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.

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)

The Third Edition is Here!

I’ve had many requests over the last couple of years for print copies of the guidebook. I decided that if I was going to print more, the book should be the best, most up-to-date version possible. So that’s what I’ve been working on, updating the book. It’s been four years since the printing of the second edition, and eight years since the first. I continue to discover and learn about the desert plants and so, to this third edition of the book, I have added 13 new plants (for a total of 155) and 90 new or additional photographs for the plants previously included.

And now I finally have a limited number of print copies available of the third edition of Wandering through Wadis: A nature-lover’s guide to the flora of South Sinai!!

The book is printed on thick quality paper bound with spiral wire 2 cm round. The book is 21 cm x 14.5 cm, about A5 paper size. It weighs 518 grams. Something to consider when deciding if you would want to carry it with you on hikes.
A bonus to reading the eBook version, especially on a tablet, is that you can easily zoom in on the photographs of the plants.

Also, depending on your device, it may weigh less than the print copy. My tablet, in a case, weighs 400 grams (100 less than the print copy).
One useful feature of the PDF version, especially when read on a laptop or PC, are the bookmarks that help you easily navigate through the book.

You can download a sample of the book as a PDF file for free here . This requires an email address. If you’d rather not enter an address, click the ‘Preview’ button on the top of this page to view the file online.

Print copies cost LE 400, including free delivery in Dahab. Shipping is possible within Egypt. Send me a message to arrange purchase and delivery of your copy.

The eBook version has also been updated and can be purchased online for $8 here. Contact me if you would like to arrange alternative payment and delivery options. Enter code WADIBLOG for a 10% discount.

Happy Wandering!

~Bernadette

Huntsman Spider

I have not been able to photograph a huntsman spider yet, but a friend in St. Katherine has and generously shared her pictures so I could write a post about this beauty!

This is a spider in the huntsman family of spiders (Sparassidae), specifically Eusparassus walckenaeri. There are 33 spiders in the Eusparassus genus, and they can be found in Africa, Asia, Europe, and Peru. Huntsman spiders are known for their incredible speed. In fact, it’s because of their lightning speed that the Jebeleya Bedouin call them beraira.

These huntsman spiders are large with flat bodies that are dark brown to orange-brown in color, with a pattern of spots and chevrons. The bodies can be from 1 to 2.5 cm in length, with the females being larger. The legs have dark bands of color and, although the legs of most spiders are perpendicular to their bodies, the legs of huntsman spiders are not. Their legs are angled and twisted in such a way that they move with a sideways crab-like motion. (Huntsman spiders are sometimes called giant crab spiders.)

Huntsman spiders are nocturnal hunters and feed on small and large insects, especially cockroaches, so a spider would be a welcome find in your home! And there’s no reason to be afraid of them; their venom won’t hurt you.

While these spiders may be imposing hunters, they are, of course, prey to other animals, especially to a family of wasps known as “spider wasps” (Pompilidae). A female spider wasp uses its venomous sting to paralyze a spider and then drags the spider to her nest or burrow. There, she lays an egg on the spider, which is anesthetized but alive. The wasp larva hatches and proceeds to feed on the spider, saving the vital organs for last, until it finally spins a cocoon and eventually emerges as an adult wasp.

These huntsman spiders can be found in open ground, but I have never spotted one in the wadis. They can also be found indoors and I’m pretty sure I have seen (some species of) huntsman spiders scuttle through the communal seating area of a camp in Ras Sidr. Have you spotted these huntsman spiders in South Sinai?

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

Desert Plant Adaptations (III) ~ Drought-escaping Plants

I’ve written about two general strategies that plants employ to survive in desert habitats – succulence and drought-deciduousness. Today I’ll introduce the most successful adapters to life in the desert – drought-escaping plants. Plants escape drought in one of two ways. They either survive only as seeds or they use taproots.

