1
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Beltrán DF, Araya-Salas M, Parra JL, Stiles FG, Rico-Guevara A. The evolution of sexually dimorphic traits in ecological gradients: an interplay between natural and sexual selection in hummingbirds. Proc Biol Sci 2022; 289:20221783. [PMID: 36515116 PMCID: PMC9748779 DOI: 10.1098/rspb.2022.1783] [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: 09/08/2022] [Accepted: 11/22/2022] [Indexed: 12/15/2022] Open
Abstract
Traits that exhibit differences between the sexes have been of special interest in the study of phenotypic evolution. Classic hypotheses explain sexually dimorphic traits via intra-sexual competition and mate selection, yet natural selection may also act differentially on the sexes to produce dimorphism. Natural selection can act either through physiological and ecological constraints on one of the sexes, or by modulating the strength of sexual/social selection. This predicts an association between the degree of dimorphism and variation in ecological environments. Here, we characterize the variation in hummingbird dimorphism across ecological gradients using rich databases of morphology, colouration and song. We show that morphological dimorphism decreases with elevation in the understorey and increases with elevation in mixed habitats, that dichromatism increases at high altitudes in open and mixed habitats, and that song is less complex in mixed habitats. Our results are consistent with flight constraints, lower predation pressure at high elevations and with habitat effects on song transmission. We also show that dichromatism and song complexity are positively associated, while tail dimorphism and song complexity are negatively associated. Our results suggest that key ecological factors shape sexually dimorphic traits, and that different communication modalities do not always evolve in tandem.
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Affiliation(s)
- Diego F. Beltrán
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Marcelo Araya-Salas
- Centro de Investigación en Neurociencias, Universidad de Costa Rica, San José, Costa Rica
- Escuela de Biología, Universidad de Costa Rica, San José, Costa Rica
| | - Juan L. Parra
- Grupo de Ecología y Evolución de Vertebrados, Instituto de Biología, Universidad de Antioquia, Medellín, Colombia
| | - F. Gary Stiles
- Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá D.C., Colombia
| | - Alejandro Rico-Guevara
- Department of Biology, University of Washington, Seattle, WA 98195, USA
- Burke Museum of Natural History and Culture, University of Washington, Seattle, WA 98105, USA
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2
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Cuervo JJ, Morales J, Soler JJ, Moreno J. Sexual selection, feather wear, and time constraints on the pre-basic molt explain the acquisition of the pre-alternate molt in European passerines. Ecol Evol 2022; 12:e9260. [PMID: 36091343 PMCID: PMC9448967 DOI: 10.1002/ece3.9260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 11/06/2022] Open
Abstract
Avian feathers need to be replaced periodically to fulfill their functions, with natural, social, and sexual selection presumably driving the evolution of molting strategies. In temperate birds, a common pattern is to molt feathers immediately after the breeding season, the pre-basic molt. However, some species undergo another molt in winter-spring, the pre-alternate molt. Using a sample of 188 European passerine species, Bayesian phylogenetic mixed models, and correlated evolution analyses, we tested whether the occurrence of the pre-alternate molt was positively associated with proxies for sexual selection (sexual selection hypothesis) and nonsexual social selection (social selection hypothesis), and with factors related to feather wear (feather wear hypothesis) and time constraints on the pre-basic molt (time constraints hypothesis). We found that the pre-alternate molt was more frequent in migratory and less gregarious species inhabiting open/xeric habitats and feeding on the wing, and marginally more frequent in species with strong sexual selection and those showing a winter territorial behavior. Moreover, an increase in migratory behavior and sexual selection intensity preceded the acquisition of the pre-alternate molt. These results provide support for the feather wear hypothesis, partial support for the sexual selection and time constraints hypotheses, and no support for the social selection hypothesis.
