Immune investment and sperm competition in a beetle
Immune investment and sperm competition in a beetle
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DOI：
10.1046/j.1365-3032.2002.00290.x
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发表时间：
2002-09-01
影响因子：
1.5
通讯作者：
Siva-Jothy, MT
中科院分区：
文献类型：
--
作者：
Drnevich, JM;Barnes, AI;Siva-Jothy, MT
在免疫力上投入更多的人可能无法在其他生活史特征上投入同样多的钱。对适应度的总体影响取决于生活史性状投资的平衡，不必要的免疫投资可能会降低适应度。成年粉虫甲虫（tenbrio molitor L.）根据幼虫对感染风险的感知来调节其投资；投资的多少可以通过身体的颜色来评估。在不存在免疫挑战的情况下，这种预防性免疫投资可用于评估投资成本。昆虫的另一个重要的适应性特征——精子竞争能力是否与免疫力的投资相抵消，这一问题也得到了研究。在免疫力方面投入较多的雄性（深色雄性）与投入较少的雄性（浅色雄性）竞争后代的受精。随着时间的推移，深色的雄性确实失去了精子优先权，而浅色的雄性则没有。然而，在正常的雌性交配频率下，精子攻击能力的下降可能不会导致深色雄性的适应性下降；后代数量的减少并没有在一周内发生，但是那些经常接触雄性的雌性每天交配一次，这将抵消雄性交配顺序的任何长期影响。因此，对免疫的预防性投资不会立即降低男性获得受精的能力。免疫投资的成本可能由T. molitor的其他适合性状承担。
Individuals that invest more in immunity may not be able to invest as much in other life history traits. The overall effects on fitness depend on the balance of investment in life history traits and unnecessary investment in immunity may lower fitness. Adult mealworm beetles (Tenebrio molitor L.) modulate their investment according to the perceived risk of infection as larvae; the amount of investment can be assessed by body coloration. This prophylactic investment in immunity can be used to assess the costs of investment when no immune challenge is present. Whether investment in immunity is traded off against sperm competitive ability, another important fitness trait in insects, was investigated. Mates that had invested more in immunity (dark males) competed against males that had invested less (light males) for fertilization of offspring. Dark males did lose sperm precedence over time, whereas light males did not. However, this decrease in sperm offensive ability may not result in decreased fitness for darker males under normal female mating frequencies; the decrease in offspring did not occur for I week, but females that have constant access to males mate once a day, which would negate any long-term effects of male mating order. Thus, prophylactic investment in immunity does not produce immediate reductions in a male's ability to gain fertilizations. The costs to immune investment may be born by other fitness traits in T. molitor.