Co-occurrence of defensive traits in the potato aphid Macrosiphum euphorbiae

A - Papers appearing in refereed journals

Clarke, H. V., Foster, S. P., Oliphant, L., Waters, E. W. and Karley, A. J. 2018. Co-occurrence of defensive traits in the potato aphid Macrosiphum euphorbiae. Ecological Entomology. 43 (4), pp. 538-542.

AuthorsClarke, H. V., Foster, S. P., Oliphant, L., Waters, E. W. and Karley, A. J.

1. Insecticide usage selects strongly for resistance in aphid populations, but this could entail fitness costs in other resistance traits. The potato aphid Macrosiphum euphorbiae Thomas exhibits intraspecific variation in susceptibility to parasitism by braconid wasps and provides a suitable species to study the relation between the defensive traits of parasitism and insecticide resistance.

2. Clonal lines (23 in total) of M. euphorbiae were established from aphids collected in 2013 from geographically separate populations in the U.K. Clonal lines belonged to five aphid genotypes, but one genotype predominated (78% of samples), and the facultative endosymbiont Hamiltonella defensa was detected in c. 40% of lines.

3. Total esterase activity in aphid tissues varied significantly between aphid genotypes and collection areas, but there was no clear pattern in relation to H. defensa infection or between collection sites likely to differ in insecticide pressures.

4. Five clonal lines representing low to moderate levels of enzyme activity, which included different aphid genotypes and presence/absence of H. defensa infection, were assayed for their susceptibility to the parasitoid wasp Aphidius ervi Haliday. Aphid mummification varied significantly between aphid genotypes, with low values in one genotype of aphids irrespective of H. defensa presence.

5. The results revealed that aphid lines belonging to the parasitism-resistant genotype exhibited moderate levels of total esterase activity, indicating a competitve advantage
for this genotype of M. euphorbiae when exposed to chemical and biological control factors in agroecosystems.

KeywordsAphidius ervi; carboxylesterase activity; insecticide; parasitism; parasitoid
Year of Publication2018
JournalEcological Entomology
Journal citation43 (4), pp. 538-542
Digital Object Identifier (DOI)
Open accessPublished as non-open access
FunderDepartment of Environment, Food and Rural Affairs
Biotechnology and Biological Sciences Research Council
Output statusPublished
Publication dates
Online06 Apr 2018
Publication process dates
Accepted05 Mar 2018
Copyright licensePublisher copyright

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