Publication Date: 2018.
1. Unravelling the strength and modes of interspecific interactions between resident and introduced species is necessary in order to understand the basis of their coexistence or the displacement of the former by the latter. In Argentina, the indigenous Tephritidae fly Anastrepha fraterculus overlaps its distribution and host fruit with the introduced species Ceratitis capitata. 2. This study focused on the relative strength of intra- and interspecific competition during the larval stage as a potential factor supporting coexistence. Classical competition experiments (addition and substitution) were conducted between larvae of the two species reared in artificial larval diet. The study evaluated whether a temporal separation between oviposition events affects the outcome of the competition. 3. When both species started to consume the resource at the same time, A. fraterculus experienced a negative effect in larval survival, pupal weight and duration of larval stage, while for C. capitata, pupal weight decreased. When A. fraterculus started feeding 1 day earlier than C. capitata, the negative effects became milder, and when the temporal separation increased, these effects were reversed. Substitution experiments showed an increase in pupal weight when larvae had to share the resource with heterospecific larvae, and showed negative effects suffered for both species when they shared the resource with conspecific individuals. 4. These results suggest that intraspecific competition is stronger than interspecific competition, and a differential oviposition preference could generate an asynchrony of these species in nature. Such mechanisms could favour coexistence between A. fraterculus and C. capitata in an environment previously occupied only by the former.
Author affiliation: Liendo, María Clara. INTA. Instituto de Genética. Laboratorio de Insectos de Importancia Agronómica; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina
Author affiliation: Parreño, María Alejandra INTA. Instituto de Genética. Laboratorio de Insectos de Importancia Agronómica; Argentina. University of Zurich. Department of Evolutionary Biology and Environmental Studies; Suiza
Author affiliation: Cladera, Jorge Luis. INTA. Instituto de Genética. Laboratorio de Insectos de Importancia Agronómica; Argentina
Author affiliation: Vera, Maria Teresa. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; Argentina
Author affiliation: Segura, Diego Fernando. INTA. Instituto de Genética. Laboratorio de Insectos de Importancia Agronómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Repository: INTA Digital (INTA). Instituto Nacional de Tecnología Agropecuaria