scholarly journals Limits to environmental masking of genetic quality in sexual signals

2019 ◽  
Author(s):  
James Malcolm Howie ◽  
Harry Alexander Cordeaux Dawson ◽  
Andrew Pomiankowski ◽  
Kevin Fowler
Keyword(s):  
Environmental Stress ◽  
High Stress ◽  
Female Mate Choice ◽  
High Quality ◽  
Genetic Quality ◽  
Sexual Ornaments ◽  
Extreme Stress ◽  
Genetic Signal ◽  
Male Ornament ◽  
Conceptual Advance

AbstractThere is considerable debate over the value of male sexual ornaments as signals of genetic quality. Studies alternately report that environmental variation enhances or diminishes the genetic signal, or leads to crossover where genotypes perform well in one environment but poorly in another. A unified understanding is lacking. We conduct the first experimental test examining the dual effects of distinct low and high genetic quality (inbred versus crossed parental lines) and low, through high, to extreme environmental stress (larval diets) on a condition-dependent male ornament. We find that differences in genetic quality signalled by the ornament (male eyespan in Diasemopsis meigenii stalk-eyed flies) become visible and are amplified under high stress but are overwhelmed in extreme stress environments. Variance among distinct genetic lines increases with environmental stress in both genetic quality classes, but at a slower rate in high quality outcrossed flies. Individual genetic lines generally maintain their ranks across environments, except among high quality lines under low stress conditions, where low genetic variance precludes differentiation between ranks. Our results provide a conceptual advance, demonstrating a unified pattern for how genetic and environmental quality interact. They show when environmental conditions lead to the amplification of differences in signals of genetic quality and thereby enhance the potential indirect genetic benefits gained by female mate choice.

scholarly journals Female mate choice across spatial scales: influence of lek and male attributes on mating success of blue-crowned manakins

2009 ◽  
Vol 276 (1663) ◽  
pp. 1875-1881 ◽  
Author(s):  
Renata Durães ◽  
Bette A. Loiselle ◽  
Patricia G. Parker ◽  
John G. Blake
Keyword(s):  
Mate Choice ◽  
Female Choice ◽  
Mating Success ◽  
Spatial Scales ◽  
Female Mate Choice ◽  
High Quality ◽  
Genetic Quality ◽  
Female Mate ◽  
Genetic Benefits

Lekking males compete for females within and among leks, yet female choice is expected to work differently at each of these spatial scales. We used paternity analyses to examine how lek versus male attributes influence mate choice in the blue-crowned manakin Lepidothrix coronata . We tested the hypotheses that females prefer (i) to mate at larger leks where a larger number of potential mates can be assessed, (ii) to mate with unrelated or highly heterozygous males expected to produce high-quality offspring, (iii) to mate with males that display at higher rates, and that (iv) display honestly reflects male genetic quality. Our results show that (i) males at larger leks are not more likely to sire young, although females nesting close to small leks travel further to reach larger leks, (ii) siring males are not less related to females or more heterozygous than expected, (iii) within a lek, high-display males are more likely to sire young, and (iv) both male heterozygosity and display rate increased with lek size, and as a result display does not reliably reflect male genetic quality across leks. We suggest that female mate choice in this species is probably driven by a Fisherian process rather than adaptive genetic benefits.

Freshwater pearl culture in China.

2020 ◽  
Author(s):  
Lin Cao
Keyword(s):  
Shell Length ◽  
Culture Period ◽  
Production Cycle ◽  
High Quality ◽  
Host Fish ◽  
Genetic Quality ◽  
Operative Care ◽  
Artificial Breeding

