scholarly journals Environmental variability and acoustic signals: a multi-level approach in songbirds

2012 ◽  
Vol 8 (6) ◽  
pp. 928-931 ◽  
Author(s):  
Iliana Medina ◽  
Clinton D. Francis
Keyword(s):  
Sexual Selection ◽  
Environmental Variability ◽  
Extensive Study ◽  
Short Term ◽  
Intraindividual Variation ◽  
Habitat Features ◽  
Acoustic Adaptation ◽  
Song Complexity ◽  
Song Variation ◽  
Precipitation Seasonality

Among songbirds, growing evidence suggests that acoustic adaptation of song traits occurs in response to habitat features. Despite extensive study, most research supporting acoustic adaptation has only considered acoustic traits averaged for species or populations, overlooking intraindividual variation of song traits, which may facilitate effective communication in heterogeneous and variable environments. Fewer studies have explicitly incorporated sexual selection, which, if strong, may favour variation across environments. Here, we evaluate the prevalence of acoustic adaptation among 44 species of songbirds by determining how environmental variability and sexual selection intensity are associated with song variability (intraindividual and intraspecific) and short-term song complexity. We show that variability in precipitation can explain short-term song complexity among taxonomically diverse songbirds, and that precipitation seasonality and the intensity of sexual selection are related to intraindividual song variation. Our results link song complexity to environmental variability, something previously found for mockingbirds (Family Mimidae). Perhaps more importantly, our results illustrate that individual variation in song traits may be shaped by both environmental variability and strength of sexual selection.

scholarly journals Sex ratio effects on reproductive strategies in humans

2015 ◽  
Vol 2 (1) ◽  
pp. 140402 ◽  
Author(s):  
Ryan Schacht ◽  
Monique Borgerhoff Mulder
Keyword(s):  
Sexual Selection ◽  
Sex Ratio ◽  
Ethnic Group ◽  
Reproductive Strategies ◽  
Situational Factors ◽  
Male Mating ◽  
Mating Effort ◽  
Short Term ◽  
Adult Sex Ratio ◽  
Using Data

Characterizations of coy females and ardent males are rooted in models of sexual selection that are increasingly outdated. Evolutionary feedbacks can strongly influence the sex roles and subsequent patterns of sex differentiated investment in mating effort, with a key component being the adult sex ratio (ASR). Using data from eight Makushi communities of southern Guyana, characterized by varying ASRs contingent on migration, we show that even within a single ethnic group, male mating effort varies in predictable ways with the ASR. At male-biased sex ratios, men's and women's investment in mating effort are indistinguishable; only when men are in the minority are they more inclined towards short-term, low investment relationships than women. Our results support the behavioural ecological tenet that reproductive strategies are predictable and contingent on varying situational factors.

scholarly journals Experimental evidence for foraminiferal calcification under anoxia

2014 ◽  
Vol 11 (14) ◽  
pp. 4029-4038 ◽  
Author(s):  
M. P. Nardelli ◽  
C. Barras ◽  
E. Metzger ◽  
A. Mouret ◽  
H. L. Filipsson ◽  
...  
Keyword(s):  
Environmental Variability ◽  
Sediment Cores ◽  
Adult Mortality ◽  
Short Term ◽  
Essential Information ◽  
Ample Evidence ◽  
Anoxic Conditions ◽  
Inhibition Of Growth ◽  
Foraminiferal Species ◽  
First Time

