EFFECTS OF LARVAL INTERACTIONS BETWEEN THE INVASIVE DROSOPHILID ZAPRIONUS INDIANUS AND TWO OTHER LOCAL DROSOPHILIDS ON LIFE HISTORY TRAITS

IMBERTI, M; LAVAGNINO, N; FANARA, JJ

Mar del Plata

Congreso; 2nd World Conference on Biological Invasions and Ecosystem Functioning; 2011

EFFECTS OF LARVAL INTERACTIONS BETWEEN THE INVASIVE DROSOPHILID ZAPRIONUS INDIANUS AND TWO OTHER LOCAL DROSOPHILIDS ON LIFE HISTORY TRAITS   Marcos Imberti1, Nicolás Lavagnino1, Juan Fanara1     Competition is an important aspect of the ecology of insect communities exploiting ephemeral and fragmented resources. Zaprionus indianus is a drosophilid recently introduced to America via Brasil. In less than 10 years, Z. indianus spread almost all over the continent. Based on data of relative abundances of drosophilids from recent campaigns in Northern Argentina, we observed that Z. indianus shares its larval breeding sites (rotten fruits) with several others insect species and noticed an important increase of Z. indianus relative abundance through time. Therefore, Z. indianus successful colonization could be explained by its competitive ability against others drosophilids or by coexistence resulting from a wide-niche type resource utilization. We analyzed the effect of larval interspecific interactions on life history traits “larvae-adult survival” (S) and “larvae-adult developmental time” (DT) between Z. indianus and two of the species with which more often coexists in this continent, Drosophila melanogaster and D..simulans, while reared jointly in three different fruit resources. Our results showed the same pattern, for both Drosophila species wherein they significantly accelerate their DT as consequence of larval interaction with Z. indianus,.. At the same time, Z. indianus larvae showed no effect on the measured variables when reared with other drosophilids. These results could be interpreted as an evidence of high larval competition ability of Z. indianus on other species studied since the tested Drosophila species exhibited an avoiding-competition strategy in by accelerating the DT.