Theme and Variation in the Development of Insect Mouthparts

Angelini, David R.; Smith, F. W.

doi:10.1007/978-3-030-29654-4_5

Cited by 2 publications

(2 citation statements)

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“…Based on the principles of insect morphology (Snodgrass, 1935, 1958) and contemporary evolutionary developmental theory for the mandibles (see the reviews of Angelini & Smith, 2019 and Prpic, 2019), we propose that the carinate tooth line is homologous with the incisor endite of the Mandibulata, with ant‐ and Hymenoptera‐specific patterning processes. We note also that although Xyelidae have a developed mola, this structure is indistinct in other Hymenoptera (Beutel & Vilhelmsen, 2007), including crown and stem ants (Barden & Grimaldi, 2014; Boudinot et al, 2020; Wilson et al, 1967a, 1967b); if it were present, the mola is of a derived and an as‐yet unrecognized form.…”

Section: Discussionmentioning

confidence: 99%

Anatomy and evolution of the head of Dorylus helvolus (Formicidae: Dorylinae): Patterns of sex‐ and caste‐limited traits in the sausagefly and the driver ant

Boudinot

Moosdorf

Beutel

et al. 2021

Journal of Morphology

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Ants are highly polyphenic Hymenoptera, with at least three distinct adult forms in the vast majority of species. Their sexual dimorphism, however, is overlooked to the point of being a nearly forgotten phenomenon. Using a multimodal approach, we interrogate the near total head microanatomy of the male of Dorylus helvolus, the “sausagefly,” and compare it with the conspecific or near‐conspecific female castes, the “driver ants.” We found that no specific features were shared uniquely between the workers and males to the exclusion of the queens, indicating independence of male and worker development; males and queens, however, uniquely shared several features. Certain previous generalizations about ant sexual dimorphism are confirmed, while we also discover discrete muscular presences and absences, for which reason we provide a coarse characterization of functional morphology. Based on the unexpected retention of a medial carinate line on the structurally simplified mandible of the male, we postulate a series of developmental processes to explain the patterning of ant mandibles. We invoke functional and anatomical principles to classify sensilla. Critically, we observe an inversion of the expected pattern of male‐queen mandible development: male Dorylus mandibles are extremely large while queen mandibles are poorly developed. To explain this, we posit that the reproductive‐limited mandible phenotype is canalized in Dorylus, thus partially decoupling the queen and worker castes. We discuss alternative hypotheses and provide further comparisons to understand mandibular evolution in army ants. Furthermore, we hypothesize that the expression of the falcate phenotype in the queen is coincidental, that is, a “spandrel,” and that the form of male mandibles is also generally coincidental across the ants. We conclude that the theory of ant development and evolution is incomplete without consideration of the male system, and we call for focused study of male anatomy and morphogenesis, and of trait limitation across all castes.

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Section: Discussionmentioning

confidence: 99%

Anatomy and evolution of the head of Dorylus helvolus (Formicidae: Dorylinae): Patterns of sex‐ and caste‐limited traits in the sausagefly and the driver ant

Boudinot

Moosdorf

Beutel

et al. 2021

Journal of Morphology

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“…As we compare developmental mechanisms in extant species, this bias results in patterns of conservation and divergence, at either the structural or functional levels, among GN components. These patterns suggest another analogy: the motifs of theme and variation seen in Western classical music (Angelini & Smith, 2019). Here we will explore the themes and variations in the evolution of insect sex determination.…”

Section: Introductionmentioning

confidence: 98%

Theme and variation in the evolution of insect sex determination

2022

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The development of dimorphic adult sexes is a critical process for most animals, one that is subject to intense selection. Work in vertebrate and insect model species has revealed that sex determination mechanisms vary widely among animal groups. However, this variation is not uniform, with a limited number of conserved factors. Therefore, sex determination offers an excellent context to consider themes and variations in gene network evolution. Here we review the literature describing sex determination in diverse insects. We have screened public genomic sequence databases for orthologs and duplicates of 25 genes involved in insect sex determination, identifying patterns of presence and absence. These genes and a 3.5 reference set of 43 others were used to infer phylogenies and compared to accepted organismal relationships to examine patterns of congruence and divergence. The function of candidate genes for roles in sex determination (virilizer, female‐lethal‐2‐d, transformer‐2) and sex chromosome dosage compensation (male specific lethal‐1, msl‐2, msl‐3) were tested using RNA interference in the milkweed bug, Oncopeltus fasciatus. None of these candidate genes exhibited conserved roles in these processes. Amidst this variation we wish to highlight the following themes for the evolution of sex determination: (1) Unique features within taxa influence network evolution. (2) Their position in the network influences a component's evolution. Our analyses also suggest an inverse association of protein sequence conservation with functional conservation.

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Theme and Variation in the Development of Insect Mouthparts

Cited by 2 publications

References 231 publications

Anatomy and evolution of the head of Dorylus helvolus (Formicidae: Dorylinae): Patterns of sex‐ and caste‐limited traits in the sausagefly and the driver ant

Anatomy and evolution of the head of Dorylus helvolus (Formicidae: Dorylinae): Patterns of sex‐ and caste‐limited traits in the sausagefly and the driver ant

Theme and variation in the evolution of insect sex determination

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