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Affiliation(s)
- José J Cuervo
- Department of Evolutionary Ecology Museo Nacional de Ciencias Naturales (MNCN-CSIC) Madrid Spain
| | - Judith Morales
- Department of Evolutionary Ecology Museo Nacional de Ciencias Naturales (MNCN-CSIC) Madrid Spain
| | - Juan J Soler
- Department of Functional and Evolutionary Ecology Estación Experimental de Zonas Áridas (EEZA-CSIC) Almería Spain
| | - Juan Moreno
- Department of Evolutionary Ecology Museo Nacional de Ciencias Naturales (MNCN-CSIC) Madrid Spain
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3
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Eaton MD, Benites P, Campillo L, Wilson RE, Sonsthagen SA. Gull Plumages are, and are Not, What They Appear to Human Vision. ANN ZOOL FENN 2022. [DOI: 10.5735/086.059.0116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Muir D. Eaton
- Biology Department, 2500 University Ave, Drake University, Des Moines, Iowa 50310, USA
| | - Pilar Benites
- Museo de Zoología “Alfonso L. Herrera”, Facultad de Ciencias, Universidad Nacional Autónoma de México, Apartado Postal 70-399, Mexico City 04510, Mexico
| | - Luke Campillo
- School of Life Sciences, University of Hawai'i – Mānoa, 2538 McCarthy Mall, Honolulu, HI 96822, USA
| | - Robert E. Wilson
- National Museum of Natural History, Smithsonian Institution, 10th Street & Constitution Ave. NW, Washington, DC 20560, USA
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4
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Latitudinal gradients in avian colourfulness. Nat Ecol Evol 2022; 6:622-629. [PMID: 35379937 DOI: 10.1038/s41559-022-01714-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 02/25/2022] [Indexed: 12/17/2022]
Abstract
It has long been suggested that tropical species are generally more colourful than temperate species, but whether latitudinal gradients in organismal colourfulness exist remains controversial. Here we quantify global latitudinal trends in colourfulness (within-individual colour diversity) by collating and analysing a photographic dataset of whole-body plumage reflectance information for >4,500 species of passerine birds. We show that male and female birds of tropical passerine species are generally more colourful than their temperate counterparts, both on average and in the extreme. We also show that these geographic gradients can be explained in part by the effects of several latitude-related factors related to classic hypotheses for climatic and ecological determinants of organismal colourfulness. Taken together, our results reveal that species' colourfulness peaks in the tropics for passerine birds, confirming the existence of a long-suspected yet hitherto elusive trend in the distribution of global biodiversity.
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5
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Marcolin F, Cardoso GC, Bento D, Reino L, Santana J. Body size and sexual selection shaped the evolution of parrot calls. J Evol Biol 2022; 35:439-450. [PMID: 35147264 DOI: 10.1111/jeb.13986] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 01/26/2022] [Accepted: 02/05/2022] [Indexed: 11/30/2022]
Abstract
Morphology, habitat and various selective pressures (e.g., social and sexual selection) can influence the evolution of acoustic signals, but the relative importance of their effects is not well understood. The order Psittaciformes (parrots, sensu lato) is a large clade of very vocal and often gregarious species for which large-scale comparative studies of vocalizations are lacking. We measured acoustic traits (duration, sound frequency, frequency bandwidth and sound entropy) of the predominant call type for >200 parrot species to test: (1) for associations with body size; (2) the acoustic adaptation hypothesis (predicting differences between forest and open-habitat species); (3) the social complexity hypothesis (predicting more complex calls in gregarious species); and (4) influences of sexual selection (predicting correlated evolution with colour ornamentation). Larger species had on average longer calls, lower sound frequency and wider frequency bandwidth. These associations with body size are all predicted by physical principles of sound production. We found no evidence for the acoustic adaptation and social complexity hypotheses, but perhaps social complexity is associated with vocal traits not studied here, such as call repertoire sizes. More sexually dichromatic species had on average simpler calls (shorter, with lower entropy and narrower frequency bandwidth) indicating an influence of sexual selection, namely an evolutionary negative correlation between colour ornamentation and elaborate acoustic signals, as predicted by the transference hypothesis. Our study is the first large-scale attempt at understanding acoustic diversity across the Psittaciformes, and indicates that body size and sexual selection influenced the evolution of species differences in vocal signals.
