The best thing about Camp Tsavo is that we often have all sorts of wonderful people popping in once in a while. The main reason for this is that we are really privileged to be based in such a diverse ecosystem. You may remember the guest post we blogged from Munir Virani, the raptor specialist. A couple of weeks ago, we had another wonderful character stay with us for a few nights only this time it was the bugs and not the birds that brought him to Camp Tsavo. Dino Martins is a PHD student at Harvard University and just loves his bugs! He blogs regularly on Dudu (the swahili word for insect) Diaries and recently posted about his trip to Camp Tsavo and has kindly allowed us to repost it here. Enjoy!
Hello – have just been visiting Tsavo. We were based at Camp Tsavo (which used to be called the Taita Discovery Centre). It is an amazing location – a former cattle ranch nestled between Tsavo East and Mt Kasigau. It is a fantastic place to be based for anyone wanting to explore a more remote corner of the Tsavo ecosystem – and the added bonus is the cloud forest on Mt Kasigau, which is one of the most remote and beautiful forested massifs of Kenya.
Just after we arrived, we had an interesting visitor come to greet us at the dinner table! She was very friendly…
The entire place was a green as I have ever seen it. A most interesting phenomenon was the carpets of Ipomoea (morning glory flowers) that literally covered everything – bushes, trees and the ground. From a distance in some places it looked like it had snowed. Below are some photos taken by my friend, Wenfei Tong, of the flowers.
Of course with the rains there were lots and lots of bugs about. We found this stately old gentleman ambling across the road – he is an Armoured Ground Cricket – insects that only appear for a few weeks after it rains.
There were lots of butterflies around too. This flock of Pea Blues were busy sipping juices from some fresh lion dung!
There were a lot of Emperor Butterflies about too – here a tiny blue butterfly is using one as a perch!
Other butterflies around included this orange and black ‘Joker’, and lots of whites and yellows – who were all busy mud-puddling.
All over the world, especially in the tropics, butterflies gather daily to ‘mud-puddle’ as it is called, at the edges of savannah and forest pools, rivers, streams or even at damp patches on roads where a passing cow or buffalo has urinated.
They are thirsty and come to quench their thirst in the tropical midday heat. But their real thirst is not just for water or moisture. What they are really after are salts and other nutrients that seep from the earth. As the water evaporates and moves through the sand, pebbles, clay or mud, it carries with it a whole range of dissolved salts and suspended nutrients – minerals and the like from the soil.
Salt – yes, the plain old sodium chloride (NaCl) we so love to sprinkle on our fish and chips, and add excessively to food of every kind, is something of a rare commodity in nature. Plant material, especially in areas of high rainfall is relatively low in these essential salts, mainly sodium. Herbivores, therefore, need to seek out salts from other sources. In order to obtain enough of this essential nutrient they resort to range of strategies.
The need for salt applies equally to all leaf-eating creatures, both large and small. Butterflies do most of their feeding and growing on leaves as caterpillars. The same leaves that browsing mammals eat and then crave salt. The adult butterflies gather at puddles and streamsides, and at less savoury locations too, to sip the salts dissolved and slightly concentrated in water as it evaporates from the surface of the soil.
It seems pretty straightforward – gather and mud-puddle and get your dose of salt. But with insects nothing is ever so simple. Even something as ordinary as salt has become a cunning card when played by the hand of evolution.
Looking really, really carefully at the butterflies that come and gather to mud-puddle and sip salts, one notices several interesting patterns. Firstly, only males come to mud-puddle. Males of many different species gather and shuffle, jostling for space on the best spots. Since females rarely if ever gather at damp patches – how then do they obtain their much-needed salts?
The answer, of course, is from the males. Mud-puddling out in the open is risky business. Even in a crowd you’re still exposed to dangers from above and below – ravenous ants, insectivorous birds and jumping spiders to name just a few. But male butterflies, despite all the risks, still gather at damp patches in large numbers.
The reason behind this is that without the extra salts and nutrients, they stand little chance of mating and passing on their genes. Natural selection works through an interplay of invisible pressures and forces and pure chance that leads to one behaviour, trait or gene being slightly favoured over others in the endless gamble of life.
When most moths and butterflies mate, the male passes the female a special package known as a spermatophore. This sac, a nuptial gift, contains in addition to his sperm, a whole range of precious substances. The contents of the spermatophore depend on the species of butterfly involved and how much or how little time the male spent mud-puddling or feeding from dung and other such delicious, nutrient-rich substances.
Dino Martins
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