Institute for Perception, Action, and Behaviour, The University of Edinburgh School of Informatics, Edinburgh, Edinburgh EH8 9AB, UK.
Lund Vision Group, Department of Biology, Lund University, Lund SE-223 62, Sweden.
Proc Biol Sci. 2023 Jun 28;290(2001):20230767. doi: 10.1098/rspb.2023.0767.
Ball-rolling dung beetles are known to integrate multiple cues in order to facilitate their straight-line orientation behaviour. Recent work has suggested that orientation cues are integrated according to a vector sum, that is, compass cues are represented by vectors and summed to give a combined orientation estimate. Further, cue weight (vector magnitude) appears to be set according to cue reliability. This is consistent with the popular Bayesian view of cue integration: cues are integrated to reduce or minimize an agent's uncertainty about the external world. Integration of orientation cues is believed to occur at the input to the insect central complex. Here, we demonstrate that a model of the head direction circuit of the central complex, including plasticity in input synapses, can act as a substrate for cue integration as vector summation. Further, we show that cue influence is not necessarily driven by cue reliability. Finally, we present a dung beetle behavioural experiment which, in combination with simulation, strongly suggests that these beetles do not weight cues according to reliability. We suggest an alternative strategy whereby cues are weighted according to relative contrast, which can also explain previous results.
滚粪球蜣螂已知会整合多种线索，以促进其直线定向行为。最近的研究表明，定向线索是根据向量和进行整合的，即罗盘线索由向量表示，并相加得出综合的定向估计。此外，线索权重（向量幅度）似乎根据线索可靠性来设定。这与线索整合的流行贝叶斯观点一致：线索被整合以减少或最小化主体对外部世界的不确定性。定向线索的整合被认为发生在昆虫中央复合体的输入处。在这里，我们证明了中央复合体的头部方向电路模型，包括输入突触的可塑性，可以作为向量求和的线索整合的基础。此外，我们还表明，线索的影响不一定是由线索可靠性驱动的。最后，我们提出了一个蜣螂行为实验，该实验与模拟结果相结合，强烈表明这些蜣螂不会根据可靠性来加权线索。我们提出了一种替代策略，即根据相对对比度来加权线索，这也可以解释之前的结果。
