reportedly emit a musky “bat- like” odor. These flowers
open at night, when bats are active. Flowers may be
shaped like a deep vase or may be flat and brushy, so as to
load the bat’s face with pollen as it laps up nectar. Many
bat flowers are cauliflorous, growing directly from tree
trunks and branches. Some flowers are flagelliflorous,
hanging from long, whip- like branches, while others
are penduliflorous, hanging downward as streamers,
a condition common in many vines. Cauliflory,
flagelliflory, and penduliflory all have in common the
fact that the flowers are positioned in such a manner
that they are easily accessible to hovering bats.
Nectar- feeding bats typically have large eyes and
relatively strong vision, in contrast with insectivorous
bats. The sonar sense upon which insectivorous bats
depend is often reduced in nectarivorous bats, but the
olfactory sense is well developed. Nectarivorous bats
have long muzzles and weak teeth, both advantageous
in probing deeply into flowers. Finally, they have long
tongues covered with fleshy bristles that can extend
well into the flower, and in some cases their neck hairs
project forward, acting as a pollen scoop.
The pollen from bat- pollinated plants is significantly
higher in protein than that in non- bat- pollinated
plants, and bats ingest pollen as well as sugary nectar.
Pollen contains the amino acids proline and tyrosine,
useless to the plant but important to the bats. Proline
is used in making connective tissue, such as is used in
wing and tail membranes, and tyrosine is essential for
milk production.
Once ingested, nectar helps dissolve the tough pollen
coat, but bats aid this process, as their stomachs secrete
extraordinarily large amounts of hydrochloric acid.
Pollinating bats also sometimes drink their own urine,
which helps dissolve the pollen, liberating essential
proteins.
The example of chiropterophily shows that
coevolution may involve whole complexes of species,
not merely two species evolving together, and that
anatomical characteristics may be obvious, but
behavioral and physiological characteristics are also
part of the coevolutionary process.Ant Farmers: The Leaf- cutter Ants
(Also Known as the Fungus Garden
Ants— and for Good Mutualistic
Reasons)Ants are abundant and ubiquitous inhabitants of the
global tropics, and many ant species have evolved
coevolutionary relationships with plants. One group,
the attine ants (tribe Attini), has done so with fungus,Pollination of the Victoria Water- lily
The huge Victoria (or Royal) Water- lily (Victoria amazonica;
plate 10- 33) is found in quiet backwaters of Amazonian
tributaries. Ghillean Prance has documented the
amazing pollination, by beetles, of this striking plant
species. Opening in synchrony, the large, conspicuous
white flowers emit a strong odor, and are warm, up to
11° C (20° F) warmer than ambient temperature. These
characteristics combine to attract beetles (Cyclocephala
spp.), which enter the flower, only to become trapped
inside at night, when the large petals tightly close.
The imprisoned beetles feed on nectar- rich structures
throughout the night, getting thoroughly sticky as they
become covered with pollen. The next day the flowers
open, having changed petal color from white to red, as
well as lost their scent and cooled in temperature, all of
which means they are no longer an attractant to beetles.
The formerly incarcerated pollen- bearing beetles leave the
flower and fly off to seek out another white flower from
another Victoria Water- lily, where they will inadvertently
deposit pollen as they feed.Plate 10- 33. Victoria Water- lily with flower, awaiting a beetle
to pollinate it. Photo by John Kricher.174 chapter 10 tropical intimacy: mutualism and coevolution