Sunday, July 3, 2011

The harmful effects of herbicides


A few weeks ago I wrote that road side verges provide the right conditions for many species of flora and fauna. I also wrote that I had not seen herbicides being used to re­move this vegetation for many years and I was hoping that this practice had stopped. Last week I saw two teams in different parts of Malta using herbicides on pavements.
I do not understand this obsession to remove any living things from built up areas. Wild plants not only provide habitat and food for butterflies, bees and other insects but also have aesthetic value. They add colour to their drab surroundings and cover ugly concrete and rubbish. But, while accepting that some people cannot appreciate nature and use their power to anihilate it, it is unacceptable that herbicides are sprayed on pavements.
Herbicides are poisons that are used to kill vegetation. Many if not all of them can also harm humans, pets and wildlife. The toxicity of herbicides varies greatly as does the time taken for them to break down. Some are programmed to decompose after a relatively short time so that crops can be sown in soil after they have been sprayed but, while the breakdown products might not kill plants, there is no guarantee that these products do not harm humans and other animals.
Furthermore, anybody using a pavement has no option but to walk on poisoned ground. Children and pets are more vulnerable to poisons and their small size and the fact that they are closer to the ground makes absorption of poisons faster and easier. And even if children and pets had to be kept inside, a person walking on a poisoned pavement can unwittingly collect poison on his or her shoes and transfer it to his or her home where his children or pets come in contact with it.
There are indications that some herbicides are carcinogenic and, although acute toxicity comes only from exposure to large quantities of herbicides, even low doses might have long-term problems.
Using herbicides to remove vegetation might be the cheapest way to remove unwanted vegetation but our health and environment are worth more than that.

This article was published in The Times on 11.05.2011

The island bluetail damselfly

Island bluetail damselfly (Ischnura genei)
The island bluetail damselfly is a delicate insect known in Maltese as damigella. It is closely related to the more robust dragonflies. 

It lives in valleys with running water and near ponds, pools and reservoirs. 

It is a weak flyer and does not stray too far from aquatic habitats on which it depends throughout its life cycle. Like dragonflies the damselfly lays its eggs in water. The larva spends its entire life under water feeding on smaller organisms.

Two forms of this species are found in two colour forms: green and reddish-brown. Both forms can occur in a particular place and the colour might a result of different environmental temperature during the larval stage of the damselfly. 

In other insect species larvae that are developing later in the season, when the temperature is higher give rise to brown adults which are thus better camouflaged in the dry summer vegetation. As far as I know this has not been investigated in damselflies but a future study might show such a link.

Like dragonflies, it has very interesting courtship and mating habits, quite different from that of other insects.

The genital opening is near the tip of the tail, but before mating the male transfers his sperm to an accessory genital organ on the underside of his abdomen, just behind the thorax. 

He then finds a female and seizes her by the neck with a pair of claspers situated at the hind end of his body. They then fly in tandem and settle, linked together in this way.

When mating takes place, the female bends her body around under the male’s body and the sperm is transferred for fertilization.

Damselflies and dragonflies use different methods to lay eggs. Some insert them in the plants of aquatic plants or in vegetation at the water’s edge. 

Others fly over the water and drop them, while others dip the abdomen into the water to wash the eggs off the tip. Some species remain in tandem whilst the female is laying.

Their larvae or nymphs spend all their time under water hunting smaller animals. A hunting larva stalks its prey to within a centimetre or less, than shoots out the labium and seizes its prey with its claws. 

The victims are mostly insects, but large well-grown larvae can even catch tadpoles and small fish. The labium is a segmented organ, found in all insects below the mouth. In dragonfly larvae this organ bears a pair of pincer-like jaws near the tip and is elongated and hinged so that it can be extended in front of the head.

This article was published in The Times on 20.04.2011

The Scilly buttercup

Scilly buttercup (Ranunculus muricatus)
The Scilly buttercup is a species of buttercup which is sometimes also known as the spiny-fruit buttercup. It is native to Europe, but it can be found in many other places in the world, including parts of Africa, Australia, and the western and eastern United States, as an introduced species and agricultural and roadside weed. It grows in wet habitats, such as irrigation ditches. 

In Malta it is found in humid valley bottoms such as at Chadwick Lakes and Fiddien. It is an annual or sometimes biennial herb producing a mostly hairless stem up to half a meter long which may grow erect or decumbent along the ground.

The buttercups belong to a large genus of plants that can be found almost throughout the world. It consists of about 400 species some of which are terrestrial while others are aquatic. In the genus, known as Ranunculus, we also find the spearworts, water crowfoots and the lesser celendine. 

The name Ranunculus derives from the Latin words rana (frog) and ulus (little). This probably refers to many species being found near water, like frogs. Most buttercup species are poisonous when eaten by sheep, and other livestock but they are left alone because they have a bitter taste and have a blistering effect on the mouth caused by the poison.

Most of the species have bright yellow or white flowers. If the flowers are white they have a yellow center. In many species the petals are highly lustrous making it difficult to photograph them especially in direct sunlight.

In Malta at least 13 species have been recorded some of which are aquatic and can be found floating in pools and streams especially in the numerous small pools found in the rocky habitat known as garigue.

All Ranunculus species are poisonous when eaten fresh by cattle, horses and other livestock but their acrid taste and the blistering of the mouth caused by their poison means they are usually left uneaten. Poisoning can occur where buttercups are abundant in overgrazed fields where little other edible plant growth is left, and the animals eat them out of desperation. Symptoms include bloody diarrhea, excessive salivation, colic, and severe blistering of the mucous membranes and gastrointestinal tract. 

