A Life Cycle in the Rainforest

Dendrobates auratus - Canon 5D markII + 180 f3.5L 

Organisms adapt to the environment as a result of selective pressures. Here the phrase, selective pressure, refers to the sum of ecological factors that influence the survival of an individual. These individuals exist within a finite niche. Ecologically, a niche includes an organism’s conspecifics (members of the same species), competitors, predators, mates, food, space, and so on. These factors define the “n-dimensional space (niche)” of the organism and influences the way a population adapts and evolves through time. 

Green and Black Poison Dart Frog - Canon 5D markII + 180 f3.5L 

The green and black poison dart frog, Dendrobates auratus, is uniquely adapted to its rainforest habitat. Skin secretions contain a potent venom, pumiliotoxin-C, which cause unsuspecting predators to regurgitate the distasteful meal. Rather than wearing a cryptic camouflage, this frog announces its presence with bodacious color. Like the monarch butterfly whose bright orange and black patterns are impossible to ignore, the neon green frog with black stripes hops unencumbered throughout the forest understory. Ubiquitous within the leaf litter, once you find your first green and black frog, you begin to see them everywhere. 

How can this be?

Montane Forest - Canon 40D + 300 f2.8IS

Unlike most frog species, this frog is diurnal. Ever present during the daylight hours, the bright colors are a key adaptation. Known in evolutionary biology as aposematic coloration, high visibility acts as a warning. The neon green yells, “Don’t mess with me ...I’m poisonous!” Yet, the eggs and tadpoles of this species are quite tasty. Given the opportunity, fish, turtles, snakes and birds will snack on the protein-rich larvae and thus reduce the overall fitness of egg-laying adults. Unlike their parents, the pre-frog progeny lack the poisonous trademark of mom and dad. In biology, Biological success is defined by fertility, and those who have babies that have babies are considered to be evolutionarily fit.

What is the poison dart frog to do about its tasty eggs?

Flowering Bromeliad - Canon 7D + 300 f2.8IS

In a world where role-reversal is rare, the male poison dart frog bucks the trend. Male frogs call out to females and induce the ladies to lay a tiny clutch of eggs in an ephemeral pool of water. With each new day, there is a new female and new eggs. The male tends to each clutch waiting for the tadpoles to emerge. As eggs hatch, the tadpoles climb onto the back of their father where they will hitch a ride. One by one the male ascends a tree and transports the froglets to a place where no fish, turtle, or bird will hunt. He seeks a pool of water within the leaves of a bromeliad. These epiphytic relatives of the pineapple attach to branches of trees and are repositories of the daily precipitation. It is here that the tadpoles emerge and feed, hidden from the eyes of hungry predators.

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