ECOLOGY AND BREEDING PHENOLOGY OF LARVAL HYLA-ANDERSONII - THE DISADVANTAGES OF BREEDING LATE
ECOLOGY AND BREEDING PHENOLOGY OF LARVAL HYLA-ANDERSONII - THE DISADVANTAGES OF BREEDING LATE
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DOI：
10.2307/1938294
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发表时间：
1990-08-01
期刊：
影响因子：
4.8
通讯作者：
JOHNSON, EA
中科院分区：
文献类型：
--
作者：
MORIN, PJ;LAWLER, SP;JOHNSON, EA
利用松林树蛙（Hyla andersonii, Pine Barrens Treefrog）繁殖物候的自然变异，研究在繁殖季节不同时间孵化的后代在生长和存活方面是否存在差异。我们在12个人工池塘中研究了两组连续的水螅蝌蚪的生长和存活，并对可能与水螅发生季节性相互作用的水生昆虫和蟾蜍蝌蚪两种生物的丰度进行了控制。我们还测量了水生昆虫和蝌蚪的操作是否会引起水生植物丰度的季节性变化，以描述可能影响蝌蚪生长和生存的资源可用性的时间模式。孵卵间隔34 d，第一批孵卵在第二批孵卵前完成发育。单独或一起添加水生昆虫和蟾蜍蝌蚪对两组小鼠的存活率均无显著影响。虽然第一个种群的初始幼虫密度是第二个种群的1.5倍，但第一个种群比第二个种群存活更好，生长发育更快，蜕变体积更大。来自蟾蜍蝌蚪和昆虫的竞争，从相对于没有这些种间竞争者的对照组的生长速度降低推断，在第一组中比在第二组中更为明显，并且与蝌蚪的重要食物周藻的直立作物减少相吻合。虽然晚育会降低后代的生长和存活率，但晚育成虫适合度的潜在降低是有问题的，因为每只雌性每年的繁殖次数是不确定的。如果不同的亚种群只在季节的早期或晚期繁殖，如果我们的研究中看到的模式适用于自然池塘，那么繁殖延迟将是不利的。然而，如果晚些时候的繁殖意味着当年早些时候已经繁殖的成年企鹅产下更多的后代，那么在繁殖季节晚些时候生产更多的后代可能会增加适应性。
We exploited natural variation in the breeding phenology of Hyla andersonii, the Pine Barrens Treefrog, to test whether offspring hatching at different times during the breeding season differed in growth and survival. We studied the growth and survival of two successive cohorts of Hyla tadpoles in 12 artificial ponds, where we also manipulated abundances of two kinds of organisms that might interact seasonally with Hyla: aquatic insects and Bufo tadpoles. We also measured whether the abundance of periphyton changed seasonally in response to manipulations of aquatic insects and tadpoles, to describe temporal patterns of resource availability that might affect tadpole growth and survival. Additions of hatchlings occurred 34 d apart, and the first cohort completed development before the addition of the second cohort. Additions of aquatic insects and Bufo woodhousii tadpoles, separately or together, did not significantly affect survival in either cohort. Although the initial larval density of the first cohort was 1.5 times that of the second, the first cohort survived better, grew and developed more rapidly, and metamorphosed at larger size than the second cohort. Competition from Bufo tadpoles and insects, as inferred from reduced growth rates relative to controls without these interspecific competitors, was more pronounced in the first cohort than in the second, and coincided with reduced standing crops of periphyton, an important food for tadpoles. Although breeding late in the season reduced the growth and survival of offspring, potential reductions in the fitness of late-breeding adults are problematic because of uncertainties about the number of breeding efforts made by each female each year. Breeding late would be disadvantageous if different subpopulations breed only early or only late in the season, and if the patterns seen in our study hold for natural ponds. However, if late breeding efforts represent additional clutches deposited by adults that have already reproduced earlier that year, production of additional offspring later in the season could increase fitness.