November 2019

NOVEMBER 2019

Still very dry! We only had 84mm rainfall on the estate for the month of November. And 90% of it fell in just two days. There has been a lot of threatening with clouds and distant thunder as you can see from the above photo of Mount Anderson taken from the west. But, the grass has sucked all that rain up and is thriving and getting greener every day. There has also been some very hot days where 32 degrees has been reached (the lowveld has been averaging in the mid forties!) and all the little creepy crawlies have come alive as you'll see after the next photo...

First though, the month got off to a splendid start when the Springboks won the world cup. The estate was pretty quiet that weekend with only 4 houses being used. The members and guests from three of them were more than enough to celebrate that magnificent victory in the office turned party house!Go Bokke!

Now from rugby to Cricket... In my previous blog I spoke about how some frogs' calls can be quite complex, well the chirping of crickets, like the Field Cricket from the Gryllidae above, have been studied in Europe far more intensely than frogs' calls. Crickets appear to also have quite a vocabulary, with difference chirps for aggression, male beckoning female and male courting female. Also, their chirp rates' frequency fluctuates with temperature fluctuations and this is so reliable that the relationship between chirp rate and temperature is known as Dolbear's Law. Applying this law to the common american cricket, the Snowy Tree Cricket, we would be able to work out the ambient temperature, in fahrenheit, by adding 40 to the number of times the cricket chirps within the time-span of 14 seconds! Even more bizarre: There is a species of parasitic  tachnid fly with auditory organs that is attracted to the chirp of the above cricket, Once it detects the cricket it lays an egg on it and the maggot hatches and proceeds to consume the cricket from within. Since this was discovered in 1975, entomologists have discovered a few species of cricket on some Hawaiian islands that, although endowed with auditory organs and sound production organs, have evolved the ability to find females using more menial methods and do not chirp at all, to avoid attracting the fly! 

In the last blog I showed you a fly mopping up the pollen on a Hypoxis rigidula with abnormally light, lemon-yellow petals. Well ,it seems these flowers are a food source for a whole array of animals. Here, we have two caterpillars munching away at the (normal coloured) petals like there was no tomorrow! The Hypoxis is also very useful to us humans: The plant was recently described as a "Wonder Herb" and corms of the plant are now sold over the counter in health shops. The corms contain a compound called Hypoxiside, which converts to rooperol when it enters the human gut. Rooperol is a biologically active compound that balances the immune system and preparations of this are being used, in primary health care, to boost the immune systems of patients with HIV/AIDS.

This striking beetle is called a Skunk Longhorn because it expels a foul smell when it is harassed. This, and the beetle in the following photograph both belong to the Cerambycidae family and are collectively known as Long-horned Borer Beetles. This common name refers, firstly to the characteristically long antennae, and secondly to the fact that the females of these beetles use their ovipositors to drill into either wood, stems or roots and lay their egg batches therein. The female of this species lays her large batches of eggs in the wood of dead or dying trees, When the larvae hatch, they are voracious cannibals that consume their siblings until the survivors are so far apart that they are no longer a threat to each other. This boost of protein starts them gnawing away at the wood on which they feed. They avoid encountering their surviving siblings' tunnels as they create their own tunnels with the aid of vibration sensing organs, called chordotonal organs, that run along the sides of their fat white bodies. As they grow bigger, so their tunnels become wider but because wood is such a nutrient poor food source, it takes a few years for the grub to reach full size. At full size, they tunnel as close to the surface as they can and pupate there. 

This Long-horned Borer Beetle is called a Pondo Pondo Longhorn, Ceroplesis thunbergii, and it has a similar life history as the previous species. Once the pupal stage is complete, the adult chews its way to the surface of the wood or bark with well developed jaws and uses these to feed on nectar, pollen, leaves or stems of herbaceous plants. If you pick up any species of Long-horned Borer Beetles, you can watch as it rubs the base of its thorax against the rough edge of the elytra and produce a rather feeble sound. Since beetles have no auditory organs and the sound is not particularly frightening, it is uncertain why they would have evolved this ability. No species has been observed using this ability to communicate with others of its species and if there is a link between the ability to produce sounds and the vibration sensing organs in the larvae, then it still has to be discovered.

Forest Num Nums, Carissa bispinosa. zambesiensis, are flowering now which makes it easy to distinguish them by the white blooms in the gloom  of the afro-temperate forests on the estate. The small, bright red berry of this little tree from the poisonous Mikweed family is edible and tasty to boot, even though it contains a milky latex. This tree grows easily from seed and the dark, glossy green leaves, scented jasmine-like flowers and attractive berries, make it an ideal shade-loving ornamental. They are also armed with stout two-pronged spines and if planted in a row a meter apart, they will create an almost impenetrable barrier hedge. 