When Ranunculus plants are handled, naturally occurring ranunculin is broken down to form protoanemonin, which is known to cause contact dermatitis in humans and care should therefore be exercised in excessive handling of the plants. The toxins are degraded by drying, so hay containing dried buttercups is safe.

This article was published in The Times on 13.04.2011

The pomatias

Pomatias sulcatus
I recently took some pictures of an interesting species of snail but although I found its scientific name I could not find a common name for it so as its scientific name is Pomatias sulcatus, I used part of this name for the title of this article.

This species of land snail is found throughout the western Mediterranean. It is common on calcareous soils near the coast and inland. It can be found on soil, in crevices in rocky ground, under stones and among fallen leaves. Sometimes it buries itself in the soil while the specimens I photographed were living on a tree trunk. In the Maltese island it is common on Malta, Gozo and Comino as well as on some of the smaller islands.
There was and probably still is some controversy about this snail in the Maltese islands. Some biologists have listed it as a distinct species endemic to the Maltese island others as a subspecies while others believe that the snails found on Malta are not different enough from the snails found in other parts of the Mediterranean to be considered as a separate species or subspecies.

Pomatias sulcatus is not the only species of pomatias that can be found in the Maltese islands. Another species, Pomatias elegans which is known as the round mouthed snail, can be found at San Anton Gardens at Attard. It probably found its way there on imported plants. This species is common in southern Europe and lives in similar habitats as Pomatias sulcatus.

The pomatias are one of the few groups of land snails that have an operculum. This is a calcareous structure like a small lid that fits neatly in the opening of the shell sealing the soft body inside. The operculum is found in most species of marine and freshwater snails but very rarely in land snails. Its main function is to prevent desiccation especially in those species that live in the intertidal or splash zone of the coast. The presence of an operculum in the pomatias suggests that these snails evolved from marine snails. 

This article was published in The Times on 06.04.10

Poisonous insects

Ground beetle (Carabus morbillosus ssp. alterans)
Last week a Maltese soldier was hospitalized after he ate a common oil beetle (not in picture) which is also known as a blister beetle. He was not aware that the small black insect was so poisonous as it does not have any particular characteristics that indicate that it is dangerous.

In Maltese the oil beetle is known as dliela żejtnija

It is normally found crawling in humid areas feeding on vegetation. Its forewings which in most beetles cover and protect the whole abdomen are small leaving the soft elongated abdomen exposed. Compared to most other beetles that are found in the Maltese islands it is big. The female grows up to 30 mm while the maximum length of the male is 21 mm.

Although it has no distinctive warning markings, sheep and I assume goats seem to be aware of its danger. Shepherds have told me that grazing animals sometimes leave a tuft of vegetation uneaten because of the presence of this beetle. According to them if a sheep eats this beetle it immediately becomes bloated and dies. 

There are records outside Malta of horses accidentally ingesting a blister beetle (not necessarily a species found in Malta) and dying.

The poison, found in this and other related beetles, is known as cantharidin. This causes blistering of the skin and is used to remove warts although its use is not recommended because of its toxicity. 

The poison is generally obtained from a small shiny emerald-green beetle known as Spanish fly which is related to the common oil beetle. The product which is also known as Spanish Fly is given to animals to induce them to mate. Spanish fly has been used by some as an aphrodisiac because during excretion the chemical irritates and stimulates the urethra. 

This is a very dangerous practice as the amount used is very small and the difference between an effective and a toxic dose is very small.

Most toxic animals, especially insects, advertise their toxicity by having warning colours which predators learn to leave alone. Wasps have yellow and black stripes. Ladybirds have black spots on a black background and the great ground beetle (photograph) has a shiny violet body and emits a foul smell when threatened.

Until last week very few people were aware of the toxicity of this beetle. One should keep in mind that this is not the only species of poisonous beetle in the Maltese islands. There are another nine species that belong to the same family in the Maltese islands and they are probably as poisonous as the common oil beetle .

This article was published in The Times on 30.03.2011

Saturday, July 2, 2011

Pine tree pollination

Aleppo Pine (Pinus halepensis)
The Aleppo pine tree, the tree that has been planted along so many of our roads, in public gardens such as Buskett and afforestation areas such as L-Aħrax tal-Mellieħa and Miżieb, at this time of the year goes through an impressive change. 

The Aleppo pine is normally light green but just now the predominant colour is light brown although its hue varies under different conditions. If seen early on a sunny morning the tree is nearly yellow and shines as if it has a light of its own. When it rains it becomes much darker.

The changes are caused by the appearance on its branches of male and female cones. The cones are the reproductive organs of pine trees. 

The male cones produce pollen which is transferred to the female cones so that when it meets the female gametes fertilisation takes place. 

On pine trees, the transfer of pollen takes place without the intervention of any animal. Pines rely on wind to carry the pollen from male to female cones. 

This is a wasteful method as much of the pollen never reaches its target so the tree has to produce large quantities of very small, light pollen to ensure that at least some of it meets its female counterpart.

When the weather is right, that is, if it has not rained and the air is dry, the slightest breeze is enough to blow the pollen off the male cones. I

f there is no breeze swaying the branch slightly, as what happens when a bird lands on it, is enough to set the release of the pollen in motion. So much pollen can be released every time that this happens that the pollen looks like a small cloud of fine dust.

