skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Phylogenomics of peacock spiders and their kin (Salticidae: Maratus ), with implications for the evolution of male courtship displays
Abstract Understanding diversity has been a pursuit in evolutionary biology since its inception. A challenge arises when sexual selection has played a role in diversification. Questions of what constitutes a ‘species’, homoplasy vs. synapomorphy, and whether sexually selected traits show phylogenetic signal have hampered work on many systems. Peacock spiders are famous for sexually selected male courtship dances and peacock-like abdominal ornamentation. This lineage of jumping spiders currently includes over 90 species classified into two genera, Maratus and Saratus. Most Maratus species have been placed into groups based on secondary sexual characters, but evolutionary relationships remain unresolved. Here we assess relationships in peacock spiders using phylogenomic data (ultraconserved elements and RAD-sequencing). Analyses reveal that Maratus and the related genus Saitis are paraphyletic. Many, but not all, morphological groups within a ‘core Maratus’ clade are recovered as genetic clades but we find evidence for undocumented speciation. Based on original observations of male courtship, our comparative analyses suggest that courtship behaviour and peacock-like abdominal ornamentation have evolved sequentially, with some traits inherited from ancestors and others evolving repeatedly and independently from ‘simple’ forms. Our results have important implications for the taxonomy of these spiders, and provide a much-needed evolutionary framework for comparative studies of the evolution of sexual signal characters.  more » « less
Award ID(s):
1754605
PAR ID:
10253520
Author(s) / Creator(s):
; ; ; ; ; ; ;
Date Published:
Journal Name:
Biological Journal of the Linnean Society
Volume:
132
Issue:
3
ISSN:
0024-4066
Page Range / eLocation ID:
471 to 494
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract Animals communicate using a diversity of signals produced by a wide array of physical structures. Determining how a signal is produced provides key insights into signal evolution. Here, we examine a complex vibratory mating display produced by maleSchizocosa floridanawolf spiders. This display contains three discrete substrate‐borne acoustic components (known as “thumps”, “taps”, and “chirps”), each of which is anecdotally associated with the movement of a different body part (the pedipalps, legs, and abdomen respectively). In order to determine the method of production, we employ a combination of high‐speed video/audio recordings and SEM imaging of possible sound‐producing structures. Previous work has suggested that the “chirp” component is tonal, a signal trait that would be potentially unique in the genus. We measured signal tonality for all courtship components, as well as for courtship components from sixteen otherSchizocosawolf spiders. Our results suggest thatS. floridanaproduces courtship song using a combination of shared (palpal stridulation and foreleg percussion) and novel (abdominal movement) sound production mechanisms. Of particular interest, the “chirp”, which is produced using a novel abdominal production mechanism, is the only known tonal signal with acoustic properties that are unique within the genus. We argue that the potential evolution of a novel sound production mechanism has opened up a new axis of signaling trait space in this species, with important implications for how this signal is likely to function and evolve. 
    more » « less
  2. Abstract In live-bearing animal lineages, the evolution of the placenta is predicted to create an arena for genomic conflict during pregnancy, drive patterns of male sexual selection, and increase the rate of speciation. Here we test these predictions of the viviparity driven conflict hypothesis (VDCH) in live-bearing poecilid fishes, a group showing multiple independent origins of placentation and extreme variation in male sexually selected traits. As predicted, male sexually selected traits are only gained in lineages that lack placentas; while there is little or no influence of male traits on the evolution of placentas. Both results are consistent with the mode of female provisioning governing the evolution of male attributes. Moreover, it is the presence of male sexually selected traits (pre-copulatory), rather than placentation (post-copulatory), that are associated with higher rates of speciation. These results highlight a causal interaction between female reproductive mode, male sexual selection and the rate of speciation, suggesting a role for conflict in shaping diverse aspects of organismal biology. 
    more » « less
  3. Taking an evolutionary approach to the question of beauty, we discuss the expression and perception of sexual beauty across the animal kingdom. Animals experience beauty in their brains, and animal brains are tuned to features of the environment most relevant to their survival. Over evolutionary time, sexually reproducing animals have exploited that tuning to maximize their attractiveness to the opposite sex, often leading to extreme courtship traits and behaviors. These are the traits of sexual beauty. Combining modern principles of neuroscience and neuroaesthetics with established principles of evolutionary biology, we aim to understand the biological basis and evolution of beauty in all animals, including ourselves. 
    more » « less
  4. The evolution of mating signals is shaped by divergent roles and selective forces, which allow these signals to become multifunctional. Sexual dimorphism in mating signals can reflect this multifunctionality, where such dimorphism could contribute to both mate recognition and mate choice. Sexual dimorphism in mating signals is thought to arise due to divergent sex roles, driven by the interactions of several selective pressures. It has been suggested that, across taxa, both sexes can be choosy and result in sexual selection. However, whether sexual dimorphism in mating signals can predict its role in male courtship behaviour is still unclear. In this study, we used cuticular hydrocarbons (CHCs) in Drosophila species as a model to investigate the question, with CHCs serving as key chemical cues during courtship. This study investigates the relationship between CHC sexual dimorphism and its role in male courtship behaviour across 10 Drosophila species. Our results reveal variations in the degree of CHC sexual dimorphism across the test species. In addition, CHC detection was found to contribute to courtship initiation in most of the test species, but CHC sexual dimorphism did not predict male courtship behaviour. Notably, a longer courtship latency was observed following the loss of CHC detection, indicating that CHCs may convey information on mate quality. Our study suggests that sexual dimorphism in CHCs is not directly linked to its role in mating signal recognition and highlights the species-specific evolution of chemical signals in Drosophila courtship. 
    more » « less
  5. Jennions, Michael D (Ed.)
    Abstract Sexual selection can contribute to speciation when signals and preferences expressed during mate choice are coupled within groups, but come to differ across groups (generating assortative mating). When new sexual signals evolve, it is important to investigate their roles in both mate location and courtship contexts, as both signaling functions are critical in mate choice. In previous work, researchers identified two new male morphs (silent and purring) in Hawaiian populations of the Pacific field cricket, Teleogryllus oceanicus. These morphs likely evolved because they protect males from an acoustically orienting parasitoid, yet still obtain some reproductive success. But, it remains unknown how the purring morph functions in close courtship encounters. We compared the relative success of the very recently evolved purring morph to that of the ancestral and silent morphs during courtship encounters. Purring males produce a novel courtship song and were not as successful in courtship as the ancestral type, but were mounted by females as often and as quickly as the obligately silent morph that arose and spread ~20 years ago. Purring males initiate courtship more quickly than other morphs, and females from populations where purring is common exhibit higher overall mounting rates. Thus, differences in the behavior of purring males and of females from populations where purring is common may have facilitated the origin of this novel sexual signal. We found no assortative mating between males of a given morph and females from their own population, and so we hypothesize that multiple male types will be maintained within the species because each achieves fitness in different ways. 
    more » « less