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Rhopalosiphoninus deutzifoliaeDeutzia aphidOn this page: Identification & Distribution Other aphids on the same hostIdentification & DistributionImmature fundatrices of Rhopalosiphoninus deutzifoliae (see first picture below) are pale green, overlain with brownish quadrangles. Adult fundatrices (see second picture below) are pale green overlain with darker green quadrangles, with antennae and legs pale, darkened apically, and dark siphunculi and cauda. Antennal tubercles are low and strongly diverging at their inner sides. The dorsal hairs of the head are about half as long as the middle width of antennal segment III. The antennae are slightly longer than 0.5 times the body length (later apterae have the antennae 1.1-1.2 times as long as body - but see note below). There is a small rhinarium on segment V, and a terminal process at most 1.5 times as long as the base of segment VI (later apterae have a larger primary rhinarium, and the terminal process is 4.5-5.0 times as long as the base of that segment). The rostrum passes the middle coxae, with the apical rostral segment about as long as second segment of the hind tarsus. First tarsal chaetotaxy (=bristle arrangement) is 3-3-2 (fore-mid-hind). The abdominal dorsum is pale, membranous and smooth. The siphunculi are about twice as long as the cauda, with the diameter of the swollen portion 2.0-2.5 times that at the basal cylindrical portion (cf. later apterae have the largest diameter being 2.6-3.3 times at of the basal cylindrical portion). The body length of adult Rhopalosiphoninus deutzifoliae apterae is 3.2 mm. Note: Blackman comments that Rhopalosiphoninus deutzifoliae on Deutzia in spring are all fundatrices, with their progeny all being emigrant alatae. This is problematic given Miyazaki (1971) described both fundatrices and apterae (the latter collected in April, so presumably progeny of those fundatrices). Perhaps, in some situations, Rhopalosiphoninus deutzifoliae fundatrices can produce apterae.
Images above by permission, copyright Akihide Koguchi, all rights reserved. The first image below shows the developing progeny of the fundatrix. The great majority of these (if not all) can be seen to be immature alatae which, when mature, will migrate to the (currently unknown) secondary host. Alatae (not pictured) have the abdomen green, with head, thorax and sclerites on the abdomen black. The antennae are black, except segment III which is pale at base. The antennae are 1.1-1.3 times body length, with 12-20 secondary rhinaria arranged in a line along whole length of the segment III; segment IV has none. The abdomen has a large central sclerite extending on segments III-VII, marginal sclerites on segments II-V, often fused with central sclerite, and pleural sclerites present on segments I & II. Siphunculi are swollen more abruptly than in the aptera, with the basal cylindrical stem long and slender. The second picture below is taken much later in the year on Deutzia, the primary host, and is an ovipara. Her eggs on Deutzia would hatch the following spring. The third picture shows some hatched eggs, again on Deutzia.
Images above by permission, copyright Akihide Koguchi, all rights reserved. Spring populations of Rhopalosiphoninus deutzifoliae occur on leaves and stems of certain Hydrangeaceae (Deutzia spp., Hydrangea spp., & Philadelphus tenuifolius), and also apparently Weigela coraeensis in the Caprifoliaceae. They migrate to an unknown secondary host. Blackman suggested this is most likely bulbs and potatoes, since Rhopalosiphoninus deutzifoliae is a plausible primary host form of the widely-distributed, anholocyclic, bulb and potato pest Rhopalosiphoninus latysiphon. We note that, apart from other similarities, the pattern of markings on the dorsum (large darker quadrangles) is present on the apterae of both 'species'. This pattern disappears when preparing clarified mounts, so would not have been apparent to earlier workers. Rhopalosiphoninus deutzifoliae is found in Japan, China and east Siberia. Other aphids on the same hostPrimary hostsRhopalosiphoninus deutzifoliae is found on 3 Deutzia species (Deutzia crenata, Deutzia gracilis, Deutzia scabra).
Rhopalosiphoninus deutzifoliae is found on 4 Hydrangea species (Hydrangea involucrata, Hydrangea paniculata, Hydrangea petiolaris, Hydrangea sikokianaa).
Rhopalosiphoninus deutzifoliae is found on 1 Philadelphus species (Philadelphus tenuifolius).
Rhopalosiphoninus deutzifoliae is found on 1 Weigela species (Weigela coraeensis).
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