These changes take place very quickly and do not last long but few people notice them because many of us go through life without being fully aware of our surroundings. Our lives would be much richer if we had to take the time to look around more carefully and become aware of the obvious and the subtle.

This article was published in The Times on 23.03.2011

Sunday, May 1, 2011

Spring hunting

This year’s spring hunting season is nearly over and never too soon because it should have never been opened in the first place. The shooting of turtle doves and quails in spring does not make sense.

Hunters have been complaining for years that the number of migrating game birds has decreased. Older hunters talk nostalgically about the days many years ago when large numbers of turtle doves migrated over the Maltese islands. Hunters had been catching birds in spring for centuries and the birds kept coming every spring but those days are over. 

The number of turtle doves migrating over the Maltese islands started to decrease decades ago. 

The warnings have been there for all to see but the hunters still refuse to read the signs. When the turtle doves did not arrive they blamed the weather - next year will be better - but it was not. Then they blamed the oil refineries in North Africa which they said were preventing the birds from migrating. 

When Maltese hunters started to go on hunting trips to Egypt they realised that there they could still find a lot of turtle doves there so they concluded that the turtle doves had changed routes but they never blamed themselves and they still don’t.

The days when turtle doves migrated in large numbers are over because as the Maltese say ‘Tieħu bla ma trodd is-swar tħott’ which in English can be roughly translated as if you take away without putting back, even the fortifications are dismantled.

To make matters worse many hunters are not adhering to the conditions which they are supposed to follow. Birds of prey and other protected birds are still being shot. 

The Prime Minister said that no law breaking will be tolerated and the season will be closed if laws are broken. But, how many protected birds have to be killed before he can say that enough is enough? 

BirdLife which is organising another spring camp to monitor bird hunting has already stated that it has recorded hundreds of cases of law breaking. And how is the government going to justify all this with the European Commission? Spring hunting does not make sense and should not be allowed. The Maltese government should have made a bold decision in favour of nature and the environment and brought Malta in line with the rest of Europe.

Sunday, April 17, 2011

Roadside vegetation

Common mallow (Malva sylvestris)
Road verges, especially in rural areas, often provide the right conditions for many species of wild plants to grow along them. 

In a densely populated island like ours where much of the original natural habitats had to give way to buildings, roads and agriculture and as a result of this road sides have become important because they can also provide a good habitat for several species of animals especially insects and reptiles. 

They can also act as corridors linking a number of habitats together and can facilitate the dispersal and migration of plants and animals from one place to another.

Many of the plant species that grow in these spaces are adapted to live in disturbed habitats but this does not reduce their importance in the ecology of the Maltese islands. 

Unfortunately there still exists the mentality that all wild plants are weeds which compete directly with humans and must therefore be destroyed. 

In former years farmers weeded their fields with their bare hands or with a hoe. Nowadays they have an arsenal of herbicides with which to get rid of plants which are considered as competitors. And the fight is no longer limited to a small area surrounding their trees and crops.

Herbicides were also used to kill the vegetation growing along country roads. I have not seen this practice for some years now and it might have been stopped although some localities hire persons to remove wild plants growing along country roads  

This destruction of precious fauna and flora must stop. We need a complete change of attitude and start looking at verges as important habitats for our flora and fauna.

We should also start looking at roundabouts and centre-strips as potential habitats. These sites are being planted with cultivated plants with no ecological value. These plants do not support any wildlife while some need large quantities of water to maintain a resource which needs to be conserved.

Management plants to improve the biodiversity of all these sites should be drawn up to ensure that they are managed properly so that indigenous plants are encouraged to grow in them and thus provide a habitat and food for our fauna especially insects including butterflies and bees. 

This article was published in The Times on 16.03.2011

The white mignonette

White mignonette (Reseda alba)
The white mignonette is an unmistakable perennial plant found growing along road sides, on disturbed ground, in rocky habitats and garigue. 

It grows throughout the Mediterranean region but is more common in the western part. It can now also be found in the Americas and Australia as an introduced species as well as in most parts of the world as a cultivated garden plant. 

In Malta it can be seen growing on walls including old buildings and bastions but not as a garden plant.

It flowers from January to May. The inflorescence, which may take up most of the upper stem, is densely packed with many small creamy-white flowers. Each flower has five or six petals, each of which is divided into three long, narrow lobes, making it appear frilly. 

The inflorescence has a symmetrical shape which gives the plant a very attractive appearance even before the flowers are open.

Two species of mignonettes are found in Malta. The most common is the white mignonette which is known in Maltese as denb il-ħaruf  because of the shape of its inflorescence, which looks very much like a lamb’s tail.

The yellow mignonette is known as denb il-ħaruf isfar. It has pale yellow flowers but is rare and can be overlooked for the white flowered species.

The mignonettes belong to the reseda family. Reseda is a Latin word meaning to assuage or calm because these species are supposed t have sedative properties.

Another member of this family, the dyer’s rocket, which does not grow in the Maltese islands, was used in Roman times as a sedative and to treat bruises. 

A volatile oil was extracted from its roots to be used in perfumery as far back as the first millennium BC but its use came to an end in the beginning of the 20th century with the discovery of cheap synthetic dyes.

The white mignonette is the food plant of among other things the bath white. This is a species of butterfly related to the more common large and small whites. The caterpillar is blue with yellow lines on the back and sides and many black spots. 

