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The timing of herbivore-induced volatile emission in black poplar (Populus nigra) and the influence of herbivore age and identity affect the value of individual volatiles as cues for herbivore enemies.

McCormick AC, Boeckler GA, Köllner TG, Gershenzon J, Unsicker SB - BMC Plant Biol. (2014)

Bottom Line: We also determined the influence of different herbivore species, caterpillars of the gypsy moth (Lymantria dispar) and poplar hawkmoth (Laothoe populi), and different herbivore developmental stages on emission.However, the emission of most terpenes showed a more delayed reaction to the start and end of herbivory, and emission was significantly greater during the day compared to the night.These may represent the most reliable cues for herbivore enemies and, interestingly, have been shown in a recent study to be the best attractants for an herbivore enemy that parasitizes gypsy moth larvae feeding on black poplar.

View Article: PubMed Central - PubMed

ABSTRACT

Background: The role of herbivore-induced plant volatiles as signals mediating the attraction of herbivore enemies is a well-known phenomenon. Studies with short-lived herbaceous plant species have shown that various biotic and abiotic factors can strongly affect the quantity, composition and timing of volatile emission dynamics. However, there is little knowledge on how these factors influence the volatile emission of long-lived woody perennials. The aim of this study was to investigate the temporal dynamics of herbivore-induced volatile emission of black poplar (Populus nigra) through several day-night cycles following the onset of herbivory. We also determined the influence of different herbivore species, caterpillars of the gypsy moth (Lymantria dispar) and poplar hawkmoth (Laothoe populi), and different herbivore developmental stages on emission.

Results: The emission dynamics of major groups of volatile compounds differed strikingly in response to the timing of herbivory and the day-night cycle. The emission of aldoximes, salicyl aldehyde, and to a lesser extent, green leaf volatiles began shortly after herbivore attack and ceased quickly after herbivore removal, irrespective of the day-night cycle. However, the emission of most terpenes showed a more delayed reaction to the start and end of herbivory, and emission was significantly greater during the day compared to the night. The identity of the caterpillar species caused only slight changes in emission, but variation in developmental stage had a strong impact on volatile emission with early instar L. dispar inducing more nitrogenous volatiles and terpenoids than late instar caterpillars of the same species.

Conclusions: The results indicate that only a few of the many herbivore-induced black poplar volatiles are released in tight correlation with the timing of herbivory. These may represent the most reliable cues for herbivore enemies and, interestingly, have been shown in a recent study to be the best attractants for an herbivore enemy that parasitizes gypsy moth larvae feeding on black poplar.

No MeSH data available.


Effect of herbivore identity and developmental stage on volatile emission ofPopulua nigra. Four treatments include Lymantria dispar (2nd instar), L. dispar (5th instar), Laothoe populi (5th instar), and a mixture of L. dispar (5th instar) and L. populi (5th instar). Box-plots showing the same letter are not statistically significant from one another after a Tukey test performed on the fitted values after applying a GLS model, excluding the effect of the feeding intensity. P values are given in Table 1. Plots showing no letters indicate that there was no effect of the treatment on volatile emission.
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Fig3: Effect of herbivore identity and developmental stage on volatile emission ofPopulua nigra. Four treatments include Lymantria dispar (2nd instar), L. dispar (5th instar), Laothoe populi (5th instar), and a mixture of L. dispar (5th instar) and L. populi (5th instar). Box-plots showing the same letter are not statistically significant from one another after a Tukey test performed on the fitted values after applying a GLS model, excluding the effect of the feeding intensity. P values are given in Table 1. Plots showing no letters indicate that there was no effect of the treatment on volatile emission.

Mentions: In comparing P. nigra volatiles among treatments, only four compounds differed significantly in emission upon feeding by the two caterpillar species tested (the specialist L. populi and the generalist L. dispar both 5th instar): (E)-β-caryophyllene, 3-methylbutyraldoxime, myrcene and nerolidol (Figure 3), all emitted in greater abundance after damage by L. dispar. Four compounds were also different between combined damage by the two herbivore species vs. damage by the generalist herbivore alone: (E)-β-caryophyllene, 3-methylbutyraldoxime, (Z)-3-hexenol and nerolidol (Figure 3). These compounds were emitted in higher amounts by L. dispar than by the two species combined. The emission in the combined damage treatment did not differ significantly from that induced by the specialist herbivore (L. populi) alone (Figure 3, Additional file 2: Figure S2). Herbivore instar had very strong effect on volatile emission caused by L. dispar: early instar L. dispar induced significantly more emission of nitrogen-containing volatiles and most terpenoids than late instar L. dispar and L. populi (Figure 3, Additional file 2: Figure S2).Figure 3


The timing of herbivore-induced volatile emission in black poplar (Populus nigra) and the influence of herbivore age and identity affect the value of individual volatiles as cues for herbivore enemies.

