journal.pone.0136884.PDF (770.74 kB)
Leaf colour as a signal of chemical defence to insect herbivores in wild cabbage (Brassica Oleracea)
journal contribution
posted on 2023-06-09, 00:47 authored by Robert Glinwood, Jonathan P Green, Rosie Foster, Lucas Wilkins, Daniel Colaco OsorioDaniel Colaco Osorio, Susan E HartleyLeaf colour has been proposed to signal levels of host defence to insect herbivores, but we lack data on herbivory, leaf colour and levels of defence for wild host populations necessary to test this hypothesis. Such a test requires measurements of leaf spectra as they would be sensed by herbivore visual systems, as well as simultaneous measurements of chemical defences and herbivore responses to leaf colour in natural host-herbivore populations. In a large-scale field survey of wild cabbage (Brassica oleracea) populations, we show that variation in leaf colour and brightness, measured according to herbivore spectral sensitivities, predicts both levels of chemical defences (glucosinolates) and abundance of specialist lepidopteran (Pieris rapae) and hemipteran (Brevicoryne brassicae) herbivores. In subsequent experiments, P. rapae larvae achieved faster growth and greater pupal mass when feeding on plants with bluer leaves, which contained lower levels of aliphatic glucosinolates. Glucosinolate-mediated effects on larval performance may thus contribute to the association between P. rapae herbivory and leaf colour observed in the field. However, preference tests found no evidence that adult butterflies selected host plants based on leaf coloration. In the field, B. brassicae abundance varied with leaf brightness but greenhouse experiments were unable to identify any effects of brightness on aphid preference or performance. Our findings suggest that although leaf colour reflects both levels of host defences and herbivore abundance in the field, the ability of herbivores to respond to colour signals may be limited, even in species where performance is correlated with leaf colour.
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- Published
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- Published version
Journal
PLoS ONEISSN
1932-6203Publisher
Public Library of ScienceExternal DOI
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9Volume
10Department affiliated with
- Evolution, Behaviour and Environment Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2016-04-05First Open Access (FOA) Date
2016-04-05First Compliant Deposit (FCD) Date
2016-04-05Usage metrics
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