Jiang Demeng, Sieving Kathryn E, Meaux Estelle, Goodale Eben
Guangxi Key Laboratory of Forest Ecology and Conservation College of Forestry Guangxi University Nanning China.
Department of Wildlife Ecology & Conservation University of Florida Gainesville FL USA.
Ecol Evol. 2020 Apr 24;10(12):5368-5382. doi: 10.1002/ece3.6280. eCollection 2020 Jun.
Animals acquire information produced by other species to reduce uncertainty and avoid predators. Mixed-species flocks (MSFs) of birds are ubiquitous in forest ecosystems and structured, in part, around interspecific information transfer, with "nuclear" species providing information that other species eavesdrop on. We hypothesized that in a seasonal tropical forest, the amount of information produced by birds about predation would be dynamic and particularly would decrease inside MSFs when the nuclear species leave MSFs to breed. We obtained baseline information on MSF encounter rate and species composition along established sampling routes over 9 months near the Sino-Vietnamese border. We also conducted three experiments to quantify information produced by different species in response to typical predator encounters, including a moving predator stimulus presented inside of MSFs, and a stationary predator model presented both inside and outside of MSFs. MSFs were much less frequent in the breeding season with fewer individuals of the nuclear species, David's Fulvetta (), participating, though the diversity of other species remained stable. Fulvettas were the dominant producer of alarm-related information both to the moving and stationary stimuli in MSFs and were also among the most active mobbers to stimuli presented outside of MSFs. In the breeding season, they tended to call less to the moving stimulus, and substantially fewer individuals responded to the in-flock stationary stimulus. Other species increased their own information production at stationary predator stimuli (inside and outside of MSFs) during the breeding season, perhaps due to their increased investment in offspring during this time. Yet even during the breeding season, David's Fulvetta remained the highest producer of information about predators in MSFs. Hence, while we show that information production in MSFs can be somewhat dynamic, we describe a continually asymmetric communication system, in which a nuclear species is important to the whole community.
动物获取其他物种产生的信息以减少不确定性并躲避捕食者。鸟类的混合物种群落在森林生态系统中普遍存在，并且部分是围绕种间信息传递构建的，“核心”物种提供信息供其他物种窃听。我们假设在季节性热带森林中，鸟类产生的关于捕食的信息量是动态的，特别是当核心物种离开混合物种群落去繁殖时，混合物种群落内的信息量会减少。我们沿着中越边境附近既定的采样路线，在9个月内获取了关于混合物种群落遭遇率和物种组成的基线信息。我们还进行了三个实验，以量化不同物种在面对典型捕食者遭遇时产生的信息，包括在混合物种群落内呈现移动的捕食者刺激，以及在混合物种群落内外都呈现静止的捕食者模型。在繁殖季节，混合物种群落的出现频率要低得多，参与的核心物种黄腹山雀个体较少，不过其他物种的多样性保持稳定。黄腹山雀是混合物种群落中对移动和静止刺激产生与警报相关信息的主要生产者，也是对混合物种群落外呈现的刺激最活跃的围攻者之一。在繁殖季节，它们对移动刺激的鸣叫往往减少，对群落内静止刺激做出反应的个体也大幅减少。在繁殖季节，其他物种在面对静止的捕食者刺激（在混合物种群落内外）时增加了自身的信息产生，这可能是因为它们在这段时间对后代的投入增加。然而，即使在繁殖季节，黄腹山雀仍然是混合物种群落中关于捕食者信息的最高生产者。因此，虽然我们表明混合物种群落中的信息产生可能有点动态，但我们描述了一个持续不对称的通信系统，其中一个核心物种对整个群落很重要。
