Monday, October 13, 2008


Delhi has been swarming with this insect for the past week. At night, enormous clouds of them collect around mercury-vapor lamps (white light), leaving the yellow sodium-vapor lamps almost bare.

Usually we see an explosion of insect population after the first rains. But the last time it rained was two months ago and with the onset of winter, the air is now dry and dusty. In such conditions it is rather unusual to see huge swarms of insects enveloping the streetlights.

These are not the usual winged termites that flap around clumsily until they get rid of their wings, or become lizard feed. They are much smaller(~3mm), brownish in color, built like condensed houseflies with a strong preference for white incandescent lights. They are usually zipping around blindly, entering open mouths (bland), eyes (no sting) and when at rest, they prefer to dangle up-side-down.

What could this be? Shaku was unsure, " looks like one of the Heteroptera belonging to the leafhopper or plant hopper group (like cicadellids or fulgorids) sorry I cant be more precise, but I need a closer look..."

The answer came, rather surprisingly, from a front-pages of Hindustan Times (24th Oct., 2008). An article by Satyan Mohapatra, "Mutant Insects Over Delhi", claimed that this was the Brown Plant Hopper.

It quoted Dr. T.P.Rajendran (ADG-Plant Protection, IARI), "This year untimely rains began a chain reaction that led the Hopper population to explode...the rains caused an increase in pest population, which made the farmers use increasing amounts to insecticides like Carbaryl, which ended up killing off all the natural predators of the Hopper like spiders and frogs."

Apparently a mutant strain developed resistance to carbaryl, and the insect population exploded. They were having a great time until the farmers of Rhotak and Panipat harvested the rice crop. Suddenly, they had nothing else to do but to ride the next breeze to Delhi.

Will we now see an explosion of spider and lizard population in the weeks to come?

Reference / Links:
  • Mutant insects over Delhi, Satyen Mohapatra, Hindustan Times, 24th October 2008

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