Complexity of both natural and managed ecosystems involves various forms of interaction among organisms. Two or more species that exploit the same resource can engage in competitive behaviors, usually referred to as intra-guild interactions. These can be direct, i.e. one species feeds directly upon the competitor (intra-guild predation) or indirect, e.g. when the dominant organism competes for a food source which another organism is feeding on (kleptoparasitism). We investigated the potential for such interactions in a biological model composed by the South American tomato pinworm, Tuta absoluta, and three of its newly associated natural enemies: the zoophytophagous predator Nesidiocoris tenuis, and two idiobiont ectoparasitoids Bracon nigricans, and Necremnus tutae.
Nesidiocoris tenuis showed (i) to scavenge on parasitized T. absoluta larvae, and (ii) to directly attack and feed on larvae of both parasitoid species, although at a higher percentage in the case of N. tutae. In the presence of the host plant the predator reduced the emergence of both B. nigricans and N. tutae adults significantly.
This study stresses the ecological success of a generalist predator over indigenous parasitoids attacking an invasive pest. Besides, these findings provide potential elements to better design biological control programs against T. absoluta.
Intraguild interaction, Mirid predator, Bracon nigricans, Necremnus tutae, Tomato borer, Trophic network
Naselli, M., Biondi, A., Tropea Garzia, G., Desneux, N., Russo, A., Siscaro, G., and Zappalà, L. (2017). Insights on food webs associated with the South American Tomato Pinworm. Pest. Manag. Sci. DOI: 10.1002/ps.4562