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ARS Home » Pacific West Area » Maricopa, Arizona » U.S. Arid Land Agricultural Research Center » Pest Management and Biocontrol Research » Research » Publications at this Location » Publication #304292
Title: Exaggerated trait growth in insects

Author
item LAVINE, LAURA - Washington State University
item GOTOH, HIROKI - Washington State University
item Brent, Colin
item DWORKIN, IAN - Michigan State University
item EMLEN, DOUGLAS - University Of Montana

Submitted to: Annual Review of Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2014
Publication Date: 1/7/2015
Citation: Lavine, L.C., Gotoh, H., Brent, C.S., Dworkin, I., Emlen, D. 2015. Exaggerated trait growth in insects. Annual Review of Entomology. 60:453-472.

Interpretive Summary: Animal structures occasionally attain extreme proportions, eclipsing in size other, surrounding body parts. We review insect examples of exaggerated traits, such as the mandibles of stag beetles, the claspers of praying mantises, the elongated hindlimbs of grasshoppers, and the giant heads of soldier ants and termites. Extreme trait proportions have evolved in the context of reproductive competition, prey capture, feeding specialization, escape locomotion, and, in social insects, a division of labor. Developmentally, disproportionate growth can arise through trait-specific modifications to the activity of pathways involved in sex determination, appendage development, metabolism, and regulatory hormones. Although most exaggerated traits have yet to be studied mechanistically, it is already apparent that distinct developmental mechanisms underlie the evolution of the different types of exaggerated trait. We suggest this reflects the nature of selection in each instance, revealing an exciting link between mechanism, form, and function. We use this information to make explicit predictions for the types of regulatory mechanisms likely to underlie each type of exaggerated trait.

Technical Abstract: Animal structures occasionally attain extreme proportions, eclipsing in size other, surrounding body parts. We review insect examples of exaggerated traits, such as the mandibles of stag beetles, the claspers of praying mantises, the elongated hindlimbs of grasshoppers, and the giant heads of soldier ants and termites. Animal structures occasionally attain extreme proportions, eclipsing in size the surrounding body parts. We review insect examples of exaggerated traits, such as the mandibles of stag beetles (Lucanidae), the claspers of prayingmantids (Mantidae), the elongated hindlimbs of grasshoppers (Orthoptera:Caelifera), and the giant heads of soldier ants (Formicidae) and termites (Isoptera). Developmentally, disproportionate growth can arise through trait-specific modifications to the activity of at least four pathways: the sex determination pathway, the appendage patterning pathway, the insulin/IGF signaling pathway, and the juvenile hormone/ecdysteroid pathway.Although most exaggerated traits have not been studied mechanistically, it is already apparent that distinct developmental mechanisms underlie the evolution of the different types of exaggerated traits. We suggest this reflects the nature of selection in each instance, revealing an exciting link between mechanism, form, and function. We use this information to make explicit predictions for the types of regulatory pathways likely to underlie each type of exaggerated trait.