scholarly journals Postmating sexual selection and the enigmatic jawed genitalia ofCallosobruchus subinnotatus

2017 ◽  
Author(s):  
Merel M. van Haren ◽  
Johanna Liljestrand Rönn ◽  
Menno Schilthuizen ◽  
Göran Arnqvist
Keyword(s):  
Sexual Selection ◽  
Genital Tract ◽  
Egg Production ◽  
Fertilization Success ◽  
Divergent Evolution ◽  
Female Fecundity ◽  
Double Mating ◽  
Phenotypic Engineering ◽  
Callosobruchus Subinnotatus ◽  
Male Genital

SummaryInsect genitalia exhibit rapid divergent evolution. Truly extraordinary structures have evolved in some groups, presumably as a result of post-mating sexual selection. To increase our understanding of this phenomenon, we studied the function of one such structure. The male genitalia ofCallosobruchus subinnotatus(Coleoptera: Bruchinae) contain a pair of jaw-like structures with unknown function. Here, we used phenotypic engineering to ablate the teeth on these jaws. We then experimentally assessed the effects of ablation of the genital jaws on mating duration, ejaculate weight, male fertilization success and female fecundity, using a double-mating experimental design. We predicted that copulatory wounding in females should be positively related to male fertilization success. However, we found no significant correlation between genital tract scarring in females and male fertilization success. Male fertilization success was, however, positively related to the amount of ejaculate transferred by males and negatively related to female ejaculate dumping. Ablation of male genital jaws did not affect male relative fertilization success but resulted in a reduction in female egg production. Our results suggest that postmating sexual selection in males indeed favors these genital jaws, but not primarily through an elevated relative success in sperm competition but by increasing female egg production.

EFFECT OF HIGH DOSES OF OESTROGEN AND PROGESTERONE ON THE NORADRENALINE CONTENT OF THE SHORT ADRENERGIC NEURONS INNERVATING THE MALE GENITAL TRACT OF THE RAT

1970 ◽  
Vol 64 (3) ◽  
pp. 459-465 ◽  
Author(s):  
Ch. Owman ◽  
N.-O. Sjöberg ◽  
N. O. Sjöstrand ◽  
G. Swedin
Keyword(s):  
Genital Tract ◽  
Reproductive Tract ◽  
Female Genital Tract ◽  
Total Content ◽  
Prolonged Treatment ◽  
Noradrenaline Content ◽  
Adrenergic Neurons ◽  
Short Adrenergic Neurons ◽  
High Doses ◽  
Male Genital

ABSTRACT The effect of prolonged treatment with high doses of oestrogen and/or progesterone on the amount of adrenergic transmitter in the short adrenergic neurons of the male reproductive tract of castrated rats has been studied by chemical determinations and histochemical demonstration of noradrenaline. Oestrogen, progesterone, or a combination of both, had no overt effect on the total content or on the concentration of noradrenaline in the male genital organs. The results are discussed in the light of recent findings that the content of the noradrenaline transmitter in the short adrenergic neurons to the female genital tract is markedly influenced by these female sex hormones.

OBSERVATIONS ON THE FLORA OF THE MALE GENITAL TRACT IN DISEASE

1928 ◽  
Vol 2 (14) ◽  
pp. 433-436
Author(s):  
Norman M. Gibson ◽  
C. J. Wiley
Keyword(s):  
Genital Tract ◽  
Male Genital Tract ◽  
Male Genital

Male genital tract injuries after contemporary inguinal hernia repair

2002 ◽  
Vol 90 (3) ◽  
pp. 272-276 ◽  
Author(s):  
P.F. Ridgway ◽  
J. Shah ◽  
A.W. Darzi
Keyword(s):  
Inguinal Hernia ◽  
Hernia Repair ◽  
Inguinal Hernia Repair ◽  
Genital Tract ◽  
Male Genital Tract ◽  
Male Genital

Poor penetration of the male genital tract by HIV-1 protease inhibitors

AIDS ◽  
1999 ◽  
Vol 13 (7) ◽  
pp. 859 ◽  
Author(s):  
Stephen Taylor ◽  
David J. Back ◽  
Judith Workman ◽  
Susan M. Drake ◽  
David J. White ◽  
...  
Keyword(s):  
Protease Inhibitors ◽  
Genital Tract ◽  
Male Genital Tract ◽  
Hiv 1 ◽  
Male Genital

Male genital tract malformations associated with ipsilateral renal agenesis: Sonographic findings

1991 ◽  
Vol 19 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Jean-Paul Trigaux ◽  
Bernard Van Beers ◽  
Francis Delchambre
Keyword(s):  
Genital Tract ◽  
Renal Agenesis ◽  
Male Genital Tract ◽  
Male Genital

scholarly journals Protease inhibitor monotherapy is effective in controlling human immunodeficiency virus 1 shedding in the male genital tract

2016 ◽  
Vol 22 (1) ◽  
pp. 98.e7-98.e10 ◽  
Author(s):  
A. Torres-Cornejo ◽  
O.J. BenMarzouk-Hidalgo ◽  
P. Viciana ◽  
B. Sánchez ◽  
M.A. López-Ruz ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Protease Inhibitor ◽  
Genital Tract ◽  
Male Genital Tract ◽  
Immunodeficiency Virus ◽  
Protease Inhibitor Monotherapy ◽  
Human Immunodeficiency Virus 1 ◽  
Male Genital

