Department of Agriculture, Crop Production and Rural Environment, University of Thessaly, Phytokou Street, N. Ionia 384 46 Magnisias, Greece.
J Insect Physiol. 2011 Oct;57(10):1368-74. doi: 10.1016/j.jinsphys.2011.07.004. Epub 2011 Jul 27.
Although age-based effects on the reproductive success of males have been reported in several animal taxa the cost of aging on male mating success in lekking species has not been fully explored. We used the Mediterranean fruit fly, a lekking species, to investigate possible cost of aging on male reproductive success. We performed no choice and choice mating tests to test the hypothesis that aging does not affect the mating performance (mating success in conditions lacking competition) or the mating competitiveness (mating success against younger rivals) of males. The mating probability of older males decreased significantly when competing with younger males. Aging gradually reduced the mating performance of males but older males were still accepted as mating partners in conditions lacking competition. Therefore, older males are capable of performing the complete repertoire of sexual performance but fail to be chosen by females in the presence of young rivals. Older males achieved shorter copulations than younger ones, and female readiness to mate was negatively affected by male age. Older and younger males transferred similar amount of spermatozoids to female spermathecae. Females stored spermatozoids asymmetrically in the two spermathecae regardless the age of their mating partner. Aging positively affected the amount of spermatozoids in testes of both mated and nonmated males. No significant differences were observed on the amount of spermatozoids between mated and nonmated males.
尽管在几个动物类群中已经报道了年龄对雄性生殖成功的影响，但在领地性物种中，衰老对雄性交配成功的代价尚未得到充分探讨。我们使用地中海果蝇（一种领地性物种）来研究衰老对雄性生殖成功的可能代价。我们进行了无选择和选择交配测试，以检验以下假设：衰老不会影响雄性的交配表现（在没有竞争的情况下的交配成功率）或交配竞争力（与年轻对手竞争的交配成功率）。与年轻雄性竞争时，老年雄性的交配概率显著下降。衰老逐渐降低了雄性的交配表现，但在没有竞争的情况下，老年雄性仍然被接受为交配伙伴。因此，老年雄性能够表现出完整的性行为，但在年轻对手存在的情况下，雌性不会选择它们。老年雄性的交配时间比年轻雄性短，而雌性的交配意愿受到雄性年龄的负面影响。老年和年轻雄性向雌性的精包中转移的精子数量相似。无论其交配伙伴的年龄如何，雌性都会将精子不对称地储存在两个精包中。衰老会增加交配和未交配雄性的睾丸中精子的数量。在交配和未交配雄性的精子数量方面没有观察到显著差异。
