Desert Skimmer

Widespread in Africa and the Middle East, the Desert Skimmer (Orthetrum ransonnetii) is mostly found in hot, arid, rocky environments, like Sinai’s desert mountain region.

These dragonflies have almost completely black venation and completely transparent wings. (There is no amber color on the hind wings like in other species.) The males are blue, with an unwaisted body, and females are brown.

Because their larvae and nymphs are aquatic, Desert Skimmers are common at small flowing and standing pools of water, and particularly areas without a lot of vegetation.

Desert Skimmers are known to hang from vertical or sub-vertical rocks and walls. And if the weather is hot, they especially like to hang in shaded places.

Dragonflies are carnivorous, predatory insects, hunting on the wing for other flying insects, including mosquitoes, flies, butterflies and moths, and even smaller dragonflies. Their acute eyesight and strong, agile flight help make them some of the world’s most efficient hunters. Dragonflies catch up to 95% of the prey they pursue. And that’s good, because a dragonfly eats up to 1/5 of its weight every day.

Bedouin in Sinai, at least of the Jebeleya tribe, call a dragonfly a ghizlan غِزْلان

What do you call them in your native language?

Be sure to read the post about the Violet Dropwing where you can learn more about dragonflies’ amazing wings!

Pearl Plant

The distinctive yellow flower stalks and the pearl-like fruit of this desert shrub make it easy to recognize and remember. The pearl plant (Ochradenus baccatus) is quite common in the region and are spotted often on my wanders in the wadis near Dahab. In the springtime, they are buzzing with flying insects – bees, wasps, flies, hover flies, beetles, and more I’m sure. This shrub has been reported as one of the most important food sources for many animal species.

There’s one species in particular that the plant has a special relationship with – the Egyptian spiny mouse (Acomys cahirinus). The fruit – a fleshy, juicy berry – is attractive to desert animals. But when an enzyme in the flesh of the berries combines with what’s inside the seed, it creates a toxic “mustard oil bomb”, deterring most animals from munching on this fruit (and destroying the seeds in the process). The spiny mouse has adapted to this, however. They will collect fruits and bring them to a different, rocky area, one that is safer for them. There, the mice chew and eat the flesh, careful not to bite the seed which they then spit out, avoiding any nastiness and helping to disperse the plant’s seeds. One study suggests these safer places the mice choose are actually “the best places for young O. baccatus plants to germinate, grow and survive.” How’s that for some symbiotic behavior!

The Bedouin of Sinai have also found benefits of the pearl plant, using it in traditional medicine to cure joint pain. A bowl of water in which the leaves have been boiled is placed in a hole in the ground above which a makeshift tent is constructed. The patient then lies beneath its cover for 24 hours. Pearl plant is also used to cure aches and pains in a camel’s body except instead of boiling the leaves, the plant is placed on embers in a hole. In Saudi Arabia, the plant is used to lower blood cholesterol and to counteract malaria.

Recently, a friend and fellow plant-lover asked me if this species had separate male and female plants as she had noticed that some plants were full of berries, while others only had a few. In dioecious plants, only the plants that grow female flowers produce fruit. Date palms are a good example. It turns out, though, that the pearl plant is gynodioecious, meaning that some plants have only female flowers and some plants are bisexual, having both male and female flowers. This explains the phenomenon my friend noticed – two plants, side by side, both in full bloom but only one seeming to fruit fully.

I’ve always liked this plant’s Latin name, Ochradenus baccatus. Ochradenus comes from the Greek for “pale yellow” or “yellow ochre”, and baccatus means “adorned with berries”. It is also known as taily weed and shrubby or sweet mignonette in English and is called gurdhi by the Bedouin in South Sinai.

References:

Bailey, C., & Danin, A. (1981). Bedouin plant utilization in the Sinai and the Negev. Economic Botany, 35(2), 145–162.

K.C. Burns. Seed Dispersal: The Blind Bomb Maker. Current Biology, Volume 22 (Issue 13), 2012, Pages R535-R537. https://doi.org/10.1016/j.cub.2012.05.014.

