Allometric scaling in two bushcricket species (Orthoptera: Tettigoniidae) suggests sexual selection on song-generating structures

2020 ◽  
Vol 131 (3) ◽  
pp. 521-535
Author(s):  
Fran Rebrina ◽  
Marianna Anichini ◽  
Klaus Reinhold ◽  
Gerlind U C Lehmann
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Allometric Scaling ◽  
Functional Integration ◽  
Stabilizing Selection ◽  
Evolutionary Patterns ◽  
Selection For ◽  
Stridulatory Apparatus ◽  
Mirror Area ◽  
The Right

Abstract In acoustically communicating bushcrickets (Orthoptera: Tettigoniidae), most signal properties are influenced by the dimensions of the stridulatory apparatus, which in turn reflects body size and condition of the signaller. Females can assess male quality based on acoustic signals, suggesting that male stridulatory structures may be under sexual selection. We investigated scaling relationships between stridulatory structures, body size and body mass in males of the bushcricket Poecilimon veluchianus veluchianus, in comparison to the congeneric Poecilimon ampliatus. Stridulatory structures in P. v. veluchianus exhibited strong left–right correlation and coupling with body size and mass, indicating stabilizing selection for functional integration. In addition, sound-generating (the width of stridulatory teeth) and sound-radiating (mirror area on the right tegmen) structures scaled hyperallometrically to tegmen area, suggesting that both are under sexual selection. Finally, interspecies comparison revealed a steeper slope in tegmen area and stridulatory file length in relation to body size in P. ampliatus than in P. v. veluchianus, implying stronger sexual selection in the former, smaller species. Our study emphasizes the significance of a comparative allometric approach in elucidating evolutionary patterns of sound-generating and -radiating structures.

scholarly journals Evolution of correlated complexity in the radically different courtship signals of birds-of-paradise

2018 ◽  
Author(s):  
Russell A. Ligon ◽  
Christopher D. Diaz ◽  
Janelle L. Morano ◽  
Jolyon Troscianko ◽  
Martin Stevens ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Evolutionary Biology ◽  
Evolutionary Dynamics ◽  
Functional Integration ◽  
Empirical Support ◽  
Evolutionary Patterns ◽  
Evolutionary Innovation ◽  
Birds Of Paradise ◽  
Analytical Approaches

Ornaments used in courtship often vary wildly among species, reflecting the evolutionary interplay between mate preference functions and the constraints imposed by natural selection. Consequently, understanding the evolutionary dynamics responsible for ornament diversification has been a longstanding challenge in evolutionary biology. However, comparing radically different ornaments across species, as well as different classes of ornaments within species, is a profound challenge to understanding diversification of sexual signals. Using novel methods and a unique natural history dataset, we explore evolutionary patterns of ornament evolution in a group - the birds-of-paradise - exhibiting dramatic phenotypic diversification widely assumed to be driven by sexual selection. Rather than the tradeoff between ornament types originally envisioned by Darwin and Wallace, we found positive correlations among cross-modal (visual/acoustic) signals indicating functional integration of ornamental traits into a composite unit - the courtship phenotype. Furthermore, given the broad theoretical and empirical support for the idea that systemic robustness - functional overlap and interdependency - promotes evolutionary innovation, we posit that birds-of-paradise have radiated extensively through ornamental phenotype space as a consequence of the robustness in the courtship phenotype that we document at a phylogenetic scale. We suggest that the degree of robustness in courtship phenotypes among taxa can provide new insights into the relative influence of sexual and natural selection on phenotypic radiations.Author SummaryAnimals frequently vary widely in ornamentation, even among closely related species. Understanding the patterns that underlie this variation is a significant challenge, requiring comparisons among drastically different traits - like comparing apples to oranges. Here, we use novel analytical approaches to quantify variation in ornamental diversity and richness across the wildly divergent birds-of-paradise, a textbook example of how sexual selection can profoundly shape organismal phenotypes. We find that color and acoustic complexity, along with behavior and acoustic complexity, are positively correlated across evolutionary time-scales. Positive covariation among ornament classes suggests that selection is acting on correlated suites of traits - a composite courtship phenotype - and that this integration may be partially responsible for the extreme variation we see in birds-of-paradise.

scholarly journals Acoustic allometry and vocal learning in mammals

2020 ◽  
Vol 16 (7) ◽  
pp. 20200081 ◽  
Author(s):  
Maxime Garcia ◽  
Andrea Ravignani
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Empirical Research ◽  
Evolutionary Biology ◽  
Vocal Learning ◽  
Evolutionary Origins ◽  
Vocal Signals ◽  
Animal Vocalizations ◽  
Selection For ◽  
Preliminary Support

