scholarly journals 3D imaging reveals potential anticipatory responses to increasing intraspecific competition in the Drosophila male reproductive system

2021 ◽  
Author(s):  
Juliano Morimoto ◽  
Renan Barcellos ◽  
Todd Andrew Schoborg ◽  
Liebert Parreiras Nogueira ◽  
Marcos Vinicius Colaco
Keyword(s):  
Intraspecific Competition ◽  
Larval Density ◽  
Micro Ct ◽  
Accessory Glands ◽  
Sexually Selected Traits ◽  
Sexual Selection Theory ◽  
History Of ◽  
Selected Traits ◽  
Access To Food ◽  
Ejaculatory Bulb

Selection favour males that anticipate intraspecific competition levels and develop appropriate competitive traits. In holometabolous insects, larval density can act as an ecological cue of males future intraspecific competition levels while also limiting access to food allocated to sexually selected traits (e.g., testes). To date, however, most studies have been conducted in larval densities that may have little or no relevance to species ecology. Here, we manipulated Drosophila melanogaster larval density based on the natural history of the species and used 3D micro-CT imaging to show a strong modulation of testes volume based on larval density: males from high larval densities generally had larger testes. Conversely, males from high densities tended (albeit not statistically significantly) to have the smallest accessory glands and ejaculatory bulb. Overall, we used micro-CT to measure male reproductive morphology in an ecologically relevant design for which the findings broadly support predictions from sexual selection theory.

scholarly journals The hidden cost of sexually selected traits: the metabolic expense of maintaining a sexually selected weapon

2018 ◽  
Vol 285 (1891) ◽  
pp. 20181685 ◽  
Author(s):  
Ummat Somjee ◽  
H. Arthur Woods ◽  
Meghan Duell ◽  
Christine W. Miller
Keyword(s):  
Metabolic Rate ◽  
Resting Metabolic Rate ◽  
Metabolic Cost ◽  
Maintenance Costs ◽  
Sexually Selected Traits ◽  
Before And After ◽  
Hidden Cost ◽  
Sexual Selection Theory ◽  
The Difference ◽  
Selected Traits

Sexually selected weapons are among the most exaggerated traits in nature. Sexual selection theory frequently assumes a high cost of this exaggeration; yet, those costs are rarely measured. We know very little about the energetic resources required to maintain these traits at rest and the difference in energetic costs for the largest individuals relative to the smallest individuals. Knowledge in this area is crucial; resting metabolic rate can account for 30–40% of daily energy expenditure in wild animals. Here, we capitalized on the phenomenon of autotomy to take a unique look at weapon maintenance costs. Using Leptoscelis tricolor (Hemiptera: Coreidae), we measured CO 2 production rates before and after a weapon was shed. Males in this insect species use enlarged hind femora as weapons in male–male combat, and yet can shed them readily, without regeneration, upon entrapment. We found that metabolic rate decreased by an average of 23.5% in males after leg loss and by 7.9% in females. Notably, larger males had less of a drop in metabolic rate per gram of weapon lost. Our findings suggest that sexually selected weapons contribute to a large portion of resting metabolic rate in males, but these costs do not scale in direct proportion to size; larger males can have larger weapons for a reduced metabolic cost. These energetic maintenance costs may be integral to the evolution of the allometries of sexually selected weapons, and yet they remain largely unexplored.

Tests of the positive and functional allometry hypotheses for sexually selected traits in the Jamaican field cricket

2021 ◽  
pp. 104413
Author(s):  
Susan M. Bertram ◽  
Danya D. Yaremchuk ◽  
Mykell L. Reifer ◽  
Amy Villareal ◽  
Matthew J. Muzzatti ◽  
...  
Keyword(s):  
Field Cricket ◽  
Sexually Selected Traits ◽  
Selected Traits

scholarly journals Sexually Selected Traits: A Fundamental Framework for Studies on Behavioral Epigenetics

ILAR Journal ◽  
2012 ◽  
Vol 53 (3-4) ◽  
pp. 253-269 ◽  
Author(s):  
E. Jasarevic ◽  
D. C. Geary ◽  
C. S. Rosenfeld
Keyword(s):  
Sexually Selected Traits ◽  
Selected Traits

scholarly journals Selection for increased tibia length in mice alters skull shape through parallel changes in developmental mechanisms

2020 ◽  
Author(s):  
Colton M. Unger ◽  
Jay Devine ◽  
Benedikt Hallgrímsson ◽  
Campbell Rolian
Keyword(s):  
Endochondral Ossification ◽  
Morphological Changes ◽  
Cranial Base ◽  
Direct Selection ◽  
Micro Ct ◽  
Growth Plates ◽  
History Of ◽  
Selection For ◽  
Tibia Length ◽  
Shape Changes

AbstractBones in the vertebrate cranial base and limb skeleton grow by endochondral ossification, under the control of growth plates. Mechanisms of endochondral ossification are conserved across growth plates, which increases covariation in size and shape among bones, and in turn may lead to correlated changes in skeletal traits not under direct selection. We used micro-CT and geometric morphometrics to characterize shape changes in the cranium of the Longshanks mouse, which was selectively bred for longer tibiae. We show that Longshanks skulls became longer, flatter, and narrower in a stepwise process. Moreover, we show that these morphological changes likely resulted from developmental changes in the growth plates of the Longshanks cranial base, mirroring changes observed in its tibia. Thus, indirect and non-adaptive morphological changes can occur due to developmental overlap among distant skeletal elements, with important implications for interpreting the evolutionary history of vertebrate skeletal form.

