Adaptive, taxonomic, and phylogenetic aspects of female abdominal features in Oligotrophini (Diptera, Cecidomyiidae), and four new Dasineura species from the Western Palearctic

The external structure of the end part of the female abdomen in Oligotrophini was studied. Various patterns were found, some of them representing adaptations of limited value for phylogenetic considerations, but the analysis also demonstrated synapomorphies for certain genera. For example, all known species of Gephyraulus are equipped with a pair of horn-like sensilla situated dorsally near the tip of the superior lamella. This development apparently does not occur in other Oligotrophini. Six general models regarding the cuticular sculpture of the superior lamella were distinguished in Dasineura and Macrolabis. Evolution of some of the models may have occurred several times. Lectotypes of Jaapiella catariae Rübsaamen and Wachtliella dalmaticu Rübsaamen are designated. Wachtliella rosarum (Hardy) is transferred to Dasineura. Four new species are described: Dasineura mariae sp. n., D. berti sp. n., D. helenae sp. n., and D. erodiicola sp. n.     

Intracellular Bubble Formation: Differences in Gas Supersaturation Tolerances Between Tetrahymena and Euglena1

Cells of Tetrahymena pyriformis, T. thermophila, and Euglena gracilis were saturated with nitrogen gas at pressures up to 300 atm and rapidly decompressed. Damage was assessed by measuring post-decompression cell fragmentation or viability. Occurrence of intracellular bubbles was determined by cinephotomicrography performed during the decompression or by direct observations afterwards. The extreme gas supersaturations induced led to intracellular bubble formation and rupture in cells of Tetrahymena that contained food vacuoles, but only with supersaturations of 175 atm or higher; 225 atm left few cells intact. Bubbles were never observed in cells of Euglena or in Tetrahymena cells freed of food vacuoles, even when they were decompressed from substantially higher nitrogen supersaturations. Cells of Euglena were most resistant and were unaffected by supersaturations up to 250 atm.     

Dasineura ingeris sp.n. (Diptera: Cecidomyiidae) on Salix viminalis in Sweden, including comparisons with some other Dasineura species on Salix

Infestations of an undescribed gall midge species were discovered in Southern Sweden in biomass plantations and nurseries of Salix viminalis L. Terminal leaf buds are damaged and side shoots subsequently develop. This midge, Dasineura ingeris sp.n., closely resembles three other species occurring on Salix: D.terminalis (H. Loew) on S.alba L. and S.fragilis L.; D.iteobia (Kieffer) recorded from S.caprea L. and S.cinerea L.; and D.schreiteri (Stelter) (= comb.n. for Rabdophaga schreiteri Stelter) originally found as an inquiline in the galls of another gall midge, Dasineura rosaria (H. Loew), on S.repens L. No qualitative differences in morphology were observed between these four gall midge species, but results of morphometric analyses show significant differences between all of them. In oviposition preference trials, which included host plants of all four midge species, D.ingeris laid eggs mainly on S. viminalis, D.schreiteri preferably on S.repens , and D.iteobia exclusively on S.caprea. In larval performance trials D.ingeris produced many galls on S. viminalis , one gall also on S.caprea , but no galls on either S.alba or S.repens.