Effects of endomycorrhizal infection, artificial herbivory, and parental cross on growth of Lotus corniculatus L.

We examined how combinations of parentage, fungicide application, and artificial herbivory influence growth and shoot phosphorus content in pre-reproductive Lotus corniculatus, using young offspring arising from three parental crosses, two of which had one parent in common. Soil with vesicular-arbuscular mycorrhizal (VAM) fungi was treated with either water or benomyl, an anti-VAM fungicide, and added to trays containing groups of four full siblings. There were two experiments; in the first no plants were clipped while in the second two of the four plants were clipped to simulate herbivory. In both experiments plants of the two related crosses accumulated more biomass and total shoot P than did plants of the third cross. Plants inoculated with watertreated soil had greater shoot mass and P concentration than did fungicide-treated replicates but the extent of increase in P concentration varied among crosses. In Experiment 2, clipping reduced root mass and resulted in higher shoot P concentration. In this experiment there was a significant interaction of fungicide application and clipping: both unclipped and clipped plants grew better in soil not treated with fungicide, but the increase in shoot mass, total mass, and total P was greater in unclipped plants. Significant interaction of fungicide treatment and clipping is most likely due to reduced availability of carbon to the roots of clipped plants, resulting in poorer symbiotic functioning.

Social preferences of domestic hens for domestic vs. red junglefowl males and females.

The striking dimorphism of male and female junglefowl may have evolved in large part due to female choice of mates. However, domestic fowl hens consistently chose domestic, not junglefowl, males as well as females in preference tests. Either genetic predisposition to favor junglefowl morphological features over those of the domestic types utilized in these tests was overridden by experience or such genetic predisposition does not exist in the breed we tested.

Fruit composition and patterns of fruit dispersal of two Cornus spp.

Fruiting phenology and pattern of fruit removal of two shrubby dogwoods were examined in relation to fruit composition. It was predicted that fruit of the species bearing high fat fruit would disappear more rapidly and fall to the ground sooner than fruit of the species bearing low fat fruit. Field observation at two sites in central Pennsylvania contradicts these predictions. C. racemosa fruit, containing relatively high concentrations of crude fat, were retained on plants longer and fell into fruit traps later than c. amomum fruit, containing relatively low concentrations of crude fat. A substantial portion of the crops of both species fell under plants and most fallen fruit were secondarily removed. Potential explanations for patterns observed in this study are discussed.