A close up of a Bark Spider, Caerostris sp. These spiders span a stout line up to 2 meters apart between two anchors and hang there large orb web from there in the night time. When morning arrives the spider dismantles the web, leaving only the initial stout line behind, and then retreats to a nearby branch where it huddles down for the day, looking just like a piece of bark. Now, the literature says that the spider eats the silk of the web when dismantling it so as not to waste the protein, a fact I always found hard to swallow because the webs are enormous compared to the spider. Well, when my daughter visited me a year and a half ago from the US, we were enjoying a walk, with flashlights, around the perimeter of  Shingwedzi camp in the Kruger Park after 10pm.. It was very windy and we encountered a Bark Spider waiting to snag prey on its huge web. I told her the story of it eating the web. She was also skeptical and then as if on cue, perhaps the light and the wind together were too much but the spider promptly began eating its web at a great speed! In less than 2 minutes the entire web, except for the stout line, was gone! I wish we had thought to film it with our phones but we were too stunned to think about it! 

When you walk down the footpaths of the estate, along the rivers or not, there is often a slim wasp that flies from the path before you at ankle height and settles again further along the path. Then takes off  again as you approach and moves further on and settles until you approach and the moves further on and.... This is it, Ammophila ferrugineipes from the Sphecidae family of Thread-waisted Wasps. These solitary wasps dig a hole into the hard ground (of the pathway) and construct a small chamber at the end, only a few centimeters below the ground. Once complete, she memorises the location of the hole and goes off in search of caterpillars which she attacks and paralyses with her sting. She then returns to the hole with her victim, flying cumbersomely (not a real word but descriptive) if it is small enough and dragging it if it is too big, and pulls the still-living worm down into the chamber. The worm was about 10cm away from the hole when the photo was taken. After she has deposited a suitable amount of worms into the chamber, she covers the hole up and expertly camouflages it by sprinkling sand on top. She even picked up the stone in the foreground in the picture, and placed it on top of the covered hole. The wasp then leaves and has nothing further to do with its offspring. After incubation, the maggot hatches from the egg and proceeds to eat the worms who are still fresh because they are still alive! Once the great meal is complete and the maggot is at full size, it pupates and emerges as an adult afterwards. 

This large wasp resembles the previous Thread-waisted Wasp with it's narrow waist but it rather belongs to the social Paper Wasp family, Vespidae. In my June blog I spoke about the beautiful Umbrella Paper Wasp and how the Foundress constructs a nest and has helpers help her raise her young. Well, even though this much bigger wasps looks like the previous solitary wasp it is also a Paper Wasp but tends to be less afraid of human presence so their nests are frequently found under the eaves of houses. I'm sure all the members from the estate have encountered them at their houses here, particularly those from Otter's Rest because we have to remove a whole bunch of nests from there every year. These wasps, unlike the Thread-waisted Wasps, feed their young in the nest pretty much like birds do.

This delightful little furry flower goes by the name of Doll's Powder Puff, Cyanotis speciosa, and it only stands 4-5 centimeters off the ground. It can be found throughout the estate but particularly in shallow soils in rocky situations in medium to high altitude grasslands. The fact that it thrives in full sun, in shallow soils, it reproduces vegetatively as well as by seed and it can withstand drought and flood make it an ideal plant for a Green Roof. In a green roof situation it requires little maintenance as well. If you go to even higher altitudes you may find it's rarer close cousin C.lapidosa, (also excellent for a green roof) which has got beautiful mauve flowers.

This Common Slug-eater, Duberria lutrix, was very reluctant to come out of the debris that it had burrowed into after I disturbed it while clearing the area for my carport. The thick scales on its snout enable it to burrow into surprisingly hard surfaces. This being this harmless snake's only defense except to roll up into a neat ball with its head inside the roll. As its common name suggests, the snake feeds exclusively on slugs and snails who are easily tracked down by the slimy trails they leave behind. it swallows slugs whole while it expertly de-shells snails by forcing the snail body into its mouth while pushing its snout between the snail and its shell. Those who have raised and fed these snakes say that it is very comical to watch the snake's mouth bubble after eating snails.