McCormick AC, Boeckler GA, Köllner TG, Gershenzon J, Unsicker SB - BMC Plant Biol. (2014)

Effect of herbivore identity and developmental stage on volatile emission ofPopulua nigra. Four treatments include Lymantria dispar (2nd instar), L. dispar (5th instar), Laothoe populi (5th instar), and a mixture of L. dispar (5th instar) and L. populi (5th instar). Box-plots showing the same letter are not statistically significant from one another after a Tukey test performed on the fitted values after applying a GLS model, excluding the effect of the feeding intensity. P values are given in Table 1. Plots showing no letters indicate that there was no effect of the treatment on volatile emission.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4262996&req=5

Fig3: Effect of herbivore identity and developmental stage on volatile emission ofPopulua nigra. Four treatments include Lymantria dispar (2nd instar), L. dispar (5th instar), Laothoe populi (5th instar), and a mixture of L. dispar (5th instar) and L. populi (5th instar). Box-plots showing the same letter are not statistically significant from one another after a Tukey test performed on the fitted values after applying a GLS model, excluding the effect of the feeding intensity. P values are given in Table 1. Plots showing no letters indicate that there was no effect of the treatment on volatile emission.
Mentions: In comparing P. nigra volatiles among treatments, only four compounds differed significantly in emission upon feeding by the two caterpillar species tested (the specialist L. populi and the generalist L. dispar both 5th instar): (E)-β-caryophyllene, 3-methylbutyraldoxime, myrcene and nerolidol (Figure 3), all emitted in greater abundance after damage by L. dispar. Four compounds were also different between combined damage by the two herbivore species vs. damage by the generalist herbivore alone: (E)-β-caryophyllene, 3-methylbutyraldoxime, (Z)-3-hexenol and nerolidol (Figure 3). These compounds were emitted in higher amounts by L. dispar than by the two species combined. The emission in the combined damage treatment did not differ significantly from that induced by the specialist herbivore (L. populi) alone (Figure 3, Additional file 2: Figure S2). Herbivore instar had very strong effect on volatile emission caused by L. dispar: early instar L. dispar induced significantly more emission of nitrogen-containing volatiles and most terpenoids than late instar L. dispar and L. populi (Figure 3, Additional file 2: Figure S2).Figure 3

Bottom Line: We also determined the influence of different herbivore species, caterpillars of the gypsy moth (Lymantria dispar) and poplar hawkmoth (Laothoe populi), and different herbivore developmental stages on emission.However, the emission of most terpenes showed a more delayed reaction to the start and end of herbivory, and emission was significantly greater during the day compared to the night.These may represent the most reliable cues for herbivore enemies and, interestingly, have been shown in a recent study to be the best attractants for an herbivore enemy that parasitizes gypsy moth larvae feeding on black poplar.

View Article: PubMed Central - PubMed

ABSTRACT

Background: The role of herbivore-induced plant volatiles as signals mediating the attraction of herbivore enemies is a well-known phenomenon. Studies with short-lived herbaceous plant species have shown that various biotic and abiotic factors can strongly affect the quantity, composition and timing of volatile emission dynamics. However, there is little knowledge on how these factors influence the volatile emission of long-lived woody perennials. The aim of this study was to investigate the temporal dynamics of herbivore-induced volatile emission of black poplar (Populus nigra) through several day-night cycles following the onset of herbivory. We also determined the influence of different herbivore species, caterpillars of the gypsy moth (Lymantria dispar) and poplar hawkmoth (Laothoe populi), and different herbivore developmental stages on emission.

Results: The emission dynamics of major groups of volatile compounds differed strikingly in response to the timing of herbivory and the day-night cycle. The emission of aldoximes, salicyl aldehyde, and to a lesser extent, green leaf volatiles began shortly after herbivore attack and ceased quickly after herbivore removal, irrespective of the day-night cycle. However, the emission of most terpenes showed a more delayed reaction to the start and end of herbivory, and emission was significantly greater during the day compared to the night. The identity of the caterpillar species caused only slight changes in emission, but variation in developmental stage had a strong impact on volatile emission with early instar L. dispar inducing more nitrogenous volatiles and terpenoids than late instar caterpillars of the same species.

Conclusions: The results indicate that only a few of the many herbivore-induced black poplar volatiles are released in tight correlation with the timing of herbivory. These may represent the most reliable cues for herbivore enemies and, interestingly, have been shown in a recent study to be the best attractants for an herbivore enemy that parasitizes gypsy moth larvae feeding on black poplar.

No MeSH data available.