Andricus partali n. sp.

[The phenology, gall morphology, and adult morphology of this species seem to closely match North American members of the genus Dryocosmus; it isn't clear why the species was placed in Andricus]

[A photo of these galls appears on the last page of the pdf]

Gall (Fig. 6a). Globular swelling of the leaf blade projecting on both the upper and lower surface of the leaf, located adjacent to the main vein or a secondary vein. Usually there are only one or two galls on a single leaf, rarely more. The gall is up to 10 mm in diameter, green in color, sometimes with a slightly reddish tinge on the surface. The external wall is coriaceous, quite hard, and with a shiny surface. Mature galls are hollow inside and within the internal air space is a single 2-3 mm diameter, brown sphere containing the larval chamber, which can become detached and capable of rolling around inside the hollow interior of the gall.

Biology. This new species was found inducing galls on Quercus costaricensis Liebm. (Section Lobatae of Quercus, red oaks), which occurs from 2300 m to 3600 m elevation in Costa Rica and western Panama (Morales 2010). The gall appears to belong to the sexual generation. Mature galls were collected in March-April, and adults emerged soon after the galls were collected. Other hymenopterans that emerged from these galls include parasitoids, Quercastichus sp. (Eulophidae) and Torymus sp. (Torymidae).

Distribution. Only known from high elevations in Costa Rica (Cordillera de Talamanca).