BONACCORSO: A PANAMANIAN BAT COMMUNITY


from a net. The Vampyrum was apparently attracted by the alarm
calls of the fruit bat and circled for over a minute before leaving.
 MIMON. Fecal samples of Mimon crenulatum from BCI contained
insect, arachnid, and lizard remains.
 TRACHOPS. Fecal samples of Trachops cirrhosus from BCI contained
insect, whipscorpion, and lizard remains and fruit pulp. Elsewhere this
species is reported to eat lizards, such as anoles and geckos, that are
gleaned from vegetation, as well as fruit and insects (Gardner 1977,
Howell and Burch 1974).
 VERTICAL STRATIFICATION. -Mimon crenulatum, Trachops cir-
rhosus, and Tonatia sylvicola show a significant preference for flight in
the groundstory level of the forest, and the small samples for
Micronycteris brachyotis and Tonatia bidens are just below
significance levels for showing a subcanopy-canopy preference (Table
14). Thus the two similarly sized Tonatia species appear to forage in
different vertical strata.
 Phyllostomus hastatus and Vampyrum spectrum were captured or
 seen flying only in the subcanopy-canopy levels of the forest. The
 groundstory (0 to 3 m) on BCI has the densest foliage of the vertical
 strata of the forest (E. Leigh, pers. comm.). P. hastatus and V. spec-
 trum may be too large to maneuver well through the thick groundstory
 vegetation.
 HABITAT SELECTION.-Several of the gleaning carnivores prefer
 either creek or forest habitats on BCI to the exclusion or near exclu-
 sion of the other. Micronycteris brachyotis and Tonatia sylvicola are
 both common in the forest but are totally absent from the creek
 samples (Fig. 4). Trachops cirrhosus represents 4 percent of all in-
 dividuals sampled at creek stations (8th most abundant species in

 TABLE 14.-VERTICAL STRATIFICATION OF GLEANING CARNIVORES. YATES CORRECTION
 FOR CONTINUITY IS USED ON ALL CHI SQUARE TESTS (SOKAL AND ROHLF
 1969).
 No. of bats captured at No. of bats captured at
 Bat species ground level, 1 to 3 m subcanopy level, 3 to 12 m
 M. megalotis 1 3
 M. brachyotis 6 12
 M. hirsuta 6 3
 M. crenulatum 9* 1
 T. cirrhosus 14** 0
 T. sylvicola 18** 3
 T. bidens 2 8
 P. hastatus 0 4
 V. spectrum + 0 3
 *Significant by Chi Square Test (P < .05).
 **Highly significant by Chi Square Test (p < .01).
 + Based on two net captures in Costa Rica and one visual sighting on BCI.


1979