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Affiliation(s)
- Fabio Marcolin
- Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, P-1349-017, Lisboa, Portugal
| | - Gonçalo C Cardoso
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, 4485-661, Vairão, Portugal
| | - Daniel Bento
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, 4485-661, Vairão, Portugal.,CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017, Lisboa, Portugal
| | - Luís Reino
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, 4485-661, Vairão, Portugal.,CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017, Lisboa, Portugal
| | - Joana Santana
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, 4485-661, Vairão, Portugal.,CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017, Lisboa, Portugal
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6
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Differences in plumage coloration predict female but not male territorial responses in three antbird sister species pairs. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2021.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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7
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Reuland C, Simmons LW, Lüpold S, Fitzpatrick JL. Weapons Evolve Faster Than Sperm in Bovids and Cervids. Cells 2021; 10:cells10051062. [PMID: 33947050 PMCID: PMC8145498 DOI: 10.3390/cells10051062] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/25/2021] [Accepted: 04/27/2021] [Indexed: 12/13/2022] Open
Abstract
In polyandrous species, males face reproductive competition both before and after mating. Sexual selection thus shapes the evolution of both pre- and postcopulatory traits, creating competing demands on resource allocation to different reproductive episodes. Traits subject to strong selection exhibit accelerated rates of phenotypic divergence, and examining evolutionary rates may inform us about the relative importance and potential fitness consequences of investing in traits under either pre- or postcopulatory sexual selection. Here, we used a comparative approach to assess evolutionary rates of key competitive traits in two artiodactyl families, bovids (family Bovidae) and cervids (family Cervidae), where male–male competition can occur before and after mating. We quantified and compared evolutionary rates of male weaponry (horns and antlers), body size/mass, testes mass, and sperm morphometrics. We found that weapons evolve faster than sperm dimensions. In contrast, testes and body mass evolve at similar rates. These results suggest strong, but differential, selection on both pre- and postcopulatory traits in bovids and cervids. Furthermore, we documented distinct evolutionary rates among different sperm components, with sperm head and midpiece evolving faster than the flagellum. Finally, we demonstrate that, despite considerable differences in weapon development between bovids and cervids, the overall evolutionary patterns between these families were broadly consistent.
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Affiliation(s)
- Charel Reuland
- Department of Zoology, Stockholm University, Svante Arrhenius väg 18b, 106 91 Stockholm, Sweden;
| | - Leigh W. Simmons
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley, WA 6009, Australia;
| | - Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland;
| | - John L. Fitzpatrick
- Department of Zoology, Stockholm University, Svante Arrhenius väg 18b, 106 91 Stockholm, Sweden;
- Correspondence:
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8
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Kabir MS, Venkatesan R, Thaker M. Multiple Sensory Modalities in Diurnal Geckos Is Associated with the Signaling Environment and Evolutionary Constraints. Integr Org Biol 2021; 2:obaa027. [PMID: 33791567 PMCID: PMC7891680 DOI: 10.1093/iob/obaa027] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To be effective, animal signals need to be detectable in the environment, but their development and expression require resources. For multimodal communication, investment in elaborating traits in one modality could reduce the elaboration of traits in other modalities. In Cnemaspis geckos, chemical signals for conspecific communication pre-dated the evolution of visual signals, allowing us to examine the potential trade-off in signal elaboration and the current habitat associations with signal use. We studied five species of Cnemaspis and quantified visual (patch size, color characteristics) and chemical (secretory composition) traits in males, as well as key environmental parameters (temperature, humidity, light) in each of their habitats. Within species, we found some trade-off in the elaboration of signals, as the strength of several components in the visual and chemical modalities were negatively associated. Strength of some signal components in each modality was also independently associated with specific environmental parameters that affect their detection (visual traits) and persistence (chemical traits). Specifically, species with larger, brighter, and more saturated color patches were found in habitats where the brightness and chroma of light were lower. Furthermore, environments with higher substrate temperature and higher relative humidity harbored species that produced secretions with a higher percentage of saturated and aromatic compounds. Thus, the elaboration of multimodal signals in this group of Cnemaspis geckos seems to increase the efficiency of communication in the signaling-environment, but the strength of signals in different modalities is constrained by trade-offs in signal expression.
