Data from: Increases in predation favor evolutionary shifts in behavioral plasticity in Trinidadian killifish

Behavioral plasticity is expected to be favored in risky environments,
such as when prey species coexist with predators, because prey must
alternate between fitness related foraging/mating behaviors and
antipredator behaviors that enhance survival. We compared behavioral
plasticity in Trinidadian killifish that are found in sites with and
without predators. We quantified aggressive and antipredator behaviors via
a mirror assay in second-generation lab-reared and wild-caught killifish
before and after exposure to predator cues. We compared two types of
aggression including: overt aggression (ramming, biting, lunging,
tail-slapping) and display aggression (spine arching, bending into an
s-shape, and opercular flaring). We additionally compare the amount of
time the fish spent frozen as a proxy for anti-predator behavior. We show
clear differences in plasticity between populations with and without
predators. Killifish from sites with predators decreased overt aggression
in response to exposure to predator chemical cues. Killifish from sites
that lack predators showed a higher degree of canalization in aggression
presumably due to the high competition they face in those locales.
Interestingly, wild fish from sites without predators retain the ability
to detect the predator cue and respond by decreasing overt aggression and
increasing time spent frozen, though to a lesser degree compared to the
fish from sites with predators. Our results support the expectations that
development in a risky environment favors evolutionary changes in
predator-mediated behavioral plasticity.

行为可塑性（behavioral plasticity）被认为在高风险环境中更具选择优势，例如当猎物物种与捕食者共存时——此时猎物需在关乎自身适合度的觅食、交配行为，与提升生存概率的反捕食行为之间进行权衡切换。本研究以特立尼达鳉（Trinidadian killifish）为实验对象，对比了栖息于有捕食者与无捕食者生境的种群间的行为可塑性差异。我们通过镜像实验（mirror assay），分别在暴露于捕食者信号前后，对实验室繁育二代个体以及野生捕获个体的攻击行为与反捕食行为进行量化分析。我们对比了两类攻击行为：一是显性攻击（包括顶撞、撕咬、猛冲、拍尾），二是展示型攻击（包括脊柱拱起、身体弯折为S形、鳃盖扩张），同时将鱼类的静止时长作为反捕食行为的替代指标进行统计。研究结果清晰展现了有捕食者种群与无捕食者种群间的可塑性差异：栖息于有捕食者生境的鳉鱼，在暴露于捕食者化学信号后，其显性攻击行为会显著降低；而栖息于无捕食者生境的鳉鱼，其攻击行为表现出更高的渠限化（canalization）程度，推测源于该生境中较高的种内竞争压力。值得注意的是，无捕食者生境的野生鳉鱼仍保留了探测捕食者信号的能力，并会通过降低显性攻击、增加静止时长来做出响应，不过其响应程度弱于有捕食者生境的鳉鱼。本研究结果支持了相关假说：高风险环境中的发育过程，会推动捕食者介导的行为可塑性发生适应性进化改变。