Clonal mixing in the soldier-producing aphid Pemphigus spyrothecae (Hemiptera: Aphididae)

Johnson, P.C.D. , Whitfield, J.A., Foster, W.A. and Amos, W. (2002) Clonal mixing in the soldier-producing aphid Pemphigus spyrothecae (Hemiptera: Aphididae). Molecular Ecology, 11(8), pp. 1525-1531. (doi: 10.1046/j.1365-294X.2002.01530.x)

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Illuminating the genetic relationships within soldier-producing aphid colonies is an essential element of any attempt to explain the evolution of the altruistic soldier caste. Pemphigus spyrothecae is a soldier-producing aphid that induces galls on the leaf petioles of its host (trees of the genus Populus). At least a quarter of the aphids within the clonally produced gall population are morphologically and behaviourally distinct first-instar soldiers that defend the gall population from predation. Using field trapping and microsatellites, we investigated the degree of clonal mixing within natural gall populations. Field trapping in the UK showed that all the migrants of P. spyrothecae and of two other Pemphigus species were wingless first-instar soldiers. The average degree of mixing estimated from trapping P. spyrothecae migrants was 0.68% (range = 0–15%). Microsatellite genotyping of 277 aphids from 13 galls collected in Italy revealed an average mixing level of 10.4% (range = 0–59%). Six galls contained more than one clone (range = 2–5 clones). Non-kin aphids were not restricted to the soldier caste but were evenly distributed across instars. An additional gall, from which 527 occupants were genotyped, contained 12 non-kin aphids distributed among nine clones, showing that clonal diversity can be high even when mixing is very low. These observations suggest that although soldiers migrate regularly and can moult and reproduce within foreign galls, clonal mixing in this species is generally low and is unlikely to provide a barrier to the evolution of investment by the aphid clones in an altruistic soldier caste.

Item Type:Articles
Additional Information:The definitive version is available at
Glasgow Author(s) Enlighten ID:Johnson, Dr Paul
Authors: Johnson, P.C.D., Whitfield, J.A., Foster, W.A., and Amos, W.
College/School:College of Medical Veterinary and Life Sciences > Institute of Health and Wellbeing > Robertson Centre
Journal Name:Molecular Ecology
Publisher:Blackwell Science
ISSN (Online):1365-294X
Published Online:26 July 2002
Copyright Holders:Copyright © 2002 Blackwell Science Ltd
First Published:First published in Molecular Ecology 11(8):1525-1531
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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