scholarly journals The chemistry and histology of sexually dimorphic mental glands in the freshwater turtle, Mauremys leprosa

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9047
Author(s):  
Alejandro Ibáñez ◽  
Albert Martínez-Silvestre ◽  
Dagmara Podkowa ◽  
Aneta Woźniakiewicz ◽  
Michał Woźniakiewicz ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Chemical Communication ◽  
Lipid Fraction ◽  
Glandular Epithelium ◽  
Freshwater Turtle ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
General Outline ◽  
Cellular Debris ◽  
Mauremys Leprosa

Despite evidence from anatomy, behavior and genomics indicating that the sense of smell in turtles is important, our understanding of chemical communication in this group is still rudimentary. Our aim was to describe the microanatomy of mental glands (MGs) in a freshwater turtle, Mauremys leprosa (Geoemydidae), and to assess the chemical composition of their secretions with respect to variation among individuals and between sexes. MGs are paired sac-like organs on the gular region of the neck and are dimorphic in this species with males having fully functional holocrine glands while those of females appear non-secretory and vestigial. In adult males, the glandular epithelium of the inner portion of the gland provides exocytotic products as well as cellular debris into the lumen of the gland. The contents of the lumen can be secreted through the narrow duct portion of the gland ending in an orifice on the surface of the skin. Females have invaginated structures similar in general outline to male glands, but lack a glandular epithelium. Using gas chromatography coupled to mass spectrometry, we identified a total of 61 compounds in mental gland secretions, the most numerous being carboxylic acids, carbohydrates, alkanes, steroids and alcohols. The number of compounds per individual varied widely (mean (median) ± SD = 14.54 (13) ± 8.44; min = 3; max = 40), but only cholesterol was found in all samples. We found that the relative abundances of only six chemicals were different between the sexes, although males tended to have larger amounts of particular compounds. Although the lipid fraction of mental gland secretions is rich in chemical compounds, most occur in both sexes suggesting that they are metabolic byproducts with no role in chemical signaling. However, the relative amounts of some compounds tended to be higher in males, with significantly larger amounts of two carboxylic acids and one steroid, suggesting their putative involvement in chemical communication.

Dominance Structuring of a Red-Winged Blackbird Roost

The Auk ◽  
1984 ◽  
Vol 101 (3) ◽  
pp. 551-555 ◽  
Author(s):  
Patrick J. Weatherhead ◽  
Drew J. Hoysak
Keyword(s):  
Deep Water ◽  
Agelaius Phoeniceus ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Sparse Vegetation ◽  
Dense Vegetation ◽  
Dimorphic Species ◽  
Older Males

Abstract Observations of the behavior of roosting male Red-winged Blackbirds (Agelaius phoeniceus) indicated that after hatching year (AHY) males were dominant over hatching year (HY) males. This dominance resulted in AHY males occupying central roost positions in dense vegetation and HY males occupying edge positions in sparse vegetation. Overall, the birds preferred positions over deep water, although the edge positions of HY males were over deeper water than were the positions of AHY males. These results are consistent with the two-strategies roosting hypothesis (Weatherhead 1983), in that the dominance of older males allows them access to roost positions with relatively low vulnerability to predation. In this study, these positions also appeared to be microclimatically superior. These results also suggest that the bright plumage of adult males of sexually dimorphic species may be advantageous in some nonbreeding situations in addition to their more commonly recognized role in reproduction.

Spatial variability in the social organisation of the yellow-bellied glider (Petaurus australis) near Ravenshoe, north Queensland

2001 ◽  
Vol 49 (4) ◽  
pp. 397 ◽  
Author(s):  
Ross L. Goldingay ◽  
Darren G. Quin ◽  
Sue Churchill
Keyword(s):  
Adult Female ◽  
Social System ◽  
Dominant Male ◽  
Female Group ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Adult Females ◽  
The Social ◽  
Natal Home ◽  
Petaurus Australis

A detailed study was conducted over a 12-month period of 10 yellow-bellied glider groups at Nitchaga Creek in north Queensland. Adult gliders were sexually dimorphic in body size and were characterised by yellow ventral fur, which is consistent with southern populations. Gliders lived in groups of 3–6 individuals that occupied exclusive areas of about 50 ha. The structure of glider groups varied enormously: five contained one adult pair, three contained one adult male and 2–3 adult females, and two initially contained 2–3 adult males and one adult female but then persisted as bachelor groups after the death or disappearance of the adult female. Group size changed during the year as offspring matured and as individuals died. One male glider dispersed about 1 km from its natal home-range and became the dominant male in a nearby group. Young were born throughout the year, with a peak in the number of pouch-young in June. This study has confirmed the highly variable social system of the yellow-bellied glider, which appears to be mediated by local resource abundance.

