scholarly journals Oocyte development and maturity classification of boarfish (Capros aper) in the Northeast Atlantic

2012 ◽  
Vol 69 (4) ◽  
pp. 498-507 ◽  
Author(s):  
Edward D. Farrell ◽  
Karin Hüssy ◽  
Julie O. Coad ◽  
Lotte W. Clausen ◽  
Maurice W. Clarke
Keyword(s):  
Reproductive Strategy ◽  
Preliminary Analysis ◽  
Mature Male ◽  
Oocyte Development ◽  
Sexually Dimorphic ◽  
Male And Female ◽  
Northeast Atlantic ◽  
Males And Females ◽  
External Characteristics

Abstract Farrell, E. D., Hüssy, K., Coad, J. O., Clausen, L. W., and Clarke, M. W. 2012. Oocyte development and maturity classification of boarfish (Capros aper) in the Northeast Atlantic. – ICES Journal of Marine Science, 69: 498–507. This study presents the first detailed investigation of the oocyte development and maturity classification of boarfish, Capros aper, which has recently become the target of an industrial fishery in the Northeast Atlantic. A total of 2014 boarfish were collected from January to December 2010. Mature male and female boarfish were sexually dimorphic and could be readily identified based on external characteristics. A comprehensive maturity scale was developed, which indicated that the length at 50% maturity for males and females was 9.7 cm total length. Female boarfish were observed to spawn in Irish waters in June and July. Once spawning ceased the remaining mature oocytes were resorbed. Preliminary analysis of reproductive strategy indicates that the boarfish is likely an asynchronous batch spawner with indeterminate fecundity.

scholarly journals Heightened condition dependent expression of structural colouration in the faces, but not wings, of male and female flies

2021 ◽  
Author(s):  
Thomas E White ◽  
Amy Locke ◽  
Tanya Latty
Keyword(s):  
Mate Choice ◽  
Condition Dependence ◽  
Sexually Dimorphic ◽  
Male And Female ◽  
Honest Signals ◽  
Mutual Mate Choice ◽  
Close Range ◽  
Males And Females ◽  
Structural Colouration

Abstract Structurally coloured sexual signals are a conspicuous and widespread class of ornament used in mate choice, though the extent to which they encode information on the quality of their bearers is not fully resolved. Theory predicts that signalling traits under strong sexual selection as honest indicators should evolve to be more developmentally integrated and exaggerated than nonsexual traits, thereby leading to heightened condition dependence. Here we test this prediction through examination of the sexually dimorphic faces and wings of the cursorial fly Lispe cana. Males and females possess structural UV-white and golden faces, respectively, and males present their faces and wings to females during close-range, ground-based courtship displays, thereby creating the opportunity for mutual inspection. Across a field-collected sample of individuals, we found that the appearance of the faces of both sexes scaled positively with individual condition, though along separate axes. Males in better condition expressed brighter faces as modelled according to conspecific flies, whereas condition scaled with facial saturation in females. We found no such relationships for their wing interference pattern nor abdomens, with the latter included as a nonsexual control. Our results suggest that the structurally coloured faces, but not the iridescent wings, of male and female Lispe cana are reliable guides to individual quality and support the broader potential for structural colours as honest signals. They also highlight the potential for mutual mate choice in this system, while arguing for one of several alternate signalling roles for wing interferences patterns among the myriad taxa which bear them.

scholarly journals Bounce and Double Trill Songs of Male and Female Western Screech-Owls: Characterization and Usefulness for Classification of Sex

The Auk ◽  
2001 ◽  
Vol 118 (4) ◽  
pp. 1095-1101 ◽  
Author(s):  
Brian L. Herting ◽  
James R. Belthoff ◽  
D. Kroodsma
Keyword(s):  
Maximum Amplitude ◽  
Male And Female ◽  
Discriminant Model ◽  
Model Based ◽  
Riparian Woodlands ◽  
Males And Females

