scholarly journals Reproductive effort affects subsequent horn growth in sexually dimorphic male ungulates

Author(s):  
Christian Simon Willisch ◽  
Peter Neuhaus

AbstractTrade-offs between reproductive effort and subsequent growth in males are not well explored, despite their relevance in questions of individual energy allocation. Regarding the growth of sexual secondary characters in polygynous breeding male mammals, indeed, no conclusive studies exist. We investigated in male Alpine ibex (Capra ibex) the relationship between their behavioral reproductive effort, current horn size, and subsequent horn growth. While controlling for age, no evidence was found for male behavioral reproductive effort during the rut being affected by their horn size. On the other hand, reproductive effort significantly decreased age-specific horn growth during the following summer. Our study provides evidence that growth of secondary sexual characters is traded against behavioral investments in reproduction in a male mammal. It bears important implications for the understanding of energy allocation between various life-history components and the evolutionary ecology of secondary sexual characters.

2018 ◽  
Author(s):  
Keneth Sarpong ◽  
Christine L. Madliger ◽  
Christopher M. Harris ◽  
Oliver P. Love ◽  
Stéphanie M. Doucet ◽  
...  

AbstractThe production of high quality secondary sexual traits can be constrained by trade-offs in the allocation of energy and nutrients with other metabolic activities, and is mediated by physiological processes. In birds, the factors influencing male plumage quality have been well studied; however, factors affecting female plumage quality are poorly understood. Furthermore, it remains uncertain which physiological traits mediate the relationship between body condition and ornaments. In this three-year study of after-second-year female tree swallows (Tachycineta bicolor), we investigated (1) the relationship between baseline corticosterone near the end of the brood-rearing period (CORTBR) and feather colour characteristics (hue, saturation, brightness) the following year, and (2) the relationship between baseline corticosterone measured during incubation (CORTI) and brood rearing (CORTBR), and feather colour in the same year. To control for reproductive effort, we included reproductive parameters as covariates in all analyses. In this first study between CORT and the plumage colour characteristics of a species bearing iridescent feathers, we did not find any relationship between CORTBRand the colour of subsequently-produced feathers, nor did we find any relationship between CORTIand the colour of feathers displayed during that breeding season. If CORT levels at the end of breeding carry over to influence the immediately subsequent moult period as we expect, our results generally indicate that structural plumage quality may not be as sensitive to circulating CORT levels compared to carotenoid-based colouration. Future studies, particularly those employing experimental manipulations of CORT during moult in species with iridescent traits, are necessary to fully determine the role glucocorticoids play in mediating the quality of secondary sexual characteristics.


Zootaxa ◽  
2019 ◽  
Vol 4700 (1) ◽  
pp. 87-101
Author(s):  
CATHERINE A. TAUBER

A new and very unusual species of green lacewings, Ungla pseudomeleoma sp. nov. is described from Peru. Males of this species exhibit a remarkable example of generic-level homoplasy with Meleoma. Its abdominal and genitalic features are completely consistent with the genus Ungla. However, its external sexually dimorphic features resemble those of both Ungla and Meleoma. Females of the new species also express cranial modifications that resemble those of some female Meleoma species. 


2019 ◽  
Vol 40 (4) ◽  
pp. 523-529
Author(s):  
María Celeste Luna ◽  
Carlos Roberto Vásquez-Almazán ◽  
Julian Faivovich ◽  
Andrés Eduardo Brunetti

Abstract Secondary sexual characters form a diverse group of traits widely spread in amphibians. Within anurans, the Hylini tribe represents an interesting group to examine the evolution of this type of characters because it has different skin structure modifications, including ventrolateral glands, nuptial pads, and unique swollen upper lips. We analysed the skin gland composition in the upper lip of Plectrohyla guatemalensis and the ventrolateral gland of Ptychohyla hypomykter (Hylidae: Hylinae: Hylini). Each of these species is characterized by a different type of sexually dimorphic skin gland; specialized mucous glands (SMGs) in Pl. guatemalensis and specialized serous glands (SSGs) in Pt. hypomykter. The SMGs conform to the general type of sexually dimorphic skin glands in amphibians, whereas SSGs are very rare. Because SMGs are likely involved in the production of sexual pheromones, their distinctive location and their co-occurrence with other secondary sexual characters like long and pointed maxillary and premaxillary teeth in Pl. guatemalensis suggests that the system used for their delivery may be a distinguishing behavioral feature in this species. The presence of both types of glands in Pt. hypomykter (SMGs in nuptial pads, and SSGs in ventrolateral glands) suggests a different or, at least, a complementary role of these two types of glands during reproduction.


