Charpentier Corie L, Cohen Jonathan H
School of Marine Science and Policy, College of Earth, Ocean and Environment, University of Delaware, 700 Pilottown Road, Lewes, DE, 19958, USA.
Department of Marine and Coastal Sciences, Institute of Earth, Ocean, and Atmospheric Sciences, Rutgers University, 71 Dudley Rd, New Brunswick, NJ, 08901, USA.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2018 Feb;204(2):197-208. doi: 10.1007/s00359-017-1230-4. Epub 2017 Nov 21.
Chemical cues from fish, or kairomones, often impact the behavior of zooplankton. These behavioral changes are thought to improve predator avoidance. For example, marine and estuarine crustacean zooplankton become more sensitive to light after kairomone exposure, which likely deepens their vertical distribution into darker waters during the day and thereby reduces their visibility to fish predators. Here, we show that kairomones from an estuarine fish induce similar behavioral responses in adult brine shrimp (Artemia franciscana) from an endorheic, hypersaline lake, Great Salt Lake, Utah, USA. Given downwelling light stimuli, kairomone-exposed A. franciscana induce a descent response upon dimmer light flashes than they do in the absence of kairomones. Using extracellular electroretinogram (ERG) recordings, we also find that kairomones induce physiological changes in the retina that may lead to increased visual sensitivity, suggesting that kairomone-induced changes to photobehavior are mediated at the photoreceptor level. However, kairomones did not induce structural changes within the eye. Although A. franciscana inhabit endorheic environments that are too saline for most fish, kairomones from an estuarine fish amplify photobehavior in these branchiopod crustaceans. The mechanism for this behavioral change has both similarities to and differences from that described in marine malacostracan crustaceans.
鱼类释放的化学信号，即信息素，常常会影响浮游动物的行为。这些行为变化被认为有助于提高对捕食者的躲避能力。例如，海洋和河口的甲壳类浮游动物在接触信息素后对光线变得更加敏感，这可能会使它们在白天向更深的黑暗水域垂直分布，从而降低被鱼类捕食者发现的可能性。在此，我们表明来自河口鱼类的信息素会在美国犹他州大盐湖这个内陆高盐湖中的成年卤虫（Artemia franciscana）身上引发类似的行为反应。在向下的光刺激下，接触信息素的卤虫在较暗的闪光下比未接触信息素时更易引发下降反应。通过细胞外视网膜电图（ERG）记录，我们还发现信息素会在视网膜中引发生理变化，这可能导致视觉敏感度增加，这表明信息素诱导的光行为变化是在光感受器水平介导的。然而，信息素并未在眼睛内部引发结构变化。尽管卤虫栖息在内陆环境中，那里的盐分对大多数鱼类来说过高，但来自河口鱼类的信息素会增强这些鳃足类甲壳动物的光行为。这种行为变化的机制与海洋软甲亚纲甲壳动物中描述的机制既有相似之处，也有不同之处。
