Print PageIn this comparative synthesis, we explore a large group of datasets,
providing information on demographic and life-history traits of eight
species of cavity-dwelling ants of the temperate forest. Colony size is a
very important trait of insect societies analogous to body size in
solitary animals. We study here how various life-history traits interact
with colony size. The analyses of ten datasets enables us to reach generalizations,
and but also reveals species-specific characteristics. We discuss our
findings in an ecological context and compare them to patterns evident in
other species of ants. The advantages of large colony size in social insects
and of large body in solitary animals are well known. However,
the factors restricting body and colony size are less well
studied and understood. This question is especially relevant for the small
colonies of cavity-dwelling ants, which contain only 30-50 workers on average, but which can live
up to 20 years. Our study is of interest, beyond the field of social insects, because
we can show which mechanisms determine small size. In
addition, we put our expectations and findings in a broad context by
comparing them to data on solitary organisms.
Results/Conclusions
In brief, we show that (1) cavity-dwelling ants have a size distribution
of colonies typical for organisms with a low survival rate; (2) worker
production moderates in almost all species with colony size, ending the
colony growth; (3) colony size is positively correlated with social structure (number
of queens) and since these ants sometimes lose their queen when relocating
their nest, shortage of queens may limit colony size; (4) the efficiency
(i.e., per-capita productivity) decreases with colony size, and this is a
universal pattern in this group of ants. We also show that polydomy -
the occupation of more than one nest site by the colony - is a possible
way to overcome this decrease in efficiency with colony size. In addition,
we discuss also other traits, such as production of sexuals, which
correlate strongly with colony size.
