An account by Washington Wachira (photos by Washington Wachira)
A short account by Washington Wachira
Nairobi National Park is a great place to look for insects. The park is known to host a huge array of insects ranging from dragonflies, damselflies, butterflies, moths, bees, grasshoppers, locusts, crickets, ants, wasps, beetles and much more. Some common insects that we see here on a regular basis include Dragonflies and Damselflies- Dancing Jewels, Broad Scarlets, Globe Skimmers, Red-veined Dropwings, Banded Groundlings, Blue Emperors. Other insects include Safari Ants, Harvester Ants, Singing Ants, Antlions, Dung Chafers, Honey Bees and Carpenter Bees. This does not exclude all the amazing Butterflies and Moths that this park hosts.
Nairobi National Park has recorded over 151 butterfly species- often accounted for by the trips made here by scientists and tour groups. Some of the common species of butterflies here include Brown-veined White, African Emigrant, Caper White, Red Tip, Scarlet Tip, Orange Tip, Grass Yellow, Citrus Swallowtail, Mocker Swallowtail, Ciliate Blue, Green-veined Charaxes, Diadem and African Monarch.
On a day trip in July, 2020, I was keen looking around to see if some insects would pop as we drove across. The safari was mainly focused on mammals and birds, but I could not pass the chance to find some few insects. Below is an account of the few insects we founds as we searched the vast Nairobi National Park for mammals and birds.
First up was an amazing Large Orange Tip; male. This individual was in prime colour and the wings were in full hue. It is possible to distinguish between the sexes in this species. The females are darker and often have black patches on the wings, making them variably patterned. Some individuals differ in the amount of markings, but the general impression remains. It is also known than this species gets some seasonal variations, which may affect the looks in the field. Their sizes can range from 30mm to 40mm. In terms of confusing species, this species has had me tricked many times, with a cousin species- the Scarlet Tip. The females of the two species are easy to tell apart, because the Large Orange Tips have orange wing tips, while Scarlet Tips have red wing tips. Males are however more alike. The best way to tell them apart is to use the shape of the wings- Scarlet Tips have pointed wings, while Large Orange Tips have rounded wings. The Scarlet Tip is also slightly larger, but not easy to tell size in the field. The red tips of the Large Orange Tip males are also marked by several black veins that run straight into the red patches.
We later saw a nice female of the same Large Orange Tip, but this individual was heavily worn. The body pattern was rather consistent with the females of this species. However, the wings were torn towards the back ends, leaving reduced black margins. It was however a good sighting considering that we had seen both sexes of this species.
Next we came across a Common Grass Yellow. This one was not easy to photograph as he kept flying around quite fast. The day was also warmed up by the time we found this individual- butterflies tend to fly faster when it is warmer. There are many species of Grass Yellows, and they can get quite tricky to tell apart if you do not have a good look. For the Common Grass Yellow, which is quite common in many parts of Central Kenya, the wings are bright yellow and show a bit of a black border. They sometimes congregate and feed together on flowers. Huge congregations are often encountered on the road sides. They sometimes flock in the middle of the road, especially around water pools, mammal urine tracks and dung piles. Their sizes are between 25mm and 30mm.
Later in the day, we found a group of Common Grass Yellow enjoying their day at a water pool, near the Athi Basin Dam. They were joined by some Blues and Acraeas– more amazing butterflies!
During the entire day, we kept encountering many Banded Groundlings. This is the most-abundant Dragonfly in the entire Nairobi National Park and we often find them at picnic sites and along the roads. We saw a good number of males, who have the diagnostic dark bands across their clear wings. Males also have dark, almost black, bodies. The females were also in good numbers. They differ significantly from the males, in having yellow bodies, with variable amounts of black markings. The females also have clear wings and lack the dark bands that are found on males. Their sizes can be between 25mm and 30mm; although they look robust and steady as they fly. Sometimes we find them congregating in feeding groups and often follow mammals as they feed in the plains. They also follow humans along paths or grasslands. Most of the individuals we saw were flying really fast. Below is a male perched flat on some soil patch.
We later found an amazing butterfly- the Small Spotted Sailer. This is a beautiful butterfly species from the Sailers group- there are several related species, but they all have slightly different wing markings. The Small Spotted Sailer is also fond of mud-puddling, where butterflies use their feet to taste the mud pools. The sexes are usually similar, with the females looking slightly duller- we think our individual may be female. Their sizes are between 35mm and 40mm. as the name suggests, when they are flying, you see them sail effortlessly across the landscape. Very nice butterflies to watch in the field!
Our Small Spotted Sailer landed shortly after we spotted her; and was immediately joined by another insect- a House Fly. This is a very abundant insect and often visits homesteads and livestock pens. The head is bright, with red eyes- sometimes they look bright brown, depending on light conditions. The frontal area and face often has white markings. The wings are clear. They are small insects of 7mm to about 14mm. They love feeding on liquid foods and will perch on any food item that they can find.
As we advanced the drier Southern Sector of Nairobi National Park, we came across a great insect track/ sign marker- an old nest belonging to Harvester Ants. These small, but highly active ants, can be anything between 3mm and 10mm in size. They vary heavily in their sizes, and you can encounter a flock that contains some individuals that looks almost twice as large as their colleagues. They love feeding on grasses and thus are more likely to be encountered in grassy areas. The queen lives inside the hollow nest and the workers leave to find the grass seeds and bring them back to the nest. The chaff from these grasses are often seen at the nest entrance, deposited into a large scattered pile. Through this behavior, these small, amazing insects, help to disperse the seeds of the grasses they eat. This is very important for the ecosystem and keeps the grasses growing and dispersing accordingly!
Before leaving the park, we came across a nicely perched Cotton Stainer– an amazingly coloured insect. These small insects measure about 15mm and can be very common in certain areas, especially around bushy grasslands. Their name is funny but also correct- they do indeed stain cotton! Most accounts of this behavior occur when they feed on cotton buds and they end up damaging them, but they are also known to stain cotton bolls. Their nymph stage is quite unique in colour- they become brightly red, with some black and white markings. This bright red colour serves as a warning signal to potential predators- often called aposematic colouration. They can often be found copulating, and many naturalists will have found two adults fused together in this act.
We had an amazing day in Nairobi National Park, having seen lions, rhinos….. and amazing insects!