For more than 20 years, sex allocation in hymenopteran societies has been a major topic in insect sociobiology. A recurring idea was that relatedness asymmetrics arising from their haplodiploid sex determination system would lead to various parent-offspring conflicts over optimal reproduction. A possible weakness of existing theory is that only interests of nuclear genes are properly accounted ...

Thin sections of an anaerobic filamentous oral organism possibly related to Leptotrichia buccalis have been examined in the electron microscope. The organism exhibited a cell wall profile characteristic of Gram-negative bacteria, viz. a solid membrane and an outer double-layered membrane. The outer membrane could be removed by treating intact cells with trypsin or phenolwater. The organism cont...

Micro-organism populations on the leaf surface can be an indicator of environmental health in orchards. A method was developed to detect changes in these populations in apple orchards. Firstly, the variation within orchards was investigated by sampling leaves from seven locations within four trees in spring and autumn. The population density and species richness of micro-organisms when grown on...

A thermoacidophilic micro-organism, isolated from volcanic hot springs near Naples, was cultivated in vitro, and examined by electron microscopy in sections and after negative staining. The cells were almost spherical, with a diameter of about 0.7 to 1.0 mum. Their morphology was very primitive: the protoplasm was composed only of ground cytoplasm, ribosomes, and randomly distributed DNA strand...