Herbivore-induced plant volatiles, not natural enemies, mediate a positive indirect interaction between insect herbivores

Frago Enric, Gols Rieta, Schweiger R., Müller C., Dicke Marcel, Godfray A. Charles J.. 2022. Herbivore-induced plant volatiles, not natural enemies, mediate a positive indirect interaction between insect herbivores. Oecologia, 198 : 443-456.

Liste HCERES des revues (en SHS) : oui

Thème(s) HCERES des revues (en SHS) : Psychologie-éthologie-ergonomie

Résumé : Many insect herbivores engage in apparent competition whereby two species interact through shared natural enemies. Upon insect attack, plants release volatile blends that attract natural enemies, but whether these volatiles mediate apparent competition between herbivores is not yet known. We investigate the role of volatiles that are emitted by bean plants upon infestation by Acyrthosiphon pisum aphids on the population dynamics and fitness of Sitobion avenae aphids, and on wheat phloem sap metabolites. In a field experiment, the dynamics of S. avenae aphids on wheat were studied by crossing two treatments: exposure of aphid colonies to A. pisum-induced bean volatiles and exclusion of natural enemies. Glasshouse experiments and analyses of primary metabolites in wheat phloem exudates were performed to better understand the results from the field experiment. In the field, bean volatiles did not affect S. avenae dynamics or survival when aphids were exposed to natural enemies. When protected from them, however, volatiles led to larger aphid colonies. In agreement with this observation, in glasshouse experiments, aphid-induced bean volatiles increased the survival of S. avenae aphids on wheat plants, but not on an artificial diet. This suggests that volatiles may benefit S. avenae colonies via metabolic changes in wheat plants, although we did not find any effect on wheat phloem exudate composition. We report a potential case of associational susceptibility whereby plant volatiles weaken the defences of receiving plants, thus leading to increased herbivore performance.

Mots-clés Agrovoc : insecte phyllophage, Triticum aestivum, interactions biologiques, Sitobion avenae, Acyrthosiphon pisum

Mots-clés libres : Acyrthosiphon pisum, Apparent competition, Aphids, Indirect interaction, Long-term dynamics, Phloem sap, Sitobion avenae, Volatile organic compound

Classification Agris : L20 - Écologie animale

Champ stratégique Cirad : CTS 4 (2019-) - Santé des plantes, des animaux et des écosystèmes

Agences de financement européennes : European Commission

Agences de financement hors UE : Conselleria d’Educació de la Generalitat Valenciana, Agence Nationale de la Recherche, Centre de Coopération Internationale en Recherche Agronomique pour le Développement

Programme de financement européen : FP7

Projets sur financement : (EU) The role of insect symbionts in host plant use through their effect on plant-induced defenses

Auteurs et affiliations

• Frago Enric, CIRAD-BIOS-UMR CBGP (FRA) ORCID: 0000-0001-8817-1303 - auteur correspondant
• Gols Rieta, Wageningen University (NLD)
• Schweiger R., Bielefeld University (DEU)
• Müller C., Bielefeld University (DEU)
• Dicke Marcel, Wageningen University (NLD)
• Godfray A. Charles J., Oxford University (GBR)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/603740/)

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