Does the handicap principle explain the evolution of dimorphic ornaments?

Számadó, Szabolcs; Penn, Dustin J.

doi:10.1016/j.anbehav.2018.01.005

Cited by 20 publications

(9 citation statements)

References 24 publications

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“…These findings indicate that, in addition to urinary protein excretion being male-biased, there are also sex differences in how mice regulate MUP excretion according to social status. MUPs are not only sexually dimorphic; in more natural conditions they also show a male dimorphism, like the secondary sexual traits of some other species ( Számadó and Penn, 2018 ).…”

Section: Factors That Influence the Regulation Of Mup Expressionmentioning

confidence: 99%

Regulation of Sexually Dimorphic Expression of Major Urinary Proteins

2022

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Male house mice excrete large amounts of protein in their urinary scent marks, mainly composed of Major Urinary Proteins (MUPs), and these lipocalins function as pheromones and pheromone carriers. Here, we review studies on sexually dimorphic MUP expression in house mice, including the proximate mechanisms controlling MUP gene expression and their adaptive functions. Males excrete 2 to 8 times more urinary protein than females, though there is enormous variation in gene expression across loci in both sexes. MUP expression is dynamically regulated depending upon a variety of factors. Males regulate MUP expression according to social status, whereas females do not, and males regulate expression depending upon health and condition. Male-biased MUP expression is regulated by pituitary secretion of growth hormone (GH), which binds receptors in the liver, activating the JAK2-STAT5 signaling pathway, chromatin accessibility, and MUP gene transcription. Pulsatile male GH secretion is feminized by several factors, including caloric restriction, microbiota depletion, and aging, which helps explain condition-dependent MUP expression. If MUP production has sex-specific fitness optima, then this should generate sexual antagonism over allelic expression (intra-locus sexual conflict) selectively favoring sexually dimorphic expression. MUPs influence the sexual attractiveness of male urinary odor and increased urinary protein excretion is correlated with the reproductive success of males but not females. This finding could explain the selective maintenance of sexually dimorphic MUP expression. Producing MUPs entails energetic costs, but increased excretion may reduce the net energetic costs and predation risks from male scent marking as well as prolong the release of chemical signals. MUPs may also provide physiological benefits, including regulating metabolic rate and toxin removal, which may have sex-specific effects on survival. A phylogenetic analysis on the origins of male-biased MUP gene expression in Mus musculus suggests that this sexual dimorphism evolved by increasing male MUP expression rather than reducing female expression.

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Section: Factors That Influence the Regulation Of Mup Expressionmentioning

confidence: 99%

Regulation of Sexually Dimorphic Expression of Major Urinary Proteins

2022

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“…In the past, the extreme dimorphism between the sexes and elaborate and diverse decorations of males even lead to mistakenly identifying them as separate species [ 35 ]. As previously mentioned, many of these extravagant displays were supposedly explained by the Handicap Principle [ 13 ] and supported by many a study [ 36 ].…”

Section: Discussionmentioning

confidence: 99%

Does Size Matter? The Case of the Courtship Pyramids in Red Sea Ghost Crabs (Ocypode saratan)

Yosef

Korkos

Kosicki

2021

Animals

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Display, wherein males attempt to maximize fitness by attracting sexually mature females to mate, is known to drive speciation by Sexual Selection. We researched the Red Sea Ghost Crab (Ocypode saratan; RSGC), in which males build display pyramids to attract females. The study was conducted at the beach in Eilat, Israel. At each session, we measured the height (in cm) of all pyramids and the dimensions (height, breadth; in cm) of the burrow entrance. We assumed that the size of the entrance represented the relative size of the carapace width of the occupant. The mean (± SE) entrance volume was 230.8 ± 11.7 cm, and the height of the pyramid was 11.8 ± 0.49 cm (n = 54). The results of our study did not support our hypothesis because we had expected to find a linear correlation between body size and pyramid height, i.e., the larger the male, the larger the pyramid. However, our results show that the largest males in the population either built small pyramids or not at all, and the cut-off of the larger crab’s body size appears to be around 350 cm3. We discovered a step-wise function in the data in that crabs with the smallest body size of ca. 250 cm3 constructed the highest pyramids, with a declining tendency between 250–350 cm3 and extremely low pyramids beyond 350 cm3. However, our findings need to be further studied with a stress on the ambiance and elucidate whether the habitats differ in temperature, humidity, prey-base, etc., before concluding as to why the larger males desist from building pyramids. This study underwrites the importance of studying the mating systems of the macro-fauna of the beaches that are fast disappearing owing to anthropogenic development.

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“…One prominent account termed "costly signalling" theory (Spence, 1973; suggests that seemingly wasteful signals reliably communicate fitness because fitter individuals can afford more of them. Although many in ecology (and economics; Connelly et al, 2011) accept honest signalling theories such as costly signalling as a "scientific principle," others view it as an "erroneous hypothesis" (Penn & Számadó, 2020;Számadó & Penn, 2018). Interestingly, conclusions often seem to hinge on which parts of a system are tacitly assumed to be at equilibrium (Penn & Számadó, 2020).…”

Section: Proxy Failure In Ecology: Sexual Selection Nested Goals and ...mentioning

confidence: 99%