BULLETIN FLORIDA STATE MUSEUM


of fruits, flowers, and insects in Central America, even in Moist and
Wet Forests, show marked seasonal fluctuations (Foster 1973, Smythe
1974, Frankie et al. 1974, Morrison 1978).
 Pollen and nectar on BCI are available to bats as reliable food
 sources only in the dry season, and only four species of flowering
 plants are known to be used by bats (Fig. 2). Two common species,
 Ochroma lagopus and Pseudobombax septenatum, flower from mid-
 December to mid-March. While these two species are in bloom, nectar
 and pollen are very abundant. The other two pollen types used by bats
 remain unidentified. One of these is known only from February to
 March and the other from August to September.
 Fruits from 45 plant species were eaten by bats on BCI (Fig. 2).
 These included 19 trees, 11 shrubs, 4 vines, 4 epiphytes, and 7 undeter-
 mined. Mature fruits were available to bats all year, but most species
 bearing fruits eaten by bats produced ripe fruits for periods of only one
 to four months. Only Ficus insipida, F. obtusifolia, and F. yoponensis,
 have ripe fruits available nine or more months per year. Individuals in
 the populations of these fig species fruit asynchronously one to four
 times per year. F. insipida and F. yoponensis populations show two
 major fruiting peaks and troughs each year (Morrison 1978). Ripe figs
 are scarce in March and again from late August until late November.
 The plant genera Cecropia, Spondias, Vismia, and Piper have two
 or more bat-dispersed species that set fruit in sequential time periods
 (Fig. 2). Ten species of pipers are eaten by bats on BCI. Though none of
 these species is available for more than a few months, two or more
 species have ripe fruit at any one time through the year. Pipers also are
 important bat fruits in Costa Rica where several species fruit in se-
 quential series (Heithaus et al. 1974).
 During 1973 a maximum of 19 fruiting species was available from
mid-March to mid-April, and a minimum of 6 species was available in
November-December (Fig. 2). Two of the fruits available in November-
December, Ficus insipida and F. yoponensis, were relatively scarce,
but Spondias radlkoferi and S. mombin were very abundant.
 Biomass and numbers of nocturnal insects caught in light traps in
Barro Colorado forest over a 3-year period were reported by Smythe
(1974). Though these samples represent all nocturnal flying insects,
they provide a useful index of abundance and fluctuations of the poten-
tial food resources for insectivorous bats. Smythe's light trap collec-
tions showed that nocturnal insect biomass in the early wet season is
as much as eight times that at the end of the wet season and during the
dry season (Fig. 3). Large insects (> 5 mm length) were responsible for
this seasonal change in biomass, with Isoptera, Diptera, and
Lepidoptera among the orders eaten by bats that have particularly


Vol. 24, No. 4