|HERNANDEZ, M. CRISTINA|
Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2008
Publication Date: 11/1/2008
Citation: Hernandez, M. 2008. Biology of Thrypticus truncatus and T. sagittatus (Diptera:Dolichopodidae), petiole miners of water hyacinth, Eichhornia crassipes, in Argentina. With morphological descriptions of larvae and pupae. Annals of the Entomological Society of America.
Interpretive Summary: Two petiole miners are under study as candidates for Biological Control of Waterhyacinth, a mayor invasive aquatic weed. These species, Thrypticus truncatus and T. sagittatus, both have phytofagous larvae that live in the tissues of the petioles. They dig their mine across the petioles and feed sap from the vascular bundles. The feeding behavior and morphological aspects, both for adults and larvae, are described. Research on insect behavior is one of the tools used in the management of species for biological control. The research was conducted in the laboratory and in the field, in several water courses of the Paraná River basin, Argentina.
Technical Abstract: The mining flies Thyrpticus truncatus Bickel & Hernandez and T. sagittatus Bickel & Hernandez (Diptera: Dolichopodidae) are being evaluated as biological control agents for the water hyacinth, Eichhornia crassipes (Martius) Soms-Laubach (Pontederiaceae). The bahavior of adults and larvae of these species wer studied in the laboratory and in the field, in several wer courses of the Paraná River basin, Argentina. The larvae feed on sap from feeding points scarped in the vascular bundles in the peioles of E. crassipes. Pupation occurs in a chamber dug near one of the mine's openings. External mrophology of larvae and pupae, larval cephalic skeleton and tracheal system are described. The pupae of both species have the Meddeterinae ventrally flattened profile, with a transverse serrate ridge divided by a notch at the apex of the head. The mines, described herein in detail, constitute the microhabitat where the larvae live throughout their development and obtain food and protection. Both species are active and reproduce on water hyacinth from spring to the end of fall, and overwinter as larvae inside the mines in the petioles. No morphological or behavioral differences were evident between the larvae of these species, except in the apical ridges of the pupae. Both species appear to occupy the same niche on the plants.