Altitudinal variation in male reproductive investment in a polyandrous frog species (Hyla gongshanensis jingdongensis)

2016 ◽  
Vol 66 (3-4) ◽  
pp. 289-303 ◽  
Author(s):  
Long Jin ◽  
Zhi Ping Mi ◽  
Wen Bo Liao
Keyword(s):  
Reproductive Investment ◽  
Sperm Length ◽  
Tree Frog ◽  
Altitudinal Variation ◽  
Offspring Number ◽  
Wide Range ◽  
Population Comparisons ◽  
Group Spawning ◽  
Sperm Size ◽  
Testis Mass

Competition for fertilization in multi-male group spawning can drive variation in male reproductive investment (i.e., testis mass and sperm size). Inter-population comparisons of variation in energetic availability and allocation along geographical gradients allow insights into the mechanisms shaping the reproductive investments of animals. Although inter-population differences in female reproductive investment (i.e., clutch size and egg size) have been studied extensively across a wide range of taxa, little information on variation in reproductive investment in males is available. Here, we studied altitudinal variation in testis mass and sperm length among three populations in the Jingdong tree frog (Hyla gongshanensis jingdongensis), a polyandrous species, in Yunnan Province in China. The results showed that individuals exhibited smaller testes at higher altitudes while testes mass was positively correlated with body size, body condition and age. Longer sperm length was observed in the middle-altitude population. Moreover, we found that sperm number was positively correlated with testes mass and sperm length. Our correlational findings suggest that environmental constraints at high altitude select for less investment in testes and offspring number.

Brain size evolution in small mammals: test of the expensive tissue hypothesis

Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ying Jiang ◽  
Jia Yu Wang ◽  
Xiao Fu Huang ◽  
Chun Lan Mai ◽  
Wen Bo Liao
Keyword(s):  
Small Mammals ◽  
Brain Size ◽  
Reproductive Investment ◽  
Generalized Least Squares ◽  
Offspring Number ◽  
Size Evolution ◽  
Large Brain ◽  
Species Evolution ◽  
The Cost ◽  
Expensive Tissue Hypothesis

Abstract Brain size exhibits significant changes within and between species. Evolution of large brains can be explained by the need to improve cognitive ability for processing more information in changing environments. However, brains are among the most energetically expensive organs. Enlarged brains can impose energetic demands that limit brain size evolution. The expensive tissue hypothesis (ETH) states that a decrease in the size of another expensive tissue, such as the gut, should compensate for the cost of a large brain. We studied the interplay between energetic limitations and brain size evolution in small mammals using phylogenetically generalized least squares (PGLS) regression analysis. Brain mass was not correlated with the length of the digestive tract in 37 species of small mammals after correcting for phylogenetic relationships and body size effects. We further found that the evolution of a large brain was not accompanied by a decrease in male reproductive investments into testes mass and in female reproductive investment into offspring number. The evolution of brain size in small mammals is inconsistent with the prediction of the ETH.

scholarly journals Why mammalian lineages respond differently to sexual selection: metabolic rate constrains the evolution of sperm size

2011 ◽  
Vol 278 (1721) ◽  
pp. 3135-3141 ◽  
Author(s):  
Montserrat Gomendio ◽  
Maximiliano Tourmente ◽  
Eduardo R. S. Roldan
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Metabolic Rate ◽  
Sperm Competition ◽  
Small Mammals ◽  
High Mass ◽  
Metabolic Rates ◽  
Wide Range ◽  
Low Mass ◽  
Sperm Size

