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Rhopalosiphoninus aphidsOn this page: Rhopalosiphoninus calthae ribesinus staphyleae
Genus Rhopalosiphoninus [Macrosiphini]
Rhopalosiphoninus are medium sized aphids, either with the frontal region of head adorned with small scabrous spinules, or with the abdominal dorsum more or less sclerotic and pigmented. Apart from a constriction near the apex, the apical two thirds of the siphunculi are strongly and sharply swollen, the apical part before the flange with reticulate sculpturing. The cauda is short and triangular.
There are about 19 Rhopalosiphoninus species living on a great variety of plants, including Labiatae, Rosaceae, Iridaceae, Araliaceae and Grossulariaceae. They often live in cryptic habitats near the ground. Some species host alternate, but others remain on one host.
Rhopalosiphoninus calthae (Marsh marigold aphid)
Apterae of Rhopalosiphoninus calthae are shining brownish black. The antennae are dark except for the basal part of segment III, and the legs are yellowish. The dorsum has an almost complete black sclerotic shield. The black siphunculi have a narrow, almost cylindrical stem, which widens abruptly to the swollen half which is about 3 times thicker than the narrower part of the stem. The siphunculi are 3.5-4.6 times the length of the cauda.
Alatae have a large black dorsal abdominal patch and strongly swollen siphunculi like the apterae. Immatures have wax deposits, especially over their anterior part.
The marsh marigold aphid does not host alternate. It feeds on the underside of leaves of marsh marigold (Caltha palustris), especially those growing in the shade. Sexual forms occur in autumn. The male is small, black and apterous, and the ovipara lacks the sclerotic tergum and has slightly swollen hind tibiae. Rhopalosiphoninus calthae is found over most of Europe.
Rhopalosiphoninus ribesinus (Currant stem aphid)
The adult aptera of Rhopalosiphoninus ribesinus is medium-sized dull reddish brown to brownish with the dorsum sclerotized and with a rugose texture. The head is spiculose and the antennae are long and thin. The antennal tubercles are well developed with their inner faces steep-sided or apically convergent. The siphunculi are dark and strongly swollen between the constricted basal and strongly flanged apical parts. The siphunculi are 2.5-3 times the length of the short triangular cauda. The body length of Rhopalosiphoninus ribesinus apterae is 2.0-2.5 mm.
Rhopalosiphoninus ribesinus alatae (see second picture above) are dull reddish brown to brownish black with no black dorsal abdominal patch.
The currant stem aphid does not host alternate but feeds only on currants (Ribes spp.). It feeds in damp shady places mainly on the old wood of lower shoots of redcurrant, but also on the young shoots and leaves. Rhopalosiphoninus ribesinus is not thought to be of economic importance. It is found in Britain, northern Europe and west Siberia.
Rhopalosiphoninus staphyleae (Mangold aphid)
Adult apterae of Rhopalosiphoninus staphyleae on their primary host (Staphylea) are pear shaped, yellowish-white or pale yellow, with a translucent whitish spot on the anterior part of the dorsal abdomen (see pictures below). But note that apterae on the secondary host, and also in populations remaining through summer on the primary host (not pictured), are much more pigmented - being coloured dark olive green or brownish with very dark green or black dorsal markings. The antennal tubercles are rather well developed, with inner margins about parallel, but the median frontal tubercle is very little developed. The antennae are about the same length as, or slightly shorter than, the body, mostly pale, but with the apex of segment V and the whole of segment VI dark; the terminal process is 3.75-4.55 times as long as the base of antennal segment VI. Antennal segment III has 1-7 secondary rhinaria (cf. Rhopalosiphoninus latysiphon, where segment III has none). Antennal hairs are very short. The apical rostral segment is about as long as the second segment of the hind tarsus. The siphunculi are swollen, very pale with only the tip dusky or dark, and with a well developed flange. The swollen part is no more than 3.2 times thicker than the narrowest part of the stem (cf. Rhopalosiphoninus latysiphon, which has the swollen part 3.7-4.8 times thicker than the narrowest part). The siphunculi are 2.5-3.0 times the length of the cauda - which is pale, triangular with a very blunt apex and usually bearing 5 hairs. The body length of adult Rhopalosiphoninus staphyleae apterae is usually given as 1.5-2.3 mm (but in Aphids on Worlds Plants it is 2.3-3.0 mm).
Images above copyright Zoran Gavrilovic, all rights reserved.
The primary host of Rhopalosiphoninus staphyleae s. str. is bladdernuts (Staphylea spp.). Feeding by the aphid causes the leaves to curl and become mottled pale yellow. The aphid can be holocyclic in Europe, host alternating from late May onwards to its secondary hosts in the Liliaceae and Iridaceae (Tulipa, Hemerocallis, Crocus, Anthericum), and sometimes to the roots of plants (herbs, trees, grasses) in several other families. However, anholocyclic populations on the secondary hosts are also common, being found in Europe and North America, as well as Kenya, South Africa, Australia and New Zealand. The subspecies known as Rhopalosiphoninus staphyleae tulipaellus is found in Europe (and possibly America). Rhopalosiphoninus staphyleae tulipaellus is entirely anholocyclic on roots, especially on beets in store, giving it the common name of mangold aphid. Its status is unclear, but some authorities consider it a good species.