scholarly journals Can Sexual Selection Drive the Evolution of Sperm Cell Structure?

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1227
Author(s):  
Leigh W. Simmons ◽  
Francisco Garcia-Gonzalez
Keyword(s):  
Sexual Selection ◽  
Sperm Cell ◽  
Cell Structure ◽  
Dung Beetle ◽  
Divergent Evolution ◽  
Cell Phenotype ◽  
Sperm Cells ◽  
Sperm Length ◽  
Comparative Analyses ◽  
Onthophagus Taurus

Sperm cells have undergone an extraordinarily divergent evolution among metazoan animals. Parker recognized that because female animals frequently mate with more than one male, sexual selection would continue after mating and impose strong selection on sperm cells to maximize fertilization success. Comparative analyses among species have revealed a general relationship between the strength of selection from sperm competition and the length of sperm cells and their constituent parts. However, comparative analyses cannot address causation. Here, we use experimental evolution to ask whether sexual selection can drive the divergence of sperm cell phenotype, using the dung beetle Onthophagus taurus as a model. We either relaxed sexual selection by enforcing monogamy or allowed sexual selection to continue for 20 generations before sampling males and measuring the total length of sperm cells and their constituent parts, the acrosome, nucleus, and flagella. We found differences in the length of the sperm cell nucleus but no differences in the length of the acrosome, flagella, or total sperm length. Our data suggest that different sperm cell components may respond independently to sexual selection and contribute to the divergent evolution of these extraordinary cells.

scholarly journals Offspring viability benefits but no apparent costs of mating with high quality males

2010 ◽  
Vol 7 (3) ◽  
pp. 419-421 ◽  
Author(s):  
Leigh W. Simmons ◽  
Rebecca Holley
Keyword(s):  
Sexual Selection ◽  
Sexual Conflict ◽  
Alternative Hypothesis ◽  
Dung Beetle ◽  
Male Courtship ◽  
High Quality ◽  
Female Resistance ◽  
Genetic Quality ◽  
Onthophagus Taurus ◽  
Courtship Signals

Traditional models of sexual selection posit that male courtship signals evolve as indicators of underlying male genetic quality. An alternative hypothesis is that sexual conflict over mating generates antagonistic coevolution between male courtship persistence and female resistance. In the scarabaeine dung beetle Onthophagus taurus , females are more likely to mate with males that have high courtship rates. Here, we examine the effects of exposing females to males with either high or low courtship rates on female lifetime productivity and offspring viability. Females exposed to males with high courtship rates mated more often and produced offspring with greater egg–adult viability. Female productivity and lifespan were unaffected by exposure to males with high courtship rates. The data are consistent with models of sexual selection based on indirect genetic benefits, and provide little evidence for sexual conflict in this system.

scholarly journals A link between heritable parasite resistance and mate choice in dung beetles

2019 ◽  
Vol 30 (5) ◽  
pp. 1382-1387 ◽  
Author(s):  
Bruno A Buzatto ◽  
Janne S Kotiaho ◽  
Larissa A F Assis ◽  
Leigh W Simmons
Keyword(s):  
Sexual Selection ◽  
Mate Choice ◽  
Female Choice ◽  
Additive Genetic Variance ◽  
Dung Beetle ◽  
Mite Infestation ◽  
Adult Survival ◽  
Parasite Resistance ◽  
Onthophagus Taurus ◽  
Sexual Selection Theory

AbstractParasites play a central role in the adaptiveness of sexual reproduction. Sexual selection theory suggests a role for parasite resistance in the context of mate choice, but the evidence is mixed. The parasite-mediated sexual selection (PMSS) hypothesis derives a number of predictions, among which that resistance to parasites is heritable, and that female choice favors parasite resistance genes in males. Here, we tested the PMSS hypothesis using the dung beetle Onthophagus taurus, a species that can be heavily parasitized by Macrocheles merdarius mites, which are known to affect adult survival. We investigated the heritability of resistance to M. merdarius, as well as whether female O. taurus impose a mating bias against males susceptible to mite infestation. Female choice for parasite resistance is difficult to disentangle from the possibility that females are simply choosing less parasitized males due to naturally selected benefits of avoiding contracting those parasites. This is especially likely for ectoparasites, such as mites. We tackled this problem by performing a mate choice trial first, and then measuring a male’s resistance to mite infestation. Resistance to mite infestation exhibited significant levels of additive genetic variance. Although we found no relationship between mating success and parasite resistance, males with greater resistance to infestation mated for longer. If females control copula duration, given that short copulations often result in mating failure, female choice could act on parasite resistance.

