The Winged Invaders From The Sky: For past two weeks residents of Navi Mumbai have been experiencing the presence of caterpillars and moths in their city. These creatures emanating from the mangroves surrounding the city have been seen in large numbers in the residential areas. In some cases the insects have startled two wheeler riders when caterpillars have fallen on the riders using the roads. Though there have been reports of skin reactions in people who contacted the caterpillars that seems an exaggeration. Fact is, the Navi Mumbai Muncipal Corporation (NMMC) too had panicked and sent the city's Fire Force to tackle the 'insect invasion.' The Firemen sprayed trees having the insects and in their overenthusiasm even lopped branches off trees having these insects. Newspapers found it good to have the insects which created news including pictures for few days.
Small patch of mangroves with less damage
If you as resident of Rustomjee Urbania didn't know that the annual insect visitors had landed close to us, you are forgiven. Not too many residents of Urbania have noticed that mangroves in our neighborhood have dried up and turned brown. I too didn't know this and got my first glimpse of browning mangroves peeking out of an apartment at Aurelia where I had gone with a friend to look at apartments on sale. I clicked pictures of the sad looking mangroves and shared them on Green Crusaders group. This week I went over to a friend's apartment on 30th floor of G-wing after having seen large brown patches near Thane Creek shared by a group member on Green Crusaders. I could click the wide swathe of deaf mangroves in front of the TMC office on the Balkum Saket Road. I could also click small patches of brown in green stands of mangroves in the park reservation adjacent to the nalah north of Azziano. And this afternoon I went close to the Thane Creek and took a closer look at the affected mangroves. I was happy to note that the plant was not fully brown and had patches of green and no insects in it.
Browned mangroves as seen from Aurelia
The Winged Visitor's Identify Revealed Finally: Sorry for a long prelude without even telling you the reader which is the insect I am talking about. I first heard about it thirty years ago when we learnt about an insect called the Teak Defoliator or Hyblaea purea. As the common name suggests, this insect feeds on leaves or foliage of teak trees. The insect also feeds on many other species of plants numbering nearly 50. The resident at G Wing who helped me click pictures of Teak Defoliator affected mangroves told me they had them even in Ghatkopar where they lived earlier. The brown moths would invade homes post monsoon and the easy way to keep them out was by keeping doors and windows closed at evening. Moths are attracted to light and keeping a place dark too helps not attract them.
The Teak Defoliator moths are the adults and female moths lay eggs under Mangroves. The eggs hatch into larvae which eat leaves. The larvae before pupation move around and likely that is what caused them to fall on to people at Navi Mumbai. This is an annual phenomenon and happens post monsoon. This year the lush growth of mangroves after prolonged monsoon seems to have also helped increase the population of Teak Defoliator. So, don't panic if you have Teak Defoliator moths at home. They are part of our ecosystem and help control the growth of Mangroves. Wait for few more weeks for the affected Mangroves to turn green.