Steele C, Skinner C, Steele C, Alberstadt P, Mathewson C
Biol Bull. 1999 Jun;196(3):295-302. doi: 10.2307/1542954.
The feeding responses of decapod crustaceans to chemical stimuli have most often been evaluated in terms of one defining act, ignoring the organization of the behavior. To gain greater insight into foraging behavior, we considered the organization of food-search behavior in evaluating the responses of two species of crayfishes to a feeding stimulant. We also examined the effects of food deprivation on the behavioral organization and whether a behavioral dichotomy exists between food search and feeding behavior in these species. Individual crayfish of the species Procambarus clarkii and Orconectes rusticus were presented with infusions of a feeding stimulant consisting of a supernatant leachate of 100 ml water and 1 g of fish flakes. The stimulant was injected with a syringe and small-bore plastic infusion tubing into the center of a behavioral arena 25 cm square and 15 cm deep. Total injection time was 20 s. Experimental groups were presented with either the full-strength leachate (100%) or one of five dilutions: 75%, 50%, 25%, 10%, or 0% (controls) of full-strength. The feeding stimulant was presented either the day after the crayfish were fed or after one week of food deprivation. We analyzed three components of food-search behavior--detection, probing (near-field search), and locomotion (far-field, or distant, search)--recording the order of occurrence and the latency time to initiation for each behavior. When presented with the stimulus following regular feeding, both species responded to concentrations {ge}50% full-strength with probing behavior (near-field search) prior to locomotion, and to concentrations <50% full-strength with locomotion prior to, or even in the absence of, probing. Detection always occurred first. These results indicate that chemical stimuli preferentially activate distant food search in both species and that a behavioral dichotomy exists between food search and feeding behavior. One week of food deprivation had no effect on the organization of food-search behavior in P. clarkii; however, groups of unfed O. rusticus presented with 25% and 10% full-strength concentrations probed prior to locomotion, indicating a change in behavioral organization.
十足目甲壳动物对化学刺激的摄食反应通常是根据一种定义行为来评估的，而忽略了行为的组织性。为了更深入地了解觅食行为，我们在评估两种小龙虾对摄食刺激物的反应时考虑了食物搜索行为的组织性。我们还研究了食物剥夺对行为组织的影响，以及在这些物种中食物搜索和摄食行为之间是否存在行为二分法。给克氏原螯虾和铁锈色螯虾的个体注射一种摄食刺激物，该刺激物由100毫升水和1克鱼片的上清液浸出液组成。用注射器和小口径塑料输液管将刺激物注入一个边长25厘米、深15厘米的行为竞技场中心。总注射时间为20秒。实验组接受的是原液（100%）或五种稀释液之一：原液的75%、50%、25%、10%或0%（对照组）。摄食刺激物在小龙虾进食后的第二天或禁食一周后呈现。我们分析了食物搜索行为的三个组成部分——检测、探查（近场搜索）和移动（远场或远距离搜索）——记录每种行为发生的顺序和开始的潜伏时间。在正常喂食后给予刺激时，两种物种对浓度≥50%原液的反应是在移动之前先进行探查行为（近场搜索），而对浓度<50%原液的反应是在探查之前甚至没有探查时就进行移动。检测总是首先发生。这些结果表明，化学刺激物在两种物种中都优先激活远距离食物搜索，并且食物搜索和摄食行为之间存在行为二分法。一周的食物剥夺对克氏原螯虾的食物搜索行为组织没有影响；然而，未喂食的铁锈色螯虾组在接受25%和10%原液浓度刺激时在移动之前进行了探查，这表明行为组织发生了变化。
