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MacGillavry T, Spezie G, Fusani L. When less is more: coy display behaviours and the temporal dynamics of animal courtship. Proc Biol Sci 2023; 290:20231684. [PMID: 37788700 PMCID: PMC10547558 DOI: 10.1098/rspb.2023.1684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/06/2023] [Indexed: 10/05/2023] Open
Abstract
Sexual selection research has been dominated by the notion that mate choice selects for the most vigorous displays that best reflect the quality of the courter. However, courtship displays are often temporally structured, containing different elements with varying degrees of intensity and conspicuousness. For example, highly intense movements are often coupled with more subtle components such as static postures or hiding displays. Here, we refer to such subtle display traits as 'coy', as they involve the withholding of information about maximal display capabilities. We examine the role of intensity variation within temporally dynamic displays, and discuss three hypotheses for the evolution of coy courtship behaviours. We first review the threat reduction hypothesis, which points to sexual coercion and sexual autonomy as important facets of sexual selection. We then suggest that variation in display magnitude exploits pre-existing perceptual biases for temporal contrast. Lastly, we propose that information withholding may leverage receivers' predispositions for filling gaps in information-the 'curiosity bias'. Overall, our goal is to draw attention to temporal variation in display magnitude, and to advocate possible scenarios for the evolution of courtship traits that regularly occur below performance maxima. Throughout, we highlight novel directions for empirical and theoretical investigations.
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Affiliation(s)
- Thomas MacGillavry
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
| | - Giovanni Spezie
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
| | - Leonida Fusani
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
- Department of Behavioural and Cognitive Biology, University of Vienna, Vienna, Austria
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Afzal SS, Akbar W, Rodriguez O, Doumet M, Ha U, Ghaffarivardavagh R, Adib F. Battery-free wireless imaging of underwater environments. Nat Commun 2022; 13:5546. [PMID: 36163186 PMCID: PMC9512789 DOI: 10.1038/s41467-022-33223-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 09/02/2022] [Indexed: 12/04/2022] Open
Abstract
Imaging underwater environments is of great importance to marine sciences, sustainability, climatology, defense, robotics, geology, space exploration, and food security. Despite advances in underwater imaging, most of the ocean and marine organisms remain unobserved and undiscovered. Existing methods for underwater imaging are unsuitable for scalable, long-term, in situ observations because they require tethering for power and communication. Here we describe underwater backscatter imaging, a method for scalable, real-time wireless imaging of underwater environments using fully-submerged battery-free cameras. The cameras power up from harvested acoustic energy, capture color images using ultra-low-power active illumination and a monochrome image sensor, and communicate wirelessly at net-zero-power via acoustic backscatter. We demonstrate wireless battery-free imaging of animals, plants, pollutants, and localization tags in enclosed and open-water environments. The method’s self-sustaining nature makes it desirable for massive, continuous, and long-term ocean deployments with many applications including marine life discovery, submarine surveillance, and underwater climate change monitoring. The authors present an approach to underwater imaging, which does not require tethering or batteries. The low-power camera uses power from harvested acoustic energy and communicates colour images wirelessly via acoustic backscatter.
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Affiliation(s)
- Sayed Saad Afzal
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Waleed Akbar
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Program in Media Arts and Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Osvy Rodriguez
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Mario Doumet
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Unsoo Ha
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | | | - Fadel Adib
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. .,MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. .,Program in Media Arts and Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. .,MIT Sea Grant, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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Hegyi G, Laczi M, Herényi M, Markó G, Nagy G, Rosivall B, Szász E, Török J. Functional integration of multiple sexual ornaments: signal coherence and sexual selection. Am Nat 2022; 200:486-505. [DOI: 10.1086/720620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Rosenthal GG, Ryan MJ. Sexual selection and the ascent of women: Mate choice research since Darwin. Science 2022; 375:eabi6308. [PMID: 35050648 DOI: 10.1126/science.abi6308] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Darwin's theory of sexual selection fundamentally changed how we think about sex and evolution. The struggle over mating and fertilization is a powerful driver of diversification within and among species. Contemporaries dismissed Darwin's conjecture of a "taste for the beautiful" as favoring particular mates over others, but there is now overwhelming evidence for a primary role of both male and female mate choice in sexual selection. Darwin's misogyny precluded much analysis of the "taste"; an increasing focus on mate choice mechanisms before, during, and after mating reveals that these often evolve in response to selection pressures that have little to do with sexual selection on chosen traits. Where traits and preferences do coevolve, they can do so whether fitness effects on choosers are positive, neutral, or negative. The spectrum of selection on traits and preferences, and how traits and preferences respond to social effects, determine how sexual selection and mate choice influence broader-scale processes like reproductive isolation and population responses to environmental change.
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Affiliation(s)
- Gil G Rosenthal
- Department of Biology, University of Padova, Padova, Italy.,Centro de Investigaciones Científicas de las Huastecas "Aguazarca," Calnali, Hidalgo, Mexico
| | - Michael J Ryan
- Department of Integrative Biology, University of Texas, Austin, TX, USA.,Smithsonian Tropical Research Institute, Balboa, Republic of Panama
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Abstract
One hundred fifty years ago Darwin published The Descent of Man, and Selection in Relation to Sex, in which he presented his theory of sexual selection with its emphasis on sexual beauty. However, it was not until 50 y ago that there was a renewed interest in Darwin’s theory in general, and specifically the potency of mate choice. Darwin suggested that in many cases female preferences for elaborately ornamented males derived from a female’s taste for the beautiful, the notion that females were attracted to sexual beauty for its own sake. Initially, female mate choice attracted the interest of behavioral ecologists focusing on the fitness advantages accrued through mate choice. Subsequent studies focused on sensory ecology and signal design, often showing how sensory end organs influenced the types of traits females found attractive. Eventually, investigations of neural circuits, neurogenetics, and neurochemistry uncovered a more complete scaffolding underlying sexual attraction. More recently, research inspired by human studies in psychophysics, behavioral economics, and neuroaesthetics have provided some notion of its higher-order mechanisms. In this paper, I review progress in our understanding of Darwin’s conjecture of “a taste for the beautiful” by considering research from these diverse fields that have conspired to provide unparalleled insight into the chooser’s mate choices.
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Girard MB, Elias DO, Azevedo G, Bi K, Kasumovic MM, Waldock JM, Rosenblum EB, Hedin M. Phylogenomics of peacock spiders and their kin (Salticidae: Maratus), with implications for the evolution of male courtship displays. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blaa165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
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.
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Affiliation(s)
- Madeline B Girard
- Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Damian O Elias
- Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Guilherme Azevedo
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Ke Bi
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, USA
| | - Michael M Kasumovic
- Ecology & Evolution Research Centre, School of Biological, Earth & Environmental Sciences, UNSW, Sydney, NSW, Australia
| | - Julianne M Waldock
- Collections and Research, Western Australian Museum, Welshpool, Western Australia, Australia
| | - Erica Bree Rosenblum
- Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Marshal Hedin
- Department of Biology, San Diego State University, San Diego, CA, USA
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