White-crowned Black Wheatear

If you are wandering through wadis in South Sinai, it is almost guaranteed that you will see, or at least hear, a White-crowned Black Wheatear (Oenanthe leucopyga). They are resident in the rocky deserts and common around settlements and oases. The Bedouin call these birds baqa’a’ بَجَعاء

Adult birds’ approximate length, from the tip of the bill to the end of the tail, is 17 cm. They are mostly black, with a white crown, rump, and tail. Juveniles, and sometimes females, have a black crown, as seen below.

Wheatears are passerine birds. Birds in this order are sometimes called songbirds or perching birds. Their toes are arranged in such a way, three pointing forward and one backward, that facilitates perching. Wheateats eat mainly insects and have a loud, varied song. One book, Birds of Eastern Africa, describes the song as “high, loud, happy, short, fast whistles”. I think they definitely have a beautiful song. Have a listen. How would you describe it?

Tero Linjama, XC341760. Accessible at www.xeno-canto.org/341760

According to the authors of Gardens of a Sacred Landscape: Bedouin Heritage and Natural History in the High Mountains of Sinai,

White-crowned Black Wheatears build their nest in three stages. Small smooth rocks are placed in front of the nest to prevent snakes from entering (or, according to one informant, to warn of a snake’s presence by the noise of their disturbance). The nest is then covered with small stones, and finally the nest is layered with twigs. The birds are present all year long in wadis and around houses, feeding on insects (including ants and spiders); one Bedouin told us that in summer they also feed on black grapes. They often become very tame, and are welcomed by Bedouin as one of the ‘birds of happiness.’

Zalat and Gilbert (2008)

Seeing and hearing them in the wadis definitely adds some happiness to my wanders!

Ashwagandha

I had already published the third edition of Wandering through Wadis when, last April, we came across several plants in Wadi Kid that we’d never seen before in the wild. Ashwagandha was one of them.

Ashwagandha is a well-known plant and is one of many names given to Withania somnifera, which grows here in Sinai. There is a related species that is also native to the area – Withania obtusifolia. To complicate matters a bit, there seems to be have been some debate recently as to whether W. obtusifolia should be classified as a subspecies of W. somnifera. Which exact species I have photographed here is a mystery to me, but let’s learn about ashwagandha.

Withania is a genus of plants in the nightshade family. Of the 23 species, two – including W. somnifera – are considered economically important and are cultivated in various regions around the world for medicinal uses. In Ayurveda medicine, ashwagandha is used as a medicinal herb and dietary supplement. Other names for W. somnifera include Indian ginseng, poison gooseberry, and winter cherry…but I’ll stick to using ashwagandha (until I can confirm the Arabic name).

Ashwagandha is a drought-tolerant evergreen shrub that grows in dry, stony soil and can grow to be between 35 and 75 cm tall. The branches are hairy and grow out radially from the central stem. The leaves are dull green, generally egg-shaped, and 10 – 12 cm long. The flowers are small, green, bell-shaped and grow in clusters; the ripe fruit is orange-red.

Sadly, a 2020 article in the Egyptian Journal of Botany reports that of the 8 threats the authors categorized plants as facing, Withania somnifera is subject to seven: over-collecting; habitat loss; clearance for agriculture, mining and quarrying; disturbance by cars and trampling; urbanization; tourism; and climatic change and environmental conditions. Even though ashwagandha is apparently a common plant in Egypt, after reading that list of threats, I feel lucky to have come across these plants in the wild. I had seen them before as my husband had them growing in his permaculture garden. He tells me that ashwagandha seems popular with Egyptian gardeners and farmers these days. Have you come across ashwagandha in your wadi wanderings? Or have it growing in your garden?

Leaf Morphology: Arrangement

Since my guidebook was intended for nature-lovers, not necessarily plant specialists, I took care to define and explain the technical terms used in the descriptions of the plants in my book, choosing simpler English synonyms when possible. But it’s not always possible. So I thought it might be helpful to dedicate a few blog posts to delving into some of these technical terms a bit more, deepening our understanding and looking at some specific examples from our desert plants. And I thought I’d start with the terms used in leaf morphology.

In botany, morphology is the study of the size, shape, and structure of plants. Plant biologists use these characteristics for the descriptions, classification, and identification of plants. Having some understanding of these different characteristics will help you to recognize and identify the plants you see while wandering through wadis.

