DOI: 10.5061/dryad.w0vt4b8tb
title: Living in mixed-sex groups limits sexual selection in coloration and pelage appendages in bovids

description: Among mammals, bovids provide some of the most striking examples of sexual
 dimorphism in colouration and pelage appendages, such as beards and manes.
 This dimorphism is usually assumed to have evolved through sexual
 selection on males in the context of intra- or intersexual communication.
 However, the sexes look similar in several bovid species thought to be
 characterized by large opportunities for sexual selection, hinting at
 fitness costs of dimorphic traits due to other selection pressures. This
 study applies the comparative method with phylogenetic control to identify
 the factors promoting and constraining the evolution of dimorphism in
 colouration and pelage appendages across bovids. We found that trait
 dimorphism correlated positively with large breeding group size, an
 indicator of the intensity of sexual selection, and negatively with male
 territoriality, which is also likely to affect the operation of sexual
 selection. The relative rarity of colour and pelage dimorphism in species
 with territorial mating systems may be explained by weaker sexual
 selection due to difficulty in monopolizing females and/or sexual
 selection targeting other traits, such as territorial quality as an
 extended phenotype. We also found that colour and pelage dimorphism were
 reduced in species spending more time in mixed-sex groups outside the
 breeding season, possibly due to increased predation costs from
 non-uniformity This suggests that benefits from integration into mixed-sex
 groups select against the extravagant male morphologies otherwise promoted
 by sexual selection.
description: Data on colouration sexual dimorphism (CSD) and pelage appendage
 sexual dimorphism (PASD) were collected for 110 species in the family
 Bovidae. The scores for CSD and PASD were obtained by visual scoring of
 images from males and females of each species (range 2-8 pictures per
 species) obtained from: www.arkive.com; www.encyclopediaoflife.com;
 www.ultimateungulate.com; Costello JR. (2016).
 <em>Bovids of the world</em>. Princeton (USA): Princeton
 University Press. All pictures referred to the same
 subspecies.  CSD was scored on eight distinct body
 regions: (i) head; (ii) neck; (iii) flank, shoulder, humerus; (iv) rump,
 femur; (v) upper front leg; (vi) lower front leg; (vii) upper hind leg;
 and (viii) lower hind leg. CSD for each body region was scored according
 to a three-point scale: 0 - no difference; 1 - the difference in
 background colour or contrast markings (i.e. presence in one sex only); 2
 - the difference in both background colour and contrast markings.
 Background hair colour was compared to a reference of five colour
 categories: (i) white (de-pigmented); (ii) phaeomelanin - yellow/red;
 (iii) eumelanin - brown; (iv) eumelanin – grey; and (v) eumelanin - black.
 The background colour was scored as dimorphic if the same body region was
 assigned to different categories in males and females. The overall CSD
 index presented in this dataset was calculated as the sum of the scores
 for all eight body regions. PASD was
 scored on inter-sexual differences in (i) frontal hair tuft; (ii) beard or
 ventral mane; (iii) dorsal mane; (iv) cape (covering both dorsal and
 ventral parts of the neck); (v) front leg pantaloons; and (vi) hind leg
 pantaloons. A four-point visual scale was used: 0 - no difference in the
 pelage appendage between the sexes; 1 – the appendage differs in either
 size or colour between the sexes; 2 – the appendage differs in both size
 and colour between the sexes; 3 – the appendage is present in one sex
 only. The overall PASD index presented in this dataset was calculated as
 the sum of scores for all the pelage appendages in each species.
 Sexual
 aggregation in this dataset was defined as the tendency for males and
 females to form mixed-sex herds outside of the breeding context, and
 scored on a three-point scale: 1 – never forming mixed-sex groups with
 multiple males (including species in which males are solitary or live in
 segregated, unisexual groups, only joining female groups in search of
 mating opportunities); 2 - sometimes forming multi-male mixed-sex groups
 (including species in which only some males are found in multimale
 mixed-sex groups, either because not all males join these groups or
 because associations are temporary, e.g. during migrations); and 3 -
 generally forming multi-male mixed-sex groups (including species in which
 the sexes typically aggregate, although some males may temporarily join
 bachelor groups). The scoring was based on available published material
 listed in the Supplementary Material to the manuscript. Habitat
 openness was scored based on the probability of detecting large mammals in
 each of the nine different IUCN habitat categories (www.iucnredlist.org):
 tropical forest (0.1), temperate forest (0.2), wetland (0.3), tropical
 shrubland (0.5), temperate shrubland (0.6), savannah (0.7), grassland
 (0.8); rocky areas (0.8), and desert (0.95). The species-specific score
 for habitat openness was calculated as the mean detection probability
 across all habitat categories occupied by the species. Data for
 average breeding group size (Group Size) and male mating strategy (Male
 Mating Strategy) were derived from published literature reported in the
 Supplementary Material to the manuscript. Male mating strategy was defined
 as T (territorial) or NT (non-territorial).
description: # Living in mixed-sex groups limits sexual selection in coloration and
 pelage appendages in bovids
 [https://doi.org/10.5061/dryad.w0vt4b8tb](https://doi.org/10.5061/dryad.w0vt4b8tb) **Recommended citation for this dataset:** D'Ammando, Giacomo; Franks, Daniel; Bro-Jorgensen, Jakob (2024), Living in mixed-sex groups limits sexual selection in coloration and pelage appendages in bovids, Dryad, Dataset. ## Description of the data and file structure #### Sexual\_Dimorphism\_Bovids\_DAmmando.csv CSV file containing data on colour sexual dimorphism (CSD), pelage appendage sexual dimorphism (PASD), average breeding group size, male mating strategy (territorial vs non-territorial), degree of sexual aggregation, and habitat openness for 110 species of the family Bovidae. Variables: * Species = Bovid species as indicated by scientific name (genus + species) * CSD = Colour Sexual Dimorphism, scored visually by comparison of male/female pictures of each species, with the aid of a colour palette reference (in publication). * PASD = Pelage Appendage Sexual Dimorphism, scored visually by comparison of male/female pictures of each species. * Group size = average breeding group size, derived from the available literature. * Male mating strategy = T (territorial)/ NT (non-territorial), derived from the available literature. Categorical variable with two levels. * Degree of Sexual Aggregation = tendency for each species to form mixed-sex herds outside of the reproductive context. Scored as: 1 = sexes always segregated in unisexual herds; 2 = sometimes in mixed-sex herds (e.g. during seasonal migrations); 3 = always forming mixed-sex herds (although some of the males might form temporary bachelor herds). Scoring was based on available literature (reported in publication). * Habitat Openness = Average score of habitat openness for each species based on detection probabilities of large mammals in each habitat type described by the IUCN (Cabrera & Stankowich 2018). Habitat openness for each species was calculated as the average of these detection probabilities across all the habitat types where each species is found according to the IUCN Red List. ## Sharing/Access information NA ## Code/Software NA