Abstract Artificial breeding of freshwater pearl mussels is widely used to improve the yield of pearl culture. All phases of the production cycle, including collection and culture of the broodstock, release of the glochidia, provision of the host fish for glochidia to attach to, and collection of mussel seeds, can be controlled artificially. The advantages of artificial breeding are that it can help to produce high quality pearls and improve the genetic quality of pearl mussels. Collected mussel seed are transferred from holding jars into small 200 µm mesh baskets (10 cm diameter x 5 cm). Each basket was supplied individually with 0.1-0.2 L of water per minute. When the mussels' shell length reaches over 10 cm, they can be operated to culture pearl. After post-operative care the implanted mussels are stocked in ponds. The mussels are kept in nylon bags (2 mussels per bag) and are hung from bamboo or PVC pipes and placed in ponds at 1 m depth. Periodical checking of mussels, with removal of dead ones and cleaning of bags, is required throughout the culture period of 12-18 months.

scholarly journals Interacting stressors matter: diet quality and virus infection in honeybee health

2019 ◽  
Vol 6 (2) ◽  
pp. 181803 ◽  
Author(s):  
Adam G. Dolezal ◽  
Jimena Carrillo-Tripp ◽  
Timothy M. Judd ◽  
W. Allen Miller ◽  
Bryony C. Bonning ◽  
...  
Keyword(s):  
Virus Infection ◽  
Multiple Stressors ◽  
Experimental Studies ◽  
Calcium Content ◽  
Micronutrient Deficiencies ◽  
Population Declines ◽  
High Quality ◽  
Diet Diversity ◽  
Extreme Stress ◽  
High Virus

Honeybee population declines have been linked to multiple stressors, including reduced diet diversity and increased exposure to understudied viral pathogens. Despite interest in these factors, few experimental studies have explored the interaction between diet diversity and viral infection in honeybees. Here, we used a mixture of laboratory cage and small semi-field nucleus hive experiments to determine how these factors interact. In laboratory experiments, we found that high-quality diets (polyfloral pollen and high-quality single-source pollen) have the potential to reduce mortality in the face of infection with Israeli acute paralysis virus (IAPV). There was a significant interaction between diet and virus infection on mortality, even in the presence of high virus titres, suggesting that good diets can help bees tolerate virus infection. Further, we found that extreme stress in the form of pollen starvation in conjunction with IAPV infection increase exiting behaviour from small experimental hives. Finally, we showed that higher-quality pollen diets have significantly higher iron and calcium content, suggesting micronutrient deficiencies could be an under-explored area of bee nutrition.

The Testing of Adhesives for Timber

1929 ◽  
Vol 33 (218) ◽  
pp. 91-128
Author(s):  
WM. D. Douglas ◽  
C. B. Pettifor
Keyword(s):  
Present State ◽  
Test Piece ◽  
High Stress ◽  
Research Committee ◽  
High Quality ◽  
Scientific Societies ◽  
Aircraft Structures ◽  
Simple Property ◽  
Timber Joints ◽  
Control Variation

Mr. Douglas : From very early days adhesives have played an important part in the joiners’ trade. The necessity for consistent high quality in glues and cements became acute when they were used under conditions of high stress in aircraft structures. It is natural, therefore, to find that aeronautical interests have been largely represented on research committees which have investigated the use of adhesives. At the end of 1919 the Adhesives Research Committee of the Department of Scientific and Industrial Research was formed to continue the work of the Adhesives Committee of the Conjoint Board of Scientific Societies. It was realised that one of the obstacles to the study of adhesives was the unsatisfactory nature of the tests which determine their strength in timber joints. Many properties of glue (such as viscosity, jelly strength, etc.) have been used to control variation during manufacture or as an indication of probable relative strengths in timber joints, but it has never been generallyadmitted that any simple property of the glue itself can be accepted as representative of the ability of that glue to effect a joint with timber. In the present state of our knowledge, therefore, it appears to be necessary to make final appeal to the timber glue test piece.

scholarly journals Adiposity, compared with masculinity, serves as a more valid cue to immunocompetence in human mate choice

2013 ◽  
Vol 280 (1751) ◽  
pp. 20122495 ◽  
Author(s):  
Markus J. Rantala ◽  
Vinet Coetzee ◽  
Fhionna R. Moore ◽  
Ilona Skrinda ◽  
Sanita Kecko ◽  
...  
Keyword(s):  
Mate Choice ◽  
Female Mate Choice ◽  
Good Genes ◽  
Secondary Sexual Traits ◽  
Genetic Quality ◽  
Secondary Sexual Trait ◽  
Sexual Traits ◽  
Handicap Hypothesis ◽  
The Relationship ◽  
Secondary Sexual