The Male Genital Tract of Two Genera of Indian Squirrels

1954 ◽  
Vol 35 (4) ◽  
pp. 471 ◽  
Author(s):  
M. R. N. Prasad
Keyword(s):  
Genital Tract ◽  
Male Genital Tract ◽  
Male Genital

Post-Copulatory Sexual Selection

2021 ◽  
Author(s):  
Patricia L.R. Brennan ◽  
Dara N. Orbach
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Female Choice ◽  
Reproductive Tract ◽  
Seminal Fluid ◽  
Fertilization Success ◽  
Female Reproductive Tract ◽  
Cryptic Female Choice ◽  
Trade Offs ◽  
Morphological Criteria

The field of post-copulatory sexual selection investigates how female and male adaptations have evolved to influence the fertilization of eggs while optimizing fitness during and after copulation, when females mate with multiple males. When females are polyandrous (one female mates with multiple males), they may optimize their mating rate and control the outcome of mating interactions to acquire direct and indirect benefits. Polyandry may also favor the evolution of male traits that offer an advantage in post-copulatory male-male sperm competition. Sperm competition occurs when the sperm, seminal fluid, and/or genitalia of one male directly impacts the outcome of fertilization success of a rival male. When a female mates with multiple males, she may use information from a number of traits to choose who will sire her offspring. This cryptic female choice (CFC) to bias paternity can be based on behavioral, physiological, and morphological criteria (e.g., copulatory courtship, volume and/or composition of seminal fluid, shape of grasping appendages). Because male fitness interests are rarely perfectly aligned with female fitness interests, sexual conflict over mating and fertilization commonly occur during copulatory and post-copulatory interactions. Post-copulatory interactions inherently involve close associations between female and male reproductive characteristics, which in many species potentially include sperm storage and sperm movement inside the female reproductive tract, and highlight the intricate coevolution between the sexes. This coevolution is also common in genital morphology. The great diversity of genitalia among species is attributed to sexual selection. The evolution of genital attributes that allow females to maintain reproductive autonomy over paternity via cryptic female choice or that prevent male manipulation and sexual control via sexually antagonistic coevolution have been well documented. Additionally, cases where genitalia evolve through intrasexual competition are well known. Another important area of study in post-copulatory sexual selection is the examination of trade-offs between investments in pre-copulatory and post-copulatory traits, since organisms have limited energetic resources to allocate to reproduction, and securing both mating and fertilization is essential for reproductive success.

MOUNTING EVIDENCE IN SUPPORT OF A HYPOTHESIS

2021 ◽  
pp. 217-218
Author(s):  
Skandhan KP ◽  
Chaitrali G ◽  
Prasad B.S
Keyword(s):  
Genital Tract ◽  
Sperm Count ◽  
Study Analysis ◽  
Male Genital Tract ◽  
Male Genital

Aim: A study analysis supporting reports on a hypothesis. Background: The function of epididymis is considered as responsible for making a meaningful motionless state for spermatozoa assuring sperms do not escape from male genital tract by its motility. A hypothesis stated repeated ejaculation shall lead to increase sperm count and motility. Review results: Studies showed frequent ejaculations done by men and similar studies conducted in animals support this hypothesis. Conclusion: This method should be benecial to at least patients whose sperm count and motility is less. Clinical signicance: when hypothesis is proved, clinician may advice this patients with oligozoospermia, oligoasthenozoospermia to follow repeated ejaculation instead of storing semen for several days as advised currently

scholarly journals Sperm removal during copulation confirmed in the oldest extant damselfly,Hemiphlebia mirabilis

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2077 ◽  
Author(s):  
Adolfo Cordero-Rivera
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Short Range ◽  
Body Position ◽  
Reproductive Behaviour ◽  
Scramble Competition ◽  
Stage I ◽  
Female Genitalia ◽  
Second Stage ◽  
Male Genital

Postcopulatory sexual selection may favour mechanisms to reduce sperm competition, like physical sperm removal by males. To investigate the origin of sperm removal, I studied the reproductive behaviour and mechanisms of sperm competition in the only living member of the oldest damselfly family,Hemiphlebia mirabilis, one species that was considered extinct in the 1980s. This species displays scramble competition behaviour. Males search for females with short flights and both sexes exhibit a conspicuous “abdominal flicking”. This behaviour is used by males during an elaborate precopulatory courtship, unique among Odonata. Females use a similar display to reject male attempts to form tandem, but eventually signal receptivity by a particular body position. Males immobilise females during courtship using their legs, which, contrarily to other damselflies, never autotomise. Copulation is short (range 4.1–18.7 min), and occurs in two sequential stages. In the first stage, males remove part of the stored sperm, and inseminate during the second stage, at the end of mating. The male genital ligula matches the size and form of female genitalia, and ends by two horns covered by back-oriented spines. The volume of sperm in females before copulation was 2.7 times larger than the volume stored in females whose copulation was interrupted at the end of stage I, indicative of a significant sperm removal. These results point out that sperm removal is an old character in the evolution of odonates, possibly dating back to the Permian.

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