The hypothesis that sperm competition should favour increases in sperm size, because it results in faster swimming speeds, has received support from studies on many taxa, but remains contentious for mammals. We suggest that this may be because mammalian lineages respond differently to sexual selection, owing to major differences in body size, which are associated with differences in mass-specific metabolic rate. Recent evidence suggests that cellular metabolic rate also scales with body size, so that small mammals have cells that process energy and resources from the environment at a faster rate. We develop the ‘metabolic rate constraint hypothesis’ which proposes that low mass-specific metabolic rate among large mammals may limit their ability to respond to sexual selection by increasing sperm size, while this constraint does not exist among small mammals. Here we show that among rodents, which have high mass-specific metabolic rates, sperm size increases under sperm competition, reaching the longest sperm sizes found in eutherian mammals. By contrast, mammalian lineages with large body sizes have small sperm, and while metabolic rate (corrected for body size) influences sperm size, sperm competition levels do not. When all eutherian mammals are analysed jointly, our results suggest that as mass-specific metabolic rate increases, so does maximum sperm size. In addition, species with low mass-specific metabolic rates produce uniformly small sperm, while species with high mass-specific metabolic rates produce a wide range of sperm sizes. These findings support the hypothesis that mass-specific metabolic rates determine the budget available for sperm production: at high levels, sperm size increases in response to sexual selection, while low levels constrain the ability to respond to sexual selection by increasing sperm size. Thus, adaptive and costly traits, such as sperm size, may only evolve under sexual selection when metabolic rate does not constrain cellular budgets.

scholarly journals Patternize: An R Package For Quantifying Color Pattern Variation

2017 ◽  
Author(s):  
Steven M. Van Belleghem ◽  
Riccardo Papa ◽  
Humberto Ortiz-Zuazaga ◽  
Frederik Hendrickx ◽  
Chris Jiggins ◽  
...  
Keyword(s):  
Association Studies ◽  
Genetic Association Studies ◽  
Image Data ◽  
Principal Component ◽  
R Package ◽  
Color Pattern ◽  
Color Patterns ◽  
Wide Range ◽  
Potential Applications ◽  
Population Comparisons

The use of image data to quantify, study and compare variation in the colors and patterns of organisms requires the alignment of images to establish homology, followed by color-based segmentation of images. Here we describe an R package for image alignment and segmentation that has applications to quantify color patterns in a wide range of organisms. patternize is an R package that quantifies variation in color patterns obtained from image data. patternize first defines homology between pattern positions across specimens either through manually placed homologous landmarks or automated image registration. Pattern identification is performed by categorizing the distribution of colors using an RGB threshold, k-means clustering or watershed transformation. We demonstrate that patternize can be used for quantification of the color patterns in a variety of organisms by analyzing image data for butterflies, guppies, spiders and salamanders. Image data can be compared between sets of specimens, visualized as heatmaps and analyzed using principal component analysis (PCA). patternize has potential applications for fine scale quantification of color pattern phenotypes in population comparisons, genetic association studies and investigating the basis of color pattern variation across a wide range of organisms.

Effect of population density on relationship between pre- and postcopulatory sexual traits

2019 ◽  
Vol 69 (3) ◽  
pp. 281-292 ◽  
Author(s):  
Yun Lin Cai ◽  
Chun Lan Mai ◽  
Xin Yu ◽  
Wen Bo Liao
Keyword(s):  
Population Density ◽  
Sexual Size Dimorphism ◽  
Sexual Selection Theory ◽  
Sexual Traits ◽  
Taxonomic Groups ◽  
Sperm Size ◽  
The Relationship ◽  
Comparative Phylogenetic Analysis ◽  
Testis Mass ◽  
Varying Population

Abstract Sexual selection theory states that the premating (ornaments and armaments) sexual traits should trade off with the postmating (testes and ejaculates) sexual traits, assuming that growing and maintaining these traits is expensive and that total reproductive investments are limited. Male-male competition and sperm competition are predicted to affect how males allocate their finite resources to these traits. Here, we studied relative expenditure on pre- and postmating sexual traits among 82 species for three mammalian orders with varying population density using comparative phylogenetic analysis. The results showed that population density affected sexual size dimorphism (SSD) in both Artiodactyla and Carnivora, but not in Primates. However, relative testis mass and sperm size were not affected by population density. Moreover, we did not find associations between the SSD and testis mass or sperm size in three taxonomic groups. The interspecific relationships between pre- and postcopulatory sexual traits did not change with increased population density. Our findings suggest that population density did not affect variation in the relationship between pre- and postcopulatory sexual traits for these three mammalian orders.

