A summer stroll

Take a stroll on the Common and although it looks hot and dry, you will be amazed at what you find. One of the storyboards has a display of the flowers you might come across ... Erica subdivaricata is just starting to flower ... and the Sour Fig (Carpobrotus edulis) flowers are opening too.

This beautiful little aristea, Aristea dichotoma, was flowering resolutely in the hot sun. It was identified by Fiona Watson and she observes that it seems to prefer to grow where it gets some shade. The leaves are tough, narrow and point vertically upwards to avoid direct sunlight. In this photo you can see the three-winged fruit.

The Common Sugarbush (Protea repens) was flowering too, and was covered in honeybees. Strictly speaking, this particular bush was planted here, but it might well have occurred here naturally in days gone by. Come along to the AGM on Monday 28 February, to find out more about the flowers of Meadowridge Common and the fascination of bees. These butterfly flowers are definitely not indignous. They are Gaura lindheimeri and hail from Texas and Louisiana.

You will notice lots of snails in the low shrubs on the Common. These are introduced snails - snailiens - that have become a bit of a pest in the Cape. More about them here.

Snailiens on the Common

Theba pisana
Common names: White Garden Snail - Sandhill Snail - Vine Snail - Dune Snail - White Italian Snail - Duineslak

Theba pisana was introduced by humans to South Africa sometime before 1881. It comes from the Mediterranean area – hence its name "White Italian Snail" - and has also spread to Australia, California and western Europe, as well as parts so South America and Bermuda, the Azores and Madeira. This snail lives mostly in the winter- and all-year-round-rainfall regions of the western and southern Cape from the Orange River mouth to East London. It seems to prefer to live near the coast, and is found in gardens, on road verges, in pastures, grainlands and vineyards, as well as in pristine coastal fynbos.

Is it a pest?
Yes – it is an agricultural and garden pest in the Cape where its population densities can be extremely high, but not enough is known about it to say exactly how pestiferous it is.

Life cycle
The snails in the photos above are aestivating (sitting out the summer) on Meadowridge Common. They are well adapted to survive the hot dry summer as they can drop their body temperature to well below 44 °C during the hottest time of the day. The reason you see them in bushes is because the temperature on the ground in summer is frequently higher than the snail’s body temperature, so they climb upward and aestivate above the ground where temperatures are lower.
The breeding season starts in late summer and autumn when mating occurs when their aestivation is broken after the onset of the first heavy rains of the season.
Egg-laying extends until late winter and spring. The bulk of the snails die after laying eggs, although not always – some have been known to live for 4 years.
The eggs hatch in later winter and spring.

What does that mean?
Aestivate Spend the summer in a state of torpor, a “summer sleep” rather like hibernating during the heat of summer.

Most of the information here comes from the book by Dai Herbert, The introduced terrestrial Mollusca of South Africa. It is available from SANBI and the Kirstenbosch Bookshop.

Spring walks on the Common

Stuart Hall holding up the metre-long leaf of Moraea fugax. Roger Graham (right) - the Chairman of the Friends of Meadowridge Common.

Fiona Watson handing over a CD of her description of the species that occur on Meadowridge Common to Stuart Hall at the end of the walk.

Fiona Watson - Botanical Officer, The Friends of Meadowridge Common.

"Don't stand on the Lampranthus reptans!"

The Friends of the Meadowridge Common hosted two spring walks on the Common recently. Stuart Hall, a botanist studying at UCT, led the first walk on Saturday 11 September and Olwen Gibson the second one on 18 September.
Meadowridge Common, a remnant of critically endangered lowlands fynbos, has been included in the booklet City of Cape Town Nature Reserves, a network of amazing urban biodiversity, and indeed, over 140 species of indigenous flowering plants have been identified by Fiona Watson on this small 7 ha open space - four of them in danger of extinction.

Flowers that were seen included Oxalis species and Lampranthus reptans flowers as well as species of Romulea in red, mauve and orange. Dainty white trachyandras that were just opening as were the sky-blue Heliophila africana. White botterblom (Sparaxis bulbifera) and yellow Senecio littoreus were also flowering, as was Pelargonium triste. The walks were well attended, with over 50 arriving for the first walk, and just less than half that for the second walk.

Lunate ladybirds and blister beetles

This morning on the Common I spotted this Lunate Ladybird (Cheilomenes lunata) sweeping a daisy bush for aphids. (Other beetles you might find on the Common.)

There were also several Spotted Blister Beetles (Ceroctis capensis) on the Fonteinbos or Bloukeur bushes (Psoralea pinnata). These beetles belong to the family Meloidae many of which secrete a poison, cantharadin, which may blister human skin, and if eaten, prove fatal!

Cape Autumn Widow

Flying around the Common now are lots of pretty brown butterflies. These are Cape Autumn Widows (Dira clytus) that are related to the Table Mountain Beauty. They are known as browns and belong to the family Nymphalidae and subfamily Satyrinae. The underside of the wing in most browns is cryptically coloured and eyespots are common. Foodplants are grasses and sedges.
Cape Autumn Widow butterflies fly slowly just above grass, often settling on bare patches of ground. The females scatter eggs in flight. The larvae are well camouflaged and feed on various grasses. Their preferred habitat is grassy areas on mountain slopes and lower ground.
Information from Field guide to insects of South Africa by Mike Picker, Charles Griffiths and Alan Weaving, Struik.

Jumping-ball Moths and the Glossy Wild-currant

Glossy Wild-currant, Shiny-leaved Rhus, Blinktaaibos
Searsia lucida (formerly Rhus lucuda) ANACARDACEAE (the mango family)

At the moment the fruits on the Glossy Wild-currant can be seen on the Common.
A fascinating insect-plant relationship plays itself out with the Glossy Wild-currant Rhus lucida and the Jumping Gall Moth Scyrotis athleta. In the sand and leaf-litter beneath Searsia lucida one can sometimes see small (about 6 mm) oval balls that jump. In the ball is the larva of a moth, Scyrotis athleta (family Cecidosidae). The movement and jumping is a response to heat and facilitates repositioning of the ball into ideal pupating conditions in the soil and leaf-litter. It is quite a mystery how such a small larva in such a confined space is able to exert the force required to jump (up to 10 cm). Janse (1920) concluded that it is done by careful positioning inside the ball and rapid contracting and relaxing of muscles.

The balls start off as bumps (galls) that form on the leaves of Searsia lucida. A female moth lays her egg probably by inserting her ovipositor into the leaf. The gall is formed around the hatched larva possibly as a result of the feeding action inside the leaf. This is still being investigated. The larva feeds inside the gall and when mature the external layer of the gall bursts open and the ball falls to the ground. Jumping can continue for up to 6 weeks and the moth emerges a few months later. (Information and more photos on the website biodiversityexplorer.)

Erica subdivaricata

Erica subdivaricata ERICACEAE (erica family)

This beautiful erica grows up to 1 m and has small, bell-shaped, white (sometimes just tinged with pale pink) flowers that come out from January on the Common. It occurs on lower slopes and flats in the south-western Cape, the Agulhas Plain and from Malmesbury to Bredasdorp, seeming to prefer slightly damp, partially shady spots.

It flowers in March on the Common.