Queen control of egg fertilization in the honey bee

The study investigated the precision with which honey bee queens can control the fertilization of the eggs they lay. Because males and workers are reared in different-sized cells, the honey bee is one of the few Hymenoptera in which it is possible for the experimenter to know which type of egg a queen “intends” to lay. Eggs were collected from both worker and drone (male) cells from four honey bee colonies. Ploidy of the embryo was determined using polymorphic DNA microsatellites. All 169 eggs taken from worker cells were heterozygous at at least one microsatellite locus showing that the egg was fertilized. All 129 eggs taken from drone cells gave a single band at the B124 locus, strongly suggesting haploidy. These data show that honey bee queens have great, and quite possibly complete, ability to control the fertilization of the eggs they lay. Data from the literature suggest that in two species of parasitoid Hymenoptera (Copidosoma floridanum, Colpoclypeus florus) females have great, but not complete, ability to control fertilization. Received: 23 December 1997 / Accepted after revision: 17 May 1998     

The mutagenic activity of thirty polycyclic aromatic hydrocarbons (PAH) and oxides in urban airborne particulates

Data are presented on the mutagenicity of an organic extract of a composite sample of urban air particulates and of thirty PAH compounds in such samples, including four quinone derivatives, isolated quantitatively by thin-layer chromatography and identified by fluorescence or other spectral techniques. Mutagenic activity was determined by the Ames assay, using histidine auxotrophs of Salmonella typhimurium strains TA98, TA100, TA1537 and TA1538. All compounds were dissolved in dimethyl sulfoxide (DMSO) which was the least toxic of eight organic solvents tested.The mutagenic activity of a benzene extract of suspended particulates from the air of Hamilton, Ontario was significantly greater with strain TA98 than with strain TA100, suggesting the presence of more frame-shift acting mutagens. The mutagenic response of this extract was similar with and without S-9 activation.Mutagenic tests on the 30 PAH compounds indicated that only the benzo(a)pyrene quinones were direct acting mutagens. All of the chemical compounds were tested with and without S-9 activation. The following PAH showed unequivocal mutagenic activity, with S-9 activation: benz(a)anthracene, benzo-(a)pyrene, benzo(ghi)perylene, benzo(rst)pentaphene, benzophenanthrene, chrysene, 1, 2, 3, 4-dibenzanthracene, 2, 3, 6, 7-dibenzanthracene, and 3-methyl cholanthrene. The quinones of 1, 6-; 3, 6-; and 6, 12-benzo(a)pyrenes showed weak mutagenic activity but 3, 6-benzo(a)pyrene elicited also a photodynamic response.