Intraspecific variation in a generalist herbivore accounts for differential induction and impact of host plant defences.
Plants and herbivores are thought to be engaged in a coevolutionary arms race: rising frequencies of plants with anti-herbivore defences exert pressure on herbivores to resist or circumvent these defences and vice versa. Owing to its frequency-dependent character, the arms race hypothesis predicts that herbivores exhibit genetic variation for traits that determine how they deal with the defences of a given host plant phenotype. Here, we show the existence of distinct variation within a single herbivore species, the spider mite Tetranychus urticae, in traits that lead to resistance or susceptibility to jasmonate (JA)-dependent defences of a host plant but also in traits responsible for induction or repression of JA defences. We characterized three distinct lines of T. urticae that differentially induced JA-related defence genes and metabolites while feeding on tomato plants (Solanum lycopersicum). These lines were also differently affected by induced JA defences. The first line, which induced JA-dependent tomato defences, was susceptible to those defences; the second line also induced JA defences but was resistant to them; and the third, although susceptible to JA defences, repressed induction. We hypothesize that such intraspecific variation is common among herbivores living in environments with a diversity of plants that impose diverse selection pressure.
Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands. kant@science.uva.nl
Merijn R
MR
Kant
Maurice W
MW
Sabelis
Michel A
MA
Haring
Robert C
RC
Schuurink
D000818:Animals; D003517:Cyclopentanes / Q000633:toxicity; D004351:Drug Resistance / Q000502:physiology; D005298:Fertility / Q000502:physiology; D008401:Gas Chromatography-Mass Spectrometry; D014644:Genetic Variation; D018551:Solanum lycopersicum / Q000737:chemistry*; D054883:Oxylipins / Q000633:toxicity; D010937:Plant Growth Regulators / Q000633:toxicity; D013045:Species Specificity; D040102:Tetranychidae / Q000145:classification / Q000187:drug effects / Q000235:genetics*
D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; C011006:jasmonic acid