Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2008
Publication Date: 12/1/2008
Citation: Mena-Correa, J., Sivinski, J.M., Gates, M.W., Ramirez-Romero, R., Aluja, M. 2008. Biology of Eurytoma sivinskii, an unusual eurytomid (Hymenoptera) parasitoid of fruit fly (Diptera: Tephritidae) pupae. Florida Entomologist. 91(4):598-603. Interpretive Summary: Fruit flies infest hundreds of fruits and vegetables and create quarantine problems wherever they occur. Biological control, the use of “natural insect enemies” is a promising means of suppressing pest fly populations and supporting export programs. Scientists at the Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida search for new natural enemies in collaboration with colleagues from the Instituto de Ecologia (Xalapa, Veracruz, Mexico). One new parasitoid was found to attack the pupae of many flies, including non-pest species. Because of this lack of specificity, it is not likely to be useful in biological control. Explorations and host-range testing will continue.
Technical Abstract: Eurytomidae are diverse biologically, being entomophagous, phytophagous or both and typically attack egg, larval and/or pupal stages of their hosts. Here, we describe some aspects of the natural history of a recently described Mexican species, Eurytoma sivinskii (Hymenoptera: Eurytomidae) found attacking Anastrepha obliqua (Diptera: Tephritidae) pupae in the soil. In the laboratory, we determined that, with one exception (one third-instar larva of 625 exposed), E. sivinskii attacked the pupae, and not the larvae of the related A. ludens and that it is a generalist, solitary ectoparasitoid that can facultatively hyperparasitize other larval-prepupal and pupal parasitoids such as Opius hirtus (Hymenoptera: Braconidae), Coptera haywardi (Hymenoptera: Diapriidae) and Pachycrepoideus vindemiae (Hymenoptera: Pteromalidae). Eurytoma sivinskii developed in the pupae of various other Anastrepha, including, A. serpentina and A. striata, as well as in cyclorraphous Diptera such as Musca domestica and a tachinid. However, it was unable to attack pupae of Palaeosepsis sp. (Diptera: Sepsidae). The life cycle (egg to adult) was completed in 23.1 (± 2.1) days (mean + S.E.) at 27 ± 2°C. Males emerged on average two days before females, but the sex ratio was consistently skewed towards females. Overall (considering all experiments) females laid 1-8 eggs per host (2.59 + 1.56 [mean + S.E.]), preferentially in the medial and anterior parts of the host, but invariably only one adult. Our results suggest that E. sivinskii does not represent a potential candidate for fruit fly biological control programs because of its broad host range and its ability to facultatively hyperparasitize other fruit fly parasitoids.