Termite Eruptions

There is something special about the first big rains of the summer season in the Timbavati and the most evocative is the smell of dry earth soaking up the cool rains, so characteristic that it even has a name – ‘petrichor’ There is a sudden emergence of countless tortoises, terrapins, snails, frogs and millipedes after the first wetting and we are full of excitement with the wonderful knowledge that within days the entire landscape will transform.

There is also the realisation that if you don’t want to be full before chef Ryan has even laid out your starter on the dinner table, it is best to keep your mouth closed on the night drive back to camp, otherwise you risk getting more than your fair share of termites going where you don’t want them to go!  That is right, that first night after the initial big rains is full of termites, literally millions of winged termites take to the sky on their nuptial flight in an attempt to spread the colonies genes and disperse to find an intercolonial mate and kick start a new colony.

Now, before you start freaking out and thinking that this sounds like a nightmare of sorts, let me first explain why these termite eruptions are such a spectacle to see, and then also put your mind at ease by clarifying that these emergences end almost as quickly as they start. So, the window of winged wonders is a rather brief period of time – and this is one of the elements that makes these events so wondrous – that these colonies can coordinate their eruptions so synchronously.

Tanda Tula - worker termite

Tanda Tula - alate emergence

The Greater Kruger is home to many species of termites, but the ones that stand out most belong to two different genus groups; the Macrotermes (the large mound-building termites) and Odontotermes (also building large mounds, but with the majority underground).  As these termites are also some of the biggest around, it is their emergences that we take note of.  For those that are a little lost as to exactly what an emergence is, it is that event whereby winged reproductive termites are released from their natal colony to fly off, find a mate and hopefully start a new colony.

Termites themselves live in a caste system, with morphologically distinctive castes of workers (those that build the mound and tend to the queen), soldiers (there to protect the colony), a king (he has one job; sperm donor) and the queen (she is the recipient of the sperm, and is most simply described as an egg-factory, pushing out tens of thousands of eggs a day in a mature colony).  These eggs hatch as nymphs, and depending upon what genes are turned on or off through the presence of pheromones, they can develop into workers, soldiers or future kings and queens.  It is this latter group of winged reproductive that are released through special chute tunnels during an eruption.  They are the only caste that have wings and can fly, and for the most part, the only termites that most of us get to see, and even if we colloquially refer to them as ‘flying ants’, they are in fact termites.

Termite eruptions or emergence are very time sensitive events.  The winged reproductive are not agile – or fast – fliers, and as they flutter away from their natal mounds they are no more than sitting ducks in the air for a myriad of aerial predators.  To counter this, termites go for quantity over quality and release so many alates at once that the predators just cannot catch and eat them all, and despite their cumbersome flight, there will still be thousands of individuals that make it through the barrage of beaks waiting for them and make it to new breeding grounds.

Now, this would all be for naught if when they made it to the new area, there were no potential mates from other colonies waiting for them!  As a result, every species of termites has a unique set of triggers that results in the release of their alates so as to coordinate the release across space to increase the chances of meeting up with a mate from a new colony.  These triggers usually relate to air pressure, temperature (usually 25-29 degrees Celsius) and relative humidity (often in excess of 80 percent), but are also initiated by the first rains of summer.

Last week – after our first big rains – the termites of Tanda Tula were all embarking on these eruptions, and we sat and watched in wonder as hundreds upon hundreds of termites emerged from the single mound we were observing.  Although the alates got our attention, closer inspection revealed countless minute workers scurrying around the exit chutes helping the alates emerge, as well as an army of soldiers waiting in the vicinity to deter attacks from ground predators.  The alates would pop up from underground, flap their wings a couple of times and leap off into the unknown to face whatever predators were waiting for them.  In a sense, it reminded me of scenes from Saving Private Ryan!  On this particular day, the alates had a comparatively easy exit and were only greeted by a few rollers, Barn Swallows and a single Wahlberg’s Eagle, however, I remember watching a similar scene last summer when the wind direction forced all emerging alates to fly in one direction, and waiting for them must have been over a hundred European Rollers, dozens of Hornbills and Drongos and an equal number of Swallows flying above.  On this occasion, I imagine the termite casualties would have been well over 95 percent.

Even in this extreme case though, the numbers of alates emerging from the colony are so vast that hundreds will still make it through, and when they do, they can complete their mission of finding a mate!  This is one of the most incredible scenes during these eruptions, and it usually takes place right in the camp where all the flying alates in the area get attracted to the lights in camp. Upon arriving back after the night drive, the path lights are alive with termites confused by the presence of light and flying circles around them.  It is not all bad though, as these lights prove to be fantastic meeting spots for mates, and as quickly as the termites arrive, they soon disappear as the future kings are attracted to the queens as they release sex-attracting hormones.  Once they land on the ground, they quickly shed their wings and find a mate. Below the lights one can see dozens of pairs of termites running around after one another; queen in front and her suitor shadowing behind.  The pair will soon find a suitable patch of earth and bury down into the ground, creating an underground chamber and then mating.

At first the royals produce only a few eggs and tend to them themselves, but if the site is well selected and all elements fall into place, the nest will begin to grow, and within 2-5 years could form a viable new colony.

After less than half an hour, all that remains around the lights in camp that were almost completely hidden by termites a little earlier, are the discarded wings of the alates, and a bunch of terrestrial predators (frogs, geckos, scorpions and other larger insects) all stuffed from the good feed they have just enjoyed.  Waking up in the morning, tiny mounds of dark soil (dug up from below) litter the area and are the only indication of where the future kings have queens have begun their subterranean existence.  If all goes well for them, within a few years, it will be their own offspring emerging from these mounds to partake in these seasonal eruptions that truly are a spectacle to see!

So, for those visiting next summer, if you are lucky enough to be visiting Tanda Tula during the first rains of the season, you will sure be in for a treat!

Until then, take care!