BONACCORSO: A PANAMANIAN BAT COMMUNITY


TABLE 15.-WEIGHTS OF SLOW-FLYING HAWKING INSECTIVORES. COLUMN HEADINGS ARE
 DEFINED IN TABLE 1.

Bat species X S.D. N Wgt/wgt,,,
 Emballonuridae
S. leptura* 4.2 1
C. maximiliani* 5.2 1 -
S. bilineata males 7.7 0.56 11 1.47
S. bilineata females 8.7 0.70 3 -
P. kappleri* 11.2 2 1.46
 Vespertilionidae
R. tumida 4.2 2 -
M. nigricans 4.4 0.67 11 1.05
 Mormoopidae
P. saupurensis 16.5 1 -
P. parnellii 22.6 1.48 30 1.37
*Males and females are probably dimorphic in body weight.

 VERTICAL STRATIFICATION.-Pteronotus parnellii usually fly within
3 m of the ground (Table 16). Myotis nigricans and S. bilineata com-
monly fly in groundstory and subcanopy levels of the forest.
Peropteryx kappleri is a specialist on insects of the subcanopy (Brad-
bury and Vehrencamp 1976). This also is indicated by the capture of all
four BCI individuals in high nets, and numerous visual observations I
made in Belize.
 HABITAT SELECTION.-P. parnellii is the second most abundant
 species in the forest but is very rare over creeks (Fig. 4). The single
 specimen of P. suapurensis was captured in forest.
 Myotis nigricans was captured only at forest stations, whereas
Rhogeessa tumida was captured only at or near creeks. These two-
similar-sized species thus may differ in habitat requirements.
 Visual observations of Saccopteryx bilineata during its crepuscular
 foraging indicate that individuals repeatedly fly in circles around
 feeding territories in small clearings of the forest (e.g. treefalls) or over
 creeks. Frequently I have watched Saccopteryx chase intruding con-

 TABLE 16.-VERTICAL STRATIFICATION OF SLOW-FLYING HAWKING INSECTIVORE SPECIES.
 No. of bats captured at No. of bats captured at
 Bat species ground level, 1 to 3 m subcanopy levels, 3 to 12 m
 S. bilineata 7 4
 C. maximiliani 2 0
 P. kappleri 0 4
 R. tumida 1 0
 M. nigricans 3 3
 P. parnellii 74* 1
 *Highly significant by Chi Square Test (P < .01) with Yates Correction for Continuity (Sokal and Rohlf 1969).


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