Altitudinal variation in somatic condition and reproductive investment of male Yunnan pond frogs (Dianrana pleuraden)

2017 ◽  
Vol 266 ◽  
pp. 189-195 ◽  
Author(s):  
Chun Lan Mai ◽  
Yan Hong Liu ◽  
Long Jin ◽  
Zhi Ping Mi ◽  
Wen Bo Liao
Keyword(s):  
Reproductive Investment ◽  
Altitudinal Variation ◽  
Somatic Condition

scholarly journals Long sperm fertilize more eggs in a bird

2015 ◽  
Vol 282 (1799) ◽  
pp. 20141897 ◽  
Author(s):  
Clair Bennison ◽  
Nicola Hemmings ◽  
Jon Slate ◽  
Tim Birkhead
Keyword(s):  
Sperm Competition ◽  
Reproductive Traits ◽  
Fertilization Success ◽  
Swimming Velocity ◽  
Sperm Length ◽  
Complex Interactions ◽  
Female Reproductive Traits ◽  
Sperm Size ◽  
The Relationship ◽  
Main Factor

Sperm competition, in which the ejaculates of multiple males compete to fertilize a female's ova, results in strong selection on sperm traits. Although sperm size and swimming velocity are known to independently affect fertilization success in certain species, exploring the relationship between sperm length, swimming velocity and fertilization success still remains a challenge. Here, we use the zebra finch ( Taeniopygia guttata ), where sperm size influences sperm swimming velocity, to determine the effect of sperm total length on fertilization success. Sperm competition experiments, in which pairs of males whose sperm differed only in length and swimming speed, revealed that males producing long sperm were more successful in terms of (i) the number of sperm reaching the ova and (ii) fertilizing those ova. Our results reveal that although sperm length is the main factor determining the outcome of sperm competition, complex interactions between male and female reproductive traits may also be important. The mechanisms underlying these interactions are poorly understood, but we suggest that differences in sperm storage and utilization by females may contribute to the outcome of sperm competition.

scholarly journals How sperm competition shapes the evolution of testes and sperm: a meta-analysis

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200064
Author(s):  
Stefan Lüpold ◽  
Raïssa A. de Boer ◽  
Jonathan P. Evans ◽  
Joseph L. Tomkins ◽  
John L. Fitzpatrick
Keyword(s):  
Sperm Competition ◽  
Meta Analysis ◽  
Empirical Studies ◽  
Reproductive Behaviour ◽  
Analytical Framework ◽  
Sperm Length ◽  
Other Information ◽  
Theoretical Predictions ◽  
Testes Size ◽  
Sperm Size

Females of many species mate with multiple males, thereby inciting competition among ejaculates from rival males for fertilization. In response to increasing sperm competition, males are predicted to enhance their investment in sperm production. This prediction is so widespread that testes size (correcting for body size) is commonly used as a proxy of sperm competition, even in the absence of any other information about a species' reproductive behaviour. By contrast, a debate about whether sperm competition selects for smaller or larger sperm has persisted for nearly three decades, with empirical studies demonstrating every possible response. Here, we synthesize nearly 40 years of sperm competition research in a meta-analytical framework to determine how the evolution of sperm number (i.e. testes size) and sperm size (i.e. sperm head, midpiece, flagellum and total length) is influenced by varying levels of sperm competition across species. Our findings support the long-held assumption that higher levels of sperm competition are associated with relatively larger testes. We also find clear evidence that sperm competition is associated with increases in all components of sperm length. We discuss these results in the context of different theoretical predictions and general patterns in the breeding biology and selective environment of sperm. This article is part of the theme issue ‘Fifty years of sperm competition’.

scholarly journals Fertilization Modes And The Evolution of Sperm Characteristics In Marine Fishes: Paired Comparisons of The Externally And Internally Fertilizing Species