This article was published in The Times on 08.03.2011

Sand crocus

The sand-crocus is a small flowering plant that must to be looked at closely to be appreciated properly. 

It is found throughout the Mediterranean area. In Malta it grows in patches of shallow soil in rocky areas. It is a perennial plant which spends the dry summer months beneath the surface as a bulb. 

In autumn, following the first substantial rainfall it produces a small number of slender leaves. The first flowers appear in February when the surrounding vegetation is still green and they continue to flower until April by which time much of the surrounding vegetation begins to dry up.

In Maltese it is known as żagħfran tal-blat. Another similar but less common species, the Maltese sand-crocus (żagħfran tal-blat ta’ Malta) is endemic to the Maltese islands. This species is distinguished from the more widespread species by having very narrow petals.

The sand-crocuses belong to a genus known as the Romulea. The name of this genus is derived from that of Romulus one of the two brothers who are said to have founded Rome because one member of this genus is very common in the Roman countryside.

The sand-crocuses belong to the iris family. This family is represented in the Maltese islands by several species of irises including the barbary nut (fjurdulis salvaġġ) and the southern dwarf iris (bellus), the field gladiolus (ħabb il-qamħ tar-raba) and the crocuses. 

This article was published in The Times on 02.02.2011

Shooting of the spoonbills

It happened again. Last Friday’s storm forced several flocks of migrating spoonbills to seek shelter in the Maltese islands. 

The spoonbills were wintering in Africa, possibly in Tunisia where I have seen this species wintering in saltpans. The spoonbill can be found in Eurasia from Spain to Japan but in Europe it is restricted mainly to the Netherlands, Spain, Austria, Hungary and Greece. 

The birds shot last Friday were returning to their breeding grounds in Europe.

The shooting of a single spoonbill is despicable. Shooting several is contemptible and shameful. It can easily make an impact on the number of breeding spoonbills in a colony and it could be years before the size of the colony recovers.

These massacres have been going on for a long time and it is about time that they are stopped. 

When I was a kid I was once shocked to see tens of hunters shooting at several flocks of herons trying to seek shelter in St Thomas Bay during a storm. At the time shooting herons was not illegal and the hunters were all bragging and showing off their trophies. 

I remember one hunter claiming to have shot twenty one birds but he collected only seven as the rest were too badly mutilated and could not be stuffed and mounted for his collection. Things should have changed but unfortunately they have not. 

This is not an issue of hunters being faced with new legislation and finding it ‘impossible’ to adapt. Spoonbills have been protected for thirty years. Many of today’s hunters were not even born when it became illegal to shoot at a spoonbill while most hunters below the age of fifty started hunting when the spoonbill was already protected.

Hunters have been shooting at protected birds for three decades and it is about time for this reprehensible activity to be stopped. The hunting federation has condemned the illegal shooting of the spoonbills but this is not enough. 

The hunting organisations have had more than enough time in which to control their members but have failed to do so. They are now trying to convince one and all that if they are allowed to hunt in spring they will behave and will not shoot at protected birds but actions speak louder than words.

The government should stop trying to appease hunters. It should not even consider allowing hunting in spring when birds are returning to their breeding grounds and it should bring Malta in line with the rest of Europe once and for all. (This article was published on 23.02.2011).

The rockets

The white wall rocket which is also known as the white mustard, ġarġir abjad in Maltese, is a very common annual plant with small white flowers. 

It can be seen from early autumn to late spring in disturbed soils especially in fields. The closely related perennial wall rocket (ġarġir isfar) has yellow flowers. Were it not for the fact that both species grow in large numbers, sometimes covering whole patches of ground, they would easily be overlooked.

The rockets belong to the crucifer family, an important family which is sometimes also known as the mustard or cabbage family. The name crucifer means “cross-bearing” because the flowers have four petals arranged in the shape of a cross. 

Members of this family can be found growing on most continents especially in northern temperate regions although their stronghold are the countries surrounding the Mediterranean. 

The crucifer family consists of about 3,700 species among which are several that have been selectively bred to produces several vegetables including cabbages, turnips, radishes and rapeseed. The stocks (ġiżi) also form part of this family. Some species are also of medicinal importance.

One species in this family has been cultivated for a very long time and has been selectively bred into so many varieties that it now provides ten of the most common vegetables. These include the cabbages, cauliflowers, brussels sprouts, kohlrabi and broccoli among others. 

These vegetables are recommended as healthy foods because they are rich in vitamin C and soluble fibres as well as many nutrients and other chemicals which are known to have anti-cancer properties.

The best known species, the cabbage, is one of the oldest vegetables. In Greek times it was believed that the cabbage plant sprouted form the perspiration of Zeus and was given to women just before giving birth to induce a good flow of breast milk. The Romans used it as an antidote to alcohol so as to prevent a hangover. 

This article was published in The Times on 15.02.2011

Tuesday, March 29, 2011

Colours in the Maltese countryside

Every winter I notice that during this dark season the flowers are most wild flowers blooming at this time of the year are yellow. As the days get longer, the sun brighter and the air warmer other colours especially reds and pink start to appear more often. 

At the peak of the spring flowering season yellow ceases to be the dominant colour.

