Green leaf volatiles

Mechanical damage tends to cause damage-associated molecular patterns (DAMPs) involving plant-derived substances and breakdown products.

Herbivore-associated molecular patterns (HAMPs) involve characteristic molecules left by different types of herbivores when feeding.

The oral secretions of herbivores appear to play an essential role in triggering the release of species-specific herbivore-induced plant volatiles.

"[4] In addition to GLVs, herbivore induced plant volatiles (HIPVs) include terpenes, ethylene, methyl salicylate and other VOCs.

[4] For example, female parasitoid wasps from two different families, Microplitis croceipes and Netelia heroica, can be attracted to plants that are emitting GLVs due to wounding from caterpillars.

[11] Maize plants emit volatiles to attract the parasitic wasps Cotesia marginiventris and Microplitis rufiventris to attack African cotton leafworm.

The parasitic wasps (Vespula germanica and V. vulgaris) prey on caterpillar (Pieris brassicae)-infested cabbage leaves that emit GLVs.

The stimulus of aphid predation is chemically transmitted through the plant to coordinate an increase release of GLV’s.

In one case, it was noted that secretions from certain species of caterpillars significantly decrease the effect amount of GLV emissions.

[8] Results from the study showed lower rates of fungal growth and higher GLV emissions on the HPL over-expressing mutants, while the HPL silencing mutants showed higher rates of fungal growth and lower GLV emissions, which supports the hypothesis that GLVs have antimicrobial properties.

[9] These GLVs cause more aphids to come and to feed on the plant for longer, giving the virus better chances of being ingested and spread more widely.

Schuman also finds that laboratory studies are overrepresented despite the wide differences in herbivore behaviour between natural and artificial settings.