(Photos: Rajani Kurup et al.)
Many carnivorous plants use tasty nectars, appealing scents and bright colors to attract insects into their traps. Scientists at the Jawaharlal Nehru Tropical Botanic Garden and Research Institute in India have discovered another method: tantalizing ultraviolet light.
Rajani Kurup, Anil John Johnson, Sreethu Sankar and Sabulal Baby discovered that the mouth of the Nepenthes khasiana plant glows under UV light. Ants find this color, which is almost invisible to humans under normal conditions, very attractive.
The researchers exposed these pitcher plants to ants in a field. Some of the plant mouths were painted with an acetone coating that blocks UV light. These painted plants attracted few ants, indicating that the UV emissions are essential to luring prey.