The most common flowers in winter are the cape sorrel (ħaxixa ngliża), and the crown daisy (lellux – which means bright yellow or shiny in Maltese). Another common species is the perennial hyoseris which is known in Maltese as żigland tal-pizzi. This might seem like a coincidence but in nature it is evolution that shapes life.

Flowers are the reproductive structures of plants. They consist of male and female sexual organs. The female organs are the ovaries which produce the ovules. The stamens are column-like structures. They are topped by an anther where pollen is produced. When pollen reaches the ovules fertilisation takes place and seeds are formed. Some flowers are fertilised by their own pollen but evolution has pushed plants towards cross-fertilisation as this ensures genetic diversity and makes plants better able to deal with changes in the environment. 

Pollen may be transferred by wind or in rare cases by water. Wind-pollinated flowers do not need to attract pollinators and they are usually small, unattractive structure with no fragrance. The pollen is small and light and contains little if any proteins and is thus of no nutritional value to animals. Other plants require animals, such as insects, birds or bats to transfer the pollen from one flower to another. 

These plants have showy flowers and attract animals by providing them with nectar and nutrient-rich pollen. They usually have large coloured petals and nectar guides which show pollinators were to look for nectar. These guides are sometimes visible only in UV light which we cannot see but which can be seen by bees. Flowers also attract pollinators by scent.

I have not yet seen any studies about the colour of flowers during different seasons but I think that yellow being a bright colour is easier to see in low light intensity. In winter brightly coloured flowers attract more insects as they are more easily seen in low light. In spring, having a yellow colour does not give them an advantage over plants with other colours. 

This article was published in The Times on 09.02.2011

Friday, February 4, 2011

Goat snails

Goat Snail (Cantareus apertus)
Ask any Maltese who collects snails for cooking about which species of snail can be eaten and the answer is always that only one snail, the edible snail, can be eaten. 

All other species are inedible because they have a bitter taste. The edible snail is listed in books as għakrux raġel but most people refer to it as bebbuxu tal-ikel

In Gozo a ninety four year old man informed me that in the past Gozitans ate the red banded snail which is known in Maltese as għakrux mara. He said that there was nothing wrong with the taste of this snail but it was not easy to extract the snail from the shell as when it was cooked it remained deep inside the shell and one had to gently break the shell and wash away the shell fragments. 

This required a lot of time and patience so snail collectors have learnt that this species of snail is inedible but do not known the reason why.

These same people insist that the worst tasting snail is the goat snail which is known in Maltese as mogħża or sometimes bebbuxu iswed because of its very dark flesh. All those I asked said that it has a very bad taste but none had ever tried eating it. 

But in southern Italy the goat snail is cooked regularly. 

The people of Salento prepare the municeddhi cu lla panna which they proudly claim to be a specialty of the area. They collect the snails when they have the white seal known as operculum. This is a hard substance which many snails produce to seal themselves within the shell so as to avoid desiccation during dry periods. These people claim that this snail has a more delicate taste and is less bitter than the edible snail. 

It is so popular that it can be found for sale in open air markets and traditional fruit and vegetable vendors. It might be that the people of Salento have learnt to collect these snails when they do not have any bitter taste while the Maltese never learnt this.

The goat snail is a common species in the Maltese countryside. It is found in Mediterranean countries in garigue and steppe habitats especially near cultivated fields in areas where its favorite food plant, the squill, grows in abundance. It is seen in the rainy season and quickly disappears when it is not raining. It has been introduced in Australia and America where it has become a pest. 

This article was published in The Times on 02.02.11

Blue bottles

Bluebottle (Calliphora vicina)
The bluebottle is a common fly. It sometimes enters houses but in winter you are more likely to see it in the countryside especially on sunny days as it sunbathes in a sheltered place to warm up its body. 

It is slightly larger than the much common housefly and has a grey head and abdomen and a bright metallic blue abdomen. 

The body and legs are covered in short stiff hair which is not easily seen with the naked eye unless you manage to get very close to a sedentary fly.

The eggs are laid in decaying meat or other organic material on which the maggots can feed. The maggots are fully grown in a few days and when mature they move to a dry patch of soil and bury themselves below the surface to pupate. 

The cocoon takes from two to three weeks to metamorphose into an adult fly.

In autumn bluebottles visit the flowers of the carob tree. They are attracted to the flowers because of their strong smell of rotting vegetation and are important pollinators of this tree.

The bluebottle is known in Maltese as żarżura while the closely related greenbottle is known as dehbija tal-ħmieġ, These two names might have been coined by naturalists or they might have been used in the past but are not used anymore as the Maltese nowadays refer to most flies as dubbien without being aware of the various species that they meet in their everyday life.

These two species belong to a group of flies known as blow-flies. This name comes from the old English term for meat on which a fly had laid eggs, which was fly-blown. It is estimated that there are over 1,100 species of blowflies. Six of them are found n the Maltese islands. Blowflies are known carriers of disease including dysentery. 

This article was published in The Times on 26.01.11

Warning colours

Soldier bug (Spilostethus pandurus)
Animals with bright colours or contrasting patterns often have an active means of defence that they want to. This is known as warning or aposematic colouration. 

These species do not bother to hide themselves as they advertise the fact that they have an effective mode of defence being either unpalatable or other dangerous. 

Many insects such as several species of bugs and ladybirds have bitter tasting chemicals produced by special glands. Wasps warn potential predators that they have a painful sting.

Predators quickly learn that insects with particular colours or patterns should be left alone. They learn by mistakes which means that some individuals are eaten but their sacrifice is good for the survival of the species as a whole.

