Economic foraging in a floral marketplace: Asymmetrically dominated decoy effects in bumblebees

While most models of decision-making assume that individuals assign options absolute values, animals often assess options comparatively, violating principles of economic rationality. Such ‘irrational’ preferences are especially common when two rewards vary along multiple dimensions of quality and a third, ‘decoy’ option is available. Bumblebees are models of decision-making, yet whether they are subject to decoy effects is unknown. We addressed this question using bumblebees (Bombus impatiens) choosing between flowers that varied in their nectar concentration and reward rate. We first gave bees a choice between two flower types, one higher in concentration and the other higher in reward rate. Bees were then given a choice between these flowers and either a ‘concentration’ or ‘rate’ decoy, designed to be asymmetrically dominated on each axis. The rate decoy increased bees’ preference in the expected direction, while the concentration decoy did not. In a second experiment, we manipulated ..., a)  Study system We conducted experiments with bumblebees (Bombus impatiens) (n=103) from commercially-reared queenright colonies (n = 8) (Koppert, USA); sample sizes per colony are shown in Table S1. Colonies were maintained in small boxes (~40cm3) on 30% (w/w) sucrose solution and honeybee-collected pollen (~0.5g/day, Koppert Biological Systems, USA). We connected colonies sequentially to a flight arena (l × w × h: 122 × 61 × 61 cm), using a clear plastic tube with sliding doors to control the entry and exit of bees into the arena. The floor of the flight arena was lined with green laminate and the sides and top consisted of black mesh screens. The arena was lit from above by a 40-watt LED light placed atop the arena and the room was illuminated with fluorescent light on a 12/12-hour light/dark schedule. b)  Experimental arrays and floral stimuli The vertical arrays used for experiments consisted of black corrugated plastic sheets with 24 holes for ‘flowers’ arranged in a 6 × 4 grid. ..., , # Economic foraging in a floral marketplace: Asymmetrically dominated decoy effects in bumblebees [https://doi.org/10.5061/dryad.08kprr5bb](https://doi.org/10.5061/dryad.08kprr5bb) There are two datasets: Decoy.data.csv and decoy4data.csv ## Description of the data and file structure #### Decoy.data.csv The concentration of the flower chosen was used to calculate the proportion of visits to each flower type out of the total number of visits. Column A: Bee identification (number) Column B: Bee identification (color) Column C: Colony identification (letter) Column D: Date of data collection Column E: Treatment name (Binary, Trinary 1, Trinary 2) Column F: Treatment renamed (Binary, Concentration trinary, Rate trinary) Column G: Visit number Column H: Trinary number Column I: Visit number within a trial Column J: Flower color (B=blue, Y=yellow) Column K: Flower state (empty or full) Column L: Concentration of sucrose reward (20%, 30%, 40%, or 50%) Column M: Concentration ...虽然绝大多数决策模型均假定个体为选项赋予绝对价值，但动物往往通过相对比较评估选项，违背了经济理性原则。这类「非理性」偏好尤其常见于两种奖励在多个质量维度上存在差异，且存在第三种「诱饵」选项的情境。熊蜂是决策研究的经典模式生物，但目前尚不清楚它们是否会受诱饵效应影响。本研究以甘蓝熊蜂（Bombus impatiens）为研究对象，让其在花蜜浓度与报酬率存在差异的人工花朵间做出选择。实验首先让熊蜂在两种花型间开展选择：一种花蜜浓度更高，另一种报酬率更高。随后，再让熊蜂在这两种花型与分别针对浓度、报酬率设计的诱饵选项中做选择，这些诱饵在各维度上均呈非对称占优状态。结果显示，报酬率诱饵可使熊蜂的偏好朝预期方向增强，而浓度诱饵则未产生该效应。在第二项实验中，我们对……进行了操控。 a) 研究系统 本研究使用了来自美国Koppert公司商业化饲养的8个有王蜂群的103只甘蓝熊蜂（Bombus impatiens），各蜂群的样本量详见附表S1。蜂群饲养于体积约40cm³的小型箱盒中，饲喂30%（质量分数）蔗糖溶液及蜜蜂采集的花粉（每日约0.5g，购自美国Koppert Biological Systems）。通过带滑动门的透明塑料管将蜂群依次连接至飞行竞技场（长×宽×高：122×61×61 cm），以控制熊蜂进出竞技场。飞行竞技场地面铺有绿色饰面板，侧壁与顶部采用黑色尼龙网。竞技场上方由置于顶部的40瓦LED灯提供照明，饲养室采用荧光灯照明，维持12小时光照/12小时黑暗的光周期。 b) 实验阵列与花卉刺激材料 本实验使用的垂直阵列由黑色瓦楞塑料板制成，板上设有24个用于模拟花朵的孔洞，呈6×4网格排布。…… # 花卉市场中的经济性觅食：熊蜂的非对称占优诱饵效应 https://doi.org/10.5061/dryad.08kprr5bb 本数据集包含两个文件：Decoy.data.csv 与 decoy4data.csv ## 数据与文件结构说明 #### Decoy.data.csv 通过所选花朵的花蜜浓度，可计算各花型在总访问次数中的占比。 列A：熊蜂编号（数字标识） 列B：熊蜂颜色标识 列C：蜂群编号（字母标识） 列D：数据采集日期 列E：处理组名称（二项组、三项组1、三项组2） 列F：重命名后的处理组名称（二项组、浓度三项组、报酬率三项组） 列G：访问序号 列H：三项组编号 列I：单轮实验内的访问序号 列J：花朵颜色（B=蓝色，Y=黄色） 列K：花朵状态（空/已满） 列L：蔗糖奖励浓度（20%、30%、40%或50%） 列M：浓度……