Wednesday, September 29, 2010

The scarab beetles

Some days ago I found several beetles along the water’s edge at Mellieha Bay. Several more were floating on the water. 

All were dead except for a couple which I collected and moved to a safer place. 

These beetles, like many other insects are attracted to light and they must have been confused by some lights after having emerged from their cocoon and fell in the sea.

The beetles belonged to a very common species of the scarab family. Like many members of this family it does not have a common English name and is known as a scarab beetle.

 In Maltese most beetles are known as ħanfus. Like every identified plant and animal it has a unique scientific name - Phyllognathus excavatus. The males of this species have a structure on their head that resembles the horn of a rhinoceros. There are other scarab beetles with such a horn on their head which are popularly known as rhinoceros beetles.

At this time of the year it is the most common scarab beetle. It is found throughout the Mediterranean to the as to Iran and Crimea and in Senegal.

The scarab beetle family consists of over 30,000 species. Many of these beetles have bright metallic colours ranging in size from 1.5 to 160 mm. The larvae are soft bodied pale yellow or white grubs. 

Most live underground or under leaves away from sunlight. The majority are scavengers and many species live on dung, dead animals or decaying vegetation.

One of the best known species of scarab is the dung beetle which was revered as sacred in ancient Egypt. Dung beetles collect dung which they shape into the shape of a ball and then roll to an underground nest. They lay eggs in it so that on hatching the larvae find a readily available rich source of food. 

This article was published in The Times on 30.09.2010

Wednesday, September 22, 2010

The oak eggar


The oak eggar is a beautiful large moth. It is seen in August and September mainly in Buskett and its surroundings. 

The males are red brown and fly during the day and many people mistake them for butterflies.

 Last Sunday, while watching the migration of raptors at Buskett I saw at least three oak eggars being caught and eaten by bee eaters, the brightly coloured migratory birds that specialise in hunting flying insects especially bees.

Female oak eggars are larger and paler than males and are nocturnal. It is said that females fly slowly at dusk dropping eggs on the vegetation below but I still have to see this interesting behaviour.

The eggs are laid on ivy which grows in abundance especially on the north-facing walls in Buskett. In Maltese the oak eggar is known as baħrija tal-ballut but it should be pointed out that despite its name, this species does not feed on oak, but is called so because its cocoon is shaped like an acorn.

The caterpillar is covered in brown hairs and has a black line between each segment on each of which there is a small tuft of white hair along the sides. I have seen and photographed the caterpillar on the leaves of the bramble at Wied il-Luq and also walking on the ground in the vicinity of this common plant.

The oak eggar belongs to the Lasiocampidae family of moths which has over 2000 species worldwide. These are usually large moths with feather-like antennae. The caterpillars are covered in long hair. Four species are found in the Maltese islands. 

This article was published in The Times on 22.0./2010

Wednesday, September 15, 2010

The prickly pear


The prickly pear

The prickly pear tree is often planted around fields in Malta and Gozo as a windbreak and for its fruit.

 Like all cacti it is a native of the American continent and did not arrive in Europe before the discovery of this continent.

 This species is believed to be the earliest species of cactus to be cultivated and nowadays many hybrids and varieties exist. Its exact origins are not known but it probably came from Mexico where similar species can still be found growing wild.

It is nowadays cultivated in many arid and semiarid regions of the world, especially around the southern and eastern coast of the Mediterranean. In Mexico it is also grown for the young leaf-like stems which form part of many traditional Mexican recipes.

Prickly pear is known in Maltese as bajtar tax-xewk. Several varieties can be found in Malta each of which has a distinctive name. The three most common varieties are the “yellow’ variety is known as isfar or Malti, the ‘red’ known as as l-aħmar or l-ingliż and the ‘white’ known as abjad or Franċiż.

 Other less common varieties include tax-xitwa which ripens between October and December, l-Ispanjol which has large reddish fruit, and the lanġasi which has pear-shaped fruit.

It is widely believed that prickly pears have medicinal properties. Many chemical compounds have been extracted from it which have been found to be useful against several conditions especially inflammations. In Malta it was used mainly against stomach aches, bone pain, inflammations, and insect stings. 

It is nowadays being used in cosmetics and in food supplements. The fruit is also used to make jams, jellies and liqueurs. The local bajtra is one while Tungi Spirit which is produced on the island of Saint Helena is another.

 The Mexicans have been using prickly spears to produce a spirit known as colonche for thousands of years.