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Affiliation(s)
- M S Kabir
- Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, 560 012, India
| | - R Venkatesan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560 065, India.,Department of Biological Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur, West Bengal 741 246, India
| | - M Thaker
- Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, 560 012, India
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9
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Measuring Pre- and Post-Copulatory Sexual Selection and Their Interaction in Socially Monogamous Species with Extra-Pair Paternity. Cells 2021; 10:cells10030620. [PMID: 33799610 PMCID: PMC7999480 DOI: 10.3390/cells10030620] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 01/08/2023] Open
Abstract
When females copulate with multiple males, pre- and post-copulatory sexual selection may interact synergistically or in opposition. Studying this interaction in wild populations is complex and potentially biased, because copulation and fertilization success are often inferred from offspring parentage rather than being directly measured. Here, I simulated 15 species of socially monogamous birds with varying levels of extra-pair paternity, where I could independently cause a male secondary sexual trait to improve copulation success, and a sperm trait to improve fertilization success. By varying the degree of correlation between the male and sperm traits, I show that several common statistical approaches, including univariate selection gradients and paired t-tests comparing extra-pair males to the within-pair males they cuckolded, can give highly biased results for sperm traits. These tests should therefore be avoided for sperm traits in socially monogamous species with extra-pair paternity, unless the sperm trait is known to be uncorrelated with male trait(s) impacting copulation success. In contrast, multivariate selection analysis and a regression of the proportion of extra-pair brood(s) sired on the sperm trait of the extra-pair male (including only broods where the male sired ≥1 extra-pair offspring) were unbiased, and appear likely to be unbiased under a broad range of conditions for this mating system. In addition, I investigated whether the occurrence of pre-copulatory selection impacted the strength of post-copulatory selection, and vice versa. I found no evidence of an interaction under the conditions simulated, where the male trait impacted only copulation success and the sperm trait impacted only fertilization success. Instead, direct selection on each trait was independent of whether the other trait was under selection. Although pre- and post-copulatory selection strength was independent, selection on the two traits was positively correlated across species because selection on both traits increased with the frequency of extra-pair copulations in these socially monogamous species.
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10
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Cally JG, Stuart-Fox D, Holman L, Dale J, Medina I. Male-biased sexual selection, but not sexual dichromatism, predicts speciation in birds. Evolution 2021; 75:931-944. [PMID: 33559135 DOI: 10.1111/evo.14183] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/13/2021] [Indexed: 01/04/2023]
Abstract
Sexual selection is thought to shape phylogenetic diversity by affecting speciation or extinction rates. However, the net effect of sexual selection on diversification is hard to predict because many of the hypothesized effects on speciation or extinction have opposing signs and uncertain magnitudes. Theoretical work also suggests that the net effect of sexual selection on diversification should depend strongly on ecological factors, though this prediction has seldom been tested. Here, we test whether variation in sexual selection can predict speciation and extinction rates across passerine birds (up to 5812 species, covering most genera) and whether this relationship is mediated by environmental factors. Male-biased sexual selection, and specifically sexual size dimorphism, predicted two of the three measures of speciation rates that we examined. The link we observed between sexual selection and speciation was independent of environmental variability, though species with smaller ranges had higher speciation rates. There was no association between any proxies of sexual selection and extinction rate. Our findings support the view that male-biased sexual selection, as measured by frequent predictors of male-male competition, has shaped diversification in the largest radiation of birds.
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Affiliation(s)
- Justin G Cally
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Devi Stuart-Fox
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Luke Holman
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - James Dale
- School of Natural and Computational Sciences, Massey University (Albany Campus), Auckland, 0632, New Zealand
| | - Iliana Medina
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3052, Australia
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11
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Knapp A, Knell RJ, Hone DWE. Three-dimensional geometric morphometric analysis of the skull of Protoceratops andrewsi supports a socio-sexual signalling role for the ceratopsian frill. Proc Biol Sci 2021; 288:20202938. [PMID: 33529562 PMCID: PMC7893235 DOI: 10.1098/rspb.2020.2938] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/12/2021] [Indexed: 12/19/2022] Open
Abstract
Socio-sexual selection is predicted to be an important driver of evolution, influencing speciation, extinction and adaptation. The fossil record provides a means of testing these predictions, but detecting its signature from morphological data alone is difficult. There are, nonetheless, some specific patterns of growth and variation which are expected of traits under socio-sexual selection. The distinctive parietal-squamosal frill of ceratopsian dinosaurs has previously been suggested as a socio-sexual display trait, but evidence for this has been limited. Here, we perform a whole-skull shape analysis of an unprecedentedly large sample of specimens of Protoceratops andrewsi using a high-density landmark-based geometric morphometric approach to test four predictions regarding a potential socio-sexual signalling role for the frill. Three predictions-low integration with the rest of the skull, significantly higher rate of change in size and shape during ontogeny, and higher morphological variance than other skull regions-are supported. One prediction, sexual dimorphism in shape, is not supported, suggesting that sexual differences in P. andrewsi are likely to be small. Together, these findings are consistent with mutual mate choice or selection for signalling quality in more general social interactions, and support the hypothesis that the frill functioned as a socio-sexual signal in ceratopsian dinosaurs.