A small herd of Cape Buffaloes escaped from the Origstad Nature Reserve earlier in the month and I eagerly assisted by checking south and west of the reserve, in the Haartebees Vlakte, for any signs of them. I didn't find any buffalo but I did find a rocky "rainforest", like on the escarpment near the town of Graskop. In this mystical forest, besides the biggest Yellowwood that I have seen in the area, I found a Bottlebrush tree. I have always had such difficulty telling the two species we get here, the Transvaal Bottlebrush (Greyia sutherlandii) and the Woolly Bottlebrush (G.radlkoferi), apart, with the flower of the former being more cylindrical and the flower of the latter being more round. And the leaves of the former being glabrous and the leaves of the latter being hairy, with different individuals have hairier and smoother leaves etcetera etcetera. Coincidently, on the Plant Specialist Group outing I attended last month, I mentioned this difficulty to John Burrows, a well known botanist. He told me that the leaves of the Transvaal one are sticky at the bottom and shiny smooth, I won't get it wrong when I see it, he said. Well, he was right, of course. This one had the clearly cylindrical flowers of the Transvaal Bottlebrush and the leaves were sticky at the bottom and shiny (see insert). This puts my doubts to rest and I can now confidently say that I have NOT yet encountered a specimen of Transvaal Bottlebrush on the estate, only its close cousin, the Woolly Bottlebrush, Greyia radlkoferi. The other one can and should occur here and I will be more alert from now that I finally know the difference.

A Van Son's Thick-toed Gekko hatchling, Pachydactylus vansonii, found right up on the Goudkoppies plains. This 45mm long individual must have recently hatched, together with its single sibling, in the vicinity (The mother lays only 2 hard-shelled eggs). The adult is also boldly marked but with a very different pattern. Strange, though, because everywhere I have looked mentions that this is a lowveld gekko, not found in temperate areas except when transported there by humans (accidentally or not) and associated with houses. There's certainly no houses close to the Goudkoppies plains and it gets really cold up there but clearly they exist there and are breeding there. 

Wow, this moth looks a lot like a butterfly, especially an African Monarch like its name Monarch Looper (Cartaletis libyssa) would suggest. The second part of its common name, Looper, refers to the caterpillar who has less pairs of legs than your average caterpillar, leaving it with legs at the front of its body and at the back of its body. So when it moves, it reaches out and grabs the substrate with its front legs then lifts its back legs and the rest of its body up and brings it forward to the front legs. Then it lets go with the front legs and reaches out for its next foothold further along the substrate and repeats the process, giving it a looping gait. We commonly call them Inchworms which I think is more correct because all worms that do this belong to the Geometridae family of moths, which means: To measure the earth.

A spectacular Stemmed Clivia, Clivia caulescens. I know of a few members who love this plant but seldom get a chance to get here in November when they are flowering to see colonies of them in the forested gorges. This year they were out in force and the deeper part of the Upper Majubane was festooned with them. I had planned to go with Malcolm, the manager of MTPA's Emoyeni, to Clivia gorge beyond the Steenkamp's waterfalls this month but it was cancelled at the last moment. This gorge is apparently crowded with these plants so it must be quite a eye full during the flowering time. Perhaps next year.

I finally have got to see a Baboon Spider specimen on the estate. Unfortunately I cannot seem to find which species it is but it belongs in the subfamily Harpactrinae (Southern Baboon Spiders) in the Tarantula family. I have always known that they occur here because their burrows are easily recognisable but they are not easily coaxed out of it like their lowveld counterparts. Unlike most spiders, these are active hunters who do not rely on silk to catch their prey but instead actively hunt and ambush their prey in the night. The only time they use silk is to line their burrows and some species cover the entrance to their burrow to waterproof it. this individual was taking advantage of the lights around the office at night while it hunted the insects attracted by them, 

Finally, a rather depressing photograph of the larger of the Steenkamp's waterfalls taken a fortnight ago. It is reduced to almost a trickle as we enter mid summer with barely any rainfall. We had two heavy rainfalls in the latter part of the month but it fell so quickly and violently that all it did was cause a mini-flood and the water levels only rose for a few days, then dropped back down again. There is hope, though, because as I write this we have enjoyed 60mm of rain in 2 days (recorded as December rainfall) and it has been perfect rainfall: soft and continuous, allowing full absorption. Suddenly everything is looking greener, much greener than when I started this blog.

That's all for November. It is already time for the Silly Season again so we are preparing for a busy estate. Some very exciting news: Don has veiwed a small troop of Samango Monkeys in the Steenkamp's gorge. They have obviously migrated over the watershed from the Sabie valley side and it's great to have them here. let's hope they stay and become residents. I have gone searching but have so far come out empty handed. They are quiet, shy and retiring unlike their cousins so are difficult to spot. Keep a look out and try to snap a photo for me if you spot them to put into my files. 

See you soon!