Allometric relationships and character evolution in Onthophagus taurus (Coleoptera: Scarabaeidae)

2000 ◽  
Vol 78 (7) ◽  
pp. 1199-1206 ◽  
Author(s):  
Claudia Palestrini ◽  
Antonio Rolando ◽  
Paola Laiolo
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Small Body ◽  
Dung Beetle ◽  
Allometric Relationships ◽  
Secondary Sexual Traits ◽  
Onthophagus Taurus ◽  
Sexual Traits ◽  
External Body ◽  
Secondary Sexual

Allometric relationships in primary sexual traits (male and female genitalia), secondary sexual traits (male horns and female carinae), and non-sex-related traits (external body traits, epipharynx traits) were studied in the dung beetle Onthophagus taurus. Model II regressions of log-transformed data were used to quantify relationships, with pronotum width as regressor and indicator of overall body size. Slopes (allometric values) for the different trait categories were significantly different, with secondary sexual traits showing the highest values (higher than 1.0), followed by external body traits (slightly lower than 1.00) and epipharynx traits (around 0.2). Primary sexual traits and body size were mostly uncorrelated and genital sizes were virtually constant. Allometries of secondary sexual traits were quite different in the two sexes: the relationship between male horn length and pronotum width was approximately sigmoidal, while that between female carina length and pronotum width was linear. External body traits had significantly higher allometric values in females than in males. Our results suggest that traits in the different categories are under different kinds of selection. Genital allometries can be explained on the basis of sexual selection by cryptic female choice or by the lock-and-key hypothesis. Among secondary sexual characters, male horn morphology seems to be mostly "environmentally" determined and sexual selection would affect only a component of the developmental mechanism of horn expression. External body characters are likely under natural selection, even though a few traits could be sex-related. Finally, in both sexes, internal epipharynx traits seem to be subject to the same selective pressure, probably because males and females use the same feeding niche. The constancy of genital sizes in O. taurus suggests that in developmental processes, more is invested in primary sexual traits (to produce genitalia of the proper size) than in secondary sexual or body traits. Males receiving low quantities of food may incur costs associated with a small horn or small body size, but do not incur costs associated with small genitalia. Females probably share the same developmental pattern.

scholarly journals Persistent directional growth capability in Arabidopsis thaliana pollen tubes after nuclear elimination from the apex

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kazuki Motomura ◽  
Hidenori Takeuchi ◽  
Michitaka Notaguchi ◽  
Haruna Tsuchi ◽  
Atsushi Takeda ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pollen Tube ◽  
Sperm Cell ◽  
Pollen Tubes ◽  
Vegetative Nucleus ◽  
Sperm Cells ◽  
Apical Region ◽  
Basal Region ◽  
Specific Expression ◽  
Directional Growth

AbstractDuring the double fertilization process, pollen tubes deliver two sperm cells to an ovule containing the female gametes. In the pollen tube, the vegetative nucleus and sperm cells move together to the apical region where the vegetative nucleus is thought to play a crucial role in controlling the direction and growth of the pollen tube. Here, we report the generation of pollen tubes in Arabidopsis thaliana whose vegetative nucleus and sperm cells are isolated and sealed by callose plugs in the basal region due to apical transport defects induced by mutations in the WPP domain-interacting tail-anchored proteins (WITs) and sperm cell-specific expression of a dominant mutant of the CALLOSE SYNTHASE 3 protein. Through pollen-tube guidance assays, we show that the physiologically anuclear mutant pollen tubes maintain the ability to grow and enter ovules. Our findings provide insight into the sperm cell delivery mechanism and illustrate the independence of the tip-localized vegetative nucleus from directional growth control of the pollen tube.