Introduction

2016 ◽  
Author(s):  
Gergely Baics
Keyword(s):  
Urban Governance ◽  
Free Market ◽  
Social Consequences ◽  
Social Environments ◽  
Market System ◽  
The Social ◽  
Political Economies ◽  
History Of ◽  
Access To Food ◽  
Private Domain

This introductory chapter provides an overview of the book's main themes. This book tells story of New York's transition from a tightly regulated public market system of provisioning in the Early Republic to a free-market model in the antebellum period. It examines what a municipal market system was and how it worked to supply urban dwellers; how and why access to food moved from the public to the private domain by the 1840s; how these two distinctive political economies shaped the physical and social environments of a booming city; and what the social consequences of deregulation were for residents of America's first metropolis. On the whole, the book offers a comprehensive account based in political economy and the social and geographic history of the complex interplay of urban governance, market forces, and the built environment in provisioning New Yorkers.

scholarly journals When should a rare inherited connective tissue disorder be suspected in bicuspid aortic valve by primary-care internists and cardiologists? Proposal of a score

2020 ◽  
Author(s):  
Guglielmina Pepe ◽  
Betti Giusti ◽  
Stefania Colonna ◽  
Maria Pia Fugazzaro ◽  
Elena Sticchi ◽  
...  
Keyword(s):  
Primary Care ◽  
Aortic Valve ◽  
Connective Tissue ◽  
Bicuspid Aortic Valve ◽  
Aortic Surgery ◽  
Connective Tissue Disorder ◽  
Tertiary Center ◽  
History Of ◽  
Selected Traits ◽  
Size Threshold

Abstract Size threshold for aortic surgery in bicuspid aortic valve (BAV) is debated. Connective tissue disorders (CTDs) are claimed as a clinical turning point, suggesting early surgery in BAV patients with CTD. Thus, we aimed at developing a score to detect high risk of carrying CTDs in consecutive BAVs from primary care. Ninety-eight BAVs without ectopia lentis or personal/family history of aortic dissection were studied at the Marfan syndrome Tuscany Referral Center. Findings were compared with those detected in 84 Marfan patients matched for sex and age. We selected traits with high statistical difference between MFS and BAV easily obtainable by cardiologists and primary-care internists: mitral valve prolapse, myopia ≥ 3DO, pectus carenatum, pes planus, wrist and thumb signs, and difference between aortic size at root and ascending aorta ≥ 4 mm. Clustering of ≥ 3 of these manifestations were more frequent in Marfan patients than in BAVs (71.4% vs 6.1%, p < 0.0001) resulting into an Odds Ratio to be affected by MFS of 38.3 (95% confidence intervals 14.8–99.3, p < 0.0001). We propose a score assembling simple clinical and echocardiographic variables resulting in an appropriate referral pattern of BAVs from a primary-care setting to a tertiary center to evaluate the presence of a potential, major CTD.

scholarly journals Defense against outside competition is linked to cooperation in male–male partnerships

2019 ◽  
Vol 31 (2) ◽  
pp. 432-439
Author(s):  
Jennifer K Hellmann ◽  
Kelly A Stiver ◽  
Susan Marsh-Rollo ◽  
Suzanne H Alonzo
Keyword(s):  
Reproductive Success ◽  
Group Living ◽  
Dominant Male ◽  
Spawning Activity ◽  
Conflict And Cooperation ◽  
Behavioral Dynamics ◽  
Sexually Selected Traits ◽  
Before And After ◽  
Living Species ◽  
Selected Traits

Abstract Male–male competition is a well-known driver of reproductive success and sexually selected traits in many species. However, in some species, males work together to court females or defend territories against male competitors. Dominant (nesting) males sire most offspring, but subordinate (satellite) males are better able to obtain fertilizations relative to unpartnered males. Because satellites only gain reproductive success by sneaking, there has been much interest in identifying the mechanisms enforcing satellite cooperation (defense) and reducing satellite sneaking. One such potential mechanism is outside competition: unpartnered satellites can destabilize established male partnerships and may force partnered satellites to restrain from cheating to prevent the dominant male from replacing them with an unpartnered satellite. Here, we manipulated perceived competition in the Mediterranean fish Symphodus ocellatus by presenting an “intruding” satellite male to established nesting and satellite male pairs. Focal satellite aggression to the intruder was higher when focal satellites were less cooperative, suggesting that satellites increase aggression to outside competitors when their social position is less stable. In contrast, nesting male aggression to the intruder satellite increased as spawning activity increased, suggesting that nesting males increase their defense toward outside competitors when their current relationship is productive. We found no evidence of altered spawning activity or nesting/satellite male interactions before and after the presentation. These results collectively suggest that response to outside competition is directly linked to behavioral dynamics between unrelated male partners and may be linked to conflict and cooperation in ways that are similar to group-living species.

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