causing characteristic leaf tissue yellowing. Abstrusomyzus phloxae mainly reproduces parthenogenetically all year, but oviparae have been found in Nova Scotia. The species is widely distributed in North America.
Other aphids on the same host
Abstrusomyzus phloxae is recorded on 1 species of Apocynum, Apocynum androsaemifolium.
Blackman & Eastop list 11 species of aphid as feeding on Apocynum androsaemifolium worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 8 as occurring in Britain (Show British list).