Saturday, December 28, 2013

The white wall rocket

The white wall rocket is a very common annual plant. It grows in disturbed habitats such as uncultivated fields and roadsides. Despite or because of the fact that it is very common few people actually take enough interest to look closely at the flowers.

The flowers are white sometimes with a tinge of violet. Their structure is similar to that of other members of the mustard family to which the rockets belong. It is made up of four petals arranged in the form of a cross. The family is also known as the crucifers, meaning cross bearing, or sometimes as the cabbage family.

After having lain dormant for a whole summer, the seeds of the white rocket sprout quickly soon after the first autumn rains. Within weeks the plant starts flowering.

The white rocket is native to southern Europe and the Mediterranean. Probably as a result of climate change it is now found further north and has even reached southern England.
The crucifer family is of importance because several species have been cultivated for thousands of years. 

Members of the family include the cabbages, broccoli, cauliflower, turnip and mustard. The leaves of the white rocket are similar to those of the cultivated rocket and they are sometimes added to salads to add a spicy taste. The leaves are said to have diuretic properties but it seems that the plant is not used medicinally.

Many species of crucifers are food plants for the caterpillars of various species of white butterflies including the small and cabbage whites which can become pests of cultivated plants.

Members of the crucifer family are characterised by fruit in the form of a capsule known as a siliqua. The siliqua is an elongated structure with seeds inside. The capsule breaks open along a line of weakness in dry condition. In some species the siliqua breaks open explosively and the seeds are thrown far and wide away from the parent plant.  

This article was published in the Times of Malta on 18 December 2013.


The yellow-legged gull



An injured yellow-legged gull found at Għadira Bay last Sunday.
I regularly visit the Ghadira Nature Reserve to check what birds are present and to take pictures. Last Sunday as soon as I got there a man came to the reserve’s reception centre and informed the weekend wardens that there were two large birds on the beach. One had a broken wing and could not fly and the other was dead. 

One of the young wardens immediately went to the beach to save the injured bird, an immature yellow-legged gull as was the dead bird. The injured bird was picked up and taken to the reserve so that it would be taken to a vet.

The day before this incident somebody went to the reserve to inform the warden that he saw two hunters shooting at gulls from a boat in the bay.

The yellow-legged gull has been protected by Maltese law for over thirty years. It is illegal to shoot at them kill them or harm them in any way.

The yellow-legged gull is a large bird. Males can have a wingspan of over one and a half metres.

Adults are recognised by their silvery grey back and upper wings. Immature birds are mottled grey and can be confused with other similar species. The yellow-legged is the only gull likely to be seen around the Maltese islands during the summer months.

The yellow-legged is Malta’s largest breeding bird. The largest colony is found on the plateau of the small island of Filfla. Other colonies can also be found along the cliffs in both Malta and Gozo.


It is only recently that the yellow-legged gull started to be recognised as a separate species. In previous year, it was considered as a subspecies of the herring gull. The herring gull is a similar gull but adults have pink instead of yellow legs. At one time the yellow-legged gull was assumed to be the same species as the Caspian gull but with the help of DNA analyses it was realised that it is a separate species and is nowadays known scientifically as Larus michahellis. Throughout these changes in scientific classification and common name this species retained its Maltese name, gawwija prima.

This article was published in the Times of Malta on 11 December 2013.

Black-headed gull


To many people in Malta say that there are no birds to see. They could not be more wrong. They only have to visit one of the bays or harbours in winter to watch gulls, terns and other seabirds.

The good thing about gulls and other sea birds is that most of the time they come so close to the shore that they can be observed without using binoculars although a camera is a bonus.
At this time of the year the most common gull and the one you are most likely to see is the black-headed gull.

Black-headed gulls breed throughout most of Europe and Asia as well as along the eastern coast of Canada. Most populations are migratory. Migratory and wintering birds arrive in the Maltese islands in autumn and many remain until early spring. The numbers one can see close to the coast vary from day to day. On calm days they prefer to wander further out at sea but on windy and stormy days they congregate in sheltered areas especially in harbours.

Despite its name for most of the year the black-headed has a white head with a small black spot behind its eyes. It is only during the breeding season that it has a chocolate-brown hood. The Maltese name, gawwija rasha kannella, is a better description as the hood is not black. Sometimes one can see one or two birds in breeding plumage in late February or March before these birds leave for their breeding grounds further north in Europe.

Other species of gulls as wells as terns and the occasional grebe or cormorant can also be seen around the coast.

The Mediterranean gull, which winters in smaller numbers, is known in Maltese as gawwija rasha sewda because its head, face and part of the neck turn black during the breeding season.


The yellow-legged gull, gawwija prima, is much larger and can be seen throughout the year because it breeds in the Maltese islands.  

This article was published in the Times of Malta on 4 December 2013.

A fly to keep away pests

The tachinids are flies belonging to a family known scientifically as Tachinidae.
The tachinid family consists of over 8,200 species. About 1,600 species are found in the Palearctic region, which is the faunistic regionl region in which we live. Just over forty species have been recorded in the Maltese Islands.

The first list of Maltese tachinids can be found in a book on Italian flies written in 1859 by Camillo Róndani, an Italian entomologist noted for his interest in flies.

The author recorded nineteen species of tachinid flies from the Maltese islands. At the time Italian naturalists included the Maltese islands as part of the Italian territory and listed species of  Maltese plants and animals as part of  Italy’s flora and fauna.

Of the nineteen species recorded by Róndani, six are no longer found in the Maltese islands. The disappearance of these species could be due to natural causes but it is likely that it is a result of human activities such as the degradation and destruction of the Maltese countryside. Biodiversity is also reduced by the use of pesticides as well as the burning of vegetation during the summer months.