Presence of the leech Placobdella costata in the south of the Iberian Peninsula

2014 ◽  
Vol 59 (2) ◽  
Author(s):  
David Romero ◽  
Jesús Duarte ◽  
Lucía Narváez-Ledesma ◽  
Miguel Farfán ◽  
Raimundo Real
Keyword(s):  
North America ◽  
Iberian Peninsula ◽  
Fresh Water ◽  
Mediterranean Area ◽  
Southern Spain ◽  
Freshwater Turtle ◽  
Emys Orbicularis ◽  
The North ◽  
Mauremys Leprosa ◽  
Fragmented Population

AbstractPlacobdella costata is a leech specific to freshwater turtle Emys orbicularis. Both genera are native to North America and have co-evolved and undergone dispersion through the Palearctic. The leech is present throughout the Mediterranean area, always associated with E. orbicularis. Their only known presence in the Iberian Peninsula is in the north and center of the peninsula. Here we present the first description of the leech in southern Spain (Andalusia) in association with a small fragmented population of fresh-water turtles in which E. orbicularis and Mauremys leprosa coexist. Unusually, the leech was found attached to the carapace of a male M. leprosa.

scholarly journals Cuticular hydrocarbons for identifying Sarcophagidae (Diptera)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hannah E. Moore ◽  
Martin J. R. Hall ◽  
Falko P. Drijfhout ◽  
Robert B. Cody ◽  
Daniel Whitmore
Keyword(s):  
Cuticular Hydrocarbons ◽  
Gas Chromatography Mass Spectrometry ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
History Museum ◽  
Chemical Profiles ◽  
Males And Females ◽  
Species Specific ◽  
Flesh Flies ◽  
Eleven Species

AbstractThe composition and quantity of insect cuticular hydrocarbons (CHCs) can be species-specific as well as sexually dimorphic within species. CHC analysis has been previously used for identification and ageing purposes for several insect orders including true flies (Diptera). Here, we analysed the CHC chemical profiles of adult males and females of eleven species of flesh flies belonging to the genus Sarcophaga Meigen (Sarcophagidae), namely Sarcophaga africa (Wiedemann), S. agnata Rondani, S. argyrostoma Robineau-Desvoidy, S. carnaria (Linnaeus), S. crassipalpis Macquart, S. melanura Meigen, S. pumila Meigen, S. teretirostris Pandellé, S. subvicina Rohdendorf, S. vagans Meigen and S. variegata (Scopoli). Cuticular hydrocarbons extracted from pinned specimens from the collections of the Natural History Museum, London using a customised extraction technique were analysed using Gas Chromatography–Mass Spectrometry. Time of preservation prior to extraction ranged between a few weeks to over one hundred years. CHC profiles (1) allowed reliable identification of a large majority of specimens, (2) differed between males and females of the same species, (3) reliably associated males and females of the same species, provided sufficient replicates (up to 10) of each sex were analysed, and (4) identified specimens preserved for up to over one hundred years prior to extraction.

The role of gonadal steroids in feedback regulation of gonadotropin secretion at different stages of primate development

1987 ◽  
Vol 114 (2) ◽  
pp. 257-268 ◽  
Author(s):  
J. S. D. Winter ◽  
L. Ellsworth ◽  
G. Fuller ◽  
W. C. Hobson ◽  
F. I. Reyes ◽  
...  
Keyword(s):  
Feedback Inhibition ◽  
Feedback Regulation ◽  
Serum Testosterone ◽  
Significant Rise ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Gonadotropin Secretion ◽  
Central Inhibition ◽  
Serum Gonadotropin ◽  
One Year