According to the ‘good genes’ hypothesis, females choose males based on traits that indicate the male's genetic quality in terms of disease resistance. The ‘immunocompetence handicap hypothesis’ proposed that secondary sexual traits serve as indicators of male genetic quality, because they indicate that males can contend with the immunosuppressive effects of testosterone. Masculinity is commonly assumed to serve as such a secondary sexual trait. Yet, women do not consistently prefer masculine looking men, nor is masculinity consistently related to health across studies. Here, we show that adiposity, but not masculinity, significantly mediates the relationship between a direct measure of immune response (hepatitis B antibody response) and attractiveness for both body and facial measurements. In addition, we show that circulating testosterone is more closely associated with adiposity than masculinity. These findings indicate that adiposity, compared with masculinity, serves as a more important cue to immunocompetence in female mate choice.

scholarly journals Offspring viability benefits but no apparent costs of mating with high quality males

2010 ◽  
Vol 7 (3) ◽  
pp. 419-421 ◽  
Author(s):  
Leigh W. Simmons ◽  
Rebecca Holley
Keyword(s):  
Sexual Selection ◽  
Sexual Conflict ◽  
Alternative Hypothesis ◽  
Dung Beetle ◽  
Male Courtship ◽  
High Quality ◽  
Female Resistance ◽  
Genetic Quality ◽  
Onthophagus Taurus ◽  
Courtship Signals

Traditional models of sexual selection posit that male courtship signals evolve as indicators of underlying male genetic quality. An alternative hypothesis is that sexual conflict over mating generates antagonistic coevolution between male courtship persistence and female resistance. In the scarabaeine dung beetle Onthophagus taurus , females are more likely to mate with males that have high courtship rates. Here, we examine the effects of exposing females to males with either high or low courtship rates on female lifetime productivity and offspring viability. Females exposed to males with high courtship rates mated more often and produced offspring with greater egg–adult viability. Female productivity and lifespan were unaffected by exposure to males with high courtship rates. The data are consistent with models of sexual selection based on indirect genetic benefits, and provide little evidence for sexual conflict in this system.

scholarly journals Compensatory investment in zebra finches: females lay larger eggs when paired to sexually unattractive males

2008 ◽  
Vol 276 (1657) ◽  
pp. 707-715 ◽  
Author(s):  
Elisabeth Bolund ◽  
Holger Schielzeth ◽  
Wolfgang Forstmeier
Keyword(s):  
Zebra Finch ◽  
Carotenoid Content ◽  
Zebra Finches ◽  
Differential Allocation ◽  
Egg Volume ◽  
High Quality ◽  
Genetic Quality ◽  
Classical Version ◽  
Extra Pair Paternity ◽  
Maternal Resources

The classical version of the differential allocation hypothesis states that, when females reproduce over their lifetime with partners that differ in their genetic quality, they should invest more in reproduction with high-quality males. However, in species with lifetime monogamy, such as the zebra finch, partner quality will typically remain the same. In this case, the compensatory investment (CI) hypothesis predicts higher investment for low-quality males, because low genetic quality offspring are more dependent on maternal resources. Here, we show that female zebra finches invested more resources, both in terms of egg volume and yolk carotenoid content, when paired to a low genetic quality male, as judged from his previous ability to obtain extra-pair paternity in aviary colonies. We also found that females deposited slightly larger amounts of testosterone into eggs when paired to a low parental quality male, as judging from his previous success in rearing offspring. This is, to our knowledge, the first experimental support for the CI hypothesis in a species with lifetime monogamy. We stress that in more promiscuous species, the benefits of classical differential allocation may partly be neutralized by the supposed benefits of CI.

scholarly journals Variation in preference for a male ornament is positively associated with female eyespan in the stalk-eyed fly Diasemopsis meigenii

