To complicate or to simplify? Phylogenetic tests of complexity trends and genital evolution in ground spiders (Araneae: Dionycha: Gnaphosidae)

Azevedo, Guilherme H. F.; Griswold, Charles E.; Santos, Adalberto J.

doi:10.1093/zoolinnean/zly016

Cited by 7 publications

(4 citation statements)

References 52 publications

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“…This observation supports the assumption that, in the NE Atlantic-Mediterranean group of genera, the male hectocotyli evolved faster than female bursae copulatrices and the latter lagged somewhat behind. In a case study of Gnaphosidae (Araneae), animals that display genital complexity more advanced in males than in females similar to that seen in Atlantic-Mediterranean Sepiolinae, Azevedo et al (2018) showed that the evolution of copulatory organs is mainly based on cryptic female choice mechanisms. Thus, females cryptically chose males based mainly on stimuli that male genitalia produce regardless of female genital shape (Eberhard 2015).…”

Section: Dichotomous Identification Key To the Genera Of Sepiolinaementioning

confidence: 91%

“…Indeed, the hectocotylus appears to play a role in speciation within Sepiolinae, since it is one of the two elements in the genus-and species-specific lock-and-key copulatory mechanism that limits extra-specific fertilization (Bello 2019a). Incidentally, the high specific variability of male copulatory organs is a feature widely distributed among disparate taxa (e.g., Simmons 2014;Azevedo et al 2018).…”

Section: Introductionmentioning

confidence: 99%

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Evolution of the hectocotylus in Sepiolinae (Cephalopoda: Sepiolidae) and description of four new genera

Bello

2020

EJT

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The subfamily Sepiolinae (Mollusca: Cephalopoda: Sepiolidae), currently containing the genera Sepiola Leach, 1817, Euprymna Steenstrup, 1887, Inioteuthis Verrill, 1881, Rondeletiola Naef, 1921 and Sepietta Naef, 1912, is characterized by the hectocotylization of the left dorsal arm, i.e., its transformation into a copulatory organ thanks to modifications of sucker/pedicel elements. The hectocotylus morphology varies to a great extent across genera and species. In particular, one to several pedicels in its proximal third lose their sucker and become highly and diversely modified in shape to constitute a copulatory apparatus. An evolutionary gradient was observed in the copulatory apparatus morphology, from the simple modification into a papilla of just one pedicel from the third element of the ventral sucker row (some nominal species of Euprymna) to a quite complex structure involving several variously modified pedicels from both the ventral and dorsal sucker rows (Inioteuthis). In some species, elements in the distal portion of the hectocotylus may also be highly modified, such as the columnar suckers in Euprymna. The hectocotylian diversity allows to distinguish nine groups of species that do not match the current generic subdivision of Sepiolinae. Additional morphological characters (number of sucker rows on arms, female bursa copulatrix, occurrence and shape of visceral light organs, etc.) corroborate the subdivision of Sepiolinae into nine subtaxa, i.e., genera. Accordingly, a cladogram is drawn to describe the possible phylogenetic relationships among the nine clades. To comply with these results, all current genera are redefined and four new genera are described, namely Adinaefiola gen. nov., Boletzkyola gen. nov., Eumandya gen. nov. and Lusepiola gen. nov.

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Section: Dichotomous Identification Key To the Genera Of Sepiolinaementioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Evolution of the hectocotylus in Sepiolinae (Cephalopoda: Sepiolidae) and description of four new genera

Bello

2020

EJT

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“…The rapid divergence of genitalic structures in spiders is fascinating (Ramos et al ., 2005; Kuntner et al ., 2009; Azevedo, Griswold & Santos, 2018). Several commonly cited hypotheses could explain the evolution of spider genitalia: the classic non‐sexual selection ‘lock‐and‐key’ hypothesis, which suggests that the divergent evolution of genitalia has resulted from hybridization avoidance (Hosken & Stockley, 2004; Sloan and Simmons, 2019); sexual selection hypotheses, such as cryptic female choice that affects male paternity success (Eberhard, 1996; Eberhard, 2015; Eberhard & Lehmann, 2019), sperm competition (Eberhard, 2015; Eberhard & Lehmann, 2019) and sexual conflict that propel sexually antagonistic coevolution (Arnqvist & Rowe, 2002; McNamara et al ., 2019).…”

Section: Introductionmentioning

confidence: 99%

Intra‐specific variation of non‐genitalic and genitalic traits in two euophryine jumping spider species

Lai

Maddison

et al. 2020

Journal of Zoology

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Intra‐specific variation pattern is informative to understanding the evolution of morphological traits, but has been rarely studied in jumping spiders. Here we investigate the intra‐specific variation of non‐genitalic and genitalic traits in two euophryine jumping spider species that show considerable difference in sexual dimorphism: Chapoda recondita (Peckham & Peckham, 1896) and Antillattus cambridgei (Bryant, 1943). The results show the pre‐copulatory sexually selected traits (e.g. male chelicerae) tend to have positive intra‐specific allometry, and thus may have evolved under strong directional selection. The genitalic traits and some non‐genitalic traits tend to show negative allometries. Unlike non‐genitalic traits, the genitalic traits usually have high size‐corrected intra‐specific variation (CV’). Factors that may account for the negative allometry and high size‐corrected intra‐specific variation in genitalic traits are discussed. Pre‐ and post‐copulatory sexual selection may coexist in species and whether there is a trade‐off between these two selection mechanisms remains to be investigated.

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“…However, because male and female genitalia generally have a common developmental/genetic architecture (Ledón-Rettig et al 2017;Nomura et al 2019), what is the role played by development in biasing (co)evolution? Despite often coevolving, male and female genitalia may still exhibit strikingly divergent degrees of elaboration, rates of differentiation and diversity of associated developmental genes Azevedo et al 2018;Nomura et al 2019;Simmons and Fitzpatrick 2019). May these differences be explained by contrasting roles of development and function acting differentially on males and females?…”

mentioning

confidence: 99%

Copulatory function and development shape modular architecture of genitalia differently in males and females

et al. 2020

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Genitalia are multitasking structures whose development is mediated by numerous regulatory pathways. This multifactorial nature provides an avenue for multiple sources of selection. As a result, genitalia tend to evolve as modular systems comprising semi‐independent subsets of structures, yet the processes that give rise to those patterns are still poorly understood. Here, we ask what are the relative roles of development and function in shaping modular patterns of genitalia within populations and across species of stink‐bugs. We found that male genitalia are less integrated, more modular, and primarily shaped by functional demands. In contrast, females show higher integration, lower modularity, and a predominant role of developmental processes. Further, interactions among parts of each sex are more determinant to modularity than those between the sexes, and patterns of modularity are equivalent between and within species. Our results strongly indicate that genitalia have been subjected to sex‐specific selection, although male and female genitalia are homologous and functionally associated. Moreover, modular patterns are seemingly constant in the evolutionary history of stink‐bugs, suggesting a scenario of multivariate stabilizing selection within each sex. Our study demonstrates that interactions among genital parts of the same sex may be more fundamental to genital evolution than previously thought.

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To complicate or to simplify? Phylogenetic tests of complexity trends and genital evolution in ground spiders (Araneae: Dionycha: Gnaphosidae)

Cited by 7 publications

References 52 publications

Evolution of the hectocotylus in Sepiolinae (Cephalopoda: Sepiolidae) and description of four new genera

Evolution of the hectocotylus in Sepiolinae (Cephalopoda: Sepiolidae) and description of four new genera

Intra‐specific variation of non‐genitalic and genitalic traits in two euophryine jumping spider species

Copulatory function and development shape modular architecture of genitalia differently in males and females

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