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Affiliation(s)
- A. Knapp
- Department of Earth Sciences, The Natural History Museum, London, UK
- Department of Organismal Biology, Queen Mary University of London, London, UK
| | - R. J. Knell
- Department of Organismal Biology, Queen Mary University of London, London, UK
| | - D. W. E. Hone
- Department of Organismal Biology, Queen Mary University of London, London, UK
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12
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Groot AT, Vedenina V, Burdfield-Steel E. Editorial: Multimodal Mating Signals: Evolution, Genetics and Physiological Background. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2020.630957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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13
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Price‐Waldman RM, Shultz AJ, Burns KJ. Speciation rates are correlated with changes in plumage color complexity in the largest family of songbirds. Evolution 2020; 74:1155-1169. [DOI: 10.1111/evo.13982] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 04/15/2020] [Accepted: 04/19/2020] [Indexed: 12/16/2022]
Affiliation(s)
- Rosalyn M. Price‐Waldman
- Department of BiologySan Diego State University San Diego California 92182
- Department of Ecology and Evolutionary BiologyPrinceton University Princeton NJ 08544
| | - Allison J. Shultz
- Ornithology DepartmentNatural History Museum of Los Angeles County Los Angeles California 90007
| | - Kevin J. Burns
- Department of BiologySan Diego State University San Diego California 92182
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14
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Miles MC, Schuppe ER, Fuxjager MJ. Selection for Rhythm as a Trigger for Recursive Evolution in the Elaborate Display System of Woodpeckers. Am Nat 2020; 195:772-787. [PMID: 32364790 DOI: 10.1086/707748] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Evolution is never truly predictable, in part because the process of selection is recursive: it operates on its own output to generate historical contingencies, so emergent traits can reshape how others evolve in the future. Studies rarely attempt to directly trace how recursion underlies present-day phenotypic pattern on a macroevolutionary basis. To address this gap, we examined how different selection regimes-each operating on a different timescale-guide the evolution of the woodpecker drum display. Approximately 200 species drum with distinctive speed and length, which are important for territorial competition. We discovered remarkable variation in drum rhythm, with some species drumming at constant rates and others changing speed along a range of mathematical functions. Rhythm undergoes divergent character displacement among sympatric sister species, a process that wanes as other reproductive boundaries emerge over time. Tracing the recursive effects of this process, we found that modifying rhythm may then potentiate or constrain speed/length elaboration. Additionally, increased sexual size dimorphism predicts the emergence of rhythms associated with constrained evolutionary rates of speed/length, implying that selection can also constrain itself. Altogether, our findings illustrate how recursion introduces contingencies that allow diverse phenotypes to arise from similar selection regimes.
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15
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Iglesias-Carrasco M, Duchêne DA, Head ML, Møller AP, Cain K. Sex in the city: sexual selection and urban colonization in passerines. Biol Lett 2019; 15:20190257. [PMID: 31480935 DOI: 10.1098/rsbl.2019.0257] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Urbanization leads to a rapid and drastic transformation of habitats, forcing native fauna to manage novel ecological challenges or to move. Sexual selection is a powerful evolutionary force, which is sometimes predicted to enhance the ability of species to adapt to novel environments because it allows females to choose high-quality males, but other times is predicted to reduce the viability of populations because it pushes males beyond naturally selected optima. However, we do not know whether or how sexual selection contributes to the likelihood that animals will establish in urban areas. We use a comparative analysis of passerine birds to test whether traits associated with pre- and post-mating sexual selection predict successful colonization of urban areas. We found that plumage dichromatism was negatively associated with urban tolerance, but found no relationship with sexual size dimorphism or testes mass relative to body mass. While we cannot determine the exact reason why species with high plumage dichromatism occur less in cities, it is likely that urban areas increase the costs of expressing bright coloration due, for instance, to dietary constraints, limited male parental care or increased predation.
