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Abstract Many organisms actively manipulate the environment in ways that feed back on their own development, a process referred to as developmental niche construction. Yet, the role that constructed biotic and abiotic environments play in shaping phenotypic variation and its evolution is insufficiently understood. Here, we assess whether environmental modifications made by developing dung beetles impact the environment‐sensitive expression of secondary sexual traits. Gazelle dung beetles both physically modify their ontogenetic environment and structure their biotic interactions through the vertical inheritance of microbial symbionts. By experimentally eliminating (i) physical environmental modifications and (ii) the vertical inheritance of microbes, we assess the degree to which (sym)biotic and physical environmental modifications shape the exaggeration of several traits varying in their degree and direction of sexual dimorphism. We expected the experimental reduction of a larva's ability to shape its environment to affect trait size and scaling, especially for traits that are sexually dimorphic and environmentally plastic. We find that compromised developmental niche construction indeed shapes sexual dimorphism in overall body size and the absolute sizes of male‐limited exaggerated head horns, the strongly sexually dimorphic fore tibia length and width, as well as the weakly dimorphic elytron length and width. This suggests that environmental modifications affect sex‐specific phenotypic variation in functional traits. However, most of these effects can be attributed to nutrition‐dependent plasticity in size and non‐isometric trait scaling rather than body‐size‐independent effects on the developmental regulation of trait size. Our findings suggest that the reciprocal relationship between developing organisms, their symbionts, and their environment can have considerable impacts on sexual dimorphism and functional morphology.
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Size and sex in early developmental stages in a frog‐biting mosquito
Abstract Sexual size variation in adult holometabolous insects may arise from selective pressures impacting ontogenetic stages associated with diverse habitats and resource use. In addition, scaling relations of these sexually dimorphic traits play an important role in morphological diversification. In mosquitoes, given the sexual differences in feeding strategies, investigations of the ontogeny of sexually dimorphic traits are of particular interest to understanding their reproductive biology and implementing early sex‐separating technologies for vector control. However, our current knowledge of the morphological scaling of body parts over development across sexes is centered around a few well‐known species of anthropophilic mosquitoes. In general, there is a noticeable gap in our understanding of the developmental biology of mosquitoes with limited medical consequences. One such mosquito isUranotaenia lowii(Diptera: Culicidae), a species of growing interest due to its unique host use of feeding exclusively on frogs by eavesdropping on their mating calls. This study takes a step forward toward filling this gap by investigating sexual size dimorphism during the ontogeny ofUr. lowii. We examined larval and pupal stages to focus on traits that allow sex identification to evaluate various sex‐sorting techniques that provide a foundation for experimental manipulation. We found that sex identification inUr. lowiiis possible during both larval and pupal stages. In the fourth larval instar, thorax length, abdomen length, and total body length differ significantly between the sexes, showing allometric scaling. In the pupal stage, the allometry of the head and thorax to body size remains consistent, as these parts fuse into the cephalothorax. Successful sorting based on cephalothorax length enables highly accurate pupal sex identification. This research sheds light on the biology ofUr. lowii,an understudied mosquito species, and lays the foundation for future studies on the developmental and reproductive biology of frog‐biting mosquitoes.
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- Award ID(s):
- 2054636
- PAR ID:
- 10578259
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Entomologia Experimentalis et Applicata
- Volume:
- 173
- Issue:
- 5
- ISSN:
- 0013-8703
- Format(s):
- Medium: X Size: p. 425-434
- Size(s):
- p. 425-434
- Sponsoring Org:
- National Science Foundation
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