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Black cherry aphidOn this page: Identification & Distribution Biology & Ecology: Life cycle Ant attendance Other aphids on the same host
Identification & Distribution:
On its primary host Myzus cerasi cause the leaves to curl and produce ant-attended leaf nests (see first picture below). The adult aptera that lives in the leaf nest on the primary host is a small to medium sized aphid, shiny, very dark brown to black with a sclerotized dorsum. The legs and antennae are yellowish and black and the cauda is brown. The siphunculi are cylindrical and black with the distal part slightly curved outward. The body length of Myzus cerasi apterae is 1.8-2.6 mm.
Most populations of the black cherry-aphid host alternate migrate from cherry (Prunus cerasus, Prunus avium) as the primary host to bedstraws (Galium), eyebrights (Euphrasia) and speedwell (Veronica spp) as the secondary hosts. However, colonies can be found that remain on the secondary host plants year round, reproducing sexually and overwintering as eggs; these are sometimes given the status of a subspecies, Myzus cerasi veronicae. Forms on Prunus cerasus and Prunus avium are also sometimes considered as different subspecies or even species. The return migration occurs in September-October. It is distributed throughout the Palaearctic zone and is now almost cosmopolitan.
Biology & Ecology
Overwintering eggs are laid in autumn on cherry trees (Prunus cerasus and Prunus avium). These hatch in spring to give rise to colonies of aphids living in leaf nests on the trees. Colonies are often very large and frequently thickly covered in honeydew, despite the usual attendance of ants.
Myzus cerasi seems able to tolerate a much more contaminated environment than most species of aphids, although we are unaware of any studies carried out to investigate how this achieved. Certainly we have found they develop very high levels of crowding within the leaf nests without switching to producing alates. Alate production is instead most likely induced by climatic factors (temperature or photoperiod).
Most populations of the black cherry-aphid are thought to migrate from cherry to bedstraws (Galium), eyebrights (Euphrasia) and speedwell (Veronica spp) as the secondary hosts, although it must be said that despite frequently examining these latter hosts, we have seldom encountered Myzus cerasi on these hosts. One exception was some lady's bedstraw (Galium verum) which hosted a colony bedstraw shoot aphid (Staegeriella necopinata) along with an immature Myzus cerasi (see picture below - the Myzus is the one pointing vertically downwards).
Myzus cerasi is avidly attended by ants. The colony below was attended by Myrmica rubra.
Gruppe (1990) looked at ant associations with Myzus cerasi in Germany. The trophobiotic association of Myzus cerasi with ants was not obligatory, colonies of the aphid being found without ants. Lasius niger and Myrmica laevinoides were the commonest species found with Myzus cerasi. Keeping ants away from cherry trees using sticky bands resulted in the development of fewer colonies of the aphid compared with untreated trees. On trees with ants, development of aphid colonies started from the central part and spread to many adjacent buds and shoots, where new colonies formed. Only isolated colonies occurred on trees without ants.
Other aphids on same host:
Blackman & Eastop list Myzus cerasi as found on 33 Prunus species worldwide, and provide formal identification keys.