Hõrak P, Tegelmann L, Ots Indrek, Møller Anders Pape
Institute of Zoology and Botany, Riia 181, EE-51014 Tartu, Estonia, , , , , , EE.
Institute of Zoology and Hydrobiology, Tartu University, Vanemuise 46, EE-51014 Tartu, Estonia, , , , , , EE.
Oecologia. 1999 Nov;121(3):316-322. doi: 10.1007/s004420050934.
Life history theory predicts a trade-off between number and quality of offspring. Reduced quality with increasing brood size may arise from a decrease in body condition or in immunocompetence that would be important in fighting off virulent parasites by immunologically naive offspring. We tested the effect of rearing conditions on immune function of nestling great tits (Parus major) by reducing or increasing broods by two hatchlings. In the middle of the nestling period (on day 8), nestlings from enlarged broods developed lower T cell responses [as measured from the cutaneous swelling reaction to injection with phytohaemagglutinin (PHA)] and tended to have lower total leukocyte and lymphocyte concentrations in their peripheral blood than nestlings from reduced broods. Brood size manipulation affected the PHA response of nestlings most strongly in small clutches, suggesting that nestling immune function was dependent on their parents' condition, as estimated by original clutch size. Intra-brood differences in nestling mortality were unrelated to immune parameters, but nestlings in broods without mortality had a stronger PHA response, higher concentration of lymphocytes and higher body mass on day 15 than nestlings in broods with mortality. These results support the prediction that the immune function of altricial birds is affected by rearing conditions, and that growth and immune parameters are related to inter-brood differences in nestling survival.
生活史理论预测了后代数量与质量之间的权衡。随着窝雏数增加而质量下降，可能源于身体状况或免疫能力的降低，而这对于免疫功能尚未成熟的后代抵御毒性寄生虫至关重要。我们通过将窝雏数增加或减少两只雏鸟，来测试育雏条件对大山雀（Parus major）雏鸟免疫功能的影响。在雏鸟期中期（第8天），与来自窝雏数减少的雏鸟相比，来自窝雏数增加的雏鸟T细胞反应较低[通过对注射植物血凝素（PHA）后的皮肤肿胀反应来测量]，并且外周血中的总白细胞和淋巴细胞浓度往往更低。窝雏数操纵对小窝雏的雏鸟PHA反应影响最大，这表明雏鸟的免疫功能取决于其父母的状况，可通过原始窝雏数来估计。雏鸟死亡率的窝内差异与免疫参数无关，但在第15天，无死亡雏鸟的窝中的雏鸟比有死亡雏鸟的窝中的雏鸟具有更强的PHA反应、更高的淋巴细胞浓度和更高的体重。这些结果支持了以下预测：晚成鸟的免疫功能受育雏条件影响，并且生长和免疫参数与雏鸟存活的窝间差异有关。