A species of scale insect thrives on the prickly pear. 

This insect produces carmic acid which is used to make cochineal, a red dye used in red food colouring and cosmetics. The dye was used by the Aztec and Mayans in Oaxaca, Mexico, and exported to Europe. In the mid 19th century an attempt was made to grow these insects on Maltese prickly pears and start producing cochineal in Malta but the project never took off the ground and was abandoned after some years. 

This article was published in The Times on 07.09.2010

The sounds of Malta's summer

Cicada (Cicada orni)
This year, summer started later than usual and it seems that it is ending earlier as well. It has already rained and the temperature is going down but summer is not just sunny days and high temperatures. Summer, like every other season has its characteristic sounds and smells which together differentiate it from every other season.

The sound I associate most with a Maltese summer is that of the cicada the large insect that looks like a fly that spends days on end making a loud buzzing noise. 

During the night, when the cicada stops singing, the cricket takes over. This nocturnal insect used to be very common but like many other insects, especially those that live in agricultural areas, it has decreased in number probably because of the use of pesticides. 

Country people used to catch crickets and take them home to hear them sing. They caught them by placing a wet cloth on the ground in a field in which tomatoes were being grown. In the morning they collected the crickets from beneath the cloth and placed them in special cages or in a tin can.

Those walk in parts of the countryside where the bear’s breaches grows can also hear the sound of its seed pods as they crack open in the heat. The sound which resembles that of a small pistol is followed by that of its large seeds of falling on the large dry leaves of this plant.

Spanish sparrows gather in large trees to roost every evening but in summer their numbers and the noise they make reaches a peak as the population is augmented by the recently fledged birds.

In early July the first autumn migrants appear in the Maltese islands. The first birds to arrive are the waders which leave their breeding grounds in the far north immediately as soon as their short breeding season is over. They have to move south as weather at such latitudes is very unpredictable and it can snow even in August.

For those with trained ears the shrill call of another migrant bird, the kingfisher, becomes another common summer sound. Kingfishers arrive in August. They often perch on a rock along the coast waiting for a right-sized fish to swim by. It flies low over the water often making a short sharp whistle, chee, repeated two or three times. 

The most common sound nowadays is that of the ubiquitous car which can be heard even from Comino where no cars are present and because of this we often miss the beautiful natural sounds which were once part of the Maltese environment.

This article was published in The Times on 15.09.2010

Saturday, September 4, 2010

The rosemary leaf beetle lives on herbs

Rosemary leaf beetle (Chrysolina americana)
The rosemary leaf beetle is a common beetle that lives on rosemary and other herbs. Its scientific name is Chrysolina americana. Despite its scientific name, it is a native of southern Europe. In the early 1990s it appeared in Britain and during the last decade it has become an established pest on rosemary, lavender and related plants.

It is an attractive beetle with metallic green and purple stripes down its back. . In the sunlight these stripes reflect all the colours of the rainbow - rather like oil on water. This effect is very beautiful to see but difficult to capture on camera.

It is usually found in groups on stems or feeding on the new growth of plants. The larvae are small slug-like grubs which are usually found on the underside of leaves. They are light grey with horizontal dark stripes running the length of their body.

Their favourite food plant, the rosemary is a medium-sized bush of the Mediterranean, recognised by its narrow fleshy leaves, small pale blue flowers and more than anything else by its typical aromatic smell. The bush is usually about one metre high but when hanging down from a vertical rock face it can grow up to two metres. It flowers throughout the year.

The rosemary leaf beetle, known in Maltese as żabbella tal-klin, belongs to the Chrysomelidae family, a group of beetles known as the leaf beetles. This is a family of over 35,000 species, one of the largest and most commonly-encountered of all beetle families. About 60 of these species are found in the Maltese islands. Another common member of this large family is the red leaf beetle, żabbella ħamra in Maltese, which is found in vegetation in the countryside. Adult and larval leaf beetles feed on all sorts of plant tissue. Many are economically important pests of agriculture. 

This article was published in The Times on 05.01.2010

The hyacinth bean

The hyacinth bean is also known as the Indian bean, Egyptian bean or lablab. It is a species of bean that is widespread as a food crop throughout the tropics especially in Africa, India and Indonesia. It is a traditional food plant in parts of Africa but is little-known outside the continent although it has the potential to improve nutrition, boost food security, foster rural development and support sustainable land use in many parts of the world.

