Aphis maidiradicis Forbes 1891

Victor, Eastop, F. & Blackman, Roger L., 2005, Some new synonyms in Aphididae (Hemiptera: Sternorrhyncha), Zootaxa 1089, pp. 1-36 : 5-7

Aphis maidiradicis Forbes 1891 = Aphis (Protaphis) middletonii Thomas 1879 Aphis menthaeradicis Cowan 1895 = Aphis (Protaphis) middletonii Thomas 1879

Colonies of Aphis (Protaphis) found on roots of various plants in North America are all very similar and the number of taxa involved has always been in doubt (see Palmer 1952). We have done a multivariate analysis of morphometric variation (method of canonical variates) in 7 characters within and between 27 samples of apterous viviparae and 13 samples of alate viviparae from various plants, especially Compositae and Zea mays , in the BMNH colln ( Fig. 1 ). Samples of both apterae and alatae from Opuntia in S Africa and Apocynum in USA had similar scores that discriminated them from all other samples, but apart from this the analysis failed to reveal any clustering of samples which might indicate the existence of more than one taxon, and notably failed to differentiate between samples from Compositae (putative armoraceae) and Zea (putative maidiradicis ). This method has proved powerful for discriminating closely­related taxa in other species groups ( Blackman 1992; Blackman & DeBoise 2002), so we conclude that a single name should be applied, the oldest available being A. middletonii Thomas (1879) .

In the N American literature, populations identified as A. armoraciae are stated to produce alate males, whereas maidiradicis and menthaeradicis have apterous males, and oviparae of menthaeradicis are said to have very few scent glands on their hind tibiae ( Palmer 1952); however, the criteria for naming these populations are unclear, and experimental work is needed to show whether these differences are of any taxonomic significance.

Figures

FIGURE 1. Plots of mean scores on the first and second canonical variates for (a) 27 samples of apterae and (b) 13 samples of alatae, of the Aphis middletonii group from various sources in the BMNH collection (identified on slide labels as armoraciae, maidiradicis, menthaeradicis or middletonii). Samples comprised 4 – 13 individuals collected on the same host at the same locality and on the same date (with the exception of two samples of trapped alatae). Seven linear parameters were measured on each specimen (lengths of siphunculus, third antennal segment, base of sixth antennal segment, processus terminalis, last segment of rostrum (combined third and fourth), hind tibia, second segment of hind tarsus). Data were analysed using the discriminant analysis package in Statistica (StatSoft Inc., Tulsa, USA), with the sample as the grouping variable. Collection data: Apocynum androsaemifolium, Utah, vii. 1946; Artemisia campestris, Washington, 1994; Aster, California, ix. 1930; Aster, Warmea HT, viii. 1960; Aster, Jamaica, viii. 1927; Baccharis, California, x. 1944; Castilleja, Oregon, vi. 1980; Chenopodium album, S Dakota, vii. 1963; Cichorium intybus, Washington, v. 1994; “ Compositae ”, N Carolina, iv. 1964; “ composite root ”, Mexico, v. 1981; Conyza bonariensis, Brazil; Conyza canadensis, California, viii. 1940; “ corn ”, Utah, ix. 1958; Daucus carota, California, xi. 1975; Echinops ritro, California, xi. 1971; Erigeron linifolius, California, ix. 1975; Hibiscus, California, iv. 1962; Leontodon autumnalis, New Brunswick, ix. 1956; Opuntia, S Africa, x. 1975; Picris echioides, California, ix. 1941; Portulaca oleracea, California, ix. 1975; Rudbeckia serotina, Manitoba, vii. 1963; Senecio root, California, vii. 1941; Sonchus oleraceus, California, ix. 1975; Zea mays, Idaho, ix. 1935; Zea mays, Mexico, viii. 1981; Zea mays, Utah, ix. 1955; pan traps, Louisiana, v. 1969; water traps, Campinas, Brazil, 1966 – 70.