InfluentialPoints.com
Biology, images, analysis, design...
Aphids Find them How to ID AphidBlog
"It has long been an axiom of mine that the little things are infinitely the most important" (Sherlock Holmes)

 

 

Genus Rhopalosiphoninus

Rhopalosiphoninus aphids

Species Overview: Genus Rhopalosiphoninus  Rhopalosiphoninus ribesinus  Rhopalosiphoninus calthae 

Genus Rhopalosiphoninus [Macrosiphini]

These 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 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 ribesinus (Currant stem aphid)

This is a medium-sized dull reddish brown to brownish black aphid 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. They are 2.5-3 times the length of the short triangular cauda. The body length of apterae is 2.0-2.5 mm.

The currant stem aphid does not host alternate but feeds only on Currants (Ribes spp.). It feeds on the old wood of lower shoots, apparently because it prefers a humid atmosphere. It is not thought to be of economic importance.

 

Rhopalosiphoninus calthae (Marsh marigold aphid)

Apterae of Rhopalosiphoninus calthae are shining brownish black. The siphunculi are black and strongly swollen, and 3.5-4.6 times the length of the cauda. Immatures have wax deposits especially over the anterior part of the aphid.

 

The dorsum has an almost complete black sclerotic shield.

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.

Acknowledgements

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).

Useful weblinks