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Rusty moss aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution
The Muscaphis eschirichi fundatrix (not pictured) on their primary host, Sorbus, is purplish black with rather shiny black siphunculi. The second generation are almost all alatae. It is presumed they leave the Sorbus for their secondary hosts, mosses (but see note below). In northern Russia this happens from late June to early August. These emigrant alatae have large numbers of protruberant transversely-oval secondary rhinaria on their antennae (32-53 on segment III, 19-38 on segment IV and 10-28 on segment V). The siphunculi of both the fundatrices and alatae are long, black and truncate, with a large terminal aperture.
Apterae of Muscaphis escherichi (see two pictures below) on the secondary host (mosses) are shiny red-brown, ochreous or olive brown with legs and antennae slightly paler (cf. Muscaphis cuspidati which is dark greenish brown, with a shiny black dorsum). The dorsum is mostly reticulate. The antennae are 0.5-0.6 times as long as the body, with the terminal process 0.95-1.05 times as long as the base of the last antennal segment. Antennal hairs are very short. The apical rostral segment (RIV+V) is 1.2-1.5 times the second hind tarsal segment (HTII) (cf. Muscaphis cuspidati, which has RIV+V 0.9-1.2 times RIV+V). The siphunculi are narrowly conical, slightly dorsoventrally flattened, tapering towards a rounded apex, and with a small, subapical aperture. The cauda is covered by abdominal tergite VIII; its basal part is broad, the distal part slender.
Note: Blackman treats the moss-feeding Muscaphis escherichi as the secondary host generations of the Sorbus-feeding aphid, first named Toxopterella drepanosiphoides and then as Muscaphis drepanosiphoides. This is on the basis of transfer experiments from Sorbus to the moss Plagiothecium laetum by Stekolshchikov & Shaposhnikov (1993). However, gynoparae and males have never been collected from mosses. Albrecht (2015) considers that Muscaphis drepanosiphoides and Muscaphis eschirichi are separate species, because they are morphologically distinctive, especially regarding the siphunculi. Favret in Aphid Species File treats the host alternating taxon as Muscaphis escherichi ssp. drepanosiphoides, and the anholocyclic taxon as Muscaphis escherichi ssp. escherichi.
First image above copyright Anders Albrecht, second image copyright CBG Photography Group;
Alatae produced on the secondary host (not pictured) have 15-20 secondary rhinaria on antennal segment III, 7-11 on segment IV, and 5-6 on segment V.
The host-alternating 'population' (Favret's Muscaphis escherichi ssp. drepanosiphoides) is assumed to have Sorbus as its primary host and mosses as its secondary host. There remains some doubt about this because, although the species is found on many species of mosses, the only successful transfer experiment has been to the moss Plagiothecium. The sexual phase on Sorbus apparently occurs in northern continental Europe, Czech Republic, Russia, Canada and North Korea. In northern Russia gynoparae and males appear on Sorbus in late August, and mature oviparae are present in September-October. The populations on moss in England are thought to be anholocyclic.
Other aphids on the same host
Muscaphis escherichi has been recorded from 5 Sorbus species (Sorbus americana, Sorbus aucuparia, Sorbus pohuashanensis, Sorbus sambucifolia, Sorbus sitchensis).
Muscaphis escherichi has been recorded from many species of moss, including Eurhynchium praelongum, Pseudoscleropodium purum, Ptilium crista-castrensis, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Mnium undulatum, Mnium rostratum, and Hyleconium splendens.