Acoustic allometry is the study of how animal vocalizations reflect their body size. A key aim of this research is to identify outliers to acoustic allometry principles and pinpoint the evolutionary origins of such outliers. A parallel strand of research investigates species capable of vocal learning , the experience-driven ability to produce novel vocal signals through imitation or modification of existing vocalizations. Modification of vocalizations is a common feature found when studying both acoustic allometry and vocal learning. Yet, these two fields have only been investigated separately to date. Here, we review and connect acoustic allometry and vocal learning across mammalian clades, combining perspectives from bioacoustics, anatomy and evolutionary biology. Based on this, we hypothesize that, as a precursor to vocal learning, some species might have evolved the capacity for volitional vocal modulation via sexual selection for ‘dishonest' signalling. We provide preliminary support for our hypothesis by showing significant associations between allometric deviation and vocal learning in a dataset of 164 mammals. Our work offers a testable framework for future empirical research linking allometric principles with the evolution of vocal learning.

scholarly journals Sexual selection on size and shape in Japanese beetles (Popillia japonica)

2020 ◽  
Vol 31 (4) ◽  
pp. 1073-1083 ◽  
Author(s):  
Clint D Kelly
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Mating Success ◽  
Insect Pest ◽  
Popillia Japonica ◽  
Female Size ◽  
Male Body ◽  
Japanese Beetle ◽  
Size Dimorphism ◽  
Selection For

Abstract The mobility hypothesis argues that species in which males compete for mates in scrambles often exhibit female-biased size dimorphism because smaller male body size should increase male mobility and success in searching for mates. Sexual dimorphism can be further exaggerated if fecundity or sexual selection concurrently selects for larger female size. Scramble competition can select for trait characteristics that optimize locomotion; for example, long and slender wings should be favored if aerial speed is important to mating success. I tested these predictions in the scrambling Japanese beetle (Popillia japonica), a female-biased size dimorphic insect pest that is invasive to North America. Multivariate selection analyses support the prediction that smaller body size and larger wings in males benefit their mating success. My analyses also revealed significant selection for larger wings in females but, contrary to prediction, direct sexual selection favors smaller body size in females. These results support the mobility hypothesis and partially explain the evolution of female-biased size dimorphism in this species. Sexual selection favored rounder bodies in females and more tapered bodies in males, whereas, in both sexes, the effect of wing shape appears less important to fitness than wing size.

scholarly journals Effect of Phenotype Selection on Genome Size Variation in Two Species of Diptera

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Carl E. Hjelmen ◽  
Jonathan J. Parrott ◽  
Satyam P. Srivastav ◽  
Alexander S. McGuane ◽  
Lisa L. Ellis ◽  
...  
Keyword(s):  
Body Size ◽  
Cell Count ◽  
Genome Size ◽  
Large Body ◽  
Population Variation ◽  
Phenotypic Traits ◽  
Stabilizing Selection ◽  
Large Body Size ◽  
Slow Development ◽  
Selection For

Genome size varies widely across organisms yet has not been found to be related to organismal complexity in eukaryotes. While there is no evidence for a relationship with complexity, there is evidence to suggest that other phenotypic characteristics, such as nucleus size and cell-cycle time, are associated with genome size, body size, and development rate. However, what is unknown is how the selection for divergent phenotypic traits may indirectly affect genome size. Drosophila melanogaster were selected for small and large body size for up to 220 generations, while Cochliomyia macellaria were selected for 32 generations for fast and slow development. Size in D. melanogaster significantly changed in terms of both cell-count and genome size in isolines, but only the cell-count changed in lines which were maintained at larger effective population sizes. Larger genome sizes only occurred in a subset of D. melanogaster isolines originated from flies selected for their large body size. Selection for development time did not change average genome size yet decreased the within-population variation in genome size with increasing generations of selection. This decrease in variation and convergence on a similar mean genome size was not in correspondence with phenotypic variation and suggests stabilizing selection on genome size in laboratory conditions.

Swarming and mating behavior of a mayfly Baetis bicaudatus suggest stabilizing selection for male body size

2002 ◽  
Vol 51 (6) ◽  
pp. 530-537 ◽  
Author(s):  
Barbara L. Peckarsky ◽  
Angus R. McIntosh ◽  
Christopher C. Caudill ◽  
Jonas Dahl
Keyword(s):  
Body Size ◽  
Mating Behavior ◽  
Stabilizing Selection ◽  
Male Body ◽  
Male Body Size ◽  
Baetis Bicaudatus ◽  
Selection For

Sexual selection for increased male body size and protandry in a spider

2004 ◽  
Vol 68 (5) ◽  
pp. 1041-1048 ◽  
Author(s):  
Alexei A. Maklakov ◽  
Trine Bilde ◽  
Yael Lubin
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Male Body ◽  
Male Body Size ◽  
Selection For
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