It grows as a vine and produces purple flowers and striking purple-green coloured pods. It grows profusely and produces edible leaves, flowers, pods, seeds and roots although one must be careful when eating the dry beans as these contain a poison which can be removed by prolonged boiling.

It is not normally grown in Malta but I recently found several plants of this species growing profusely close to a wall in an abandoned field at Mġarr. I first found it last summer when the plants were in full flower. Last week they had hundreds of bean pods. The plants are very large even though it seemed that nobody had been taking any care of them for a very long time.

Being a native of Africa the hyacinth bean tolerates drought and can grow in places where the rainfall is less that 500 mm and it is able to extract water from at least 2 metres depth although it does loose its leaves during prolonged dry periods.

In many parts of the tropics it is grown as forage and as an ornamental plant. It is also said to have medicinal properties.

It seems that this bean grows easily in the Maltese climate and will be able to grow even if the climate changes and becomes drier as it is drought tolerant and does not require large quantities of water. It would make sense for local farmers to grow it instead of other plants that require large quantities of water. 

At current extraction rates in a few years time Maltese ground water will not be fit for agriculture or drinking and the amount of water being pumped up must be reduced drastically to make it sustainable. 

Introducing new crops which require less water is one way of conserving Malta’s limited ground water. One should not expect local farmers to experiment and try new crops on their own initiative. It should be the Department of Agriculture that carries out more research in this direction and encourage local farmers to start producing crops better adapted to Malta’s changing climate. 

This article was published in The Times on 13.01.2010

Friday, September 3, 2010

A true predator kills and eats another organism

In ecological terms predation is described as the interaction whereby one organism feeds on its prey. Predators may or may not kill their prey before eating them but the end result is beneficial to the predator and harmful to the prey. This has led to selective pressures on one another which have lead to an evolutionary arms race between the predator and prey resulting in various anti-predator adaptations.

Predators are usually classified by the way they feed and the way they interact with their prey. A true predator is one which kills and eat anther organism. It may hunt actively for its prey or sit and wait for it to approach within striking distance. Some predators such as the lion kill larger prey which they dismember and chew while others like dolphins eat their prey whole. Some predators like snakes poison their prey to subdue it or kill it before eating it.

Prey species have evolved several ways to avoid being preyed upon. One common form of defence is aggression. The electric eel uses an electric current to kill prey and to defend itself from other predators. Others animals use their tusks, horns and hoofs to defend themselves.

An interesting form of defence, common in birds, is mobbing. This is when animals attack and harass a predator to drive it away. This can be seen in many species of birds such as gulls which attach predator, including men, when these get anywhere near their nests.

Some animals are camouflaged to avoid being seen while others are brightly coloured and do not bother to hide themselves. Their colouration is recognised and remembered by predators as a danger signal and are left alone. These animals such as the ladybirds, wasps and the caterpillars of the spurge hawkmoths, are usually poisonous or bad tasting.

The humped crab spider is an aggressive predator that lives on flowers with which it easily blends. It prefers the large yellow flowers of the crown daisy, which are now in flower. It lies motionless in wait for an insect to land on the flower and then catches it with its forelegs. It bites it to inject a poison and holds on to it until it is paralysed or dead before it starts to suck its body. 

This article was published in The Times on 20.01.2010

Garigue

Garigue is one of the main natural habitats in Malta. The other main habitats are the steppe, maquis and woodland. 

It is found in other parts of the Mediterranean in areas with limestone soils usually near the coast where the conditions are not as hot and dry as further inland. 

In Maltese garigue is known as xagħri. In Greece it is known as phrygana, in Spain as tomillares and in Israel as batha. 

In the American west a similar habitat is known as chaparral. Garigue is best described as open rocky areas with pitted and fissured ground in which one can find a thin layer of soil. In other parts of the Mediterranean and probably in Malta as well garigue was formed as a result of the cutting down of the original trees to create land for agriculture by prehistoric man as well as by grazing of domestic animals and fires.

Garigue vegetation is low and usually consists of aromatic shrubs such as the Mediterranean thyme (sagħtar) Mediterranean heath (erika), spurges (tengħud), the olive-leaved germander (żebbuġija) and the white hedge-nettle (te Sqalli) amongst others. Very often one particular species of plant dominates a particular area.

It is believed that these shrubs produce aromatic oils and other chemicals which leach into the soil and these prevent the growth of other plants in the vicinity especially annuals. 