AbstractBoth sexes of adult Western Screech-Owls (Otus kennicottii) sing in response to playback of conspecific song within their territories. Two primary songs are the bounce and double trill. Using sonographic analysis of tape-recorded vocalizations, our study quantified characteristics of bounce and double trill songs uttered by individuals within a population of Western Screech-Owls inhabiting riparian woodlands in southwestern Idaho. We asked if songs of males and females differed and, if so, how accurately could songs be classified by sex. On average, male bounce songs were ∼30% lower in frequency than bounce songs of females, but song duration, note duration, number of notes per bout, and internote duration did not differ. Similarly, double trill songs of males were significantly lower in frequency than those of females, and double trill songs uttered by females had significantly greater internote distances in the leading portion. A discriminant model based on frequency at maximum amplitude of bounce songs correctly classified all males and females in our sample. Presence of sex-specific patterns of vocalizations in that species would allow owls to assess the sex of potential intruders and respond appropriately. Moreover, sonographic analysis of Western Screech-Owl songs provides a means for noninvasive classification of sex.

Thyroxine levels in male and female white-tailed deer (Odocoileus virginianus)

1978 ◽  
Vol 56 (6) ◽  
pp. 945-949 ◽  
Author(s):  
G. A. Bubenik ◽  
A. B. Bubenik
Keyword(s):  
Population Structure ◽  
Odocoileus Virginianus ◽  
Wildlife Management ◽  
Mature Male ◽  
Male And Female ◽  
Annual Rhythm ◽  
Males And Females ◽  
Juvenile Males

Four major findings are described: (1) The episodic secretion of thyroxine in mature male white-tailed deer is most pronounced in the warmer months (June and September) and least demonstrated during the coldest months (November and January); (2) no clear annual rhythm of thyroxine was demonstrated in juvenile or mature male or mature barren female white-tailed deer. The monthly mean levels in mature males and females oscillate between 11 and 14 μg/100 ml throughout the year; (3) the seasonal levels of thyroxine in mature males are almost identical with the thyroxine levels of adult barren females; (4) the seasonal thyroxine levels of juvenile males are constantly higher than levels found in mature males. However, when these deer reach the age of 3 years, their thyroxine levels decrease to those of the adult.The collected data could serve as a tool of evaluation of population structure for wildlife management purposes.

scholarly journals The status of Asthenopus Curtus (Hagen) (Ephemeroptera: Polymitarcyidae) ()

1978 ◽  
Vol 8 (1) ◽  
pp. 103-105 ◽  
Author(s):  
Lewis Berner
Keyword(s):  
Adult Male ◽  
Single Species ◽  
Sexually Dimorphic ◽  
Male And Female ◽  
The Status ◽  
Males And Females

Abstract Study of a series of reared adult male and female mayflies in the genus Asthenopus from the Amazon demonstrated that males had been described by Hagen as A. curtus and females as A. amazonicus. As only a single species is represented by the strongly sexually dimorphic males and females, all should be designated as A. curtus (Hagen) and A. amazonicus (Hagen) is, therefore, a synonym.

DESCRIPTION OF COWICHANIA INTERSTITIALIS N. GEN., N. SP., AND PROPOSAL OF COWICHANIINAE N. SUBFAM., WITH REMARKS ON PHYLOGENY AND CLASSIFICATION OF HYDRYPHANTIDAE (ACARI: PARASITENGONA: HYDRYPHANTOIDEA)

1983 ◽  
Vol 115 (5) ◽  
pp. 523-527 ◽  
Author(s):  
Ian M. Smith
Keyword(s):  
New Species ◽  
Sexually Dimorphic ◽  
Dorsal Shield ◽  
Male And Female

AbstractMale and female adults of Cowichania interstitialis n. gen., n. sp. are described, and Cowichaniinae n. subfam. is proposed for members of this genus and species. Adults of the new species are autapomorphic among Hydryphantidae in having an entire, uniformly sclerotized dorsal shield, the dorsoglandularia displaced laterally, the genital field located well posteriorly on the idiosoma, and unique sclerotized plates surrounding the coxal plates laterally and posteriorly, and are unusual in having slightly stalked genital acetabula and sexually dimorphic chaetotaxy on the tibiae of the pedipalps. Provisional remarks on phylogeny and higher classification of Hydryphantidae are also presented.

