The main focus of this thesis is the study of sensory systems in
the context
of changing body-size. In particular the study of ant sensory
systems and
how these are shaped by miniaturisation. The study of insect
visual
ecology and physiology is used as a basis to develop a framework
for the
study of ant antennal sensilla and chemosensation, to interpret
anatomical
variation from a functional and organ design perspective. This
thesis
reviews the anatomy and nomenclature of antennal sensilla through
two
case studies on an extremely large species Myrmecia pyriformis
and a
small species Temnothorax rugatulus. These two studies
additionally
quantify intraspecific variation and discuss the potential
functional
consequences of this variation for self-organising insect
societies and task
allocation. A large scale comparative study takes the tools
developed in
previous chapters to focus in on how chemosensilla vary in their
numbers,
size and distribution through the Fomicid phylogeny. The gross
anatomy of
the antenna and changes in shape from club to filiform antennae
are
described in detail. Anatomical data are analysed to identify
scaling trends
and potential adaptations driven by miniaturisation. Ecological
and
phylogenetic considerations are discussed wherever relevant. The
wide
ranging impacts of body size changes are reviewed, incorporated
into the
interpretation of results and used to propose promising avenues
for future
research. Finally, ant body size and some of the different
methods used in
the literature to measure size and size variability are
critically analysed.
The functional implications of body size variability within
species are
discussed using Iridomyrmex purpureus as an example.
This thesis makes use of a variety of microscopy techniques. In
addition to
the methods sections of each chapter a dedicated methods chapter
is
included. This chapter reviews some of the techniques used in the
main
data chapters and in the additional publications produced over
the course
of this thesis