Warning colouration is so effective that harmless organisms sometimes mimic harmful animals and use the same colours to defend themselves even though they themselves are not dangerous. 

To be effective the number of mimicking organisms must be much less than that of the unpalatable or dangerous species as otherwise predators would not learn to leave them alone. This type of mimicry is known as Batesian mimicry. 

Another type of mimicry is known as Mullerian mimicry. This occurs when different species of unpalatable or dangerous animals adopt the same colouration thus reinforcing the message and ensuring that fewer individuals need to be sacrificed for predators to learn to leave animals with similar colours or patterns alone.

The soldier bug, known in Maltese as suldat, is a common insect that can be seen running on the ground or at the base of several species of plants. 

At this time of the year it can also be seen on sunny days on a south facing stone or trunk to warm itself up in the early morning sun. It belongs to the suborder Heteroptera (true bugs) which forms part of the order Hemiptera. At first glance it could easily be mistaken for a fire bug another common insect known in Maltese as seffud tal-ġamar, a case of Mullerian mimicry. 

This article was published in The Times on 19.01.11

The early orchids

Fan-lipped orchid
We have several of species of orchids in the Maltese islands. The best time to see many of them in flower is in March but some species flower earlier or later than that and to see all of them one needs to look for them throughout the flowering season.

From a botanical point of view I prefer to think of the year as starting in September which is the month when we usually get the first substantial rains after summer. 

The earliest orchid to flower is thus the autumn ladies tresses which is in flower as early as October and November. 

This is a very small innocuous plant with white or pale green flowers growing in a spiral around a vertical spike. It is a rare species which I have not seen for a number of years. In Maltese it is known as ħajja u mejta meaning ‘dead and alive’ a name generally given to all orchids because they are characterised by having two tubers one of which is swollen and the other shrivelled.

In December one can find the Cretan blue orchid (dubbiena bikrija). This was formerly known as the brown orchid and was considered as a very variable species. Some botanists now believe that this is not one species but three each of which has distinguishing characteristics but one needs to examine them carefully to be able to tell them apart.

Last weekend while taking pictures at Wardija I found the fan-lipped orchid (orkida ħamra) and very soon I expect to find an early flowering species, the scented bug orchid (orkida tfuħ). Soon after that another species which in recent years was renamed will appear - the conical orchid (orkida tat-tikek). This was formerly known as the milky orchid.

The last orchid to flower is the common pyramidal orchid (orkida piramidali) which can be seen in flower in April and May when the surrounding vegetation has already started to dry up and shrivel. 

The changing nomenclature of this group of plants can sometimes be very confusing and frustrating but this should not put people off from enjoying their beauty. This is the best time to start looking for orchids and to start a photographic collection of all the local species. 

All one has to do is to dedicate a few enjoyable hours every week to wander in the countryside. Orchids can be difficult to find but once you see one plant you will start seeing others in the vicinity and then you start wondering how you could have missed seeing them earlier. 

This article was published in The Times on 12.01.11

The annual daisy


The annual daisy is a small flowering plant with a typical daisy structure consisting of several white petals surrounding many small yellow florets. It is a common plant which can be found in various habitats especially in damp humid places throughout the Mediterranean flowering from November to March.

 In Maltese it is known as bebuna.


The closely related southern daisy, margerita salvaġġa in Maltese, is larger and flowers in autumn and winter. These two species are very similar and difficult to tell apart unless one looked carefully at the whole structure of the plant especially the leaves.

The two species belong to the aster family which also known as the daisy or sunflower family. This is the largest family of flowering plants consisting of more than 23,000 species. 

The asters are found throughout the world but they are most common in cooler regions.

Their most characteristic feature is the shape of the inflorescence which is often mistaken for a single flower as it consists of a dense cluster surrounded by large petals. 

The inflorescence consists of two types of flowers. In the centre one finds several small flowers with five small petals which form a tube. At the outer side of the circle there are similar flowers each of which has a large petal. Together these flowers give rise to the daisy shaped flowering head that characterises these flowers.

In this large family we find many important species. Many are cultivated commercially and are important agricultural crops. Among these we find the lettuce, globe artichokes, and Jerusalem artichokes. Another important species is the chamomile. The pot marigold is grown for herbal tea and the potpourri industry. 

This article was published in The Times on 05.01.11

Wednesday, January 26, 2011

Borage

Winter has officially just started but in the Maltese islands this time of the year is more like a northern spring. The countryside is all green and many plants are starting to flower. Last Sunday I saw the first blue flowers of the borage which will be there for one to enjoy throughout the rest of winter and most of spring.

