BONACCORSO: A PANAMANIAN BAT COMMUNITY


digest and excrete the fruit, usually before flying away from the roost
to forage for other fruits; thus little chance would exist for this pulp to
show up in netted animals. The Carollia colonies in the Anacardium
trees observed consist of 6 to 8 individuals, and each colony probably
had access to more A. excelsum fruits than they could eat.
 Anacardium excelsum is the only fruit eaten by bats on BCI that is
not effectively dispersed by them (Dipteryx panamensis though not
dispersed by Artibeus jamicensis is dispersed by A. lituratus.). In the
colonies I observed that Anacardium fruits are carried within the
hollow tree roosts, but even if they are eaten elsewhere, it is the single
large seed, and not the fruit pulp, that is eaten.
 There are significant seasonal changes in diet and niche breadths of
both species of Carollia (Table 9). These bats are extreme fruit
generalists in the first half of the wet season. In the dry season and lat-
ter half of the wet season, niche breadths are narrower. C. castanea
feeds almost entirely on pipers during the dry season, but in much of
the wet season Markea panamensis, a tree, is an important dietary
item. Throughout the year pipers constitute 30 to 40 percent of the
food items eaten by C. perspicillata with various trees sequentially
becoming important food sources. Most important are Dipteryx,
Anacardium, and Quararibea in the dry, early wet, and late wet
seasons respectively. Also in the early wet season insects are impor-
tant in the diet of C. perspicillata.
 Overlap between the diets of the two Carollia is moderate in terms
of food species. A CX value of 0.585 is obtained from lumping the
dietary data from the year's fecal samples. Food overlap was highest
in the May-July sampling, CX is 0.798. This latter value and the annual
value of overlap would be somewhat smaller if it were possible to cor-
rect for Anacardium eaten in roost trees by C. perspicillata. Even
though roosts were not monitored, it is unlikely that C. castanea eats
much of this fruit, as it is larger than all other important fruits in the
diet of C. castanea and probably too large for efficient handling.
 HABITAT SELECTION.-Of the three habitats sampled, the Carol-
 linae were most common in the second growth forest and least com-
 mon in the mature forest, as are their most important food plants. C.
 castanea accounted for 21.7% of all bats captured in second growth
 young forest, 2.7% of the bats in creeks, and 1.4% of the bats in
 mature forest (Fig. 4). C. perspicillata constituted 15.8%, 16.0%, and
 5.4% of the individuals captured in those habitats. Whereas many
 species of pipers grew abundantly in the sunlight of the open canopy
 second growth and along the creeks (though less so along creeks), only
 one species, P. cordulatum, was abundant in the shade of the mature
 forest.