In the eye of the tadpole


Tadpole responses to environments with limited visibility: what we (don’t) know and perspectives for a sharper future

Access our peer-reviewed Perspective article here.

Throughout my encounters with different languages I have always been fascinated by words that cannot easily be translated. Some words hold a certain weight, cultural insinuation, or biological inference that isn’t fully described when translated on a word-to-word basis. For me, as a young French girl, my family would describe me as “gourmande” which is essentially a lover of delicacies in large quantities. Not so easy to translate into English without the misinterpretation of being a glutton. . .

Anyway. One of my favourite untranslatable words is umwelt, which from German is directly translated into “environment” in English, but is more profound at its core. In high school I learned this was the word used to describe the world perceived (or experienced) by a particular organism. For example, I might mistakenly design a task where I ask an animal to differentiate between two colors that they are biologically unable to distinguish (like red and purple for dogs) or I may not consider colors that are vital for the animal’s perception (like UV in birds and bees), and from there draw false conclusions. Being misled in this way stems from not considering an organism’s umwelt which has limited our understanding of aggression, cooperation, and intelligence throughout the animal kingdom.

The various nurseries where tadpoles are deposited to develop. Water samples in the top panel corresponds to the pool where they were sampled in the bottom panel.

But, we’re doing a bit better now. And that’s what this Perspective article is all about– briefly, (to get you up to speed on the system set up) various tadpoles from different species are deposited in a large range of aquatic nurseries. From size to water color and pool turbidity, it seems pretty intuitive that these vastly different rearing environments would have different implications for the larvae developing within them. What happens to tadpole eyeballs when they grow up in the dark? How does growing up in the dark affect behaviour (i.e., scavenging, predation, sociality)? Does that carry over across metamorphosis?

From a proximate perspective could the eye actually change? Is there even a precedence for this? (yes, there is. . . think along the lines of Vitamin A ratio shifts recorded in fishes 😉 ) From a behavioural perspective, what happens to predatory tadpoles (e.g. Dendrobates tinctorius) when their visual landscape breaks down; what about the tadpoles that depend on visual cues from their parents for feeding (e.g. oophagy by Oophaga pumilio)?

What happens, indeed! I have no clue. But look at this big ol’ gaping hole ready for questions!

Curious for more hypotheses and my first drawings published in a real, live journal? Check out our recently published paper in Frontiers in Ecology and Evolution.