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Overcoming mechanical adversity in extreme hindleg weapons

The size of sexually selected weapons and their performance in battle are both critical to reproductive success, yet these traits are often in opposition. Bigger weapons make better signals. However, due to the mechanical properties of weapons as lever systems, increases in size may inhibit other me...

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Autores principales: O’Brien, Devin M., Boisseau, Romain P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6221328/
https://www.ncbi.nlm.nih.gov/pubmed/30403752
http://dx.doi.org/10.1371/journal.pone.0206997
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author O’Brien, Devin M.
Boisseau, Romain P.
author_facet O’Brien, Devin M.
Boisseau, Romain P.
author_sort O’Brien, Devin M.
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description The size of sexually selected weapons and their performance in battle are both critical to reproductive success, yet these traits are often in opposition. Bigger weapons make better signals. However, due to the mechanical properties of weapons as lever systems, increases in size may inhibit other metrics of performance as different components of the weapon grow out of proportion with one another. Here, using direct force measurements, we investigated the relationship between weapon size and weapon force production in two hindleg weapon systems, frog-legged beetles (Sagra femorata) and leaf-footed cactus bugs (Narnia femorata), to test for performance tradeoffs associated with increased weapon size. In male frog-legged beetles, relative force production decreased as weapon size increased. Yet, absolute force production was maintained across weapon sizes. Surprisingly, mechanical advantage was constant across weapon sizes and large weaponed males had disproportionately large leg muscles. In male leaf-footed cactus bugs, on the other hand, there was no relationship between weapon size and force production, likely reflecting the importance of their hindlegs as signals rather than force-producing structures of male-male competition. Overall, our results suggest that when weapon force production is important for reproductive success, large weaponed animals may overcome mechanical challenges by maintaining proportional lever components and investing in (potentially costly) compensatory mechanisms.
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spelling pubmed-62213282018-11-19 Overcoming mechanical adversity in extreme hindleg weapons O’Brien, Devin M. Boisseau, Romain P. PLoS One Research Article The size of sexually selected weapons and their performance in battle are both critical to reproductive success, yet these traits are often in opposition. Bigger weapons make better signals. However, due to the mechanical properties of weapons as lever systems, increases in size may inhibit other metrics of performance as different components of the weapon grow out of proportion with one another. Here, using direct force measurements, we investigated the relationship between weapon size and weapon force production in two hindleg weapon systems, frog-legged beetles (Sagra femorata) and leaf-footed cactus bugs (Narnia femorata), to test for performance tradeoffs associated with increased weapon size. In male frog-legged beetles, relative force production decreased as weapon size increased. Yet, absolute force production was maintained across weapon sizes. Surprisingly, mechanical advantage was constant across weapon sizes and large weaponed males had disproportionately large leg muscles. In male leaf-footed cactus bugs, on the other hand, there was no relationship between weapon size and force production, likely reflecting the importance of their hindlegs as signals rather than force-producing structures of male-male competition. Overall, our results suggest that when weapon force production is important for reproductive success, large weaponed animals may overcome mechanical challenges by maintaining proportional lever components and investing in (potentially costly) compensatory mechanisms. Public Library of Science 2018-11-07 /pmc/articles/PMC6221328/ /pubmed/30403752 http://dx.doi.org/10.1371/journal.pone.0206997 Text en © 2018 O’Brien, Boisseau http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
O’Brien, Devin M.
Boisseau, Romain P.
Overcoming mechanical adversity in extreme hindleg weapons
title Overcoming mechanical adversity in extreme hindleg weapons
title_full Overcoming mechanical adversity in extreme hindleg weapons
title_fullStr Overcoming mechanical adversity in extreme hindleg weapons
title_full_unstemmed Overcoming mechanical adversity in extreme hindleg weapons
title_short Overcoming mechanical adversity in extreme hindleg weapons
title_sort overcoming mechanical adversity in extreme hindleg weapons
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6221328/
https://www.ncbi.nlm.nih.gov/pubmed/30403752
http://dx.doi.org/10.1371/journal.pone.0206997
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