Normally when we talk about our travels, we tend to focus on the big stuff – the large mammals, fearsome reptiles and brightly coloured birds – and it is all too easy to overlook the small stuff. On my recent trip to Costa Rica, I saw plenty of bigger creatures – monkeys, sloths, crocodiles, toucans, macaws – but what about the little critters? After all, the rainforest is home to millions of different species of insects.

It’s not just the little biting insects I’m thinking of either. They can be found in Costa Rica of course, you can’t escape them in the rainforest, although they are less of a pest than in the Amazon. Beautiful butterflies catch the eye wherever you travel in the country, with iridescent Blue Morphos wafting through the forest and bold Zebra Butterflies standing out in the cloudforest. Looking carefully you can easily find beetles and millipedes on the forest floor, although you have to be lucky to find the Hercules Beetle, one of the largest insects in the world.

Morpho peleides

  • The brilliant blue color in the
    butterfly’s wings is caused by
    the diffraction of the light
    from millions of tiny scales
    on its wings.
  • The entire Blue Morpho
    butterfly lifecycle, from
    egg to adult is only 115 days

Somewhat less pleasant are the convoys of army ants which march through the undergrowth, clearing everything in their path. If you watch carefully, you can see dismembered limbs of insects and even small birds and mammals being carried along in their tide. For me though, it is another type of ant, the leaf-cutter ants which really fascinates.

forest-floor

I’ve seen leaf-cutter ants many times in the rainforest. The ants find the paths cleared by us humans through the forest undergrowth perfect highways, and I have often had to step over convoys of ants, each carry a freshly cut leaf back to their colony. However, staying at El Remanso in the Osa Peninsular, my guide Felix really brought the complex society of the leaf-cutter ants to life.

Leaf-cutter ants are of course the only other species on the planet that practices agriculture, and their society is said to be the most complex in the animal kingdom after humanity. The ants strip plants of their greenery, capable of stripping a tree to the branches in a matter of days, and can be seen hauling pieces of leaves many times bigger than themselves underground to cultivate the fungus which feeds the colony. Each colony is a vast city containing a many as ten million ants with dozens of entrance mounds leading to hundreds of subterranean chambers.

At first the ants just look like – well ants – but Felix was quick to point out the different castes.
Tiny minimis scout around the convoys and protect the heavily laden workers from parasites,
often hitching a lift on the back of a leaf, while majors are the soldier caste using their fearsome
jaws to defend the colony. Holding a soldier careful by the thorax, my guide demonstrated its
strength as the little ant clamped its jaws onto his hat and refused to let go, bearing the weight of
the hat, many times its own weight in its powerful grip. I learnt to respect the soldiers after that
and give them a wide berth.

Leafcutter ants can carry more than 5000 times their body weight and cut and process fresh vegetation (leaves, flowers, and grasses) to serve as the nutritional substrate for their fungal cultivars.

Hidden deep underground, a single queen is mother to the entire colony, living for over a dozen years laying thousands of eggs each day. Felix explained how the queen is shifted from chamber to chamber underground, giving birth to daughter queens who fly high above the rainforest carrying a scrap of fungus with them to start a new colony. Only the strongest males can catch the young queens who mate just once on their first flight, storing the sperm needed to populate the entire colony.

I thought there was no way to see inside the colony, but back in San Jose for a travel conference I met someone even more obsessed with the leaf-cutter ants than myself. At La Quinta lodge in Sarapiqui, Leo Herra has created an artificial colony with a glass wall, allowing visitors to peer inside the world of the ants and search out the queen and her nursemaids. That is a must-see for my next trip to Costa Rica.