Abstract

Reef manta rays (Mobula alfredi) are social elasmobranchs that have structured societies and actively interact with preferred social partners. Being able to detect cues and signals produced by conspecifics is vital in enabling social behavior. Many elasmobranch species communicate via body and fin postures, but it is not yet known if or how mobulid rays communicate or respond to cues produced by conspecifics. These rays have specialized cephalic lobes that are highly flexible and used in feeding, but may have other functions such as gestural communication. In this study, we developed a standardized method to assess manta ray behavior in the wild via focal sampling and frame-by-frame video analysis. From observations recorded at cleaning stations in Raja Ampat, West Papua, we described various types of cephalic lobe positioning and movements made by free-ranging M. alfredi and investigated these in different behavioral contexts. We found that cephalic lobe curls were modulated when approaching both conspecifics and human divers, as well as during interactions with cleaner fish, suggesting that these lobes may be used in sensing water movements, olfactory sensing, and/or gestural communication. Cephalic lobes were moved independently of one another, but we found no evidence of individual laterality. The lack of chemosensory capacity on the lobes suggests that gestural communication is the most likely function, but further research is required to determine this. These results are informative in understanding the function of gestural communication in manta ray social interactions and add to our growing understanding of elasmobranchs’ sophisticated social behavior.

Significance statement

Social animals rely on communication and cues produced by conspecifics to respond to opportunities and threats. Many elasmobranch species use body and fin postures as gestural signals during competitive, courtship, and other social interactions. Reef manta rays (Mobula alfredi) are social elasmobranchs that form groups in near-shore, shallow water habitats. They possess paired, flexible cephalic lobes positioned on the side of the head which are specialized for feeding but may have a variety of functions. Here, we describe, quantify, and suggest likely explanations for the movement and positioning of cephalic lobes during various manta ray social behaviors, including conspecific, human, and cleaner fish interactions. Our results suggest that lobe movements may be used in detecting water movements, olfactory sensing, and/or gestural communication, and are an important aspect of social behavior in this species.

中文翻译：

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社交互动过程中调节了蝠cephal的头叶运动

摘要

礁蝠ta（Mobula alfredi）是具有组织结构的社会并积极与首选的社会合作伙伴进行互动的社会弹性分支机构。能够检测特定对象产生的线索和信号对于实现社会行为至关重要。许多弹性分支物种通过身体和鳍的姿势进行交流，但尚不清楚是否能使蝶类光线交流或如何响应物种的线索。这些射线具有特殊的头状叶，其高度灵活并用于进食，但可能具有其他功能，例如手势交流。在这项研究中，我们开发了一种通过焦点采样和逐帧视频分析来评估野外蝠ta行为的标准化方法。根据在西巴布亚拉贾安帕特清洁站记录的观察结果，我们描述了各种类型的头顶叶的位置和通过自由放行进行的运动M. alfredi并在不同的行为背景下进行了调查。我们发现，在接近物种和人类潜水者时以及与清洁鱼互动时，头状叶的卷曲受到调节，这表明这些叶可用于感知水流，嗅觉和/或手势交流。头叶彼此独立移动，但我们没有发现个体偏侧的证据。肺叶缺乏化学感应能力，表明手势交流是最可能的功能，但需要进一步的研究来确定这一点。这些结果有助于理解手势沟通在蝠ta社交互动中的功能，并加深了我们对弹性分支机构复杂的社交行为的理解。

重要性声明

社交动物依靠特定物种产生的交流和线索来应对机会和威胁。在竞争，求爱和其他社会互动中，许多弹性分支物种将身体和鳍的姿势用作手势信号。礁蝠ta（Mobula alfredi）是在近岸浅水生境中形成群体的社会弹性分支。它们具有成对的，柔软的头状叶，位于头部的侧面，专门用于喂养，但可能具有多种功能。在这里，我们描述，量化并提出有关各种蝠ta社交行为（包括同种，人类和清洁鱼之间的相互作用）期间头状叶运动和定位的可能解释。我们的结果表明，叶片运动可用于检测水运动，嗅觉和/或手势交流，并且是该物种社会行为的重要方面。