In leaf morphology, one of the key characters studied is leaf arrangement, the number and placement of leaves along the stems. This arrangement of leaves is called phyllotaxy and we’ll talk today about four general categories – alternate, opposite, whorled, and rosette – although there are various levels and ways of categorizing these patterns.

Leaf morphology (Debivort) CC BY-SA 3.0

A node is the point where the leaf emerges from a stem or twig, and arrangement is always regular.

In the alternate pattern, sometimes called spiral, each leaf or leaflet grows from a different node.

In the opposite arrangement, two leaves or leaflets grow per node, on opposite sides of the stem.

If, in this opposite pattern, the successive leaf pairs grow at right angles, it is called decussate. These perpendicular pairs of leaves are typical of plants in the mint (Lamiaceae) family, like the ones pictured below.

In the whorled arrangement, three or more leaves or leaflets are connected at one node. Blepharis attentuata, pictured below, grows whorls of four leaves.

When the leaves of the plant emerge from the base in a whorled arrangement, spreading out in a circle, it is called a rosette.

Understanding the various patterns of leaf arrangement will help you to understand plant descriptions that you read in my book and other sources. And if you come across a plant you do not know, take note of its leaf arrangement (Photos are a great way to document this.) because it could be an important characteristic to consider when identifying the plant. In the next few posts, we’ll learn about other key characters in leaf morphology that will help us identify the plants.

One of my favorite desert plants is the caper bush; its leaves grow in an alternate pattern. I also love germander (Teucrium sp), both for its delicious fragrance and its neat geometrical leaf pattern. Do you recognize these leaf patterns in any of your favorite desert plants?

Darkling Beetles

Even if you spot no other critter while wandering through wadis, you are almost guaranteed to see at least one darkling beetle, likely scurrying across the sand to find safety under a desert plant.

Darkling beetles are what we commonly call the beetles that make up the Tenebrionidae family of beetles (Order Coleoptera). There are more than 20,000 species of darkling beetles worldwide. In Egypt, there are about 400 different species, around 120 of those can be found in Sinai. I believe most of the darkling beetles that I have photographed belong to the Adesmia genus, but I have not been able to narrow down the identification any further.

Though most darkling beetles are dark in color, they are actually named for their nocturnal habits. A few beetles are colored or patterned, sometimes with red. Many of the larger species, like the ones pictured here, are flightless. The elytra (the rigid, forewings) are fused.

The domed shape of these darkling beetles, particularly those in the Adesmia genus, remind the Jebeliya Bedouin of donkeys. They refer to them as ‘uwir al banat, or “newborn donkey for girls”. 1

Darkling beetles are common in desert areas, where they fill an ecological niche as plant scavengers. They are generalist omnivores though, meaning they can feed on a wide variety of plants and animals. As both larvae and adults, they feed on fresh or decaying plant matter like leaves or rotting wood. They will also eat fungi, dead insects and larvae. You will find darkling beetles living under logs and stones, in termite and ant nests, in plant debris, and in the dry dung of animals.

I always enjoy coming across these beetles while I’m wandering. They are entertaining to watch as they scuttle out of the way or over rocks. They are a good reminder that I am not alone out there, that there is a variety of wildlife surviving in our desert wadis.

On a lunch break in Wadi Lebba a few years ago, a darkling beetle was brave enough to approach our picnic spot so I shared a bite of orange with him.

If you’ve not spotted a darkling beetle on your wanders yet, watch the ground a few meters in front of you on your next hike. Or stop for a break near some plants. If you’re quiet, you might even hear them scrambling around.

References:

1- Zalat, S., & Gilbert, F. (2008). Gardens of a Sacred Landscape: Bedouin Heritage and Natural History in the High Mountains of Sinai. Cairo: The American University in Cairo Press.

Blackstart

It’s been awhile since I’ve featured a bird on the blog, so today let’s meet the Blackstart (Oenanthe melanura), called bal’ala by the Jebeliya Bedouin.