Borage, which is known in Maltese as fidloqqom, is also known as starflower. It probably originated in Syria and surrounding countries but is now found throughout the Mediterranean as well as in much of Europe, North Africa, Asia Minor as well as South America.
Borage has been cultivated for a long time for culinary and medicinal uses. Nowadays it is grown mainly for the production of a health supplement known as starflower oil or borage oil.
The active substances are found in the leaves and in the flowers which contain mucilage, nitrates of calcium and potassium, etc. Thanks to its mucilage borage is a demulcent and sooths respiratory problems. It is also used as diuretic, depurative as well as to treat inflammation and itchiness. For skin conditions one should soak the flowers and leaves in the water before having a bath.
The leaves are used in salads or as a garnish while the flowers are the source of a blue colouring agent used in desserts. Different parts of the plant are used in various dishes in many parts of Europe including Germany, Spain and Greece. I once tried a recipe from the Ligurian region of Italy in which the leaves are used for the filling of ravioli and the flowers to make a very good tasting sauce.
The English name is similar to its scientific name borago. There are many explanations for the origins of this name such as borago being a corruption of corago from cor (heart) and ago (I bring) but the most likely origin is from Arabic abou-rach, “father of sweat” because when drunk as an infusion it encourages sweating as it has been known since antiquity to have an effect on the adrenal glands and by increasing the production of adrenaline it gives courage. (This article was published in The Times on 28.12.10)

The cottony scale insect

The cottony cushion scale is native to Australia. It was identified in New Zealand in 1878 but spread to every place around the world where citrus trees are cultivated. In Malta it was found in a garden at St Georges near San Giljan in 1907. Immediate action was taken to slow its spread to other parts of the Maltese islands until a system to control it biologically which was giving successful results in other countries could be used in Malta. The action taken might have slowed down its spread but did not stop this insect from reaching the central parts of Malta, including Lija, Attard and Balzan which at the time were well known for the cultivation of orange trees.
Last summer a small numbers of scale insects decided to set up home on some of my aubergine plants. I allowed them to grow so that I would be able to photograph them and follow their life cycle. This species of scale insects has an oval shape and can grow up to half a centimeter long. Mature insects attach themselves to a host plant by means of waxy secretions and remain stationary. In summer they produce a white egg sac on grooves on their back in which they deposit hundreds of red eggs. A few days ago I photographed minute nymphs coming out of the egg sac. These nymphs are the dispersal stage of the insect. They crawl from one plant to another but they are so are so light that they are often lifted up by the wind and carried to other areas to establish new populations.
The nymphs damage the host plant as they suck fluids from the veins of leaves and small twigs. As they grow they break out of their skin (exoskeleton) and move to another spot leaving behind their telltale skin and waxy secretions. When they become larger they move to larger twigs and eventually to the branches or tree trunk.
Most cottony cushion scales are hermaphrodites. They fertilise themselves and produce hermaphrodite insects. Males do exist. When a male fertilises a female both hermaphrodites and males are produced.
This insect is of interest because it was one of the first pests to be successfully controlled biologically. Between 1888 and 1889 a species of ladybird, the vedalia beetle, was imported into the United States from Australia to control this pest which was threatening California’s citrus trees. The experiment was a success and farmers in other countries started to use the beetle to control the scale insect wherever it appeared. In 1911 the vedalia beetle, which is known in Maltese as nannakola tas-salib, was imported into Malta by the Department of Agriculture to control the spread of the cottony scale insect which by that time was infesting citrus trees in most parts of Malta. (This article was published in The Times on 22.12.10)

Lantana

Lantana (Lantana camara)
In Malta the lantana grows very well and although it is widely planted as an ornamental garden plant it has not become a pest as it has in many tropical and sub-tropical countries.

 It is originally native of the American tropics. Its native range includes Mexico, Colombia and Venezuela as well as in the state of Texas in the United States.

 In Malta it is commonly known both in English and Maltese as lantana but it is also known as the Spanish flag, West Indian lantana and the red or yellow sage and in some places as ham ‘n eggs or bacon and eggs. The latter two names are popular in the United States because of the yellow and pink inflorescence.

In countries with a climate similar to that of its country of origin it can become a serious pest can push out native vegetation. It has invaded many parts of India, Australia and Africa. A farmer in Zimbabwe whom I was visiting many years ago had to use tractors to pull out the large lantana bushes that had taken over some of his fields.

The plant is slightly toxic and animals can become ill after eating it. Its berries are edible although they are toxic when still green.

A plus point for this species is that it’s flowers attracts many butterflies, moths and bees. In the United States it is often planted in butterfly gardens. I often spend a long time taking pictures of insects visiting the flowers of a lantana hedge at Buskett Gardens.

In parts of India the stalks of the lantana are now being used to make household furniture while the smaller branches are tied together to make brooms. Lantana is also used in herbal medicine. Leaf extracts are said to have antimicrobial, fungicidal and insecticidal properties. 

This article was published in The Times on 13.12.10

Grasshoppers

As autumn turns to winter one starts seeing less insects in the countryside. Last Sunday while taking pictures at Selmun the only insects I saw in any number were grasshoppers. Several jumped into the large spaces between the stones of an old wall and walked slowly on the white limestone dust into the inner part of the wall until they disappeared from view. 

Grasshoppers overwinter as eggs, nymphs or adults so the ones I was observing could be looking for a suitable place to lay eggs or to hibernate.

Grasshoppers are familiar insects with short antennae and large hind legs. Sometimes the hind legs have short projections that are rubbed against the lower edges of the forewing to make a noise during the day. The legs are hard and can exert a lot of force and this gave rise to the idea in Malta that grasshoppers are armed with a knife which they use for self defense.

It is estimated that there are about 11,000 species of grasshopper in the world. Most live in tropical areas especially in rain forests. About 25 species are found in the Maltese islands. Some species are very common and you will see them jumping away from you wherever you walk in the countryside. Most are greyish brown and blend perfectly well with their surroundings. 

Some species have brightly coloured hind wings which are normally kept hidden under the forewings. They are uncovered only when they are flying. Te bright colours have an important function. 

