Skip to main content

Animal Pollination in the Tropics: Hummingbirds to Hawkmoths

Inside a tropical rainforest, there's not a lot of wind, apart from high up in the canopy, and plant species tend to be very rare and quite far away from each other. Therefore wind pollination is not an effective means of plant reproduction. The preferred method is animal pollination, and many fascinating processes have evolved both in the pollinizer (the plant) and pollinator (the animal).

It's a coevolutionary process - both plants and pollinators become specialized to attract each other. Tropical plants have evolved flowers that entice their preferred pollinator - be it hummingbird, insect, or bat - so that the pollinator will hopefully carry the plant's genes, via the pollen, to another plant of the same species. Sometimes it entices by rewards like nectar - making it a mutualistic relationship - sometimes by trickery,* but it will match its characteristics to the characteristics of a specific pollinator and discourage all other pollinators. At the same time, the pollinators have evolved traits - like a long beak or a long tongue - to better pollinate certain flowers.

photo by Danny Perez
For instance, hummingbird-flowers are usually bright red or orange (hummingbirds have excellent eyesight), non-odorous (they don't have a good sense of smell), and tubular. They produce nectar that is high in sugar but low in nutrients, supplying the highly-active hummingbird with a source of energy. (It's not the hummingbird's primary food source though - that would be insects.) The tubular flowers and the hummingbird's long, thin beak are a perfect match and because the flowers don't have a landing platform, the hummingbird must hover to feed. These characteristics discourage other would-be pollinators.

hummingbird hawkmoth - photo by Sue Snowdon

On the flip side of this we have the hawkmoth - the nighttime version of the hummingbird - who is also capable of hovering. Flowers pollinated by hawkmoths are also tubular - to accommodate the hawkmoth's long tongue - and do not provide a firm place to land. These jasmine-scented flowers bloom at night and are white, making them easier for the hawkmoth to see and smell in the dark. (Not sure what kind of flower the hawkmoth is pollinating above.)

Then we have the bees and the butterflies...

photo by Danny Perez

Bee-flowers are typically yellow, blue, or ultraviolet (colors they can see) and sweet-scented (which they can smell).

Bosque del Cabo, Costa Rica

Butterfly-flowers are usually brightly colored and odorless - butterflies have good vision but a weak sense of smell.

So we have the birds, bees, butterflies, and moths, but it's the bats - very important rainforest pollinators - that will get their own post... "Chiropterophily: Bat Pollination"



* There's a species of orchid that tricks male tachinid flies into believing it is a tachinid female so that when the male fly copulates with the "female," he is actually just pollinating the orchid.

Note: Though the text is about pollination in the tropics, the only photo actually taken in the tropics was my butterfly pic - but the others are oh so beautiful.

Comments

Popular posts from this blog

Chiropterophily: Bat Pollination

I see you! Geoffroy's tailless bat (Anoura Geoffroyi) - photo by Nathan Muchhala Ever since coming across this word, I can't stop saying it: chiropterophily. Chiropterophily, or pollination of plants by bats, is very common in the tropics. Hundreds of tropical plant species are exclusively or at least partly pollinated by nectar-feeding bats. Many tropical flowers are night-blooming, specializing in attracting bats. Bat-flowers are typically white, cream, or pale green in color, making them easier to see in the dark. They usually have a musky, fermented odor - like that of the bat - or sometimes a fruity odor. They have a large, sturdy, open shape with long, bushy anthers so that the bat's head and chest get coated in pollen when it visits. In return for the bat pollinating the flower, the flower provides the nectar that these high-energy flying mammals need.* Tube-lipped nectar bat (Anoura fistulata) - photo by Nathan Muchhala Nectivorous bats have both good eyesight an

Eyeshine in Nocturnal Animals

Peters' Epauletted Fruit Bat (Epomophorus crypturus), Kruger National Park - photo by Peet van Schalkwyk Have you ever noticed how under certain lighting conditions some animal's eyes seem to glow? Animals that are nocturnal hunters - and a few of them that are not - have something called eyeshine . Eyeshine is the light that we see reflected back from the animal's tapetum lucidum (a membrane behind the animal's retina). Light enters the eye, passes through the retina, strikes the reflective membrane, and is reflected back through the eye toward the light source. This phenomenon makes the most of what little light there is at night for these nocturnal creatures. a moth with pink eyeshine Humans can display the red-eye effect in flash photography, but we do not have a tapetum lucidum , and thus, do not have eyeshine. Eyeshine is best observed by wearing a head lamp or holding a flashlight at eye level against your temple because the light is reflected right back into

Bats of Bosque del Cabo

Our first night here we saw bats (not sure of the species) flying around at dusk right outside the back of our bungalow, lots of them! And they would fly very near us! What an experience! bats outside Lapa at dusk * * * Some nighttime views from our bungalow's observation deck... Off to bed... * * * At dawn, you could sit out on the observation deck and observe the bats finding their way back home. What an early morning treat! bats outside Lapa at dawn * * * Bosque del Cabo has (that I currently know of): White-Lined Sac-Winged Bats  ( Saccopteryx bilineata / leptura ) in a cave on the Pacific beach (which I learned after our trip) Spix's Disk-Winged Bats  ( Thyroptera tricolor ) - observed in rolled heliconia leaves Jamaican Fruit-Eating Bats  ( Artibeus jamaicensis ) - observed pollinating the Guapinol or Stinky Toe Tree Tent-Making Bats  ( Uroderma bilobatum )  - note: several bat species roost under leaf tents, including the Caribbean or Honduran White