Abstract

HERNANDEZ, M. Cristina. Larval feeding behavior of the truncatus group of Thrypticus (Diptera: Dolichopodidae) that breed in the aerenchyma of Pontederiaceae. Rev. Soc. Entomol. Argent. [online]. 2007, vol.66, n.3-4, pp.121-126. ISSN 0373-5680.

Larval feeding behavior of the truncatus group of Thrypticus (Diptera: Dolichopodidae) that breed in Pontederiaceae species are presented. The larvae of T. circularis Bickel & Hernández develop in globous petioles of Eichhornia crassipes (Martius) Solms- Laubach (Pontederiaceae), digging a mine near the epidermis and forming several holes to the exterior. T. romus Bickel & Hernández develop in E. azurea (Sw.) Kunth petioles; the mine is curved and short compared with other Thrypticus species. T. formosensis Bickel & Hernández develops in Pontederia cordata L. (Pontederiaceae), and digs the mine between the epidermis and the big central cell of the petioles. T. taragui Bickel & Hernández breeds in submersed stems of P. subovata (Seub. in Mart.) Lowden, and forms a mine close to the epidermis with branches to the central vascular stele. The mines of T. yanayacu, T. chanophalus and T. azuricola could not be associated with the corresponding species. Neither predators nor parasites were found associated with the group, but some cases of cannibalism were observed when two mines were confluent. The truncatus group species have a very specific feeding habit, live completely enclosed within host plant tissues, and feed on the sap obtained from holes chewed in the vascular bundles of the petioles, possibly using yeast as supplementary nourishment. Extensive field collections and laboratory tests indicate that each species in the truncatus group is associated with a specific host plant in the Pontederiaceae. Such specialization suggests a long association between the members of this group and their respective host plants.

Keywords : Truncatus group of Thrypticus; Eichhornia crassipes; E. azurea; Pontederia spp; Phytophagy.

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