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Aphis cephalanthiButtonbush aphidOn this page: Identification & Distribution Biology & Ecology Other aphids on the same hostIdentification & DistributionAdult apterae of Aphis cephalanthi are dark purplish brown to almost black with dark siphunculi and cauda. They have wax spots arranged in four spinal and marginal rows along the abdomen. The antennal terminal process is less than the length of antennal segment III, but always much longer than half the length of that segment. The hairs on antennal segment are 0.013-0.018 mm in length (cf. Aphis impatiens which have shorter hairs on that segment). Well-developed marginal tubercles are present on most abdominal segments (cf. Aphis impatiens which usually only has tubercles on segments I & VII). Unusually for an Aphis, the tubercles on abdominal tergite VII are posterior to, and on a level with, the spiracles. The siphunculi are usually shorter than 1.5 times the length of the second hind tarsal segment (HTII). The body length of adult Aphis cephalanthi apterae is 0.9-1.7 mm.
Both images above by permission, copyright Claude Pilon, all rights reserved. Alatae of Aphis cephalanthi have similar wax markings to the apterae, with 9-15 secondary rhinaria on antennal segment III, and 0-5 on segment IV. Image above by permission, copyright Claude Pilon, all rights reserved.
Aphis cephalanthi lives on the leaves, stems and flowerheads of buttonbush (Cephalanthus occidentalis), a shrub or small tree of the coffee family (Rubiaceae) that occurs as two subspecies. One subspecies of the shrub is widely distributed in eastern North America and the other is more patchily distributed in western North America. The aphids are attended by ants. Oviparae and alate males occur in late September and the species overwinters as eggs laid on buttonbush - there is no host alternation. Aphis cephalanthi is widely distributed in North America wherever its host occurs, and in Cuba. There is also a possible record from South Africa.
Hottes & Frison (1931) claimed that Aphis impatientis Thomas, 1878 is synonymous with Aphis cephalanthi Thomas, 1878, but later authors have not accepted this synonomyzation. Lagos et al. (2014) found that phylogenetic analyses of COI sequences indicated that Aphis cephalanthi does not even belong to the Aphis asclepiadis species group, and therefore cannot be a synonym of Aphis impatientis, which is a member of that group. Morphological examination of the specimens collected by Hottes and Frison in 1929 on Cephalanthus occidentalis revealed that all have a longer rostrum (0.12 mm), longer setae on antennal segment III (0.013-0.018), greater width of the marginal tubercle on abdominal segment I (0.015-0.018), and longer siphunculi (0.18-0.20) than Aphis impatientis (Lagos-Kutz et al., 2016). In addition, Aphis cephalanthi has marginal tubercles on abdominal segments II, III, and IV, as well as on segments I & VII.
Guyton (1924)reported that colonies of Aphis cephalanthi in Pennsylvania, USA in June were attended by the ant Crematogaster lineolata.
Needham (1931) found larvae of the chamaemyiid Leucopis nigricornis in the midst of colonies of Aphis cephalanthi, feeding voraciously on the aphids. Chamaemyiids are rather uncommon predators - for a picture of one feeding on mealy plum aphids (Hyalopterus pruni) on their secondary host see here. Needham noted that despite being legless the larvae could adhere to the convex surface of a bare stem or crawl about upon it. The living larvae were whitish, with a covering of bluish powder similar to that of the aphids and, on the middle of the back, there were several darker M-marks, connected in the middle by an interrupted mid-dorsal line. Some larvae were observed pupating in the midst of the aphis colony, attaching their puparium to the plant stem. The puparium was at first yellowish, but later it turned reddish brown.
In addition Needham also found the coccinellid Hippodamia 13-punctata feeding on Aphis cephalanthi on buttonbush. The pictures below show an adult and larva of Hippodamia 13-punctata feeding on another species of aphid, Rhopalosiphum nymphaeae.
Images above copyright Gilles San Martin under a Creative Commons Attribution-Share Alike 2.0 Generic license.
Blackman & Eastop list only 1 species of aphid as feeding on buttonbush (Cephalanthus occidentalis) worldwide, namely Aphis cephalanthi. Baker (2015) does not list that aphid as occurring in Britain.
We are especially grateful to Claude Pilon for pictures of Aphis cephalanthi.
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) and Blackman & Eastop (2006) supplemented with Blackman (1974), Stroyan (1977), Stroyan (1984), Blackman & Eastop (1984), Heie (1980-1995), Dixon & Thieme (2007) and Blackman (2010). 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).
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