PHYSIOLOGICAL AND BEHAVIORAL-EFFECTS OF CONIFERYL BENZOATE ON AVIAN REPRODUCTION

Various plant secondary metabolites related to cinnamic acid are of in terest because of their repellency to birds and their occurrence in ec ologically important food items. Coniferyl benzoate (CB), a phenylprop anoid ester that occurs in quaking aspen (Populus tremuloides) is of p articular ecological interest because of its effect on ruffed grouse ( Bonasa umbellus) feeding behavior and its possible influence on the po pulation dynamics of this bird. During detoxification processes, CB an d other analogous compounds are metabolized into by-products, such as ferulic acid (FA), that can cause antireproductive effects. We tested whether consumption of CB produces antire-productive effects similar t o FA using male and female Japanese quail (Coturnix coturnix) as avian models for ruffed grouse. The parameters we investigated included: th e production, morphology, and development of eggs; reproductive charac teristics influenced by estrogen; serum prolactin levels; and male rep roductive behavior. Dietary CB did not produce antireproductive effect s similar to FA at intake levels that Japanese quail and ruffed grouse would freely consume. Consumption of CB by Japanese quail significant ly reduced egg production and body mass but did not affect male reprod uctive performance. Coniferyl benzoate's effect on egg production may be explained by lower energy acquisition and retention rather than end ocrine changes per se. Contrary to previous reports, it is unlikely th at FA, or similar compounds act directly as estrogen mimics or antagon ists. Although, CB did reduce egg production in quail, it is unlikely that it would affect egg production in wild ruffed grouse. Detoxificat ion costs and the effects of CB on nutrient utilization may explain wh y ruffed grouse avoid high dietary levels of CB.