scholarly journals The evolution of monogamy is associated with reversals from male to female bias in the survival cost of parasitism

2021 ◽  
Vol 288 (1950) ◽  
Author(s):  
Tyler N. Wittman ◽  
Robert M. Cox

The extent to which parasites reduce host survival should depend upon how hosts balance trade-offs between reproduction and survival. For example, parasites are predicted to impose greater survival costs under polygynous or promiscuous mating systems in which competition for mates favours increased reproductive investment, particularly in males. We provide, to our knowledge, the first comparative test of the hypothesis that the mating system of the host is an important determinant of (i) the extent to which parasites reduce survival, and (ii) the extent to which males and females differ in the survival cost of parasitism. Using meta-analysis of 85 published estimates of the survival cost of parasitism from 72 studies of 64 species representing diverse animal lineages, we show that parasites impose a mean 3.5-fold increase in the odds of mortality on their hosts. Although this survival cost does not differ significantly across monogamous, polygynous and promiscuous mating systems, females incur a greater survival cost than males in monogamous species, whereas males incur a greater survival cost than females in polygynous and promiscuous species. Our results support the idea that mating systems shape the relative extent to which males and females invest in reproduction at the expense of defence against parasites.

Author(s):  
Thassya C. dos Santos Schmidt ◽  
Doug E. Hay ◽  
Svein Sundby ◽  
Jennifer A. Devine ◽  
Guðmundur J. Óskarsson ◽  
...  

AbstractLife-history traits of Pacific (Clupea pallasii) and Atlantic (Clupea harengus) herring, comprising both local and oceanic stocks subdivided into summer-autumn and spring spawners, were extensively reviewed. The main parameters investigated were body growth, condition, and reproductive investment. Body size of Pacific herring increased with increasing latitude. This pattern was inconsistent for Atlantic herring. Pacific and local Norwegian herring showed comparable body conditions, whereas oceanic Atlantic herring generally appeared stouter. Among Atlantic herring, summer and autumn spawners produced many small eggs compared to spring spawners, which had fewer but larger eggs—findings agreeing with statements given several decades ago. The 26 herring stocks we analysed, when combined across distant waters, showed clear evidence of a trade-off between fecundity and egg size. The size-specific individual variation, often ignored, was substantial. Additional information on biometrics clarified that oceanic stocks were generally larger and had longer life spans than local herring stocks, probably related to their longer feeding migrations. Body condition was only weakly, positively related to assumingly in situ annual temperatures (0–30 m depth). Contrarily, body growth (cm × y−1), taken as an integrator of ambient environmental conditions, closely reflected the extent of investment in reproduction. Overall, Pacific and local Norwegian herring tended to cluster based on morphometric and reproductive features, whereas oceanic Atlantic herring clustered separately. Our work underlines that herring stocks are uniquely adapted to their habitats in terms of trade-offs between fecundity and egg size whereas reproductive investment mimics the productivity of the water in question.


Author(s):  
Leigh W. Simmons

‘Mating systems, or who goes with whom, and for how long’ examines the variation in how males and females associate during the breeding season, ranging from brief couplings with multiple partners to lifelong monogamy. It also shows how the discovery that females mate with many partners, even in supposedly monogamous species such as songbirds, was made possible by modern genetic techniques. Variation in mating systems holds considerable implications for the operation of sexual selection. The way that animal mating systems have been explained historically is outlined before considering how a more contemporary understanding of genetic and social relationships has reshaped our thinking and how understanding a species’ mating system can have practical applications.