When danger approaches these insects rely on their excellent camouflage for protection but if a predator approaches too closely they fly away startling their enemy with their bright colour for long enough to be able to fly away. They do not fly very far away but as soon as they land they disappear again.

Grasshoppers eat mostly vegetation and some species can become pests.

They have an incomplete metamorphoses as when they hatch the young look like small wingless adults which grow progressively larger as they break out of one exoskeleton after the other until they reach adulthood.

In Africa and in other parts of the world where they occur in large numbers, grasshoppers can be an important source of proteins, minerals and vitamins especially in times of food shortage. 

This article was pubished in The Times on 8.12.10

Sunday, January 23, 2011

The tree house leek first grown as a house plant

Tree house leek (Aeonium arboreum)
There are many species on non-indigenous plants in the Maltese countryside. 

These are native to other countries but have established themselves and become naturalised in the Maltese islands. Many of them were brought to Malta as garden plants 

The Cape sorrel, (ħaxixa ngliża) was grown at the Argotti Gardens in Floriana at the beginning of the nineteenth century . It is a native of South Africa but found the conditions in the Maltese countryside to be so favourable that after a short while it established itself in the Maltese countryside and became very common everywhere.

Another alien species is the tree house-leek which is known in Maltese as kalluwa

This species was first grown in Malta as a garden plant. It was often planted close to farmhouses and eventually started to grow wild in the Maltese countryside.

 It is now considered as a naturalised alien species. It is a succulent, subtropical member of the genus Aeonium. 

This name is derived from the ancient Greek word aionos which means immortal. This genus consists of about thirty-five species most of which are native to the Canary Islands. A few species are found in Madeira, Morocco and in eastern Africa. 

The climate of the Canary Islands is fairly similar to that of the Mediterranean and many of the species manage to grow very well in Mediterranean countries including Malta.

Between the end of December and late February the tree house-leek produces a large number of bright yellow flowers that grow on an ovoid structure. The leaves are attached to the main stem and grow wrapped around it to form a rosette.

The tree house-leek is the most commonly cultivated aeonium.

 In winter it produces numerous bright yellow flowers on compact ovoid structures. Several varieties and hybrids exist including some with brown or variegated leaves. In gardens they can grow up to two metres but in Malta I have never seen a plant more than one metre high.

This article was published in the Times on 1.12.10

The unusual friar's cowl

Friar's Cowl (Arisarum vulgare)
The friar’s cowl is an unusual plant found throughout the Mediterranean region.

 I am sure that whoever gave it its name in English was a religious person who got his inspiration from the monks and friars’ habit. In Maltese this plant is called garni tal-pipi which can be translated as smoking pipes’ arum.

It is a member of the arum family. Other members of this family include the Italian lord and ladies (garni) a common species that flowers in early spring.

The friar’s cowl is a perennial that is it can live for more than one year although during the summer months it can be found only as an underground tuberous rhizome. 

In autumn the rhizome grows new leaves and a short while later a flower appears above the surrounding vegetation. The flower is brown with a curved tongue-like structure growing out of it. The flower is surrounded by a tubular leave whose top part is shaped like a hood.

 This is the part we normally see. This leave has many dark spots that resemble ants. It is believed that these are a part of the defence system of the plant as it is a form of visual insect mimicry that serves as an herbivore repellent. This structure is so unusual and beautiful that I do not tire of taking pictures of it.

The friar’s cowl flowers throughout autumn and winter. 

In North Africa the rhizomes are used as food. Before being eaten the rhizomes must be washed in copious amounts of water to remove needle-like crystals of calcium oxalate which produce pain when they come in contact with the lips, tongue or skin. Cooking can also remove the effect of these crystals. It is also claimed that parts of the plant can are used to treat ear and spleen tumours.

This article was published in The Times on 24.11.10

Three species of hawk moths in different localities

Caterpillar of the Convolvulus Hawk moth (Agrius convolvuli)
 
In the past few days I found the caterpillars of three species of hawk moths in different localities around Malta. They belonged to the death’s head hawk moth, the convolvulus hawk moth and the Maltese spurge hawk moth. The first two are the largest moths in the Maltese islands. 

Hawk moths are medium sized to large moths with narrow wings and streamlined abdomens that make it possible for them to fly rapidly and for long distances. Some hawk moths can fly at 50 kilometres per hour and are among the fastest insects.

The convolvulus hawk moth is found throughout Europe and Africa. Its caterpillar (photograph) feeds on bindweeds which are known scientifically as Convolvulaceae hence the English name of this moth. 

In Maltese it is known as baħrija tal-leblieb. Leblieb is bindweed in Maltese. 

The caterpillar of this species, like that of most other hawk moths, has a horn-like structure at the posterior end of its body. It is dark in colour unlike the caterpillars of the two other species I found which are both very brightly coloured. 

The caterpillar of the convolvulus was crossing a path at Il-Majjistral Park. It was probably searching for a place to pupate. Hawk moths spend the winter months as a pupa.

 Before turning into a pupa the caterpillars of these moths burrow into the soil and remain under the surface or in a small chamber until they metamorphose into an adult moth. In topical species the change can take place in about three weeks but in colder parts of the world the adult emerges in spring or summer.

The adult convolvulus moth  is grey with pink, black and white spots on both sides of the abdomen. It spends the day on a wall or tree bark where it can be very well camouflaged. When disturbed it humps its thorax to scare any predator away.

This article was published in The Times on 10.11.10