Previous Year Question
Consider the following:
Butterflies
Fish
Frogs
How many of the above have poisonous species among them?
Only one
Only two
All three
None of the above
Correct Answer: C
Detailed Solution
1. Butterflies
Some species of butterflies accumulate toxic or distasteful chemical substances in their bodies.
For example, the larva of the Monarch butterfly obtains cardenolides from milkweed plants and stores them in its body.
These chemical substances make the butterfly poisonous or distasteful to birds and other predators.
The bright colours of the butterfly may act as warning signals for predators.
2. Fish
Natural toxins are found in some species of fish.
Tetrodotoxin, an extremely powerful neurotoxin, may occur in certain organs of pufferfish.
Some marine fish may accumulate ciguatoxin through their food, and their consumption can cause ciguatera poisoning in humans.
Therefore, poisonous species are also found among fish.
3. Frogs
Toxic alkaloids occur in the skin of some frog species, including poison dart frogs.
These toxins protect the frogs from predators.
Many poison frogs obtain these alkaloids from their natural diet containing ants, mites and other small arthropods.
Their bright colours frequently represent aposematic coloration that warns of toxicity.
Therefore, poisonous species occur among all three groups—butterflies, fish and frogs.