BIOLOGY AND TAXONOMY OF BRITISH PONTANIA SPECIES, GALL-PRODUCING SAWFLIES

Nasreddine  R. SAAD

The biology of some Pontania species (Hymenoptera: Tenthredinidae), associated with willows, particularly P.viminalis, is investigated. The oviposition and mating behavior of P.viminalis is presented in detail. Adults of Pontania (P.viminalis, P.pedunculi and P.proxima) prefer to oviposit on the same host plant species from which they were reared.

Morphological studies were made on twelve species of Pontania. Many new characters have been used for the first time. Comparative studies showed that the genus Pontania as studied in here, may be divided into three species‑groups (vesicator group (P.vesicator, P.pustulator, P.dolichura and P.tuberculata); viminalis‑group (P.viminalis, P.Pedunculi, P.arcticornis, P.collactanea and P.crassipes) and proxima‑group (P.proxima. P.triandrae and P.bridgmanii) instead of the already existing five species‑groups based on the shape of the gall. Redescription for the twelve species and new preliminary keys for the species and species-groups are provided. The work is supported by studies on type‑specimens of some of the species.

Morphometric studies for each species‑group separately showed that though there is an overlap between the species within the same species‑group, the species differ considerably in morphology.

Electrophoretic studies confirmed the morphological separation of four species of Pontania.