Blackstarts are common resident birds in South Sinai and are relatively unafraid of humans so there’s a good chance you’ll come across one in your wanders and maybe even get a chance to spend some time in their company. You might be serenaded by their song:

David Marques, XC82635. Accessible at http://www.xeno-canto.org/82635

These birds have bluish-grey to grey-brown plumage with darker colored wings. They are named (Oenanthe melanura) for their black tails, which they tend to have fanned out. In classical Greek, mela means black and oura, tail. Their bodies can be up to 14 cm long.

Blackstarts live in rocky wadis, deserts, and mountain slopes, where they can often be seen hopping around on the ground, feeding on insects.

Blackstarts are monogamous and pairs remain together in their breeding territory throughout the year. The female builds the nest, a shallow cup made of grass and leaves, in rock crevices and lines it with hair and fine plant material. She will lay 3 – 4 eggs, which are blue with reddish brown speckles. The eggs, if they aren’t preyed upon by a Golden Spiny Mouse, hatch after about 13 days. Both parents feed the chicks, which fledge, or grow flight feathers and are ready to learn to fly, after 14 days.

Camel Spider

Camel spiders, sun spiders, barrel spiders, wind scorpions – all of these common names for Galeodes arabs are misleading as these fascinating critters are neither spiders nor scorpions but rather solpugids, a group of arachnids in the order Solifugae. More appropriately, they are also commonly known as Egyptian Giant Solpugids.

You may have heard of them; camel spiders have been the subject of many urban legends about their size, speed, and appetite. Despite knowing that they posed no threat to me – they are not venomous but can inflict a painful bite – seeing my first one last weekend in Wadi Kid still kind of creeped me out, partly because it was as big as my hand!

Camel spiders can grow up to 15 cm long. They have eight legs, as do most arachnids, plus two large pedipalps, or sensory appendages, in the front that look like legs. (The one I spotted was missing its front right leg.) These pedipalps have a “friction-based adhesive quality” that allows the them to grasp their prey and climb smooth surfaces.1 Camel spiders have one pair of small eyes on the top of their heads and, with their eight legs, can move quite quickly – up to 16 kph!

These solpugids are voracious predators and eat insects, rodents, lizards, and even small birds. Their favorite prey are grasshoppers though. Camel spiders have two powerful chelicerae, or jaws, that they use to chop or saw their prey into a pulp. They begin by partially severing the neck, using one pair of chelicerae to hold the prey and the other to cut. Alternating the movements quickly between the two pairs of chelicerae, they continue along the whole body. At the same time, they use regurgitated digestive fluids to liquefy the flesh and suck up the nutrients. (And if this doesn’t sound too horrifying to you, visit the first link in the resources given below to read about their mating practices!)

These two distinctive jaws give rise to the name used by the Jebeliya Bedouin for camel spiders – abu hanakain, the father of two mouths.

Solifugae, the order these camel spiders belong to, means those who flee from the sun in Latin. These solpugids often seek shade from the intense desert sun in a person’s shadow and may seem to be “chasing” a person, but really all they want is a break from the heat.

Have you spotted any Egyptian Giant Solpugids during your wanders through South Sinai?

Resources:

1 – Bittel, J. (2017, August 9). Camel Spiders are Fast, Furious, and Horrifically Fascinating. Smithsonian Magazine.

National Geographic – Camel Spider

Aly, D. & Khalil, R. (2011). Wildlife in South Sinai. Cairo. Funded by the E.U. in cooperation with G.O.S.S.

Sand Wasp

It’s springtime and the air is full of the sweet scent of flowers and the sound of buzzing insects. Some of the buzzers I’ve spotted recently in my garden are strikingly-colored sand wasps (Bembix sp.).

Sand wasps are solitary hunting wasps that build their nests in the ground. Worldwide, there are over 350 different species in the Bembix genus. They are typically yellow and black and are reported to be particularly diverse in dry habitats. Bedouin in Sinai call all wasps dabra.

Adult sand wasps feed on nectar, but the females are skilled hunters, capturing prey to feed their larvae. The females dig nests in the ground using their mandibles and front legs. The nests are simple burrows with an enlarged chamber at the bottom, the brood cell, which they keep stocked with fresh prey for their developing larvae. It is not uncommon for several females to dig their nests in a common area, but they are not social; they do not cooperate or share the labor.

