There are two prominent, nonmutually exclusive hypotheses to explain the timing of reproduction in animals: energetic constraint and adaptive behaviour. 2. We tested these hypotheses by quantifying the costs and benefits of nesting at different times in the season for male bluegill sunfish Lepomis macrochirus, a species with paternal care, in Lake Opinicon (Ontario, Canada). 3. The value of nesting at different times during the breeding season (RSb) was determined from spawning individuals as RSb = Pb x Cb x Sb x Ob, where Pb is the probability of spawning during each bout b, Cb is the expected brood size, Sb is the expected brood survivorship to 'swim-up', and Ob is the survivorship of free-swimming fry to age 1 year. 4. The results show that the value of nesting peaks during the middle of the season. However, nesting patterns varied with male condition and not all males nested at the peak. 5. Larger males, which were able to nest multiple times, first nested early in the season when overwinter survivorship of offspring and renesting opportunities later in the season were maximized. These males had the highest seasonal reproductive success. 6. Smaller males, which nested a single time, delayed nesting until the middle of the season when spawning opportunities and brood sizes were greatest. 7. These data suggest that both energetics and adaptive behaviour play roles in determining the timing of reproduction.
摘要
有两种显著且并非相互排斥的假说来解释动物繁殖的时间安排：能量限制和适应性行为。2. 我们通过量化在加拿大安大略省奥皮尼康湖，雄性蓝鳃太阳鱼（Lepomis macrochirus）（一种有亲代抚育行为的物种）在季节中不同时间筑巢的成本和收益，来检验这些假说。3. 繁殖季节不同时间筑巢的价值（RSb）由产卵个体确定，公式为RSb = Pb x Cb x Sb x Ob，其中Pb是每次产卵回合b中产卵的概率，Cb是预期的窝卵数，Sb是预期的窝卵存活到“上浮期”的概率，Ob是自由游动的鱼苗存活到1岁的概率。4. 结果表明，筑巢价值在季节中期达到峰值。然而，筑巢模式因雄性个体状况而异，并非所有雄性都在峰值时筑巢。5. 体型较大、能够多次筑巢的雄性，在季节早期首次筑巢，此时后代的越冬存活率和后期的再次筑巢机会最大化。这些雄性具有最高的季节性繁殖成功率。6. 体型较小、只筑巢一次的雄性，将筑巢推迟到季节中期，此时产卵机会和窝卵数最大。7. 这些数据表明，能量学和适应性行为在决定繁殖时间方面都发挥着作用。