Abstract. Benthic foraminiferal tests are widely used for paleoceanographic reconstructions from a range of different environments with varying dissolved oxygen concentrations in the bottom water. There is ample evidence that foraminifera can live in anoxic sediments. For some species, this is explained by a switch to facultative anaerobic metabolism (i.e. denitrification). Here we show for the first time that adult specimens of three benthic foraminiferal species are not only able to survive, but are also able to calcify under anoxic conditions, at various depths in the sediment, and with or without nitrates. In fact, several specimens of Ammonia tepida (1–4%), Bulimina marginata (8–24%) and Cassidulina laevigata (16–23%) were able to calcify at different redox fronts of sediment cores, under laboratory conditions. This demonstrates ongoing metabolic processes, even in micro-environments where denitrification is not possible. Earlier observations suggest that the disappearance of foraminiferal communities after prolonged anoxia is not due to instantaneous or strongly increased adult mortality. Here we show that it cannot be explained by an inhibition of growth through chamber addition either. Our observations of ongoing calcification under anoxic conditions mean that geochemical proxy data obtained from benthic foraminifera in settings experiencing intermittent anoxia have to be reconsidered. The analysis of whole single specimens or of their successive chambers may provide essential information about short-term environmental variability and/or the causes of anoxia.

Female Virtual Intrasexual Competition and Its Consequences

2016 ◽  
Author(s):  
Jose C. Yong ◽  
Norman P. Li ◽  
Katherine A. Valentine ◽  
April R. Smith
Keyword(s):  
Sexual Selection ◽  
Physical Attractiveness ◽  
Deep Level ◽  
Intrasexual Competition ◽  
Same Sex ◽  
Short Term ◽  
Psychological States ◽  
Psychological Mechanisms ◽  
Real People ◽  
Key Dimensions

Intrasexual competition is a key component of sexual selection. Evolutionarily, women compete for access to and retention of mates on key dimensions that men have evolved to value and prioritize in their long- and short-term mates, in particular physical attractiveness. Such competition evolved to be adaptive in ancestral environments as the perceived competition consisted of real individuals. However, underlying psychological mechanisms for competition are excessively triggered and more continuously engaged in modern environments, because these psychological mechanisms for social comparison and competition, at a deep level, do not differentiate between real people and imagined intrasexual competition in the form of mass media images. Utilizing an evolutionary mismatch framework, this chapter explores ways that women are psychologically influenced by the pervasive presence of virtual same-sex competitors for mates. Various negative psychological states in modern societies (e.g., depression, eating disorders) may be linked to virtual intrasexual competition.

scholarly journals The endemic and endangered Maugean Skate (Zearaja maugeana) exhibits short-term severe hypoxia tolerance

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Andrea J Morash ◽  
Jeremy M Lyle ◽  
Suzanne Currie ◽  
Justin D Bell ◽  
Kilian M Stehfest ◽  
...  
Keyword(s):  
Environmental Variability ◽  
Cellular Stress Response ◽  
Hypoxia Tolerance ◽  
Conservation Strategies ◽  
Low Oxygen ◽  
Short Term ◽  
Environmental Challenges ◽  
Preferred Habitat ◽  
Short Term Exposure ◽  
Dissolved O2

Abstract The endangered and range-restricted Maugean skate (Zearaja maugeana) is subjected to large environmental variability coupled with anthropogenic stressors in its endemic habitat, Macquarie Harbour, Tasmania. However, little is known about the basic biology/physiology of this skate, or how it may respond to future environmental challenges predicted from climate change and/or increases in human activities such as aquaculture. These skate live at a preferred depth of 5–15 m where the dissolved oxygen (DO) levels are moderate (~55% air saturation), but can be found in areas of the Harbour where DO can range from 100% saturation to anoxia. Given that the water at their preferred depth is already hypoxic, we sought to investigate their response to further decreases in DO that may arise from potential increases in anthropogenic stress. We measured oxygen consumption, haematological parameters, tissue–enzyme capacity and heat shock protein (HSP) levels in skate exposed to 55% dissolved O2 saturation (control) and 20% dissolved O2 saturation (hypoxic) for 48 h. We conclude that the Maugean skate appears to be an oxyconformer, with a decrease in the rate of O2 consumption with increasing hypoxia. Increases in blood glucose and lactate at 20% O2 suggest that skate are relying more on anaerobic metabolism to tolerate periods of very low oxygen. Despite these metabolic shifts, there was no difference in HSP70 levels between groups, suggesting this short-term exposure did not elicit a cellular stress response. The metabolic state of the skate suggests that low oxygen stress for longer periods of time (i.e. >48 h) may not be tolerable and could potentially result in loss of habitat or shifts in their preferred habitat. Given its endemic distribution and limited life-history information, it will be critical to understand its tolerance to environmental challenges to create robust conservation strategies.