2006 ◽  
Vol 273 (1591) ◽  
pp. 1287-1292 ◽  
Author(s):  
Samuel Cotton ◽  
David W Rogers ◽  
Jennifer Small ◽  
Andrew Pomiankowski ◽  
Kevin Fowler
Keyword(s):  
Significant Variation ◽  
Sequential Sampling ◽  
Individual Preference ◽  
Mate Preferences ◽  
Mate Preference ◽  
Sexually Dimorphic ◽  
Sexual Ornaments ◽  
Wide Range ◽  
Rejection Response ◽  
Male Ornament

There is currently much interest in mate preferences for sexual ornaments. However, few studies have focused on individual variation in mate preference despite its importance for the rate and direction of sexual selection. Females of the sexually dimorphic stalk-eyed fly, Diasemopsis meigenii , exhibit an unambiguous rejection response towards unattractive males bearing small ornaments. We investigated individual mate preferences using repeated sequential sampling of female rejection or acceptance responses to a wide range of male ornament phenotypes. We found significant variation in the strength of individual preference. In addition, preference was positively associated with female eyespan, a condition-dependent trait putatively linked to visual acuity.

Extrapair paternity in the red bishop (Euplectes orix): is there evidence for the good-genes hypothesis?

Behaviour ◽  
2002 ◽  
Vol 139 (6) ◽  
pp. 777-800 ◽  
Author(s):  
Georg Klump ◽  
Thomas W.P.Friedl
Keyword(s):  
Pairwise Comparison ◽  
Paternity Analysis ◽  
Good Genes ◽  
Sexually Dimorphic ◽  
High Quality ◽  
Genetic Quality ◽  
Extrapair Paternity ◽  
Previous Season ◽  
Multilocus Dna Fingerprinting

AbstractWe investigated the pattern and frequency of extrapair paternity in a colony of the red bishop, a sexually dimorphic and highly polygynous passerine. In particular, we tested whether there was evidence in support of the good-genes hypothesis, stating that females seek extrapair copulations with high-quality males to enhance the genetic quality of their offspring. Paternity analysis of 432 nestlings from 187 broods using non-radioactive multilocus DNA-fingerprinting revealed that 17.6% of nestlings were extrapair young (EPY) and 30.5% of all broods investigated contained at least one EPY. In a pairwise comparison, extrapair fathers were found to have significantly longer tarsi than the within-pair fathers they cuckolded. Furthermore, extrapair fathers were more often territory owners in the previous season,

scholarly journals A model of the interaction between ‘good genes’ and direct benefits in courtship-feeding animals: when do males of high genetic quality invest less?

2002 ◽  
Vol 357 (1419) ◽  
pp. 309-317 ◽  
Author(s):  
L. F. Bussière
Keyword(s):  
Sexual Selection ◽  
Simple Model ◽  
Parental Investment ◽  
Good Genes ◽  
High Quality ◽  
Genetic Quality ◽  
Individual Female ◽  
Female Partners ◽  
Direct Benefits ◽  
Courtship Feeding

Conflict between mates over the amount of parental investment by each partner is probably the rule except in rare cases of genetic monogamy. In systems with parental care, males may frequently benefit by providing smaller investments than are optimal for individual female partners. Females are therefore expected to choose males that will provide the largest amounts of parental investment. In some species, however, the preferred males provide less care than their rivals. Focusing on species in which males invest by feeding their mates, I use a simple model to demonstrate the conditions under which males preferred by females may have optimal donations that are smaller than those of less–preferred rivals. Pre–mating female choice may sufficiently bias the perception of mate availability of preferred males relative to their rivals such that preferred males gain by conserving resources for future matings. Similarly, ‘cryptic’ biases in favour of high–quality ejaculates by females can compensate for smaller than average donations received from preferred males. However, post–fertilization cryptic choice should not change the optimal donations of preferred males relative to their rivals. I discuss the implications of this work for understanding sexual selection in courtship–feeding animals, and the relevance of these systems to understanding patterns of investment for animals in general.

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