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Subspecies lappae (Burdock mealy root aphid)Identification & Distribution Biology & Ecology
Identification & Distribution:Adult apterae of Dysaphis lappae are dirty olive greenish to brownish, sometimes with a purple tinge. Older adults may have yellowish margins to the abdomen. The rostrum reaches behind the hind coxae. There are rather large marginal tubercles on the prothorax and abdominal segments I-V. The siphunculi are about 1.5-2.0 times the length of the cauda. The body length of female adult apterous Dysaphis lappae is 1.7-2.5 mm.
The alate is pinkish grey, slightly wax powdered with a rather extensive dark dorsal patch. The alate has 37-55 secondary rhinaria on the third antennal segment, 9-19 on the fourth segment and 0-1 on the fifth segment. Dysaphis lappae nymphs are pinkish grey.
There are three subspecies with different hosts:
The burdock mealy root aphid lives on the basal parts of stems, root collar and roots of burdock species (Arctium minus, Arctium lappa and Arctium tomentosum ). Sexual forms are found in autumn. It is usually attended by ants. Dysaphis lappae is found in Britain, most of Europe, Transcaucasia, Central Asia, Western Siberia, parts of North Africa and introduced to Brazil.
Biology & Ecology:
There is very little information available on the ecology of Dysaphis lappae lappae. Up to 2015, the only British records were those of Theobald (1927) (reported in Blackman (2010) ), from Berkshire and Surrey in May. It has also been recorded in Ireland
We found large colonies of this species on the root collar of burdock (Arctium sp.) (see pictures above of burdock flower and tented root collar) at Rye Harbour Nature Reserve in East Sussex on July 30th 2015, and again on August 4th 2015. Removal of soil particles around the root collar revealed the large colony shown below:
Note especially the orange-red suffusion around and between the siphunculi. This is especially prominent on the nymphs, but is also present on the adults (see centre of picture below) as a purplish suffusion in the same area.
The only mention of this localized colour patch in published descriptions of the species is reference to a 'purple tinge'. The colour is lost in alcohol preserved specimens.
Both colonies were ant-attended, which may explain the rather sparse mealy wax covering on these aphids. Colonies were tented over with sand particles and vegetable matter. Once colonies were exposed, the ants departed making no attempt to protect the aphids.