Effect of Density and Extra Dung on Brood Parasitism in the Dung Beetle, Onthophagus Taurus

2012 ◽  
Vol 26 (2) ◽  
pp. 253-259 ◽  
Author(s):  
Mary Crowe ◽  
Erin Raspet ◽  
Jan Rychtar ◽  
Sat Gupta
Keyword(s):  
Brood Parasitism ◽  
Dung Beetle ◽  
Onthophagus Taurus

scholarly journals Influence of Campylobacter fetus subsp. fetus on ram sperm cell quality

2008 ◽  
Vol 57 (11) ◽  
pp. 1405-1410 ◽  
Author(s):  
Tidhar Zan Bar ◽  
Ronen Yehuda ◽  
Tomer Hacham ◽  
Sigal Krupnik ◽  
Benjamin Bartoov
Keyword(s):  
Sperm Cell ◽  
Sperm Cells ◽  
Male Factor ◽  
Motility Index ◽  
Fas Receptor ◽  
Campylobacter Fetus ◽  
Fetus Subsp ◽  
Ram Sperm ◽  
Female Sheep

Campylobacter fetus subsp. fetus infection can occur in female sheep, causing infertility or abortion. Despite extensive research on the effect of these bacteria on female fertility, little research has been done on the influence of C. fetus subsp. fetus on the male factor. Our objective was to examine the influence of C. fetus subsp. fetus on ram sperm. Motility index, percentage of live spermatozoa, mean αt value (an indication of the chromatin stability of the sperm cell) and percentage of sperm cells expressing the FAS receptor were measured in sperm incubated in the presence or absence of C. fetus subsp. fetus. The motility index and viability of sperm incubated with the bacteria were lower than those of untreated sperm samples after 5 h. In bacteria-incubated sperm cells, the percentage expressing FAS receptor was already significantly elevated at 15 min. Bacteria-incubated sperm showed a greater prevalence of morphological damage. The bacteria were attached to tail and acrosome regions, and the sperm damage was concentrated in both the motility and chromatin regions. Bacteria-infected sperm cells showed a decrease in motility, increase in early acrosome reaction and chromatin damage. Similar effects were induced by incubation of the sperm with supernatants from C. fetus subsp. fetus cultures. Thus this study demonstrates that C. fetus subsp. fetus has a detrimental effect on the quality of ram sperm.

scholarly journals Evolution and plasticity of morph‐specific integration in the bull‐headed dung beetle Onthophagus taurus

2020 ◽  
Vol 10 (19) ◽  
pp. 10558-10570
Author(s):  
Patrick T. Rohner ◽  
Anna L. M. Macagno ◽  
Armin P. Moczek
Keyword(s):  
Dung Beetle ◽  
Onthophagus Taurus

scholarly journals A Study of Aflatoxin on Sperm Cell Quality for Elderly People

2018 ◽  
Vol 6 (2) ◽  
pp. 45-49
Author(s):  
Akila CR ◽  
Dinesh Babu J ◽  
Sravan Kumar P ◽  
Vinaya B
Keyword(s):  
Elderly People ◽  
Sperm Cell ◽  
Sperm Cells

Mycotoxins represent poisonous materials produced via certain types of growths. Among different mycotoxins, aflatoxins are viewed as plainly hazardous, taking into account that they are portrayed as cancer-causing for creatures and individuals. The admission of aflatoxins by means of feeds or nourishments should cause pernicious results on creatures' or people's wellbeing. Exploration on creatures has indicated that the overall casing circumstance just as a portion of the blood boundaries, particularly those of the liver may be adversely influenced with aflatoxin the executives. As to conceptive device, in spite of the fact that not remarkably examined, a few specialists bolster the helpless impacts of aflatoxins both on women or on grown-up guys. More precisely, in male, the scale and weight of the genital organs, the spermatogenesis, the number, the motility and the morphology of sperm cells just as hormones' fixations can be influenced after presentation of the creatures to aflatoxins, making barrenness inconveniences additional normal. Most examination allude to lab and significantly less to viable creatures, while least complex two investigations look for counsel from the doable issues of barrenness on men in view of aflatoxins. Since imitation is made one out of the greatest fundamental areas of creature cultivation, exceptional intrigue should be paid to supplements with the goal that the chance of the aflatoxin admission by creatures could be evacuated, the creature wellbeing extraordinarily in regards to the conceptive gadget may be covered and financial misfortunes could be enhanced.

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