2021 ◽  
Author(s):  
Takeshi Ito ◽  
Masaya Morita ◽  
Kazuo Inaba ◽  
Kogiku Shiba ◽  
Hiroyuki Munehara ◽  
...  
Keyword(s):  
Sperm Competition ◽  
Sperm Motility ◽  
Sperm Head ◽  
Marine Fishes ◽  
Head Length ◽  
Sperm Length ◽  
Sperm Velocity ◽  
Internal Fertilization ◽  
Sperm Characteristics ◽  
Testis Mass

Abstract Background: Fertilization modes may affect sperm characteristics, such as morphology, velocity, and motility. However, there is surprisingly little information on how fertilization mode affects sperm evolution because several factors (e.g. sperm competition and phylogeny) are intricately intertwined with this factor when phylogenetically distant species are compared. Here, we compared sperm characteristics between six externally and four internally fertilizing marine fishes from three different groups containing close relatives, taking into account the level of sperm competition. We also analysed the relationship between relative testis mass (as an index of sperm competition level) and sperm characteristics.Results: Sperm head morphology was significantly longer in species with internal fertilization than in those with external fertilization, suggesting that a longer head is advantageous for swimming in viscous ovarian fluid or the complex ovarian structure. In addition, sperm motility differed between external fertilizers and internal fertilizers; sperm of externally fertilizing species were only motile in seawater, and sperm of internally fertilizing species were only motile in an isotonic solution. These results suggest that sperm motility has adapted according to the fertilization mode. In contrast, total sperm length and sperm velocity did not correlate with fertilization mode, perhaps because of the different levels of sperm competition. Relative testis mass is positively correlated with sperm velocity and negatively correlated with the ratio of sperm head length/flagellum length. This finding suggests that species with high levels of sperm competition have sperm that are fast and have relatively long flagella compared to head length. These results contradict a previous assumption that the evolution of internal fertilization increases total sperm length. In addition, copulatory behaviour with internal insemination may involve a large intromittent organ, but this is not essential in fish, probably due to the avoidance of water resistance.Conclusions: We propose a new scenario of sperm evolution in which internal fertilization increases sperm head length but not total sperm length and changes sperm motility. In contrast, sperm competition affects sperm length and velocity. Our findings provide a new perspective on the evolutionary biology of sperm in fish.

Variation in somatic condition and testis mass in Feirana quadranus along an altitudinal gradient

2018 ◽  
Vol 68 (3) ◽  
pp. 277-288 ◽  
Author(s):  
Tao Tang ◽  
Yi Luo ◽  
Chun Hua Huang ◽  
Wen Bo Liao ◽  
Wen Chao Huang
Keyword(s):  
Sex Ratio ◽  
Resource Availability ◽  
Altitudinal Gradient ◽  
Reproductive Investment ◽  
Male Competition ◽  
Population Variation ◽  
Operational Sex Ratio ◽  
Testis Size ◽  
Somatic Condition ◽  
Testis Mass

AbstractThe competition for fertilization among sperm from different males can drive variation in male reproductive investments. However, the mechanisms shaping reproductive allocation and the resulting variations in reproductive investment relative to environmental variables such as resource availability and male-male competition remain poorly known in frogs. Here, we investigated inter-population variation in male somatic condition and testis mass across four populations of the swelled vent frog Feirana quadranus along an altitudinal gradient. We found that relative testis mass did not increase with altitude, which was inconsistent with previous predictions that an increase in latitude and/or altitude should result in decreased sperm production in anurans due to shortened breeding seasons and the decline in resource availability. We also found no increase in somatic condition and male/female operational sex ratio with altitude. However, the somatic condition exhibited a positive correlation with testis mass, which indicated the condition-dependent testis size in F. quadranus. Moreover, an increase of testis mass with increasing male/female operational sex ratio suggest that male-male competition can result in an increased intensity of sperm competition, thereby increasing testis mass.

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