Abstract. The serum gonadotropin response to castration was assessed in 8 foetal, 2 neonatal, 30 juvenile, and 2 adult rhesus monkeys (M. mulatta). In the 30 castrated juvenile monkeys and 8 sham-operated controls, concentrations of oestrone, oestradiol, androstenedione, dihydrotestosterone, testosterone and 17OH-progesterone were measured in 10 ml serum pools before, one month after, and one year after the surgical procedure. Castration during foetal life (83–137 days gestation) was followed within 48–72 h by a significant rise in serum FSH levels in males, but had no effect on the already high levels in females. Similarly, castration of males during the first post-natal month raised serum FSH and LH into the adult castrate range; however, after 3 months of age serum gonadotropin levels again declined to the normal juvenile range in spite of the open feedback loop. Orchiectomy of pre-pubertal juvenile monkeys (age 3 months–28/12 years) had no immediate effect on serum gonadotropins, but was followed by a delayed rise in FSH (at age 23/12–43/12 years) and LH (at age 27/12–44/12 years) to adult castrate levels. Orchiectomy of older prepubertal (by serum testosterone) or adult males resulted within a few days in a progressive and sustained rise in serum FSH and a more gradual rise in LH. Prepubertal gonadotropin regulation appeared to be sexually dimorphic, since ovariectomy in juvenile females (age 3 months–15/12 years) was followed by generally elevated, if somewhat erratic, serum FSH values, with a secondary rise in both FSH and LH levels at 2–21/12 years. In both sexes, prepubertal castration caused a significant and sustained decline in serum concentrations of oestradiol; castrated males also showed a decline in serum testosterone levels. Although prepubertal castration also caused in both sexes a slight decline in serum oestrone, and ovariectomy a decline in serum androstenedione and dihydrotestosterone, these effects were not sustained one year later, and values were not significantly different from sham-operated controls. Taken together, these data lend support to a model of primate sexual maturation in which the primary regulator of gonadotropin secretion in both sexes during the prolonged juvenile phase is central inhibition of the hypothalamic GnRH regulator. However, during foetal and neonatal life, and again following the onset of puberty, the major modulator of gonadotropin secretion becomes sex steroid-mediated feedback inhibition.

A Review of the Eriococcid Genera (Hemiptera: Sternorrhyncha: Coccoidea) of South America

Zootaxa ◽  
2010 ◽  
Vol 2459 (1) ◽  
pp. 1 ◽  
Author(s):  
CHRIS HODGSON ◽  
DUG MILLER
Keyword(s):  
South America ◽  
Type Species ◽  
Host Plants ◽  
Sexually Dimorphic ◽  
South American ◽  
Adult Males ◽  
Adult Females ◽  
First Instar ◽  
The Status ◽  
Original Illustrations

