Temporal variation in the operational sex ratio and male mating behaviours in reindeer ( Rangifer tarandus )

2017 ◽  
Vol 140 ◽  
pp. 96-103 ◽  
Author(s):  
Robert B. Weladji ◽  
Guillaume Body ◽  
Øystein Holand ◽  
Xiuxiang Meng ◽  
Mauri Nieminen
Keyword(s):  
Sex Ratio ◽  
Temporal Variation ◽  
Rangifer Tarandus ◽  
Operational Sex Ratio ◽  
Male Mating

Short term changes in sex ratio and density alter coercive male mating tactics

Behaviour ◽  
2010 ◽  
Vol 147 (11) ◽  
pp. 1431-1442 ◽  
Author(s):  
James Cureton II ◽  
Raelynn Deaton ◽  
Rachel Martin
Keyword(s):  
Sex Ratio ◽  
Reproductive Activity ◽  
Operational Sex Ratio ◽  
Mating Frequency ◽  
Male Mating ◽  
Mating Tactics ◽  
Short Term ◽  
Classic Theory ◽  
Males And Females ◽  
The Impact

AbstractShort term fluctuations in operational sex ratio (OSR) and density can strongly influence male mating, often exacerbating conflict between males and females. Livebearing fishes of the genus Gambusia are ideal for investigating sexual conflict because males of all sizes mate coercively. In this study, we tested how short-term fluctuations in OSR and density influence coercive male mating behaviours. Specifically, we tested the prediction that as OSR becomes more female biased, males will mate with all available females. In contrast, as OSR becomes more male biased, male aggression will inhibit mating frequency. As predicted, males mated with more females as the number of available females increased. Moreover, males were less aggressive as the proportion of females increased and more aggressive as the number of males increased. This resulted in an inverse relationship between mating and aggression with OSR and density. Coercive males attempt to maximize their reproductive success by mating with all available females, which supports classic theory on the impact of OSR and density on reproductive activity.

scholarly journals Influence of operational sex ratio and male age on mating competition intensity in reindeer (Rangifer tarandus)

2021 ◽  
pp. 1-15
Author(s):  
Jeffrey G. Driscoll ◽  
Franco M. Alo ◽  
Amélie Paoli ◽  
Robert B. Weladji ◽  
Øystein Holand ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Rangifer Tarandus ◽  
Operational Sex Ratio ◽  
Competition Intensity ◽  
Mating Competition ◽  
Male Age

Seasonal and diurnal variation in the proportions of female morphs of the damselfly Enallagma cyathigerum

2007 ◽  
Vol 57 (2) ◽  
pp. 217-230 ◽  
Author(s):  
Jessica Bots ◽  
Henri Dumont ◽  
Tim Adriaens ◽  
Robby Stoks ◽  
Luc De Bruyn ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Sex Ratio ◽  
Diurnal Variation ◽  
Temporal Variation ◽  
Operational Sex Ratio ◽  
Male Density ◽  
Seasonal And Diurnal Variation ◽  
Body Colouration ◽  
Male Mate ◽  
Female Morph

AbstractIn many damselfly species a female-limited colour polymorphism is encountered which is assumed to be the result of sexual conflict. Typically, one morph resembles the male's body colouration (andromorph), while the other is dissimilar (heteromorph). Little is known about the extent of temporal variation in female morph proportions at the water where mating occurs. Knowledge about such variation should help to identify the factors that affect female morph proportion and the scales at which these factors operate. The objective of this study is to assess the occurrence of diurnal and seasonal variation in female morph proportions at the water for the damselfly Enallagma cyathigerum. Diurnal variation was evaluated at six nearby populations, while seasonal variation was examined at one of these populations. Furthermore, we considered temporal variation in female morph proportion in relation to proxies of male harassment (i.e., male density and operational sex ratio). Our findings indicate that female morph proportion varies throughout a day but is uniform on a seasonal scale. Variation in female morph proportions could not be explained by concomitant variation in male density or operational sex ratio. We suggest future study of male mate choice may consider temporal variation in female morph proportions at the water.

