scholarly journals Elaborate visual and acoustic signals evolve independently in a large, phenotypically diverse radiation of songbirds

2014 ◽  
Vol 281 (1788) ◽  
pp. 20140967 ◽  
Author(s):  
Nicholas A. Mason ◽  
Allison J. Shultz ◽  
Kevin J. Burns

The concept of a macroevolutionary trade-off among sexual signals has a storied history in evolutionary biology. Theory predicts that if multiple sexual signals are costly for males to produce or maintain and females prefer a single, sexually selected trait, then an inverse correlation between sexual signal elaborations is expected among species. However, empirical evidence for what has been termed the ‘transfer hypothesis’ is mixed, which may reflect different selective pressures among lineages, evolutionary covariates or methodological differences among studies. Here, we examine interspecific correlations between song and plumage elaboration in a phenotypically diverse, widespread radiation of songbirds, the tanagers. The tanagers (Thraupidae) are the largest family of songbirds, representing nearly 10% of all songbirds. We assess variation in song and plumage elaboration across 301 species, representing the largest scale comparative study of multimodal sexual signalling to date. We consider whether evolutionary covariates, including habitat, structural and carotenoid-based coloration, and subfamily groupings influence the relationship between song and plumage elaboration. We find that song and plumage elaboration are uncorrelated when considering all tanagers, although the relationship between song and plumage complexity varies among subfamilies. Taken together, we find that elaborate visual and vocal sexual signals evolve independently among tanagers.

2019 ◽  
Author(s):  
Lucie Rigaill

AbstractVarious animal species have evolved a sexual communication system with females displaying and males discriminating information about the timing of ovulation through sexual signals. More research is now investigating the potential ovulatory signalling function of female red skin colour in human and non-human primates. However, to date it is still challenging to draft satisfying hypotheses about the evolution and function of female red skin colour, due to methodological discrepancies between human and non-human primate studies. The present study used a within-individual design and objective methods to analyse the relationship between fine-scale variation in cheek and lip colour (luminance and redness) and the estimated day of ovulation in 15 cycling women. Lip, but not cheek, colour appeared to contain information about the timing of ovulation, with lips getting darker around ovulation. This study adds to the growing evidence that female red skin colour may play a role in sexual signalling in human and non-human primates but also underlines variation in trait forms and functions at the species-level.


2020 ◽  
Vol 131 (4) ◽  
pp. 785-800
Author(s):  
Adam A Rosso ◽  
Daniel J Nicholson ◽  
Michael L Logan ◽  
Albert K Chung ◽  
John David Curlis ◽  
...  

Abstract Given that sexual signals are often expressed more highly in one sex than the other, they can impose a sex-specific cost of reproduction through parasitism. The two primary paradigms regarding the relationship of parasites to sexual signals are the good genes hypothesis and the immunocompetence handicap hypothesis; however, there are other ecological, morphological and energetic factors that might influence parasite infections in a sex-specific fashion. We tested the relationship between expression of a sexual signal (the dewlap) and ecological, morphological and energetic factors mediating ectoparasite (mite) load between male and female Panamanian slender anoles (Anolis apletophallus). We found that males were more highly parasitized than females because of the preponderance of ectoparasites on the larger dewlap of males. Indeed, ectoparasite infection increased with both body size and dewlap size in males but not in females, and parasite infection was related to energy storage in a sex-specific fashion for the fat bodies, liver and gonads. Our work and previous work on testosterone in anoles suggests that this pattern did not arise solely from immunosuppression by testosterone, but that mites prefer the dewlap as an attachment site. Thus, the expression of this sexual signal could incur a fitness cost that might structure life-history trade-offs.


PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256490
Author(s):  
Christin Hoffmann ◽  
Julia Amelie Hoppe ◽  
Niklas Ziemann

Against the background of the speed-accuracy trade-off, we explored whether the Pace of Life can be used to identify heterogeneity in the strategy to place more weight on either fast or accurate accomplishments. The Pace of Life approaches an individual’s exposure to time and is an intensively studied concept in the evolutionary biology research. Albeit overall rarely, it is increasingly used to understand human behavior and may fulfill many criteria of a personal trait. In a controlled laboratory environment, we measured the participants’ Pace of Life, as well as their performance on a real-effort task. In the real-effort task, the participants had to encode words, whereby each word encoded correctly was associated with a monetary reward. We found that individuals with a faster Pace of Life accomplished more tasks in total. At the same time, they were less accurate and made more mistakes (in absolute terms) than those with a slower Pace of Life. Thus, the Pace of Life seems to be useful to identify an individual’s stance on the speed-accuracy continuum. In our specific task, placing more weight on speed instead of accuracy paid off: Individuals with a faster Pace of Life were ultimately more successful (with regard to their monetary revenue).


2009 ◽  
Vol 276 (1664) ◽  
pp. 2093-2101 ◽  
Author(s):  
C. Alonso-Alvarez ◽  
Lorenzo Pérez-Rodríguez ◽  
Jesus T. Garcia ◽  
Javier Viñuela

The immunocompetence handicap hypothesis proposes that testosterone mediates a trade-off between sexual signalling and immunocompetence in males. Such a trade-off could favour the reliability of sexual signals on the basis that testosterone required for signal expression also promotes immunosuppression. However, the immunosuppressive activity of testosterone has not been convincingly demonstrated. We propose that the optimal solution to the testosterone-mediated trade-off should change with age, explaining ambiguous results in the past. Testosterone and ageing would promote two simultaneous immunosuppressive challenges unaffordable for low-quality males. Oxidative stress, as intimately related to ageing and immunosenescence, could contribute to enhance signal reliability. In this context, traits coloured by carotenoids (yellow–red traits) could play a crucial role due to the immunostimulatory and antioxidant properties of these pigments. Here, old and middle-aged male red-legged partridges were treated with testosterone or manipulated as controls. In the presence of high-testosterone levels, middle-aged males increased both circulating carotenoid levels and colour expression, whereas their cell-mediated immunity was not significantly altered. However, in old males, neither circulating carotenoids nor sexual signalling increased when treated with testosterone, but immunosuppression was detected. The link between testosterone and carotenoids could favour the reliability of sexual signals throughout the life.


Author(s):  
Marko Geslani

The introduction reviews the historiographic problem of the relation between fire sacrifice (yajña) and image worship (pūjā), which have traditionally been seen as opposing ritual structures serving to undergird the distinction of “Vedic” and “Hindu.” Against such an icono- and theocentric approach, it proposes a history of the priesthood in relation to royal power, centering on the relationship between the royal chaplain (purohita) and astrologer (sāṃvatsara) as a crucial, unexplored development in early Indian religion. In order to capture these historical developments, it outlines a method for the comparative study of ritual forms over time.


Author(s):  
Tian Wu ◽  
Danyan Hu ◽  
Qingfen Wang

Abstract Background Noni (Morinda citrifolia Linn.) is a tropical tree that bears climacteric fruit. Previous observations and research have shown that the second day (2 d) after harvest is the most important demarcation point when the fruit has the same appearance as the freshly picked fruit (0 d); however, they are beginning to become water spot appearance. We performed a conjoint analysis of metabolome and transcriptome data for noni fruit of 0 d and 2 d to reveal what happened to the fruit at the molecular level. Genes and metabolites were annotated to KEGG pathways and the co-annotated KEGG pathways were used as a statistical analysis. Results We found 25 pathways that were significantly altered at both metabolic and transcriptional levels, including a total of 285 differentially expressed genes (DEGs) and 11 differential metabolites through an integrative analysis of transcriptomics and metabolomics. The energy metabolism and pathways originating from phenylalanine were disturbed the most. The upregulated resistance metabolites and genes implied the increase of resistance and energy consumption in the postharvest noni fruit. Most genes involved in glycolysis were downregulated, further limiting the available energy. This lack of energy led noni fruit to water spot appearance, a prelude to softening. The metabolites and genes related to the resistance and energy interacted and restricted each other to keep noni fruit seemingly hard within two days after harvest, but actually the softening was already unstoppable. Conclusions This study provides a new insight into the relationship between the metabolites and genes of noni fruit, as well as a foundation for further clarification of the post-ripening mechanism in noni fruit.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Maher Kurdi ◽  
Badrah Alghamdi ◽  
Nadeem Shafique Butt ◽  
Saleh Baeesa

