The perceptual effects of signal components: Black sword margins are crucial for signal size discrimination in green swordtails Xiphophorus hellerii

The signals that mediate mate choice can be complex, comprising multiple components, and understanding how complex signals evolve under sexual selection has been the focus of much study. However, open questions still remain about the role of the female’s sensory and perceptual processes in shaping the evolution of complex signals. Male green swordtails Xiphophorus hellerii have an elongated caudal fin that comprises color, length, and a black melanic margin; females prefer males with larger bodies, longer swords, and complete black sword margins. Here, we used a two-choice assay to quantify female preferences for animations of courting males of different sizes with or without sword margin coloration, and found that, when a black melanic margin was present, females exhibited preferences for larger males. However, when the margin was absent, females did not show size-based mate preference, though females spent equal time assessing males in both treatments.  Our results suggest the presenc..., A two-choice behavioral paradigm was used to assess a female’s preference when shown animations of two courting males that differed in size, and which did or did not have black coloration along the top and bottom margins of the sword fin (hereafter “black margin”). Stimuli were created using a digital photograph of a male swordtail who was placed on a plain gray background and whose swimming motions were animated in Powerpoint. For details, see manuscript. , , # The perceptual effects of signal components: Black sword margins are crucial for signal size discrimination in green swordtails Xiphophorus hellerii

[https://doi.org/10.5061/dryad.gf1vhhmzq](https://doi.org/10.5061/dryad.gf1vhhmzq)

## Description of the data and file structure

### Files and variables

#### File: Body\_size\_two\_choice\_data\_stripe\_and\_no\_stripe.csv

**Description: This** file contains data from each behavioral trial conducted in this study; note that each trial comprises two rows of data, since for each trial, the fish was exposed to two animated stimuli. Thus, in a pair of rows, one row shows data for responses to one stimulus, and the other row shows data for the response to the other stimulus. NOTE: Empty cells in this datasheet indicate fish and trials for which--due to stress responses--there were no data; thus, empty cells indicate instances where certain fish did not have analyzable data for certain stimulus comparisons, as discussed in the main text.

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