Mandibular morphology,task specialization and bite mechanics in Pheidole ants (Hymenoptera: Formicidae) |
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Authors: | Cristian L. Klunk Marco A. Argenta Alexandre Casadei-Ferreira Evan P. Economo Marcio R. Pie |
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Affiliation: | 1.Graduate Program in Ecology and Conservation, Federal University of Paraná, Curitiba-PR, Brazil;2.Department of Civil Construction, Federal University of Paraná, Curitiba-PR, Brazil;3.Department of Zoology, Federal University of Paraná, Curitiba-PR, Brazil;4.Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Japan |
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Abstract: | Ants show remarkable ecological and evolutionary success due to their social life history and division of labour among colony members. In some lineages, the worker force became subdivided into morphologically distinct individuals (i.e. minor versus major workers), allowing for the differential performance of particular roles in the colony. However, the functional and ecological significance of these morphological differences are not well understood. Here, we applied finite element analysis (FEA) to explore the biomechanical differences between major and minor ant worker mandibles. Analyses were carried out on mandibles of two Pheidole species, a dimorphic ant genus. We tested whether major mandibles evolved to minimize stress when compared to minors using combinations of the apical tooth and masticatory margin bites under strike and pressure conditions. Majors performed better in pressure conditions yet, contrary to our expectations, minors performed better in strike bite scenarios. Moreover, we demonstrated that even small morphological differences in ant mandibles might lead to substantial differences in biomechanical responses to bite loading. These results also underscore the potential of FEA to uncover biomechanical consequences of morphological differences within and between ant workers. |
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Keywords: | cuticle division of labour finite element analysis mandible trulleum worker polymorphism |
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