One of the many perks of waiting for lions to wake up in the evenings is that whilst Africa’s largest cats are barely twitching a whisker, it gives you the time to sit and enjoy the surroundings, where a myriad of smaller creatures are hard at work. Thousands of termites forage for detritus on the ground to take back to their mounds, providing a medium for food to support themselves and their queen; nightjars call in the distance; spotted and Verraux’s eagle owls owls fly over in search of any unsuspecting rodents or scrub hares.
One night, while we were watching the Mangheni breakaway pride of lions sleeping on the banks of the Sand River, the river became illuminated with tiny flashing lights. I instantly turned off all of the lights from the vehicle – headlights, spotlight and radio – so that we could appreciate the flashes in total darkness (trusting that the lions were still asleep). We became completely mesmerized by one of the most spectacular pyrotechnic shows provided by one of the smallest animals at Londolozi – fireflies. As the male firefly flies over the river, he emits a flash of light at a specific frequency in the hope of finding a matching signal from a female. This flash happens in the abdomen and is caused by a chemical reaction between a substance called luciferin and an enzyme in the insect’s blood called luciferase. When these two substances mix, and there is oxygen present, it causes a bright flash.
By flashing at a certain frequency, the male and female fireflies are able to determine three things; the species, sex and exact location of the individuals they see emitting light. However, as always, there are predators lying in wait. In some parts of North America, the female of species of firefly known as the Pennsylvania firefly (Photuris spp.) is able to mimic the flashes of the female of a completely different species. The unsuspecting males of the species she mimics respond to what they think is a female of their own species, only to be eaten by one of natures best con artists.
One of the most incredible things about a firefly’s light is that very little energy is wasted. When we turn on a standard light bulb, nearly 90% of the energy produced is given off as heat and only 10% is actually given off as light. Imagine a large city at night for a second. Almost every single spec of light produced in that city comes from a source, and the majority of those stem from some form of fossil fuel, the effects of which we all know too well. In the case of the firefly, nature uses natural reactions that are still baffling the many scientists who study them. Will the future hold insights into a form of renewable chemical energy that is as efficient as that created by fireflies? In fact, because of its ability to glow, luciferase is now being used in some studies in bone marrow and stem cell research, making the cells much easier to see under a microscope.
It often takes the smallest things to remind us that often, when it appears to be quiet and still, that there are quite literally thousands of processes still happening all around us, provided we take the time to appreciate them.