Winemiller K O, Rose K A
Am Nat. 1993 Oct;142(4):585-603. doi: 10.1086/285559.
A simulation model containing size-based rules for foraging, growth, and probability of survival was created to track the fates of pelagic larval fish. The relative success of cohorts comprised of equivalent initial biomass but containing different numbers and sizes of first-feeding larvae was compared in environments having different levels of patchiness and densities of food resources. In environments containing randomly distributed prey, the rate of growth and probability of survival were always greater, and duration of the larval stage was shorter for larger larvae due to the size-based rules. Broods comprised of fewer but larger first-feeding larvae resulted in the greatest number of survivors in low-prey-density environments. In prey-rich environments, broods containing the same initial biomass divided into greater numbers of small first-feeding larvae resulted in more survivors. This result occurred despite the fact that, on a per-individual basis, survival rate was much lower initially in larger broods. We used a negative binomial algorithm to generate encounter probabilities with patchily distributed prey on small spatial scales in which the previous day's experiences had no relationship to current probabilities for encounter. In prey-poor environments, the strategy of producing fewer large larvae was superior at all levels of small-scale prey patchiness. In prey-rich environments, broods containing larger numbers of smaller larvae resulted in more survivors in simulations for randomly distributed and moderately clumped prey. With greater clumping of prey, the greatest number of survivors resulted from the strategy of producing fewer but larger larvae. To examine the effect of large-scale prey patchiness, we solved for the percentage of a larval cohort that would have to settle and remain within a prey-rich patch, in order for a strategy of producing many small larvae to yield more survivors than a strategy of producing fewer larger larvae under the same conditions. When prey patches contained 200 prey/L (compared with 50 prey/L outside) and as few as 1% of the brood settled into the prey-rich patches, large broods comprised of 3-mm larvae yielded more survivors than small broods comprised of 10-mm larvae. Our simulations indicate that the superior evolutionary strategy is the investment in larger numbers of smaller eggs when resources are patchy on a relatively large spatial scale.
创建了一个包含基于大小的觅食、生长和生存概率规则的模拟模型，以追踪浮游幼鱼的命运。在具有不同斑块程度和食物资源密度的环境中，比较了由等量初始生物量但包含不同数量和大小的初次摄食幼鱼组成的同生群的相对成功情况。在包含随机分布猎物的环境中，由于基于大小的规则，较大幼鱼的生长速率和生存概率总是更高，幼体阶段的持续时间更短。在低猎物密度环境中，由较少但较大的初次摄食幼鱼组成的亲体产生的幸存者数量最多。在猎物丰富的环境中，包含相同初始生物量但分成更多数量小初次摄食幼鱼的亲体产生的幸存者更多。尽管事实上，就个体而言，较大亲体中的初始存活率要低得多，但仍出现了这一结果。我们使用负二项式算法来生成在小空间尺度上与斑块状分布猎物的相遇概率，其中前一天的经历与当前的相遇概率无关。在猎物匮乏的环境中，在所有小尺度猎物斑块程度水平下，产出较少大型幼鱼的策略更具优势。在猎物丰富的环境中，对于随机分布和中等聚集的猎物，包含更多较小幼鱼的亲体在模拟中产生的幸存者更多。随着猎物聚集程度增加，产出较少但较大幼鱼的策略产生的幸存者数量最多。为了研究大规模猎物斑块的影响，我们求解了一个幼鱼同生群中必须在富含猎物的斑块中定居并留存的百分比，以便在相同条件下，产出许多小幼鱼的策略比产出较少大型幼鱼的策略产生更多幸存者。当猎物斑块中含有200个猎物/升（与外部的50个猎物/升相比）且只有1%的亲体定居到富含猎物的斑块中时，由3毫米幼鱼组成的大型亲体产生的幸存者比由10毫米幼鱼组成的小型亲体更多。我们的模拟表明，当资源在相对较大的空间尺度上呈斑块状分布时，更优的进化策略是投资产出更多数量的较小卵。
