Biomimetic robots reveal flexible adjustment of sexual signalling in a wild invertebrate

Studies of vocalisations and gestures in primates, birds and fish show that signalling behaviour is flexibly adjusted depending on the presence, characteristics and behavioural states of others. Such flexibility is likely important in competitive social contexts such as sexual signalling, where attractiveness is directly affected by rival behaviour. Although sexual displays are often sensitive to the presence and proximity of rivals, less is known about the effect of changes in rival signalling. In this study, we used a biomimetic robot to manipulate rival morphology and waving behaviour in a wild population of fiddler crabs (Afruca tangeri) and investigated whether males responded flexibly by adjusting their own activity and waving. We found that males were less likely to enter their burrow when the robotic rival was waving, particularly if that rival had a small claw, spending less time in their burrow if they did enter. While outside, males produced more waves when the robotic rival ..., 1 Study area and species
The study was carried out between May and July 2022 on a wild population of A. tangeri that inhabit the Ria Formosa Natural Park on the south-eastern coast of Portugal, between Manta Rota and Cacela Velha (37.16 N, 7.53 W). At low tide, this area consists mainly of mudflats, salt marshes and dry sandy banks.
2 Robotic stimulus male
To provide a standardised rival stimulus of different sizes, we used a 3D scan of a fiddler crab specimen from a museum collection [47]. The body and major claw of this scan were 3D-printed separately by FabLab Devon (fablabdevon.org). The major claws were printed in two sizes: one where the major claw was 5 cm from manus base to pollex tip (the approximate mean length of male A. tangeri major claws in our records; see supplementary materials), and one where the major claw measured 7 cm (the largest major claw length in our records; see supplementary materials). The body was 3D printed in one size: the size of the original scan when t..., , # Biomimetic robots reveal flexible adjustment of sexual signalling in a wild invertebrate.

[https://doi.org/10.5061/dryad.ht76hdrqm](https://doi.org/10.5061/dryad.ht76hdrqm)

## Data Description

### Wave signalling behaviour

Raw data concerning the wave signalling behaviour, which is analysed via hidden Markov model (HMM): **/HMM/HMM_data.rds**

The following is a description of each column in **HMM_data.rds**:

1. *ID* - Focal Male ID, ranges from 1 to 69 (the total number of focal males in the experiment). This is a categorical label and could be replaced with characters, the numbers themselves do not have any meaning beyond being a convenient label.
2. *date* - the date on which that experimental trial took place. In format dd/mm/yyyy.
3. *st_time* - the number of minutes past midnight at which the experimental trial began (e.g. 570 minutes is 9.5 hours, indicating the trial commenced at 09:30am).
4. *temp1* - the substrate surface temperature recorded at the beginning of the tri...,