This paper reviews the present status of all genera of Eriococcidae (Hemiptera: Sternorrhyncha: Coccoidea) known from South America and provides generic diagnoses based on the adult females of all available species for each genus. Redescriptions and illustrations are provided for the adult females of Aculeococcus morrisoni Lepage, Apiococcus gregarius Hempel, Capulinia sallei Signoret, Carpochloroides viridis Cockerell, Macracanthopyga verganiana Lizer y Trelles, Pseudocapulinia lanosa Hempel and Tectococcus ovatus Hempel, which are all type species of their respective genera. In addition, modified reproductions of original illustrations are provided for the adult females of the following species as representatives or type species of South American genera: Acanthococcus aceris Signoret, Chilechiton lynnae Hodgson & Miller, Chilecoccus browni Miller & González, Coxicoccus foldi Kozár & Konczné Benedicty, Eriobalachowskya valenzualae (Balachowsky), Exallococcus laureliae Miller & González, Hempelicoccus paranaensis (Foldi & Kozár), Icelococcus nothofagi Miller & González, Intecticoccus viridis Kondo, Melzeria horni Green, Orafortis luma Hardy, Oregmopyga neglecta (Cockerell), Poliloculus stipae González, Pseudotectococcus anonae Hempel and Stibococcus cerinus Miller & González. Descriptions and illustrations are also provided of the first-instar nymphs of: Acanthococcus aceris Signoret, Aculeococcus morrisoni, Apiococcus gregarius, A. singularis Hempel (which appears to be sexually dimorphic), Capulinia sallei, Carpochloroides viridis, Chilechiton lynnae, Exallococcus laureliae, Hempelicoccus tucumanensis (González & Granara de Willink), Icelococcus lithrae Miller & González, Melzeria horni, Oregmopyga peruviana Granara de Willink & Diaz, Pseudocapulinia lanosa, Pseudotectococcus anonae and Tectococcus ovatus. In addition, illustrated descriptions of the adult males of Capulinia sallei, Carpochloroides viridis, and Tectococcus ovatus are included. The first-instar nymphs and adult males of the other genera, where they are known, are also diagnosed and discussed. Based on the molecular studies of Cook & Gullan (2004), most species currently included in Eriococcus Targioni Tozzetti known from South America are considered to belong to the genus Acanthococcus Signoret, resulting in the following new combinations: A. clapsae (González) n. comb., A. cuneifoliae (González) n. comb., A. divaricatae (González) n. comb., A. pituilensis (González) n. comb. and A. lahillei (Leonardi) n. comb. In additon, Eriococcus pumuliae González, E. santiaguensis González & Granara de Willink and E. tucumanensis González & Granara de Willink are transferred to Hempelicoccus, as H. pumuliae (González) n. comb., H. santiaguensis (González & Granara de Willink) n. comb. and H. tucumanensis n. comb. (González & Granara de Willink). The status of Opisthoscelis prosopidis Kieffer & Jorgensen, the only species from the Neotropics currently included in Opisthoscelis Schrader, is discussed, and it is concluded that this species is unlikely to belong to this genus but is currently unrecognizable. Keys are provided for the identification of the 24 genera now known from South America based on the morphology of: (i) the adult females; (ii) the first-instar nymphs; and (iii) adult males, as far as these are known. In addition, Appendix 1 lists all Eriococcidae known from South America with their current generic placement, along with a brief summary of their host plants.

Sexual shape dimorphism and selection pressure on males in fossil ostracodes

Paleobiology ◽  
2017 ◽  
Vol 43 (3) ◽  
pp. 407-424 ◽  
Author(s):  
Tatsuhiko Yamaguchi ◽  
Rie Honda ◽  
Hiroki Matsui ◽  
Hiroshi Nishi
Keyword(s):  
Selection Pressure ◽  
Time Series Data ◽  
Gaussian Mixture ◽  
Temporal Changes ◽  
Length Ratio ◽  
Series Data ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Sexual Display ◽  
Sexual Shape Dimorphism

AbstractSexual dimorphism is thought to have evolved via selection on both sexes. Ostracodes display sexual shape dimorphism in adult valves; however, no previous studies have addressed temporal changes on evolutionary timescales or examined the relationships between sexual shape dimorphism and selection pressure and between sexual shape dimorphism and juvenile shape. Temporal changes in sexually dimorphic traits result from responses of these traits to selection pressure. Using the Gaussian mixture model for the height/length ratio, a valve-shape parameter, we identified sexual differences in the valve shape of Krithe dolichodeira s.l. from deep-sea sediments of the Paleocene (62.6–57.6 Ma) and estimated the proportion of females in the fossil populations at 11 time intervals. Because the proportion of females in a population is altered by the mortality rate of adult males, it is reflective of selection pressure on males. We attempted to correlate the height/length ratios between the sexes with the proportion of females, taking into consideration that the valve shape was not linked with the selection pressure on males. In time-series data of the height/length ratio, both sexes indicate no significant changes on evolutionary timescales, even though the sex ratio of the population changed from female skewed to male skewed during the late Paleocene. The sexual shape dimorphism was not driven by sexual selection. The static allometry between the height/length ratio and length indicates that the sexual shape dimorphism did not function for sexual display. The absence of change over time in the female allometric slope suggests that the evolution of valve shape was constrained by stasis.

scholarly journals Chemical communication during mating of the harpacticoid Tigriopus japonicus

