Viceroy butterflies are notorious crooks. They sport a striking pattern of orange and black almost identical to two other species: the monarch with the terrible taste and the butterfly-queen equally bad. Birds that eat these bitter insects quickly learn to avoid them – and their convincing viceroyals. But a new study reveals that when queens are not present, viceroys themselves begin to take on a terrible flavor.
Viceroys (above) and king butterflies are widely distributed in southern Florida, where they both feed on weeds; only queens were known to store the unpleasant chemicals of plants in their bodies. But viceroys also thrive in the northern part of the state, where queens are not found. (Monarchs are relatively rare in Florida.)
To find out how viceroys protect themselves without bitter queens, the researchers chemically analyzed 80 butterflies from northern Florida and 80 from the south of the state. Indeed, those of the south had low concentrations of phenolic glycosides, chemicals similar to those that confer the terrible taste of queens. But the viceroys of the north were packed. The team then tried to feed the viceroys with lab-trained mantes, who were repelled by the northern variety. The results suggest that without a model, viceroys have developed their own foul taste, report researchers this month in Nature Biology of communication.
The discovery also challenges the conventional understanding of how certain species become imitators. Often these animals are considered to be harmless imitators of bitter-tasting species or as a mere look-alike among a host of other unpleasant species. But viceroys exist somewhere in between. With these double duplicates, where appearances are primordial, there is much more than what we perceive.