Annuals are plants that wither and die during the dry seasons but not before completing their life cycle, sometimes in just a few weeks. Their seeds are covered by a thick protective coat and are dispersed, only to wait underground as part of the desert’s “seed bank”. Contained within their seed coats are certain chemicals that prohibit germination. The seeds must wait for rain to wash these chemicals away before they can sprout. These are the plants that amaze us here in Sinai when our desert sands are suddenly covered in green after a spring rainstorm. These are also the plants that are so important to the Bedouins’ herds of goats and sheep. Some of these annuals that survive dry seasons as seeds include Astragalus spp., Artemisia spp., Diplotaxis spp., and Tribulus spp. and are pictured below.

Using taproots is also a successful strategy to avoid the problems associated with drought. A taproot is a very thick and long root that grows directly downward. Think of a carrot. The taproot is the main central root which other smaller roots grow off of. The long taproot allows the plant to reach water stored deep underground, providing an almost constant source of water. The taproots of Convolvulus lanatus, pictured below, and Artemisia monosperma are also covered with a thick bark that helps the roots to withstand the withering caused by wind.

You can learn more about these desert plants in my book, Wandering through Wadis: A nature-lover’s guide to the flora of South Sinai.

Desert Plant Adaptations (II) ~ Drought-deciduous Plants

It’s been longer than I had planned, and I’m not sure where the time went (well, a lot of it went to waiting for a new computer when my old one bit the dust), but I’m finally back with more information about how the plants in South Sinai have adapted to survive the harsh desert conditions! In the first installment of this series, I talked about succulence, the ability of plants to store water in their leaves, stems, and/or roots.

Lycium shawii, Desert Thorn

Today, I’ll discuss drought-deciduous plants. Instead of storing water like succulents, these plants use a different method to deal with drought conditions. During the dry seasons, they drop their leaves, allowing them to save water that would otherwise be lost during transpiration (similar to sweating in humans).

Because these plants don’t have their leaves to make food in the summer, their stems take over the photosynthesis process. (More on this in a future post.) Drought-deciduous plants also slow down their metabolism, making only enough energy to keep the plant alive. This means when conditions for growth are favorable again, the plants don’t have to start from zero. They’re already idling and ready to go, if we think in car terms; they don’t have to turn the ignition on first.

Lycium shawii, or Desert Thorn, is one example of a plant that is completely leafless in the summer. (It also has succulent leaves, so more than one adaptation to help it survive.) And because I don’t hike in the summertime, I don’t have photographs of this plant without leaves. But here’s a pic of their beautiful lush leaves:

In my next post, I’ll discuss the most successful adapters to life in the desert – the drought-escaping plants – so be sure to follow the blog or the Facebook page so you don’t miss out!

Nubian Ibex

Last spring, while wandering through wadis, I was lucky enough to spot a Nubian Ibex. Many years ago while driving, I saw a small herd of ibex in the distance. We stopped the car to watch them, but they were too far away to truly appreciate. Not this time!

Nubian Ibex (Capra nubiana)

Nubian Ibex are strong and stout goat-like mammals, adept and agile at climbing through the rocky mountainous terrain they typically call home.

Both male and female Nubian Ibex have backswept, ridged horns that are “flattened like sword blades”, but they are longer and heavier in males. Their coat is a light sandy brown on their upper parts with a white belly and legs. Males, and some old females, have black beards. Nubian Ibex have a distinctive pattern on their legs, with black patches above and below the knee and a white patch above their hooves.

These animals are active in the early morning and late afternoon. Ibex are herbivores, eating grass, shrubs, roots, and Acacia, and they need access to standing water.

While I have not come across another more ibex, I have seen their scat in various places that I have wandered. The scat is pellet-shaped and consists only of vegetation (not fur or feathers as in carnivores).

Encounters with ibex in South Sinai are rare as the number of these beautiful mammals has been greatly declining over the years, due in part to illegal hunting (which is why I won’t say where exactly I was wandering when I spotted this one). They are listed as a “vulnerable” species on the IUCN Red List. Their survival is also threatened by competition with local livestock and feral camels, habitat loss and degradation, and the fluctuating availability and distribution of waterholes.

My encounter with a Nubian Ibex was indeed special and not one I shall ever forget!

References:

Hoath, Richard. (2003). A Field Guide to the Mammals of Egypt. Cairo: The American University in Cairo Press.