2020 ◽  
Vol 31 (6) ◽  
pp. 1279-1290 ◽  
Author(s):  
Alice D Davies ◽  
Zenobia Lewis ◽  
Liam R Dougherty

Abstract Mate-choice copying is a form of social learning in which an individual’s choice of mate is influenced by the apparent choices of other individuals of the same sex and has been observed in more than 20 species across a broad taxonomic range. Though fitness benefits of copying have proven difficult to measure, theory suggests that copying should not be beneficial for all species or contexts. However, the factors influencing the evolution and expression of copying have proven difficult to resolve. We systematically searched the literature for studies of mate-choice copying in nonhuman animals and, then, performed a phylogenetically controlled meta-analysis to explore which factors influence the expression of copying across species. Across 58 published studies in 23 species, we find strong evidence that animals copy the mate choice of others. The strength of copying was significantly influenced by taxonomic group; however, sample size limitations mean it is difficult to draw firm conclusions regarding copying in mammals and arthropods. The strength of copying was also influenced by experimental design: copying was stronger when choosers were tested before and after witnessing a conspecific’s mate choice compared to when choosers with social information were compared to choosers without. Importantly, we did not detect any difference in the strength of copying between males and females or in relation to the rate of multiple mating. Our search also highlights that more empirical work is needed to investigate copying in a broader range of species, especially those with differing mating systems and levels of reproductive investment.


Author(s):  
R.W. Hofmann ◽  
B.D. Campbell ◽  
E.E. Swinny ◽  
S.J. Bloor ◽  
K.R. Markham ◽  
...  

During summertime in New Zealand, white clover experiences high levels of ultraviolet-B (UV-B) radiation. This frequently coincides with periods of summer drought. We investigated responses to UV-B and to the combination of UV-B and drought in various white clover populations, including New Zealand cultivars and ecotypes as well as overseas germplasm. The results were obtained under controlled environmental conditions in three independent trials. Overall, white clover growth was reduced by UV-B. The population comparisons indicated that low growth rate and adaptation to other forms of stress may be related to UV-B tolerance under well-watered conditions, but not during extended periods of drought. Flavonoid pigments that are involved in stress protection were strongly increased under UV-B and were further enhanced in the combination of UV-B and drought. The responses among these flavonoids were highly specific, with more pronounced UV-B-induced increases in quercetin glycosides, compared to their closely related kaempferol counterparts. UV-B toler ance of the less productive white clover populations was linked to the accumulation of quercetin compounds. In conclusion, these studies suggest (i) that slow-growing white clover ecotypes adapted to other stresses have higher capacity for biochemical acclimation to UV-B under well-watered conditions and (ii) that these biochemical attributes may also contribute to decreased UV-B sensitivity across white clover populations under drought. The findings alert plant breeders to potential benefits of selecting productive germplasm for high levels of specific flavonoids to balance trade-offs between plant productivity and stress tolerance. Keywords: Drought, flavonoids, genetic variation, HPLC, kaempferol, quercetin, str ess, Trifolium repens L., ultraviolet-B, white clover


Author(s):  
Rachel Olzer ◽  
Rebecca L. Ehrlich ◽  
Justa L. Heinen-Kay ◽  
Jessie Tanner ◽  
Marlene Zuk

Sex and reproduction lie at the heart of studies of insect behavior. We begin by providing a brief overview of insect anatomy and physiology, followed by an introduction to the overarching themes of parental investment, sexual selection, and mating systems. We then take a sequential approach to illustrate the diversity of phenomena and concepts behind insect reproductive behavior from pre-copulatory mate signalling through copulatory sperm transfer, mating positions, and sexual conflict, to post-copulatory sperm competition, and cryptic female choice. We provide an overview of the evolutionary mechanisms driving reproductive behavior. These events are linked by the economic defendability of mates or resources, and how these are allocated in each sex. Under the framework of economic defendability, the reader can better understand how sexual antagonistic behaviors arise as the result of competing optimal fitness strategies between males and females.


