Abstract
Throughout the animal kingdom, Haller's rule holds that smaller individuals have larger brains relative to their body than larger-bodied individuals. Such brain-body size allometry is documented for all animals studied to date, ranging from small ants to the largest mammals. However, through experimental induction of natural variation in body size, and 3-D reconstruction of brain and body volume, we here show an isometric brain-body size relationship in adults of one of the smallest insect species on Earth, the parasitic wasp Trichogramma evanescens. The relative brain volume constitutes on average 8.2% of the total body volume. Brain-body size isometry may be typical for the smallest species with a rich behavioural and cognitive repertoire: a further increase in expensive brain tissue relative to body size would be too costly in terms of energy expenditure. This novel brain scaling strategy suggests a hitherto unknown flexibility in neuronal architecture and brain modularity.
Original language | English |
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Pages (from-to) | 86-92 |
Journal | Brain, behavior and evolution |
Volume | 81 |
Issue number | 2 |
DOIs | |
Publication status | Published - 2013 |
Keywords
- trichogramma-brassicae
- cotesia-glomerata
- miniaturization
- allometry
- insects
- evolution
- parthenogenesis
- coleoptera
- ptiliidae
- rubecula