This gives rise to the characteristic open spaces of garigue areas. The flowers of garigue shrubs are an important source of nectar which is collected by bees to form honey. Malta has been well known since antiquity for its thyme honey and it is believed that the name Melita is derived from the Greek word for honey.

Much of the garigue of the Maltese islands has disappeared. Vast areas have been built upon and tracts have been covered with soil and converted into fields. Some areas have been ‘reclaimed’ and planted with trees. There are now fewer thyme bushes for bees to visit with a consequential loss in the production of thyme honey.

It is not possible to bring back lost garigue but it is important that what is left is protected. It is also possible to increase the amount of thyme and native plants in gardens and in urban areas. 

This would help native species of insects and other animals and provide bees with nectar. The Environment Landscape Consortium would do well to plant these plants in areas for which they are responsible such as roundabouts and road verges instead of non-indigenous species with no ecological value. These plants have the added value that they require very little water thus reducing the amount of water used in keeping these areas green. 

This article was published in The Times on 27.01.2010

Alien plant species on the increase

Malta’s plant and animal life can be divided into indigenous (native) and alien (introduced) species. The introduction of plants and animals in the Maltese islands has been going on since prehistoric times. 

The excavations at Għar Dalam unearthed the fossilised remains of black rat, brown rat, cattle, sheep, pig and cat as well as domesticated plants such as wheat, barley and lentils. 

The introduction of alien species continued throughout historic times and the trend is that it is increasing as a result of an increase in commercial activities.

Most introduced species do not survive in nature and if they do they disappear after a short time but some manage to establish themselves and even become common sometimes to the detriment of indigenous species.

Alien species arrive in the Maltese islands for a variety of reasons. Some are introduced for agriculture and aquaculture. The sulla (silla) is grown for fodder but can also be found on clay slopes. Some such as the castor oil tree (siġra tar-riċċnu )have been introduced as ornamental plants while the cape sorrel (ħaxixa ngliża) which is now the commonest plant in Malta was originally grown in the Argotti Botanical Garden in Floriana. 

Several species of plants were imported with bird seeds and crop seeds these include the canary grass which has become naturalised.

Successful aliens usually do not have natural enemies, they are able to disperse easily and are good opportunists and find an empty ecological niche which they can occupy. They often manage to make a foothold in stressed areas such as disturbed land and agricultural land. The shrub tobacco (tabakk tas-swar), another introduced species, is common in building rubble.

Many species of plants which have become part of the Maltese countryside were not always present. Carob, fig and almond trees have been in Malta since antiquity. The prickly pear was introduced in the 16th century for its fruit and as a hedge plant.

Some plants such as the castor oil tree can become problematic weeds. This species which has striking large leaves and small greenish flowers was probably imported as an ornamental plant and now grows in valley watercourses where it competes with indigenous species.

This article was published in The Times on 03.02.2010

Wednesday, September 1, 2010

Plantains


About nine species of plantain have been recorded in the Maltese islands. They are small plants with small wind-pollinated flowers. Many species have medicinal properties while some are edible and can be used in salads and sauces.
About 200 species of plantain have been identified. They are found in different habitats throughout the world especially in wet areas. Some species are weeds and can grow along road sides and in other disturbed habitats. The inflorescence develops on a stalk which ranges in height from 5 to 40 cm and can be in the shape of a cone or spike with large numbers of small flowers.
Plantains have been used since antiquity externally to treat insect bites, rashes and minor sores as well as internally as a treatment for coughs, bronchitis and other conditions. In folklore it was believed to be an effective cure for snakebite.
One of the most common species of plantain in Malta is the Mediterranean plantain (biżbula) which can be seen in flower from late winter to late spring in cultivated and waste ground. Another common species is the buck’s horn plantain (salib l-art). This species flowers from March to October. Another species that flowers during the same period is the greater plantain (biżbula kbira). This species can be found in damp shady valleys such as Fiddien where the specimen shown in the picture was photographed.
The greater plantain is native to most of Europe, northern and central Asia and has become a naturalised weed wherever European colonisation took place. Some Native Americans called it “Englishman’s foot because it appeared wherever the white settlers set foot.
It is a powerful coagulant and quickly staunches the flow of blood and encourages the repair of damaged tissue hence it is used to treat bruises and broken bones. It has been used as a field dressing and is often known as ‘Soldier’s Herb’. It has also been used to prevent uterine bleeding after childbirth.
Some cultivars are used in gardens for their ornamental value and because its leaves are an important food for the caterpillar of many species of butterflies. (This article was published in The Times on 31.08.2010)