Effects of operational sex ratio, mating age, and male mating history on mating and reproductive behavior in Grapholita molesta

2021 ◽  
pp. 1-12
Author(s):  
Weina Kong ◽  
Yi Wang ◽  
Yongfu Guo ◽  
Xiaohan Chai ◽  
Jie Li ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Sex Pheromones ◽  
Multiple Mating ◽  
Operational Sex Ratio ◽  
Male Mating ◽  
Reproductive Parameters ◽  
Grapholita Molesta ◽  
Mating History ◽  
Single Mating ◽  
Old Females

Abstract The short-lived polygamous moth Grapholita molesta (Busck) is an important fruit pest worldwide. Trapping males by synthetic female sex pheromones is not an effective reproductive control strategy. It is important to improve this technology by understanding the mating system of G. molesta. This study investigated mating opportunities and fertile egg production by altering the operational sex ratio, mating age, and male mating history in repeated single mating and multiple mating in the two sexes. Our results showed that the mating and reproductive parameters of virgin males were affected by the number and age of virgin females. Males preferred a female number ≤three-fifths of the male number or ≤2-day-old females, while they discriminated against a female number ≥three times of the male number or ≥5-day-old females. On the other hand, the mating and reproductive parameters of virgin females were affected by repeated single mating and especially multiple mating under different male mating histories. Females preferred once-mated males and discriminated against virgin males. These results indicated that mating systems including more and older virgin females for virgin males and different virgin males for virgin females may be suitable for suppressing G. molesta populations. Hence, these results revealed that preventing mating of virgin adults by synthetic female sex pheromones should be most effective in controlling G. molesta.

scholarly journals Sex-specific deaths in Norway and Sweden during the COVID-19 pandemic: Did mandates make a difference?

2021 ◽  
pp. 140349482110100
Author(s):  
Ralph Catalano
Keyword(s):  
Sex Ratio ◽  
Infection Control ◽  
Temporal Variation ◽  
Risky Behavior ◽  
Control Strategies ◽  
Sex Ratios ◽  
Female Mortality ◽  
All Cause Mortality ◽  
Societal Expectations ◽  
Male To Female

Aims: To determine whether differences between Norway’s and Sweden’s attempts to contain SARS-CoV-2 infection coincided with detectably different changes in their all-cause mortality sex ratios. Measuring temporal variation in the all-cause mortality sex ratio before and during the pandemic in populations exposed to different constraints on risky behavior would allow us to better anticipate changes in the ratio and to better understand its association with infection control strategies. Methods: I apply time Box–Jenkins modeling to 262 months of pre-pandemic mortality sex ratios to arrive at counterfactual values of 10 intra-pandemic ratios. I compare counterfactual to observed values to determine if intra-pandemic ratios differed detectably from those expected as well as whether the Norwegian and Swedish differences varied from each other. Results: The male to female mortality sex ratio in both Norway and Sweden increased during the pandemic. I, however, find no evidence that the increase differed between the two countries despite their different COVID-19 containment strategies. Conclusion: Societal expectations of who will die during the COVID-19 pandemic will likely be wrong if they assume pre-pandemic mortality sex ratios because the intra-pandemic ratios appear, at least in Norway and Sweden, detectably higher. The contribution of differences in policies to reduce risky behavior to those higher ratios appears, however, small.

scholarly journals Natural variation in social conditions affects male mate choosiness in the amphipod Gammarus roeselii

2021 ◽  
Author(s):  
Konrad Lipkowski ◽  
Sophie Steigerwald ◽  
Lisa M Schulte ◽  
Carolin Sommer-Trembo ◽  
Jonas Jourdan
Keyword(s):  
Population Density ◽  
Sex Ratio ◽  
Natural Variation ◽  
Natural Populations ◽  
Social Background ◽  
Social Conditions ◽  
Background Information ◽  
Male Mating ◽  
Natural Environments ◽  
Male Mate

Abstract The extent of male mate choosiness is driven by a trade-off between various environmental factors associated with the costs of mate acquisition, quality assessment and opportunity costs. Our knowledge about natural variation in male mate choosiness across different populations of the same species, however, remains limited. In this study, we compared male mate choosiness across 10 natural populations of the freshwater amphipod Gammarus roeselii (Gervais 1835), a species with overall high male mating investments, and evaluated the relative influence of population density and sex ratio (both affecting mate availability) on male mate choosiness. We investigated amplexus establishment after separating mating pairs and presenting focal males with a novel, size-matched female from the same population. Our analysis revealed considerable effects of sex ratio and (to a lesser extent) population density on time until amplexus establishment (choosiness). Male amphipods are able to perceive variable social conditions (e.g., sex ratio) and modify their mating strategy accordingly: We found choosiness to be reduced in increasingly male-biased populations, whereas selectivity increases when sex ratio becomes female biased. With this, our study expands our limited knowledge on natural variations in male mate choosiness and illustrates the importance of sex ratio (i.e., level of competition) for male mating decisions in natural environments. Accounting for variation in sex ratios, therefore, allows envisioning a distinctive variation of choosiness in natural populations and highlights the importance of considering social background information in future behavioral studies.

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