Citrus volatiles induced by herbivory of Aleurothrixus floccosus (Hemiptera: Aleyrodidae) elicit attraction to the exotic ladybird Clitostethus arcuatus (Coleoptera: Coccinellidae)

Tommy Rioja1 and Ricardo Ceballos2*
Plants undergoing insect infestation release herbivore-induced plant volatiles (HIPVs) into their environment, which are then used by natural enemies for their benefit. The pest Aleurothrixus floccosus, which affects citrus orchards in northern Chile, specifically at Pica Oasis, poses a year-round threat. Recently, the introduction of the exotic ladybird Clitostethus arcuatus has been noted as a predator of A. floccosus. This study delved into how HIPVs emitted from tangelo (Citrus reticulata × C. ×paradisi Macfad.) and lime (C. ×aurantifolia (Christm.) Swingle) infested-shoots impact the behavioral responses of C. arcuatus. The volatile compounds were collected using the headspace technique, revealing notable qualitative changes after herbivory. In two-choice bioassays, the HIPVs elicited an attractive response in C. arcuatus compared to A. floccosus. At concentrations of 10 and 100 µg mL-1, the predators displayed a distinct preference for methyl salicylate (MeSA). These findings underscore that C. arcuatus exploits the HIPVs emitted from citrus infested-shoots, fostering tritrophic interactions. Exploring the impact of whitefly attacks on other fruit trees, emerges as a significant avenue for future investigation.
Keywords: Arid agroecosystems and tritrophic interactions, citrus, C. ×aurantifolia, Citrus reticulata × C. ×paradisi, herbivore-induced plant volatiles, lime, tangelo, volatile organic compounds, woolly whitefly.
1Universidad de Tarapacá, Facultad de Ciencias Agronómicas, Campus Azapa, Arica, Chile.
2Instituto de Investigaciones Agropecuarias, INIA Quilamapu, Chillán 3800062, Chile.
*Corresponding author (rceballos@inia.cl).