Inter-specific competition and competition-free space in the tephritid parasitoids Utetes anastrephaeand Doryctobracon areolatus(Hymenoptera: Braconidae: Opiinae)

ALUJA, MARTÍN; OVRUSKI, SERGIO MARCELO; SIVINSKI, JOHN; CÓRDOVA-GARCÍA, GUADALUPE; SCHLISERMAN, PABLO; NÚÑEZ CAMPERO, SEGUNDO RICARDO; ORDANO, MARIANO

ECOLOGICAL ENTOMOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2013 vol. 38 p. 485 - 496

0307-6946

1.Utetes anastrephae(Viereck) andDoryctobracon areolatus(Sz´ epligeti) are common, native, Neotropical braconid parasitoids of tephritid fruit flies that are sympatric and often found attacking the same host. 2. The coexistence of the two species may be due in part to the longer ovipositor ofD. areolatusthat permits it to attack larvae in larger fruit than can U. anastrephae. This increases its potential host range and provides ?competitor-free space?. 3. The capacity ofU. anastrephaeto persist in smaller fruit, exploitable by D. areolatus, suggested that it was a superior competitor in multiparasitised hosts. As predictedU. anastrephaehad a competitive advantage overD. areolatusand this advantage occurred regardless of the order in which the two parasitoids attacked. Although we could not identify the precise mechanisms used for elimination of competitors, a possible cause is suggested by the formidable mandibles of the first-instar U. anastrephae. 4. However,D. areolatussurvival increased significantly if eggs had been deposited 24 h prior to exposure toU. anastrephae. Older D. areolatuslarvae might be more competitive after a period of development. 5.Utetes anastrephaefemales were less likely to oviposit into hosts previously attacked byD. areolatusthan vice versa. This was a second case of the relatively rare phenomenon of inter-specific discrimination of a previously exploited host within the opiine braconid parasitoids of frugivorous tephritids.