Abstract Background Tumour associated macrophages (TAMs) and tumour infiltrating lymphocytes (TILs) are considered dominant cells in glioblastoma microenvironment. Aim The purpose of this study was to assess the expression of CD204+ M2-polarized TAMs in glioblastomas and their relationship with CD4+TILs, Iba+microglia, and IDH1 mutation. We also exploreed the prognostic value of these markers on the recurrence-free interval (RFI). Methods The expressions of CD204+TAMs, CD4+TILs, and Iba1+microglia were quantitively assessed in 45 glioblastomas using immunohistochemistry. Kaplan–Meier analysis and Cox hazards were used to examine the relationship between these factors. Results CD204+TAMs were highly expressed in 32 tumours (71%) and the remaining 13 tumours (29%) had reduced expression. CD4+TILs were highly expressed in 10 cases (22%) and 35 cases (77.8%) had low expression. There was an inverse correlation between CD204+TAMs and CD4+TILs, in which 85% of tumours had a high expression of CD204+TAMs and a low expression of CD4+TILs. Nevertheless, there was no significant difference in IDH1 mutation status between the two groups (p = 0.779). There was a significant difference in Iba1+microglial activation between IDH1mutant and IDH1wildtype groups (p = 0.031). For cases with a high expression of CD204+TAMs and a low expression of CD4+TILs, there was a significant difference in RFI after treatment with chemoradiotherapy or radiotherapy (p = 0.030). Conclusion Glioblastoma with a dense CD204+TAMs and few CD4+TILs is associated with IDH1wildtype. These findings suggest that TAMs masks tumour cell and suppress T-cell tumoricidal functions via immunomodulatory mechanisms. Blockade of the CD204-TAM receptor may prevent this mechanism and allow the evolution of TILs.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ryo Matsuzaki ◽  
Shigekatsu Suzuki ◽  
Haruyo Yamaguchi ◽  
Masanobu Kawachi ◽  
Yu Kanesaki ◽  
...  

Abstract Background Pyrenoids are protein microcompartments composed mainly of Rubisco that are localized in the chloroplasts of many photosynthetic organisms. Pyrenoids contribute to the CO2-concentrating mechanism. This organelle has been lost many times during algal/plant evolution, including with the origin of land plants. The molecular basis of the evolutionary loss of pyrenoids is a major topic in evolutionary biology. Recently, it was hypothesized that pyrenoid formation is controlled by the hydrophobicity of the two helices on the surface of the Rubisco small subunit (RBCS), but the relationship between hydrophobicity and pyrenoid loss during the evolution of closely related algal/plant lineages has not been examined. Here, we focused on, the Reticulata group of the unicellular green algal genus Chloromonas, within which pyrenoids are present in some species, although they are absent in the closely related species. Results Based on de novo transcriptome analysis and Sanger sequencing of cloned reverse transcription-polymerase chain reaction products, rbcS sequences were determined from 11 strains of two pyrenoid-lacking and three pyrenoid-containing species of the Reticulata group. We found that the hydrophobicity of the RBCS helices was roughly correlated with the presence or absence of pyrenoids within the Reticulata group and that a decrease in the hydrophobicity of the RBCS helices may have primarily caused pyrenoid loss during the evolution of this group. Conclusions Although we suggest that the observed correlation may only exist for the Reticulata group, this is still an interesting study that provides novel insight into a potential mechanism determining initial evolutionary steps of gain and loss of the pyrenoid.


Sign in / Sign up

Export Citation Format

Share Document