Author(s):  
Katrina Hannah D. Ignacio ◽  
Jose Danilo B. Diestro ◽  
Adrian I. Espiritu ◽  
Maria Carissa Pineda-Franks

2021 ◽  
pp. 108602662199006
Author(s):  
Peter Tashman ◽  
Svetlana Flankova ◽  
Marc van Essen ◽  
Valentina Marano

We meta-analyze research on why firms join voluntary environmental programs (VEPs) to assess the impact of program stringency, or the extent to which they have rigorous, enforceable standards on these decisions. Stringency creates trade-offs for firms by affecting programs’ effectiveness, legitimacy, and adoption costs. Most research considers singular programs and lacks cross program variation needed to analyze program stringency’s impact. Our meta-analysis addresses this by sampling 127 studies and 23 VEPs. We begin by identifying common institutional and resource-based drivers of participation in the literature, and then analyze how program stringency moderates their impacts. Our results suggest that strictly governed VEPs encourage participation among highly visible and profitable firms, and discourage it when informal institutional pressures are higher, and firms have prior experience with other VEPs or quality management standards. We demonstrate that VEP stringency has nuanced effects on firm participation based on the institutional and resource-based factors facing them.


1997 ◽  
Vol 75 (4) ◽  
pp. 542-548 ◽  
Author(s):  
P. H. Niewiarowski ◽  
J. D. Congdon ◽  
A. E. Dunham ◽  
L. J. Vitt ◽  
D. W. Tinkle

Potential costs and benefits of tail autotomy in lizards have been inferred almost exclusively from experimental study in semi-natural enclosures and from indirect comparative evidence from natural populations. We present complementary evidence of the costs of tail autotomy to the lizard Uta stansburiana from detailed demographic study of a natural population. On initial capture, we broke the tails of a large sample of free-ranging hatchlings (560) and left the tails of another large sample (455) intact, and then followed subsequent hatchling growth and survival over a 3-year period. Surprisingly, in 1 out of the 3 years of study, survival of female hatchlings with broken tails exceeded that of female hatchlings with intact tails. Furthermore, no effects of tail loss on survivorship were detected for male hatchlings. However, in 2 years when recaptures were very frequent (1961, 1962), growth rates of hatchlings with broken tails were significantly slower than those of their counterparts with intact tails. We discuss our results in the broader context of estimating the relative costs and benefits of tail autotomy in natural populations, and suggest that long-term demographic studies will provide the best opportunity to assess realized fitness costs and benefits with minimum bias. We also describe how experimentally induced tail autotomy can be used as a technique to complement experimental manipulation of reproductive investment in the study of life-history trade-offs.


2015 ◽  
Vol 87 (9) ◽  
pp. 952-957 ◽  
Author(s):  
Frédéric Moisan ◽  
Sofiane Kab ◽  
Fatima Mohamed ◽  
Marianne Canonico ◽  
Morgane Le Guern ◽  
...  

2017 ◽  
Vol 47 (13) ◽  
pp. 2288-2301 ◽  
Author(s):  
S. Wilson ◽  
J. L. Bair ◽  
K. M. Thomas ◽  
W. G. Iacono

BackgroundA number of studies reports reduced hippocampal volume in individuals who engage in problematic alcohol use. However, the magnitude of the difference in hippocampal volume between individuals with v. without problematic alcohol use has varied widely, and there have been null findings. Moreover, the studies comprise diverse alcohol use constructs and samples, including clinically significant alcohol use disorders and subclinical but problematic alcohol use (e.g. binge drinking), adults and adolescents, and males and females.MethodsWe conducted the first quantitative synthesis of the published empirical research on associations between problematic alcohol use and hippocampal volume. In total, 23 studies were identified and selected for inclusion in the meta-analysis; effects sizes were aggregated using a random-effects model.ResultsProblematic alcohol use was associated with significantly smaller hippocampal volume (d = −0.53). Moderator analyses indicated that effects were stronger for clinically significant v. subclinical alcohol use and among adults relative to adolescents; effects did not differ among males and females.ConclusionsProblematic alcohol use is associated with reduced hippocampal volume. The moderate overall effect size suggests the need for larger samples than are typically included in studies of alcohol use and hippocampal volume. Because the existing literature is almost entirely cross-sectional, future research using causally informative study designs is needed to determine whether this association reflects premorbid risk for the development of problematic alcohol use and/or whether alcohol has a neurotoxic effect on the hippocampus.


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