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Affiliation(s)
- Maider Iglesias-Carrasco
- School of Biological Sciences, University of Auckland, New Zealand.,Research School of Biology, The Australian National University, Canberra, Australia
| | - David A Duchêne
- Research School of Biology, The Australian National University, Canberra, Australia
| | - Megan L Head
- Research School of Biology, The Australian National University, Canberra, Australia
| | - Anders P Møller
- Ecologie Systématique Evolution, Université Paris-Sud CNRS AgroParisTech, Université Paris-Saclay, France.,College of Life Sciences, Beijing Normal University, People's Republic of China
| | - Kristal Cain
- School of Biological Sciences, University of Auckland, New Zealand
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16
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Sexual selection predicts the rate and direction of colour divergence in a large avian radiation. Nat Commun 2019; 10:1773. [PMID: 30992444 PMCID: PMC6467902 DOI: 10.1038/s41467-019-09859-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 04/02/2019] [Indexed: 12/31/2022] Open
Abstract
Sexual selection is proposed to be a powerful driver of phenotypic evolution in animal systems. At macroevolutionary scales, sexual selection can theoretically drive both the rate and direction of phenotypic evolution, but this hypothesis remains contentious. Here, we find that differences in the rate and direction of plumage colour evolution are predicted by a proxy for sexual selection intensity (plumage dichromatism) in a large radiation of suboscine passerine birds (Tyrannida). We show that rates of plumage evolution are correlated between the sexes, but that sexual selection has a strong positive effect on male, but not female, interspecific divergence rates. Furthermore, we demonstrate that rapid male plumage divergence is biased towards carotenoid-based (red/yellow) colours widely assumed to represent honest sexual signals. Our results highlight the central role of sexual selection in driving avian colour divergence, and reveal the existence of convergent evolutionary responses of animal signalling traits under sexual selection. What factors explain variation in the pace and trajectory of evolutionary divergence between lineages? Here, the authors show that a proxy measure for sexual selection intensity predicts both the rate and direction of plumage colour evolution in a diverse radiation of New World passerine birds.
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17
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Abstract
Animal signals-involving combinations of acoustic, chemical, visual, and behavioral cues-are among the most diverse traits in nature. Testing hypotheses about signal evolution has been hampered by difficulties with comparing highly divergent signals among species. In this Primer, I describe recent advances in capturing signals and studying their evolution. I highlight new findings using an information theory-based approach to quantifying signal variation in the diverse birds-of-paradise. Growing access to signal databases in tandem with development of new analytical tools will open up new avenues for studying the proximate mechanisms and ultimate evolutionary causes of signal variation, both within and among species.
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Affiliation(s)
- Chad M. Eliason
- Integrative Research Center, Field Museum of Natural History, Chicago, Illinois, United States of America
- * E-mail:
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Cooney CR, MacGregor HEA, Seddon N, Tobias JA. Multi-modal signal evolution in birds: re-examining a standard proxy for sexual selection. Proc Biol Sci 2018; 285:rspb.2018.1557. [PMID: 30333209 DOI: 10.1098/rspb.2018.1557] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 08/29/2018] [Indexed: 01/04/2023] Open
Abstract
Sexual selection is proposed to be an important driver of speciation and phenotypic diversification in animal systems. However, previous phylogenetic tests have produced conflicting results, perhaps because they have focused on a single signalling modality (visual ornaments), whereas sexual selection may act on alternative signalling modalities (e.g. acoustic ornaments). Here, we compile phenotypic data from 259 avian sister species pairs to assess the relationship between visible plumage dichromatism-a standard index of sexual selection in birds-and macroevolutionary divergence in the other major avian signalling modality: song. We find evidence for a strong negative relationship between the degree of plumage dichromatism and divergence in song traits, which remains significant even when accounting for other key factors, including habitat type, ecological divergence and interspecific interactions. This negative relationship is opposite to the pattern expected by a straightforward interpretation of the sexual selection-diversification hypothesis, whereby higher levels of dichromatism indicating strong sexual selection should be related to greater levels of mating signal divergence regardless of signalling modality. Our findings imply a 'trade-off' between the elaboration of visual ornaments and the diversification of acoustic mating signals, and suggest that the effects of sexual selection on diversification can only be determined by considering multiple alternative signalling modalities.
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Affiliation(s)
- Christopher R Cooney
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK .,Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Hannah E A MacGregor
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.,School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Nathalie Seddon
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Joseph A Tobias
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.,Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
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