AsianScientist (May 27, 2016) – Many poisonous animals have brightly colored bodies that send a clear message to predators: don’t eat me, or you’ll get sick and die. But why do some toxic animals actually hide the warning colors from the predator’s view, showing them only at the very last moment when they have already been attacked? How can a sudden display of bright underwings at the moment of capture help insects like the spotted lanternfly?
An international team of behavioral ecologists have proposed a new explanation, which they published in Frontiers in Ecology and Evolution.
Drs. Cho Hyun-Joon and Kang Changku, then graduate students at Seoul National University, presented artificial prey to wild oriental tits (Parus minor). The birds were presented with hand-made bitter prey models that looked rather dull, emulating spotted lanternflies resting on tree bark. These bitter prey models were mixed with tasty models that were also dull but differently colored.
At the beginning, the birds picked up the bitter prey and dropped them almost immediately. But after several days of the same experiments, the birds slowly learned to use the colors to distinguish the bitter prey from the tasty prey, and they finally learned not to pick up the bitter prey.
Some of the bitter prey models were cleverly designed such that the prey suddenly displayed conspicuous color immediately after the bird grabbed the prey. This imitated the situation when the lanternfly displays the red-white-black pattern on their hind wings when being attacked.
This sudden display of conspicuous color dramatically speeded up the learning process of birds. Only after a few encounters with the bitter, inconspicuous prey with a sudden display of colour, were the birds able to distinguish these prey from other inconspicuous but tasty prey. Very quickly, the birds stopped picking up the inconspicuous bitter prey as if the sudden display made the learning much easier.
We learn faster and remember better those events that were associated with something unexpected. It seems that the same happens to birds, and that some poisonous, bitter-tasting insects exploit this by using sudden displays. Because of the sudden displays, the predators quickly learn to discriminate against the poisonous, bitter-tasting insects—and those insects survive the encounters with predators.
“This strategy helps the bitter-tasting prey in two ways,” said Kang.
“The predators that are sensitive to the toxins produced by the prey can quickly learn to avoid the prey. But, those rare predators that are not sensitive to the toxins have difficulty spotting the prey because of its relatively cryptic appearance.”
Either way, the prey wins.
The article can be found at: Kang et al. (2016) Post-attack Aposematic Display in Prey Facilitates Predator Avoidance Learning.
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Source: Laboratory of Behavioral Ecology and Evolution, Seoul National University; Photo: Shutterstock.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.
