Negative effects of elevated testosterone on female fecundity in zebra finches.

摘要: Although factors influencing androgen deposition in the avian egg and its effects on nestling fitness are recently receiving considerable attention, little is known about potential costs of high testosterone levels females. Our study aimed at determining effect injections (T) female zebra finches (Taeniopygia guttata), clutch size, mass, yolk content. Females were given a single bolus injection T range doses after laying first egg. Results show that administration negatively affected size; strength this increased with increasing T. injected highest dose showed suppressed oviposition third fourth eggs. Interestingly, made females produce eggs relatively large yolks, suggesting may mediate trade-off between number size Testosterone resulted elevated eggs, contrast to control clutches, which decreasing pattern concentration along sequence. We conclude investment be limited by physiological requirements ovulatory process.