Entomologische Berichten (2002) 62, 66-72

Martijn Egas (2002)
Spintmijten leren foerageren - nieuw licht op de evolutie van waardplantspecialisatie en gastheerrasvorming
[Spider mites learning to feed - new insights in the evolution of host plant speciation and host race formation]
Entomologische Berichten 62 (3-4), 66-72
Abstract: It is well known, at least among entomologists, that most herbivorous arthropods are very picky in their food choice. Whereas the entire world is riddled with all kinds of green edible plants, they are specifically searching for the one plant species which tastes so good. For comparison: think of yourself eating nothing but potatoes for your entire life. Why are most herbivorous arthropods so specialised? And under which conditions does evolution by natural selection lead to specialisation? In this article the answers are summarised, and an explanation is given on how the ability of herbivorous arthropods learning to feed can lead to the evolution of specialisation and host race formation. Since no theory was available on how adaptive foraging behaviour affects the evolution of specialisation, models were developed. From these models it becomes clear that even a flow level of adaptive foraging promotes specialisation via evolutionary branching. I used the two-spotted spider mite Tetranychus urticae to test the assumption on flexible foraging behaviour: depending on the available resources and the number of competitors on each resource, consumers decide where they feed. This implies that they learn which resources are available, and that they assess their performance on a resource. Several experimental studies show that T. urticae is able to learn: it changes ibehaviour with experience. Moreover, the results are consistent with the idea that foraging decisions of individuals are based on performance, and that the distribution of individuals over host plants reflects differences in performance (if the spatial scale is not too large. Adaptive learning of host plant quality may well play a major role in the emergence of novel host races among arthropod pests in agriculture (such as T. urticae), but also among herbivorous arthropods under natural conditions.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Dutch)
Database assignments for author(s): Martijn Egas

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tetranychus urticae