Diving behaviour of male and female western grebes

1988 ◽  
Vol 66 (12) ◽  
pp. 2695-2698 ◽  
Author(s):  
L. Scott Forbes ◽  
Spencer G. Sealy
Keyword(s):  
British Columbia ◽  
Body Size ◽  
Water Depth ◽  
Wave Action ◽  
Diving Behaviour ◽  
Sexually Dimorphic ◽  
Habitat Conditions ◽  
Male And Female ◽  
Males And Females

We studied diving in western grebes (Aechmophorus occidentalis), which are sexually dimorphic, at Duck and Kootenay lakes in southeastern British Columbia to determine if differences in sex, and hence body size, resulted in differences in behaviour. Springing dives were used more frequently in deeper water and when wave action was higher, but there were no clear differences between males and females. As well, the dive–pause regressions for males and females did not differ. We conclude that differences in body size are not important determinants of diving behaviour in western grebes, but that habitat conditions (e.g., water depth, wave action) are.

scholarly journals Heightened condition dependent expression of structural colouration in the faces, but not wings, of male and female flies

2021 ◽  
Author(s):  
Thomas E White ◽  
Amy Locke ◽  
Tanya Latty
Keyword(s):  
Mate Choice ◽  
Condition Dependence ◽  
Sexually Dimorphic ◽  
Male And Female ◽  
Honest Signals ◽  
Mutual Mate Choice ◽  
Close Range ◽  
Males And Females ◽  
Structural Colouration

Structurally coloured sexual signals are a conspicuous and widespread class of ornament used in mate choice, though the extent to which they encode information on the quality of their bearers is not fully resolved. Theory predicts that signalling traits under strong sexual selection as honest indicators should evolve to be more developmentally integrated and exaggerated than nonsexual traits, thereby leading to heightened condition dependence. Here we test this prediction through examination of the sexually dimorphic faces and wings of the cursorial fly Lispe cana. Males and females possess structural UV-white and golden faces, respectively, and males present their faces and wings to females during close-range, ground-based courtship displays, thereby creating the opportunity for mutual inspection. Across a field-collected sample of individuals, we found that the appearance of the faces of both sexes scaled positively with individual condition, though along separate axes. Males in better condition expressed brighter faces as modelled according to conspecific flies, whereas condition scaled with facial saturation in females. We found no such relationships for their wing interference pattern nor abdomens, with the latter included as a nonsexual control. Our results suggest that the structurally coloured faces, but not the iridescent wings, of male and female Lispe cana are reliable guides to individual quality and support the broader potential for structural colours as honest signals. They also highlight the potential for mutual mate choice in this system, while arguing for one of several alternate signalling roles for wing interferences patterns among the myriad taxa which bear them.

scholarly journals Identification of sex-linked markers in the sexually cryptic coco de mer: are males and females produced in equal proportions?

AoB Plants ◽  
2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Emma J Morgan ◽  
Christopher N Kaiser-Bunbury ◽  
Peter J Edwards ◽  
Mathias Scharmann ◽  
Alex Widmer ◽  
...  
Keyword(s):  
Sex Ratios ◽  
Differential Mortality ◽  
Sexually Dimorphic ◽  
Male And Female ◽  
Determination System ◽  
Males And Females ◽  
Heterogametic Sex ◽  
Sex Determination System ◽  
Male Specific ◽  
Genetically Determined

Abstract Lodoicea maldivica (coco de mer) is a long-lived dioecious palm in which male and female plants are visually indistinguishable when immature, only becoming sexually dimorphic as adults, which in natural forest can take as much as 50 years. Most adult populations in the Seychelles exhibit biased sex ratios, but it is unknown whether this is due to different proportions of male and female plants being produced or to differential mortality. In this study, we developed sex-linked markers in Lodoicea using ddRAD sequencing, enabling us to reliably determine the gender of immature individuals. We screened 589 immature individuals to explore sex ratios across life stages in Lodoicea. The two sex-specific markers resulted in the amplification of male-specific bands (Lm123977 at 405 bp and Lm435135 at 130 bp). Our study of four sub-populations of Lodoicea on the islands of Praslin and Curieuse revealed that the two sexes were produced in approximately equal numbers, with no significant deviation from a 1:1 ratio before the adult stage. We conclude that sex in Lodoicea is genetically determined, suggesting that Lodoicea has a chromosomal sex determination system in which males are the heterogametic sex (XY) and females are homogametic (XX). We discuss the potential causes for observed biased sex ratios in adult populations, and the implications of our results for the life history, ecology and conservation management of Lodoicea.

