• Publications
  • Influence
The development and evolution of exaggerated morphologies in insects.
TLDR
It is argued that scaling relationships are best viewed as reaction norms, and that the evolution of exaggerated morphological traits results from genetic changes in the slope and/or shape of these scaling relationships.
The Evolution of Animal Weapons
TLDR
The potential for male competition to drive rapid divergence in weapon morphology remains one of the most exciting and understudied topics in sexual selection research today.
Alternative reproductive tactics and male-dimorphism in the horned beetle Onthophagus acuminatus (Coleoptera: Scarabaeidae)
  • D. Emlen
  • Biology
    Behavioral Ecology and Sociobiology
  • 20 November 1997
TLDR
Both overall body size and relative horn length significantly affected the outcome of fights over tunnel ownership, suggesting that alternative reproductive tactics may favor divergence in male horn morphology, with long horns favored in males large enough to guard tunnels, and hornlessness favored in smaller males that adopt the “sneaking” behavioral alternative.
Male horn dimorphism in the scarab beetle, Onthophagus taurus: do alternative reproductive tactics favour alternative phenotypes?
TLDR
Combined, the two alternative reproductive tactics used by male O. taurus appear to favour opposite horn phenotypes, which may explain the paucity of intermediate morphologies in natural populations of O. Taurus.
Costs and the Diversification of Exaggerated Animal Structures
TLDR
It is shown that costs of weapon production also may drive patterns of weapon evolution, a critical but overlooked role in sexual selection and has implications for understanding the evolution of animal morphology.
Environmental control of horn length dimorphism in the beetle Onthophagus acuminatus (Coleoptera: Scarabaeidae)
  • D. Emlen
  • Biology
    Proceedings of the Royal Society of London…
  • 23 May 1994
TLDR
Results from experiments designed to assess the relative importance of genetic and environmental factors as determinants of male horn morphology support recent theories on sexual selection which predict that male ornaments will evolve to be reliable indicators of male quality.
DIVERSITY IN THE WEAPONS OF SEXUAL SELECTION: HORN EVOLUTION IN THE BEETLE GENUS ONTHOPHAGUS (COLEOPTERA: SCARABAEIDAE)
TLDR
This work uses partial sequences from four nuclear and three mitochondrial genes to develop a phylogenetic hypothesis for a worldwide sample of 48 species from the dung beetle genus Onthophagus and characterize the evolutionary radiation of beetle horns.
Competition among body parts in the development and evolution of insect morphology.
  • H. Nijhout, D. Emlen
  • Biology
    Proceedings of the National Academy of Sciences…
  • 31 March 1998
TLDR
In the case of beetle horns, the tradeoff in size is manifest as a significant negative genetic correlation among the involved body parts and constitutes a developmental source of genetic constraint on the evolution of body form.
Size and shape: the developmental regulation of static allometry in insects
TLDR
Recent advances in the fields of growth regulation and endocrinology are reviewed and used to construct a developmental model of static allometry expression in insects that serves as the foundation for a research program that will result in a deeper understanding of the relationship between growth and form.
A Mechanism of Extreme Growth and Reliable Signaling in Sexually Selected Ornaments and Weapons
TLDR
A general mechanistic model for the evolution of exaggerated traits is presented, proposing that sensitivity to the insulin response pathway can explain variation among individuals and illustrating how enhanced sensitivity to insulin/IGF signaling in a growing ornament or weapon would cause heightened condition sensitivity and increased variability in expression among individuals.
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