The causes and processes of the mid-summer population crash of the potato aphids Macrosiphum euphorbiae and Myzus persicae (Hemiptera: Aphididae)

Populations of many phloem-feeding aphid species in temperate regions increase exponentially in early summer and then ‘disappear’, usually over a time-scale of a few days, in July. To understand these dynamics, empirical investigation of the causes and modelling of the processes underlying populatio...

Full description

Saved in:
Bibliographic Details
Published in:Bulletin of entomological research 2003-09, Vol.93 (5), p.425-438
Main Authors: Karley, A.J., Pitchford, J.W., Douglas, A.E., Parker, W.E., Howardh, J.J.
Format: Article
Language:English
Subjects:
Amino Acids - metabolism
Animal Feed
Animals
Aphididae
Aphids - microbiology
Aphids - parasitology
Aphids - physiology
Biological and medical sciences
Emigration
Endangered & extinct species
Female
Fertility
Fundamental and applied biological sciences. Psychology
Insecticides
Insects
Macrosiphum euphorbiae
Male
Myzus persicae
Pest Control, Biological
Phytopathology. Animal pests. Plant and forest protection
Plant Leaves - chemistry
Plant Leaves - microbiology
Plant Leaves - parasitology
Population Density
Population Dynamics
Potatoes
Predation
Protozoa. Invertebrates
Records, symptoms, damages, economic importance, population surveys
Reproduction
Seasons
Solanum tuberosum
Solanum tuberosum - parasitology
Summer
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Populations of many phloem-feeding aphid species in temperate regions increase exponentially in early summer and then ‘disappear’, usually over a time-scale of a few days, in July. To understand these dynamics, empirical investigation of the causes and modelling of the processes underlying population change are required. Numbers of the aphids Myzus persicae (Sulzer) and Macrosiphum euphorbiae (Thomas), monitored over three years in commercial potato fields in the UK, increased to a maximum of 2–2.5 per leaflet on 16 July in 1999 and 2001, and then declined to < 0.25 per leaflet by 26 July. In 2000, aphid numbers remained very low (< 0.25 per leaflet) throughout the season. The onset of the crash in aphid numbers (16–19 July in 1999 and 2001) was consistently associated with changes in the phloem amino acid composition of potato leaflets. Natural enemies, including syrphids, parasitoids, coccinellids, chrysopids and entomopathogenic fungi, increased in abundance throughout the sampling period. The incidence of winged emigrant aphids prior to the crash was low (< 10%). Experimental manipulation during 2001 demonstrated that, during the crash period, the fecundity of aphids (caged on leaves to exclude natural enemies) was depressed by 25–45% relative to earlier in the season, and that presence of natural enemies reduced aphid numbers by up to 68%. Using these data, an excitable medium model was constructed, which provided a robust description of aphid population dynamics in terms of plant development-induced changes in aphid fecundity and temporal change in natural enemy pressure.
ISSN:0007-4853
1475-2670
DOI:10.1079/BER2003252