Cranial morphometrics of the southern fur seals Arctocephalus forsteri and A. pusillus (Carnivora : Otariidae)

1998 ◽  
Vol 46 (1) ◽  
pp. 67 ◽  
Author(s):  
S. Brunner
Keyword(s):  
New Zealand ◽  
South African ◽  
Age Groups ◽  
Physiological Age ◽  
Sexually Dimorphic ◽  
Fur Seals ◽  
Fur Seal ◽  
Males And Females ◽  
New Zealand Fur Seal

The identification and classification of unknown specimens of Arctocephalus from regions of Australasia has proven difficult. Skulls from the New Zealand fur seal (Arctocephalus forsteri) and the Australian fur seal (A. pusillus doriferus), and data from specimens of the South African fur seal (A. p. pusillus), were examined. A visual method was devised to identify and separate A. p. doriferus from A. forsteri for both sexes and for most physiological age-groups. A statistical method for morphometric separation of these species was applied to adult specimens. Characteristics of males and females for both species fell into two broad categories: sexually dimorphic – mainly those characters that increase the ability of males to hold and defend territories; and non-dimorphic – those of functional importance. Studies of geographical variation showed that adult male A. forsteri from Australia were generally larger than those from Macquarie Island and New Zealand. Characteristics of A. p. doriferus were generally larger than those of A. p. pusillus. Nine specimens of New Zealand fur seals were morphologically different from the typical A. forsteri, which indicates the presence of extreme outliers or hybrids in the sample.

GONADOTROPHIN PATTERNS IN MALE AND FEMALE RATS:

1968 ◽  
Vol 58 (4) ◽  
pp. 600-612 ◽  
Author(s):  
Robert Boyd ◽  
Donald C. Johnson
Keyword(s):  
Ascorbic Acid ◽  
Testosterone Propionate ◽  
Female Rats ◽  
Female Rat ◽  
Feedback Effects ◽  
Male And Female ◽  
Prostate Weight ◽  
Male And Female Rats ◽  
Males And Females ◽  
Normal Males

ABSTRACT The effects of various doses of testosterone propionate (TP) upon the release of luteinizing hormone (LH or ICSH) from the hypophysis of a gonadectomized male or female rat were compared. Prostate weight in hypophysectomized male parabiotic partners was used to evaluate the quantity of circulating LH. Hypophyseal LH was measured by the ovarian ascorbic acid depletion method. Males castrated when 45 days old secreted significantly more LH and had three times the amount of pituitary LH as ovariectomized females. Administration of 25 μg TP daily reduced the amount of LH in the plasma, and increased the amount in the pituitary gland, in both sexes. Treatment with 50 μg caused a further reduction in plasma LH in males, but not in females, while pituitary levels in both were equal to that of their respective controls. LH fell to the same low level in partners of males or females receiving 100 μg TP. When gonadectomized at 39 days, males and females had the same amount of plasma LH, but males had more stored hormone. Pituitary levels were unchanged from controls following treatment with 12.5, 25 or 50 μg TP daily, but plasma values dropped an equal amount in both sexes with the latter two doses. Androgenized males or females, gonadectomized when 39 days old, were very sensitive to the effects of TP and plasma LH was significantly reduced with 12.5 μg daily. Pituitary LH in androgenized males was higher than that of normal males but was reduced to normal by small amounts of TP. The amount of stored LH in androgenized females was not different from that of normal females and it was unchanged by any dose of TP tested. Results are consistent with the conclusion that the male hypothalamic-hypophyseal axis is at least as sensitive as the female axis to the negative feedback effects of TP. Androgenization increases the sensitivity to TP in both males and females.

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