DOI: 10.5061/dryad.pg4f4qrw1
title: Vertically inherited microbiota and environment-modifying behaviors indirectly shape the exaggeration of secondary sexual traits in the gazelle dung beetle

description: Many organisms actively manipulate the environment in ways that have the
 potential to 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. Larval
 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 ontogenetic
 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.
description: <em>Digitonthophagus gazella</em> dung beetles were
 reared in 12-well plates and subjected to two different treatments (in a
 fully-factorial design). For half of all individuals, the transmission of
 maternal microbiota was disrupted by sterilization. This treatment was
 crossed with a manipulation of the degree to which larvae were able to
 modify their larval environment. Experimental animals were generated using
 a full-sib/half-sib design.
description: Data is deposited as an Excel file. 
description: # Vertically inherited microbiota and environment-modifying behaviors
 indirectly shape the exaggeration of secondary sexual traits in the
 gazelle dung beetle
 [https://doi.org/10.5061/dryad.pg4f4qrw1](https://doi.org/10.5061/dryad.pg4f4qrw1) Many organisms actively manipulate the environment in ways that have the potential to 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. Larval 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 ontogenetic 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. ### Description of the data and file structure The Excel file contains all measurements for each individual that survived to adulthood. All measurements are in millimeters. The following variables are included: | Variable | Description | | -------- | ----------- | | ID | unique identifier for each individual | | 12-well plate | identifier of the 12-well plate each individual was reared in | | microbiome transmission | microbiome transmission treatment (intact vs. disrupted) | | brood ball modification | brood ball modification treatment (intact vs. disrupted) | | sire ID | identifier of the male parent | | dam ID | identifier of the female parent | | sex | sex of individual (male or female) | | pronotum width | width of the pronotum in millimeters | | tibia length | length of the foretibia in millimeters | | elytron width | width of the elytron in millimeters | | elytron length | length of the elytron in millimeters | | tibial tooth height | height of the second tibial tooth in millimeters | | horn length (males only) | length of the male head horn in millimeters | ### Sharing/Access information Dryad is currently the only platform on which these data are accessible. Contact Patrick Rohner at prohner@ucsd.edu.