13 November 2012

Flying dragons ...

Broad Scarlet Crocothemis erythraea (male)

These beautiful insects belong to the order Odonata - which means "toothed ones" (Gr odontos) - because of their immensely strong mandibles.  They had been around for many millions of years and changed little in the last 300 million years.  They lived long before the pterodactyls and even birds and some of the species had a wingspan of up to 750mm (close to 1 metre).  Fossils of dragonflies show that they have changed very little over time - the Emperor Anax imperator is clearly the same species correlating with fossil specimens of 5 million years ago.

Broad Scarlet Crocothemis erythraea (female)
There are close to 6 000 species in the world - and in South Africa 158 species had been recorded.  Of these about a fifth are endemic to South Africa, meaning they live nowhere else in the world.  The species in this article shows clear sexual dimorphism - the male and female look distinctly different in colouration. The female in picture is close to the end of her life cycle with her wings showing the wear and tear of hardship clearly.  The body length of the Broad Scarlet is 39-40mm, they are medium-sized amongst their peers and the body is particularly wide.  A characteristic of the species is the small amber patch at the base of the hindwing.  They occur throughout South Africa in suitable habitat - pools ans still reaches of rivers - usually with an abundance of vegetation on the sides and floating in the water.  They perch conspicuously and flight is strong and darting.

Dragonflies live in a variety of habitats - varying from small, fast flowing mountain streams to large ponds and gardens where females may even oviposit (lay eggs) in swimming pools.  They are indicators of a healthy ecological system, as they soon disappear when water quality deteriorates or when alien vegetation invades their habitat.

It need to be fairly warm - around 20 degrees Celsius - for dragonflies to fly. The adult flying stage emerge from Spring to Autumn and the larvae spend the cooler season in the water.  

15 July 2012

My name suggests something

Cabbage White (Pieris brassicae) - male
Sometimes it is just amazing how a light coloured butterfly keeps catching your eye throughout the day. Especially on a clear and bright winter's day with everything lush and green in the background. This one kept passing the front door every time as I walked down the corridor.  So eventually I just grabbed the camera and went outside to "shoot" it.
This specimen is the male Pieris brassicae (Cabbage white/Kool-witjie).  Its name suggests the preference of Brassica spp as larval food for this species - though the female may deposit her eggs on other plants as well.  Apparently the larvae will ruin nasturtium in a short period.

I "shot" this one in Moorreesburg (Western Cape) in our garden.

09 July 2012

"I am very shy!"

During our week in Namaqualand (see previous post) I happened to come accross an Aardvark Orycteropus afer walking around in the broad daylight.  OK - it was 17:50 and very close to nightfall when we surprised each other along the road.  I was riding briskly along on my motorbike to collect a camtrap set out on another part of the farm and actually my camera had already been stowed away in my backpack.  I had my gloves on and my head was covered in a warm beanie as the temperature was dropping quickly.  

When the animal observed me it scurried away - so I had to stop the bike, pull off the gloves with my teeth and roll the backpack from my back, get the camera out and in the run towards the fence fit the longer lens and then aim and shoot ... all in less time it would take Bolt to complete the 100m.  Nevertheless I got some decent shots of the ears and the backside of the scurrying animal.

Ears and @rse