1998 ◽  
Vol 353 (1369) ◽  
pp. 737-744 ◽  
Author(s):  
Lisa S. Kelly ◽  
Terry W. Snell ◽  
Darcy J. Lonsdale
Keyword(s):  
Reproductive Biology ◽  
Chemical Communication ◽  
Adult Males ◽  
Treated Water ◽  
Tigriopus Japonicus ◽  
Female Partners ◽  
Conspecific Female ◽  
Adult Females ◽  
Caudal Rami ◽  
Mated Female

The importance of contact and diffusible pheromones in the reproductive biology of the harpacticoid Tigriopus japonicus was studied. When given a choice, males preferred developmentally advanced conspecific female partners over less mature or congeneric females. Males judged female attractiveness on a relative scale, based on the locally available females. The attractiveness of a female copepodid was reduced with non–fatal proteolytic treatment, but only if normal females were also present. To sample the available females, males repeatedly grabbed the caudal rami and terminal urosome segment of potential partners before committing themselves to guarding one female. Males occasionally dropped their copepodid partners. Releases increased in frequency in water conditioned from virgin adult females and adult males, decreased in mated–female conditioned water and were unaffected by copepodids or their treated water. The waning attractiveness of a recently mated female was tracked over 16 h. Relationships between Tigriopus japonicus adults appeared to involve both contact and diffusible pheromones. No evidence of a diffusible copepodid pheromone was uncovered.

Offspring growth and parental care in sexually dimorphic Nazca boobies (Sula granti)

2007 ◽  
Vol 85 (6) ◽  
pp. 686-694 ◽  
Author(s):  
H.M. Townsend ◽  
T.J. Maness ◽  
D.J. Anderson
Keyword(s):  
Sexual Size Dimorphism ◽  
Poor Performance ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Parental Effort ◽  
Size Dimorphism ◽  
Sula Granti ◽  
More Care ◽  
Mean Size ◽  
Specific Food

A review of studies on nestling bird food requirements indicates that degree of sexual size dimorphism reliably predicts disparity in sex-specific food requirements, but that parents often fail to meet the excess requirement of the larger sex. We studied a population of Nazca boobies ( Sula granti Rothschild, 1902), a sexually dimorphic pelagic seabird, to determine whether parents provide more care to daughters, the larger sex. Daughters grew to a larger size than did sons during the nestling period, but did not reach the mean size of adult females, while sons exceeded the size of adult males. Estimates of parental effort exerted for sons versus daughters indicated similar levels of effort, and that females fledged in poorer condition than males did in the study year, one of intermediate breeding conditions. Results from another study conducted during better breeding conditions indicated little limitation on growth of either sex. Together, these studies are consistent with a ceiling on parental effort in a long-lived species that allows consistent self-maintenance for parents, but causes poor performance in the costlier sex under poor breeding conditions. Complementary studies of short-lived species are needed to evaluate our suggested linkage between parental effort, self-maintenance, and sexual size dimorphism.

scholarly journals Object carrying as socio-sexual display in an aquatic mammal

2008 ◽  
Vol 4 (3) ◽  
pp. 243-245 ◽  
Author(s):  
A.R Martin ◽  
V.M.F da Silva ◽  
P Rothery
Keyword(s):  
Social Groups ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Isolated Populations ◽  
Aquatic Mammal ◽  
Sexual Display ◽  
Adult Females ◽  
River Bed ◽  
Inia Geoffrensis ◽  
Dimorphic Species

Amazon river dolphins or botos ( Inia geoffrensis Blainville) were observed carrying objects in 221 social groups over a 3-year study period. Sticks, branches and clumps of grass were taken from the water surface and often repeatedly thrashed or thrown. Lumps of hard clay were collected from the river bed and held in the mouth while the carrier rose slowly above the surface and submerged again. Carriers were predominantly adult males and less often subadult males. Adult females and young dolphins rarely carried objects. Groups of dolphins in which object carrying occurred were differentially large and comprised a greater proportion of adult males and adult females. Aggression, mostly between adult males, was significantly associated with object carrying. The behaviour occurred year-round, with peaks in March and July. A plausible explanation of the results is that object carrying by adult males is aimed at females and is stimulated by the number of females in the group, while aggression is targeted at adult males and is stimulated by object carrying in the group. We infer that object carrying in this sexually dimorphic species is socio-sexual display. It is either of ancient origin or has evolved independently in several geographically isolated populations.

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