Small brains: body shape constrains tissue allocation to the central nervous system in ant-mimicking spiders

Michael B. J. Kelly*, Vanessa Penna-Gonçalves, Nikolas J. Willmott, Donald James McLean, Jay R. Black, Jonas O. Wolff, Marie E. Herberstein

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
7 Downloads (Pure)

Abstract

In Batesian mimicry, mimetic traits are not always as convincing as predicted by theory—in fact, inaccurate mimicry with only a superficial model resemblance is common and taxonomically widespread. The “selection trade-offs hypothesis” proposes a life-history trade-off between accurate mimetic traits and one or more vital biological functions. Here, using an accurate myrmecomorphic (ant-mimicking) jumping spider species, Myrmarachne smaragdina, we investigate how myrmecomorphic modifications to the body shape impact the internal anatomy in a way that could be functionally limiting. Specifically, via x-ray micro-computed tomography (microCT), we quantify how the spider's constricted prosoma, which emulates the head and thorax of ants, impacts the size of the central nervous system (CNS) and the venom glands. Although, relative to their whole-body mass, we found no significant difference in venom gland volume, the CNS of the ant-mimicking jumping spider was significantly smaller when compared with a relatively closely related non-mimic jumping spider, indicating that some trade-off between mimic accuracy and size of neural anatomy, as articulated by the “selection trade-offs hypothesis,” is a possibility. Our explorative evidence enables and encourages broader investigation of how variable mimic accuracy impacts the neuroanatomy in ant mimics as a direct test of the “selection trade-offs hypothesis.”.

Original languageEnglish
Article numbere25680
Pages (from-to)1-10
Number of pages10
JournalJournal of Comparative Neurology
Volume532
Issue number11
Early online date17 Nov 2024
DOIs
Publication statusPublished - Nov 2024

Bibliographical note

Copyright the Author(s) 2024. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • Araneae
  • central nervous system
  • microCT
  • mimicry
  • myrmecomorphy
  • RRID:NCBITaxon_74971
  • trade-off

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