Flies are the most common type of prey hunted, but sand wasps have also been observed preying on damselflies, grasshoppers, mantids, bugs, antlions, lacewings, butterflies, bees and wasps – but not beetles or spiders. The adult sand wasps catch the prey in mid-air, paralyze them with venom, and then carry them back to the waiting larvae.

After they have had their fill, the larvae spin silk cocoons and enter a prepupal stage. Pupation may not occur until the following spring, and then male wasps will emerge before female ones. Adult sand wasps probably live from several weeks to several months and spend much of their time sleeping. They spend this inactive time within their nests or in temporary sleeping burrows. The adult sand wasps may be prey themselves – to birds, lizards, robber flies, antlions, and velvet ants.

One source I consulted reports that these solitary wasps do not attack and sting humans, but another says they can deliver a painful sting if their nest is disturbed. So, like all stinging insects, it is best just to leave them in peace.

Have you spotted sand wasps on your wadi wanders or in your garden?

Resources:

Evans, H. & O’Neill, K. (2007). The Sand Wasps: Natural History and Behavior. Cambridge: Harvard University Press.

Scarce Marsh Helleborine

If you follow the Wandering through Wadis Facebook page, you might recall the photographs of orchids that I shared a few weeks ago. I had no idea that there were orchids growing in the desert, but after my friend sent me photos of the blooms she had seen, I obviously had no choice but to go see them for myself.

I had identified the orchids in my friend’s photos as Scarce (or Eastern) Marsh Helliborine (Epipactis veratrifolia) but, admittedly, I knew nothing about orchids. So I’ve been reading up on them. And I’ve learned a lot of fascinating things about orchids in general, but also about these rare beauties that are native to Sinai. (They are not found in mainland Egypt.)

Most orchids (more than 99% of all species) are epiphytic and use their roots to attach themselves to and grow on trees. The Scarce Marsh Helleborine, however, is a terrestrial, or ground, orchid and grows its roots firmly in soil.

This helleborine is a perennial herb and grows, from a fleshy rhizome, to be between 25 – 150 cm tall. The leaves are ovate (egg-shaped) and pointed at both ends. They grow along the stem and can be 8 – 25 cm long. The inflorescence, or cluster of flowers, grows atop an erect stem. The flowers are fairly open and are green to yellowish-green in color with purplish or reddish radial stripes. The lip, or bottom middle petal, is tipped in white. The upper part of the stems, bracts, ovaries, and sepals are covered in short, fine hairs. In Dahab, the orchids were found growing among native grasses in a wet area.

Like all orchids, this helleborine is dependent on a mycorrhizal symbiosis, a mutually beneficial relationship between a plant and a fungus, to complete its life cycle. The plant’s fruit capsule is full of microscopic seeds (in some species, over a million), but these seeds all lack endosperm. Endosperm is the tissue usually found inside seeds that provides nutrition to the plant as it sprouts. Because an orchid’s seeds don’t have this inborn nutrition, they rely on fungi to provide them with the nutrients they need to germinate. The chance of germination is so small that only a minute fraction of the released seeds grow into adult plants.

But before a plant can even produce any of these seeds, it must first be pollinated. And to help ensure that, the Scarce Marsh Helleborine employs a trick, a special mimicry, to lure pollinating hoverflies to its flowers. The flowers emit three chemical substances that are usually released as alarm pheromones among aphids. Aphids are the preferred diet of hoverfly larvae. So female hoverflies smell these chemicals, interpret this to mean that aphids are nearby, and proceed to lay their eggs near the source of the scent – the flowers. The hoverflies are rewarded with a small sip of nectar, but their larvae are doomed to starve because, when they hatch, there will be no aphids around to consume. (This is a strange contradiction from an evolutionary perspective because since the larvae die, the number of potential pollinators decreases.) The orchids are mimicking the aphids, taking advantage of the female hoverflies and deceiving them into pollinating the flowers.

As you can see, these rare orchid blooms are not only beautiful but also full of amazing natural wonder!

Resources:

Plants of the World Online (Epipactis veratrifolia)

Orchid tricks hoverflies (Max Planck Society)