Recognition of host-specific chemical stimulants in two sympatric host races of the pea aphid Acyrthosiphon pisum

• Published in: Ecological entomology Vol. 28; no. 4; pp. 405 - 412
• Main Authors: Del Campo, M. L., Via, S., Caillaud, M. C.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.08.2003; Blackwell Science
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Ecological speciation; feeding behaviour; Fundamental and applied biological sciences. Psychology; plant chemistry; plant-herbivore interactions; Protozoa. Invertebrata; stimulant; Stimulant; Aphidoidea; Feeding behavior; Insecta; Chemical compound; Medicago sativa; Host specificity; Trifolium pratense; Acyrthosiphon pisum; Pest; Homoptera; Leguminosae; Animal plant relation; Arthropoda; Dicotyledones; Host plant; Angiospermae; Aphididae; Spermatophyta; Intraspecific comparison; Fodder crop; Invertebrata; Recognition
• ISSN: 0307-6946; 1365-2311
• DOI: 10.1046/j.1365-2311.2003.00524.x

1. In ecological speciation , adaptation to variation in the external environment provides the crucial push that starts the process of genetic divergence and eventually leads to speciation. This emphasis on the role of ecological specialisation in speciation events has brought with it a renewed interest in its proximate mechanisms in recently diverged groups such as host races. Here, the proximate mechanisms of feeding specialisation are investigated in two host races of the pea aphid Acyrthosiphon pisum . 2. Using alfalfa and clover extracts, enclosed in diet chambers or applied on whole plants, it is shown that feeding specialisation depends on recognition of stimulants specific to the host plant, not on deterrents or toxins specific to the non‐host plants. 3. Because pea aphids mate on their host plant, feeding specialisation leads to de facto assortative mating. This study suggests that behavioural recognition of host‐specific chemicals, rather than avoidance of deterrents or/and plant toxins, contributes to gene flow restriction between the alfalfa and clover host races.