Eating Dessert
First:
How Nectar-Eaters Get Their Protein
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| Lesser Long-nosed
Bat at a Saguaro Cactus. Photo Copyright by Merlin D. Tuttle |
Nectar is loaded with sugar--a carbohydrate that provides a lot of energy. But bats cannot live on sugar alone. Nor can you! We all need other nutrients, especially protein. Most of a bat's, and our own, body tissues are made of protein, and so without protein we can't grow. And nursing mothers, be they bats or humans, need lots of protein to produce milk. It has been estimated that the average adult mammal requires 10% protein in the diet; young and growing mammals require 20%.
Nectar-feeding bats get their protein from pollen. The plants upon which these bats depend have on average 15%-30% pollen -- plenty for even the growing youngsters.
Interestingly, when scientists compared plants upon which bats fed and closely related plants that bats did NOT visit, there was a significant difference in sugar and protein content. The bat- visited plants had much more of each. In contrast, hummingbird plants also have high sugar content but not protein. Hummingbirds get their protein from insects, not pollen.
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These
four bats have pollen on their faces. Photo
Copyright by Merlin D. Tuttle
|
After a bat has visited a flower, it is so covered with pollen that
it looks yellow in color, not its natural brown color, because of the
dense covering of yellow pollen. The bat will stop foraging for anywhere
from several minutes to several hours to lick off the pollen and to rest.
Over the eons, the lives of flowers and their pollinators have evolved together.
Compare these lists of their characteristics and note the similarities.
Characteristics of bat-pollinated plants include:
- Pollen and nectar produced at night
- Strong musty odor
- Large and conspicuous flowers
- Dull color, often whitish
- Flower tubular with anthers protruding or brush-like
Characteristics of nectar-feeding bats include:
- Nocturnal foraging
- Good sense of smell
- Large eyes for orienting
- Probably color blind
- Approach flower from air
- Large body size compared to other pollinators like bees and butterflies
- Elongate snout
- Protusible tongue for probing deep into flowers
- Hairs in neck region rough-textured so as to pick up pollen
Not only do Leptos and other nectar-feeding bats pollinate saguaros, but they also pollinate other culturally important plants such as bananas, avocados, agaves (from which tequila is made), dates, figs, mangoes, and peaches. The wild plants are used for improving the cultivated stock. The fruits of the columnar cacti (such as the giant saguaro seen many cowboy movies) are an important food item for Native Americans.
Try This! Journaling Questions
Think of the ways that bat-pollinated plants are adapted
for bats. Think about these:
- How might their odor help attract bats?
- Why might the flowers be white?
- How might the shape of the flowers help the flowers?
Now think of the ways bats are adapted to find and feed from bat-pollinated plants.
- Why might their noses be long?
- Why might the tongues be so long?
- How do their long neck hairs help the bats? How do they help the
saguaros?
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