Intraindividual variation of glycohemoglobin: implications for interpretation and analytical goals

1993 ◽  
Vol 39 (11) ◽  
pp. 2305-2308 ◽  
Author(s):  
G Phillipou ◽  
P J Phillips
Keyword(s):  
Weighted Average ◽  
Affinity Column ◽  
Time Interval ◽  
Short Term ◽  
Intraindividual Variation ◽  
Clinical Control ◽  
Significant Difference ◽  
Patients With Diabetes ◽  
Analytical Imprecision

Abstract Intraindividual variation (CVi) for glycohemoglobin (GHb) was estimated from serial measurements in patients with diabetes in either stable or variable clinical control. GHb determinations were performed by an affinity column procedure with an analytical imprecision of 4.9% (weighted average; GHb 8.2-14.7%). Within the groups of patients, both a short- (28-32 days) and long-term (approximately 85 days) sampling protocol was used. The derived CVi for each category was 4.2% (n = 16, stable, short-term), 7.1% (n = 23, stable, long-term), 5.1% (n = 13, variable, short-term), and 9.8% (n = 21, variable, long-term). The mean GHb within each category was similar (approximately 11%), and there was no statistically significant difference in GHb values between categories. The results establish that the CVi for GHb is affected by both clinical control and the sampling time interval. These findings have important implications for the estimation of significant differences between serial GHb measurements and the setting of appropriate analytical precision goals.

Short-term environmental variability in cold-water coral habitat at Viosca Knoll, Gulf of Mexico

2010 ◽  
Vol 57 (2) ◽  
pp. 199-212 ◽  
Author(s):  
Andrew J. Davies ◽  
Gerard C.A. Duineveld ◽  
Tjeerd C.E. van Weering ◽  
Furu Mienis ◽  
Andrea M. Quattrini ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Environmental Variability ◽  
Cold Water ◽  
Short Term ◽  
Water Coral

Short-term environmental variability and phytoplankton abundance in a shallow tidal estuary

1987 ◽  
Vol 96 (1) ◽  
pp. 115-121 ◽  
Author(s):  
W. Litaker ◽  
C. S. Duke ◽  
B. E. Kenney ◽  
J. Ramus
Keyword(s):  
Environmental Variability ◽  
Phytoplankton Abundance ◽  
Short Term ◽  
Tidal Estuary

A Higher-Than-Average Female Voice Can Cause Young Adult Female Listeners to Think About Aggression More

2016 ◽  
Vol 35 (6) ◽  
pp. 645-666 ◽  
Author(s):  
Jinguang Zhang
Keyword(s):  
Sexual Selection ◽  
Young Adult ◽  
Adult Female ◽  
Female Voice ◽  
Voice Pitch ◽  
Short Term ◽  
Selection Theory ◽  
Sexual Selection Theory ◽  
Vocal Attractiveness

Previous research found that speakers with more attractive voices receive more favorable evaluations (aka the vocal attractiveness stereotype). But sexual selection theory predicts that, to the extent that men perceive women with higher pitched voices as more attractive, women will be more hostile toward those women because they make more threatening mate rivals. Supporting this hypothesis, Study 1 ( N = 102) showed that female participants higher in trait dominance displayed heightened aggressive cognition after being primed with a romantic (but not a control) feeling and listening to a higher- but not lower-than-average female voice. Study 2 ( N = 111) showed that this heightened aggressive cognition was activated by a long-term but not a short-term mating motive. These findings supported sexual selection theory, challenged the vocal attractiveness stereotype, and suggested a mechanism that helps maintain the honesty of female voice pitch as a mate attraction signal.

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