The use of multivariate morphometric methods in the separation of alate morphs of the rose-grain aphid, Metopolophium dirhodum

A preliminary morphometric analysis of alate Metopolophium dirhodum was carried out. The alate morphs studied were: gynoparae and alate emigrants (collected from Rosa), summer exules (collected from maize in the field and from wheat in the laboratory) and winter exules (collected from grasses). Comparing the different morphs using canonical discriminant function analysis gave good separations (always in excess of 80% and often 100%). If this result is found to hold for specimens from a wider temporal and geographical range, it may be used to determine the sources of flying alatae, particularly spring colonists.     

Do Protoplasmic Connections Function in the Phototactic Coordination of the Volvox Colony During Light Stimulation?*

SYNOPSIS. The flagellar behavior of the colonial flagellates Volvox carteri Stein and Volvox perglobator Powers was examined by placing 1.01 μm polystyrene particles in solution with swimming colonies, and photographing these particle movements. When directional light stimulation was administered to individual colonies, a cessation of flagellar activity occurred in the anterior cells of the stimulated side in both species. Since Volvox perglobator possesses prominent intercellular connections and Volvox carteri does not, the results of these experiments suggest that the connections linking colony members in some species do not function in the coordination of flagellar activity associated with light orientation behavior.