There’s some strange behavior in the Amazon jungle that has Lepidopterists scratching their heads. Bamboo shoots, one of the most coveted sources of nectar for the local ant population, are being blatantly pilfered by the cherry-spot metalmark butterflies (Adelotypa annulifera), and the ants are not retaliating. In fact, they don’t even appear to notice that the butterflies are stealing the nectar from right under their antennae.
Biologists already knew that metalmark larvae produce a nutritious goo and feed it to ants in exchange for their protection from predators, but after the larvae made the transition to adults, they had to immediately fly away or the formerly protective ants would attack and try to eat the adults. What the adult butterflies did afterward — how they mated, what they ate — remained largely a mystery.
“Ants normally treat this bamboo like their castle, aggressively fighting off intruders,” says Aaron Pomerantz, an entomology Ph.D. student at University of California, Berkeley, and National Geographic explorer. Pomerantz is the co-author with Phil Torres, who first observed this behavior, of a new study published in the Journal of the Lepidopterists’ Society.
How the butterflies are getting away with it remains unknown. Some theories are being investigated. The butterflies could use chemical signals to conceal themselves from the ants, or the ants may get some as yet unknown benefit from the butterflies in their midst.
Most of us think of butterflies as peaceful and beautiful, gently flitting from flower to flower. But when it’s a jungle out there, even butterflies do whatever it takes to survive.
National Geographic: Weird and Wild/Carrie Arnold