Sex pheromone signal and stability covary with fitness

If sexual signals are costly, covariance between signal expression and fitness is expected. Signal–fitness covariance is important, because it can contribute to the maintenance of genetic variation in signals that are under natural or sexual selection. Chemical signals, such as female sex pheromones in moths, have traditionally been assumed to be species-recognition signals, but their relationship with fitness is unclear. Here, we test whether chemical, conspecific mate finding signals covary with fitness in the moth Heliothis subflexa . Additionally, as moth signals are synthesized de novo every night, the maintenance of the signal can be costly. Therefore, we also hypothesized that fitness covaries with signal stability (i.e. lack of temporal intra-individual variation). We measured among- and within-individual variation in pheromone characteristics as well as fecundity, fertility and lifespan in two independent groups that differed in the time in between two pheromone samples. In both groups, we found fitness to be correlated with pheromone amount, composition and stability, supporting both our hypotheses. This study is, to our knowledge, the first to report a correlation between fitness and sex pheromone composition in moths, supporting evidence of condition-dependence and highlighting how signal–fitness covariance may contribute to heritable variation in chemical signals both among and within individuals.

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“…The data and scripts corresponding to this paper are archived online in the Dryad Digital Repository: [77].…”

Section: Data Accessibilitymentioning

confidence: 99%

Sex pheromone signal and stability covary with fitness

et al. 2021

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“…Previously, genetic mapping studies revealed several QTL underlying difference in sex pheromone composition in H. subflexa (Groot et al, 2013). Since variation in pheromone composition in H. subflexa is also explained by fitness variation (Blankers et al, 2021), many different genetic factors likely contribute small additional fractions to the total variance. Another explanation comes from population genetics: re-orientation of genetic covariances in response to bottlenecks may free up additive genetic variance, thereby paradoxically increasing levels of genetic variance (Carson, 1990;Templeton, 2008).…”

Section: No Change In Genetic Variancementioning

confidence: 99%

“…Specifically, the correlation between Z11-16:OH and Z11-16:OAc changed in both sign and magnitude. Since both Z11-16:OH and Z11-16:OAc reduce heterospecific mate attraction (Vetter and Baker, 1983;Vickers and Baker, 1997), and both traits covary with fitness and are condition-dependent (Blankers et al, 2021), the negative genetic correlation in the starting population could be the result of a trade-off that is selected against when artificial selection favors higher rates of acetates.…”

Section: Changing Genetic Covariancementioning

confidence: 99%

Experimental evolution of a pheromone signal

Blankers

Fruitet

Burdfield‐Steel

et al. 2021

Preprint

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Sexual signals are important in speciation, but understanding their evolution is complex as these signals are often composed of multiple, genetically interdependent components. To understand how signals evolve, we thus need to consider selection responses in multiple components and account for the genetic correlations among components. One intriguing possibility is that selection changes genetic correlations between components under selection and those not under selection, reducing evolutionary constraints. However, this hypothesis remains largely untested empirically. In this study, we investigate the evolutionary response of the multi-component female sex pheromone blend of the moth Heliothis subflexa to 10 generations of artificial selection. We observed a selection response of about 3/4s of a phenotypic standard deviation in the components under selection. Interestingly, other pheromone components that are biochemically and genetically linked to the components under selection did not change. We found that this component-specific selection response was likely facilitated due to reduced genetic coupling between the component under selection and the components not under selection, resulting from changes in genetic covariances within the 10 generations of selection. Our findings provide rare empirical support for an intriguing mechanism by which a sexual signal can respond to selection without possible constraints from indirect selection responses.

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“…Pheromones can be costly to produce and maintain (Blankers et al, 2021;Harari et al, 2011) and variation occurs both within the individual lifespan and between individuals (De Pasqual et al, 2021;Blankers et al, 2021;Pham et al, 2021). Through pheromone variation and the use of signaling strategies, females can exert sexual selection on males by manipulating the arrival of males (Greenfield, 1981;Johnson et al, 2017a) and alter intrasexual dynamics by outcompeting same-sex conspecifics (Pham et al, 2020(Pham et al, , 2021.…”

Section: Introductionmentioning

confidence: 99%

Morph-linked variation in female pheromone signaling and male response in a polymorphic moth

De Pasqual,

Selenius,

Burdfield-Steel

et al. 2024

Preprint

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Understanding the maintenance of genetic variation in reproductive strategies and polymorphisms in the wild requires a comprehensive examination of the complex interactions between genetic basis, behavior, and environmental factors.We tested the association between three color genotypes and variation in female pheromone signaling and male antennal morphology in the wood tiger moth (Arctia plantaginis). These moths have genetically determined white (WW, Wy) and yellow (yy) hindwings that are linked to mating success and fitness, with heterozygotes (Wy) having an advantage. We hypothesized that attractiveness and reproductive success are correlated, with Wy females being more attractive than the other two genotypes which could contribute to maintaining the polymorphism.Female attractiveness was tested by baiting traps with females of the three color genotypes both in low-(i.e., field setup) and in high-population density (i.e., large enclosure setup). Male’s ability to reach females was correlated to their own color genotype and antennal morphology (length, area, and lamellae count).Contrary to our prediction, morph-related reproductive success and attractiveness were not correlated. Heavier Wy females attracted a lower proportion of males compared to WW and yy females. Specifically, an increase in weight corresponded to a decreased Wy but increased yy female attractiveness. yy females were generally more attractive than others likely due to earlier pheromone release. In males, lamellae count and genetic color morph were linked to the male’s ability to locate females. Furthermore, male traits affected their ability to reach females in a context-specific way. Males with denser antennae (i.e., higher lamellae count) and white males reached the females faster than yellows in the enclosure, while yellow males located females faster than whites in the field.Our results indicate that higher yy female attractiveness was likely affected by the combined effect of early pheromone release, female weight and higher population density. Males’ searching success was affected by morph-specific behavioral strategies and local population density. Ultimately, the combined effect of genotype-related pheromone signaling strategies of females together with environment-dependent male behavior affect male response and potentially contribute to maintaining variation in fitness-related traits.

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Sex pheromone signal and stability covary with fitness

Cited by 3 publications

References 70 publications

Sex pheromone signal and stability covary with fitness

Sex pheromone signal and stability covary with fitness

Experimental evolution of a pheromone signal

Morph-linked variation in female pheromone signaling and male response in a polymorphic moth

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