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Bog myrtle aphidOn this page: Identification & Distribution Biology & Ecology Other aphids on the same host
Identification & Distribution:
Immature bog myrtle aphids are bright yellow with longitudinal rows of pale centred dark spots. Adult Myzocallis myricae alates are yellow or orange, with additional black longitudinal markings on the head and thorax. The antennae of bog myrtle aphids are shorter than their body, and the terminal process of their sixth antennal segment is less than twice the length of its basal part. The abdominal tergites 1 to 7 have paired dusky spinal and marginal sclerites. Myzocallis myricae siphunculi are short truncated cones. The tibiae have similar pigmentation to distal parts of the femora. Their body length is less than 3.5 mm.
The pictures below are micrographs of alcohol-preserved specimens of a winged adult (dorsal view) and a Myzocallis myricae nymphs (lateral view).
Myzocallis myricae does not host alternate but feeds only on bog myrtle (Myrica gale). It is largely restricted to northern and western Europe. Sexual forms occur in autumn.
Biology & Ecology:
Little has been published on the ecology or distribution of this aphid other than that it has been recorded quite widely in Ireland (Carter et al., 1987). In Scotland we found sparse aphid colonies on both the leaves (see pictures above) and hidden in the young shoots (see picture below).
The bog myrtle aphid does not seem to form dense colonies, but prefers instead to space-out over the leaf or shoots (see picture below).
Short-winged (brachypterous) specimens are common. As a result, Myzocallis myricae has, been used in a study into the cost in terms of resources for an aphid of developing flight muscles (Dixon & Kindlmann, 1999). The brachypterous form (with very short or rudimentary wings) of the bog myrtle aphid is structurally very similar to the macropterous form (with long or large wings). It has small but perfect wings but lacks flight muscles. The gonads of the brachypterous form make up a significantly greater proportion of their dry mass than do the gonads of the macropterous form. This conforms the prediction that migrants should have smaller gonads than nonmigrants.
Other aphids on same host:
Myzocallis myricae has been recorded from 1 Myrica species (Myrica gale).
Blackman & Eastop list 5 species of aphid as feeding on bog myrtle (Myrica gale) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 2 as occurring in Britain (Show British list).