2010 ◽  
Vol 64 (8) ◽  
pp. 1299-1307 ◽  
Author(s):  
Patrick Bergeron ◽  
Stefano Grignolio ◽  
Marco Apollonio ◽  
Bill Shipley ◽  
Marco Festa-Bianchet

2019 ◽  
Author(s):  
Charly Jehan ◽  
Manon Chogne ◽  
Thierry Rigaud ◽  
Yannick Moret

Abstract Background The disposable soma theory of ageing assumes that organisms optimally trade-off limited resources between reproduction and longevity to maximize fitness. Early reproduction should especially trade-off against late reproduction and longevity because of reduced investment into somatic protection, including immunity. Moreover, as optimal reproductive strategies of males and females differ, sexually dimorphic patterns of senescence may evolve. In particular, as males gain fitness through mating success, sexual competition should be a major factor accelerating male senescence. In a single experiment, we examined these possibilities by establishing artificial populations of the mealworm beetle, Tenebrio molitor , in which we manipulated the sex-ratio to generate variable levels of investment into reproductive effort and sexual competition in males and females.Results As predicted, variation in sex-ratio affected male and female reproductive efforts, with contrasted sex-specific trade-offs between lifetime reproduction, survival and immunity. High effort of reproduction accelerated mortality in females, without affecting immunity, but high early reproductive success was observed only in balanced sex-ratio condition. Male reproduction was costly on longevity and immunity, mainly because of their investment into copulations rather than in sexual competition.Conclusions Our results suggest that T. molitor males, like females, maximize fitness through enhanced longevity, partly explaining their comparable longevity.


1993 ◽  
Vol 71 (3) ◽  
pp. 451-457 ◽  
Author(s):  
Mark R. Simpson

I investigated the relationship between clutch size, female size and mass, and clutch mass in two species of arctic spiders, Alopecosa hirtipes and Pardosa glacialis (Araneae: Lycosidae). Female mass and number of young were significantly correlated with female size in both years of the study. Cocoon mass was significantly correlated with female size in 1991 only. These results are discussed within the context of reproductive trade-offs and models of reproductive effort based on size.


2007 ◽  
Vol 28 (2) ◽  
pp. 78-87 ◽  
Author(s):  
Stefan J. Troche ◽  
Nina Weber ◽  
Karina Hennigs ◽  
Carl-René Andresen ◽  
Thomas H. Rammsayer

Abstract. The ratio of second to fourth finger length (2D:4D ratio) is sexually dimorphic with women having higher 2D:4D ratio than men. Recent studies on the relationship between 2D:4D ratio and gender-role orientation yielded rather inconsistent results. The present study examines the moderating influence of nationality on the relationship between 2D:4D ratio and gender-role orientation, as assessed with the Bem Sex-Role Inventory, as a possible explanation for these inconsistencies. Participants were 176 female and 171 male university students from Germany, Italy, Spain, and Sweden ranging in age from 19 to 32 years. Left-hand 2D:4D ratio was significantly lower in men than in women across all nationalities. Right-hand 2D:4D ratio differed only between Swedish males and females indicating that nationality might effectively moderate the sexual dimorphism of 2D:4D ratio. In none of the examined nationalities was a reliable relationship between 2D:4D ratio and gender-role orientation obtained. Thus, the assumption of nationality-related between-population differences does not seem to account for the inconsistent results on the relationship between 2D:4D ratio and gender-role orientation.


2016 ◽  
Vol 26 (3) ◽  
pp. 397-402 ◽  
Author(s):  
Toshiaki Yamamoto ◽  
Noritaka Hirohashi ◽  
Eiji Fujiwara ◽  
Tatsuya Suzuki ◽  
Hatsuna Maruta ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document