A heap of wings in the morning indicates the
annual termite swarm. This heap is not arranged, this is how it looked like
at Dokmai Garden.
Many people who have lived in Chiang Mai for decades talk
about “.those insects that come out of the ground and fly everywhere”. When
you ask “do you mean termites?” they usually say “no”, thinking of the tiny,
white, wingless insects you find in any piece of buried wood.
In fact, after the first serious rain of the season (i.e. about 20 mm of
rain), the termites swarm. These are the kings and the queens, which are
much bigger and more tanned than their pale wing-less peasants. The
royalties do have wings so they can spread to new places. The name of this
insect order, which does not exist in Europe, is “Isoptera”, which means
“similar wings”, referring to the fact that the four wings look very
similar, in contrast to butterflies, beetles, wasps and flies which have
very different fore and hind wings. If you observe the swarms by a street
light, you will see there is intensive termite mating, and that gecko
lizards have the feast of the year. Keeping your lights on at home during
this special night of termite swarming is not wise, as your home might be
invaded by thousands of termites.
The wings are only used this one night. They are easily shed, and a
successfully fertilised queen will find herself a suitable place to raise a
new dynasty. If you sleep through the night of the swarms, you will still be
reminded of their activity next morning, as there will be heaps of wings
under every lamp, and at the markets there will be baskets of fried termites
for sale, as human food.
As there are many species of termites, you may experience a couple of swarms
during the early rainy season. Also, there are several ant species swarming
too. Termites are sometimes called “white ants”, but that name should be
avoided as termites are totally different from ants (order Hymenoptera),
which are more related to bees and wasps.
Termites do threat any wooden construction in your tropical garden. Although
teak and Afzelia have a reputation of being termite resistant, that is not
completely true, you need to observe any wooden construction carefully. Most
importantly, do not allow the wood to touch the soil. Bamboo and Eucalyptus
touching soil will lose their strength and collapse in about ten months. As
to termites as pests, that may occur, but quite often when the gardener
pulls up a dead young tree or bush, and sees the termites, he just sees the
vultures. The assassin might have been a fungus, a borer, a rodent, the sun,
a peeing dog or simply death due to lack of water or flooding.
Another interesting observation is that the number of mushroom species is
much lower here in the tropics than in temperate forests. I think it may
have to do with the termites, i.e. here the termites remove the fungal
substrate very quickly, while in boreal regions there are no termites, and
wood degradation is very slow, generating a vast range of fungal species.
While the tropics have a lot of biodiversity above ground, the temperate
regions have a lot of biodiversity below ground.