On a poorly known tritrophic interaction: fruit-infesting Rhagoletotrypeta pastranai Aczel (Diptera: Tephritidae) and its parasitoid Utetes anastrephae (Viereck) (Hymenoptera: Braconidae) in Celtis ehrenbergiana (Klotzsch) Liebm. (Rosales: Cannabaceae) fruits

We present information on a poorly known native tritrophic interaction involving Celtis ehrenbergiana (Klotszch) Liebm. (Cannabaceae), the fruit fly Rhagoletotrypeta pastranai Aczel (Diptera: Tephritidae), and its parasitoid Utetes anastrephae (Viereck) (Hymenoptera: Braconidae) from Buenos Aires, Argentina. Insects were collected from 70 trees and 950 fruits and immatures were reared in the laboratory. The fruit fly accounted for 41.8% of all pupae (59 out of 141 pupae), whereas the parasitoid accounted for 32.6% of fruit fly pupae (46 braconids out of 141 pupae). Fruit infestation levels by the fruit fly ranged between 0 and 191 pupae/100 g of fruit (mean = 53.3 +/- 55.3 pupae/100g of fruit), and percentage infestation levels ranged between 0 and 100% (mean = 18.2 +/- 32.1%). Most parasitoid adults emerged after 1-2 months, whereas most fruit fly adults emerged after a 12-mo diapause period. Our results show that both insects are common and abundant at our study area and, despite being non-economically important, highlight the need of studying poorly known species to gain a better insight into the ecology of biotic interactions with multiple interactors.