scholarly journals Sperm-duct gland content increases sperm velocity in the sand goby

Biology Open ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. bio037994 ◽  
Author(s):  
Leon Green ◽  
Charlotta Kvarnemo
Keyword(s):  
Sperm Velocity ◽  
Sand Goby ◽  
Sperm Duct ◽  
Gland Content

ADENOHYPOPHYSEAL LH CONTENT IN NORMAL, ANDROGEN-STERILIZED AND PROGESTERONE-PRIMED STERILE FEMALE RATS

1962 ◽  
Vol 39 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Roger A. Gorski ◽  
Charles A. Barraclough
Keyword(s):  
Ascorbic Acid ◽  
Electrical Stimulation ◽  
Quantitative Determination ◽  
Median Eminence ◽  
Hypothalamic Stimulation ◽  
Female Rats ◽  
Rat Pituitary ◽  
Gland Content ◽  
Stimulation Of

ABSTRACT We have previously suggested that the failure of the androgen-sterilized, persistent-oestrous rat to ovulate, following electrical stimulation of the median eminence structures of the hypothalamus, is due to an insufficiency in adenohypophyseal LH concentration. Using the ovarian ascorbic acid technique for quantitative determination of pituitary LH content, the present studies have demonstrated that the sterile rat pituitary gland contains one-third the LH content of the normal prooestrous gland. Furthermore, not only does progesterone priming of this persistent-oestrous rat result in a 75 % increase in LH concentration, but on hypothalamic stimulation sufficient LH is released to induce ovulation. The decrease in LH concentration which accompanies ovulation in the progesterone-primed, sterile rat is approximately 45 % of the total gland content as compared with a 51 % decrease in pituitary content in the normal cyclic rat.

scholarly journals Hurry-up and hatch: selective filial cannibalism of slower developing eggs

2008 ◽  
Vol 4 (2) ◽  
pp. 160-162 ◽  
Author(s):  
Hope Klug ◽  
Kai Lindström
Keyword(s):  
Egg Size ◽  
Adaptive Strategy ◽  
Filial Cannibalism ◽  
Sand Goby ◽  
Pomatoschistus Minutus ◽  
Fitness Consequences

Filial cannibalism (the consumption of one's own offspring) is thought to represent an adaptive strategy in many animals. However, little is known about the details of which offspring are consumed when a parent cannibalizes. Here, we examined patterns of within-brood filial cannibalism in the sand goby ( Pomatoschistus minutus ). Males spawned sequentially with two females, and we asked whether males cannibalized selectively with regard to egg size or the order in which eggs were received. Males preferentially consumed the larger eggs of the second female they spawned with. Because larger eggs took longer to hatch, and because female 2's eggs were up to 1 day behind those of female 1, such preferential cannibalism might allow males to decrease the time spent caring for the current brood and re-enter the mating pool sooner. More work is needed to understand the fitness consequences of such selective cannibalism.

scholarly journals Hitting the wall: Human sperm velocity recovery under ultra-confined conditions

2020 ◽  
Vol 14 (2) ◽  
pp. 024108 ◽  
Author(s):  
Matías A. Bettera Marcat ◽  
María N. Gallea ◽  
Gastón L. Miño ◽  
Marisa A. Cubilla ◽  
Adolfo J. Banchio ◽  
...  
Keyword(s):  
Human Sperm ◽  
Sperm Velocity

scholarly journals Female major histocompatibility complex type affects male testosterone levels and sperm number in the horse ( Equus caballus )

2015 ◽  
Vol 282 (1807) ◽  
pp. 20150407 ◽  
Author(s):  
D. Burger ◽  
G. Dolivo ◽  
E. Marti ◽  
H. Sieme ◽  
C. Wedekind
Keyword(s):  
Major Histocompatibility Complex ◽  
Reproductive Strategies ◽  
Kin Recognition ◽  
Equus Caballus ◽  
Major Histocompatibility ◽  
Sperm Number ◽  
Sperm Velocity ◽  
Testosterone Levels ◽  
Histocompatibility Complex ◽  
Male Reproductive Strategies

Odours of vertebrates often contain information about the major histocompatibility complex (MHC), and are used in kin recognition, mate choice or female investment in pregnancy. It is, however, still unclear whether MHC-linked signals can also affect male reproductive strategies. We used horses ( Equus caballus ) to study this question under experimental conditions. Twelve stallions were individually exposed either to an unfamiliar MHC-similar mare and then to an unfamiliar MHC-dissimilar mare, or vice versa. Each exposure lasted over a period of four weeks. Peripheral blood testosterone levels were determined weekly. Three ejaculates each were collected in the week after exposure to both mares (i.e. in the ninth week) to determine mean sperm number and sperm velocity. We found high testosterone levels when stallions were kept close to MHC-dissimilar mares and significantly lower ones when kept close to MHC-similar mares. Mean sperm number per ejaculate (but not sperm velocity) was positively correlated to mean testosterone levels and also affected by the order of presentation of mares: sperm numbers were higher if MHC-dissimilar mares were presented last than if MHC-similar mares were presented last. We conclude that MHC-linked signals influence testosterone secretion and semen characteristics, two indicators of male reproductive strategies.

scholarly journals Penis size and sperm quality, are all bats grey in the dark?

2018 ◽  
Vol 65 (6) ◽  
pp. 697-703 ◽  
Author(s):  
Nicolas Jean Fasel ◽  
Marta Kołodziej-Sobocińska ◽  
Ewa Komar ◽  
Marcin Zegarek ◽  
Ireneusz Ruczyński
Keyword(s):  
Sperm Quality ◽  
Copulatory Behavior ◽  
Scaling Relations ◽  
Head Width ◽  
Sperm Velocity ◽  
Selective Pressures ◽  
Penis Size ◽  
Penis Length ◽  
Selection For ◽  
Myotis Nattereri

Abstract Penises play a key role in sperm transport and in stimulating female genitals. This should impact post-copulatory competition, and expose penis characteristics to sexual selective pressures. Studies of male genitalia have repeatedly reported negative static allometries, which mean that, within species, large males have disproportionally small genitals when compared with smaller individuals. Males of some sperm-storing bat species may stand as an exception to such a pattern by arousing from hibernation to copulate with torpid females. The selection for large penises might take place, if a long organ provides advantages during post-copulatory competition and/or if females have evolved mechanisms allowing the choice of sire, relying on characters other than pre-copulatory traits (e.g., penis size). In this study, we measured dimensions of the erected penis in 4 sperm-storing bat species. Furthermore, we collected sperm and evaluated the link between penis dimensions and sperm velocity. Our results revealed steep allometric slopes of the erected penis length in Barbastella barbastellus and an inverse allometry of penis head width in Myotis nattereri. More detailed studies of copulatory behavior are urgently needed to explain the range of observed scaling relations. Furthermore, penis head width correlates with sperm velocity in Plecotus auritus. For this last species, we propose that penis shape might act as a marker of male fertility.

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