Noncompetitive mechanisms responsible for niche restriction and segregation - Nonequilibrium Ecology - page 87

Figure 5.4. Length of genitalia of two rhinoceros beetles, Chalcosoma caucasus and
C. atlas in allopatric and sympatric locations. Boxes show 5% reliable range of mean
of each population, vertical lines showmaximum and minimum values. Note that the
differences between the two species in the sympatric locations are much greater than
those for body size illustrated in Figure 5.3 , suggesting that reproductive segregation
may be the primary factor responsible for the differences. From Kawano ( 2002 ).
Reprinted by permission of the author and the University of Chicago Press.
niche restriction these explanations are the need to specialize and to
enhance mating encounters, and for niche segregation they are random
selection of niches in largely empty niche space and reinforcement of
reproductive barriers.