Fischeria bicolour, the species in the photo, is a member of the Tachinid family. It does not have a common name and is often overlooked by non-naturalists. This species is normally seen on vertical rock faces and on walls.

The larvae of all known tachinids are parasitoids. They live mainly in other insects especially on bees, wasps and ants eventually killing their host.

Tachinids play a major role in the natural control of other species including pests. Some species are used in biological pest control. Many species from around the world have been introduced into North America to control pests.

As adults, tachinid flies are not parasitic. During the adult stage many species do not feed at all but some visit flowers in search of pollen and nectar while others feed on decaying matter. 

This article was published in the Times on 27 November 2013.



The large white butterfly

The large white is one of the most common butterflies to be found in the Maltese islands. The only other butterfly which might be more common is its close relative the small white.

The large white is also known as the cabbage white or cabbage butterfly because its caterpillars feed on members of the crucifer family (or as it is sometimes called the mustard family) to which the cabbage belongs. In Maltese it is known as farfett tal-kabocci.

This species is found throughout Europe, North Africa and many parts of Asia. In 1995 it started breeding in South Africa and in 2010 it reached New Zealand.  It is found mostly in open spaces, farms and vegetable gardens.

Wherever it occurs it is considered a pest because it feeds on cultivated plates such as cauliflowers, broccoli and kohlrabi which belong to the cabbage family.   

Both males and females have white wings with black tips on the forewings but the female has two black beauty spots which the male does not.

The large white is a well-known migrant. It moves both north – south as well as laterally. It is difficult to follow its migration patterns because of the large distances it travels. In Malta it sometimes arrives in large numbers. It migrates in both spring and autumn but most large cabbage white migrations that have been recorded in the Maltese islands took place between September and November.

Most Maltese are not aware of the migration of butterflies. Butterflies do not migrate in a regular pattern and their arrival can never be predicted. Furthermore migratory butterflies were never harvested so there was never any need to await their arrival.


Both adult cabbage whites and their caterpillars have a bad taste which they get from chemicals derived from mustard-oils which they obtain from their food-plants when they are still in the larval stage. The caterpillars are brightly coloured and do not bother to hide themselves as predators tend to avoid them.  

This article was published in the Times of Malta on 20 November 2013.


Plain but beautiful

The past week was noted for the arrival in the Maltese islands of a non-resident butterfly – the plain tiger or as it is sometimes known the African monarch.

The plain tiger is widespread and common in Africa and Asia as well as on most of the islands of the south Pacific, and across much of Australia.

By butterfly standards it is considered as a medium-sized butterfly but compared to the butterflies found in the Maltese islands it is definitely a large butterfly. ts body is black with many white spots but anybody spotting this butterfly is more likely to see it flying or resting on a flower with its wings open. In this case one would see the tawny and black upper wings and perhaps the series of white spots on the hindwing.  

The plain tiger is highly migratory. In the Maltese islands it is used to be a very rare visitor but nowadays it is being recorded with increasing frequency and in larger numbers. This could be due to this species expanding its range possibly as a result of climate change.

There are no records of this butterfly ever having bred in the Maltese countryside but this does not exclude the possibility that it could breed or even become a regular breeder in the future especially if the food-plant of its caterpillar, the milkweed, becomes more common.

In Maltese it is known as farfett ta’ danaus, clearly not a folk name but a name given to it by entomologists who made up the Maltese name from its scientific name Danaus chrysippus.

This week’s bad weather might stop the arrival of more plain tigers but more might still arrive as soon as the weather changes It would be very useful if readers email me the records of any plain tigers that they have seen or that they might see in the coming days and weeks. 

This article was published in the Times of Malta on 13 November 2013.




The flesh-eating flies

The flesh-fly is one of over thirty species of flies whose larvae live mostly on living or dead flesh. Like other species of flies they are of medical and sanitary importance mainly because they help in the decomposition of organic matter and cause disease.

In Maltese the flesh-fly is known as dubbiena tal-laħam.

Flesh flies belong to the Sarcophagidae family. The family  name is made up of two Greek words sarco and phage meaning ‘flesh’ and ‘eating’. The word sarcophagus has the same roots.

The flesh–fly family consists of about 2,500 species.

Like other species of flies, flesh-flies are carriers of pathogenic agents especially bacteria, one of which is the bacillum that causes leprosy.

Flesh-flies can also cause myiasis in humans and other vertebrate animals. Myiasis is the term used to describe the invasion of tissues or organs by the larvae of flies. The name of the condition is derived from the ancient Greek word myia meaning “fly”.

Humans can become victims of flesh-flies. The larvae of flies are in fact sometimes used in hospitals to remove dead flesh from patients.

The most common victim are sheep which become host to the larvae of the blowfly. Adult blowflies lay their eggs on the sheep’s skin. When the eggs hatch, the larvae eat their way through the skin and tunnel through the sheep’s flesh causing irritation and unless treated the myiasis can result in the death of the sheep.

Flesh flies are ovoviviparous. Most insects lay eggs which hatch after some hours, days or weeks. Flesh-flies lay their eggs while day are hatching or even allow the eggs to hatch in their body before depositing the larvae onto their preferred food.

Some flesh-flies parasitize other insects such as grasshoppers and solitary bees and wasps. 

This article was published in the Times of Malta on 6 November 2013.



Lesser drone fly

The lesser drone-fly is a species of hoverfly found around the Mediterranean from Portugal to Lebanon as well as in many parts of Asia including the Caucasus, Nepal, northern Pakistan, northern India and Iran. It is also found in many parts of Africa reaching as far as South Africa. It has also been introduced in parts of North America particularly in California and Florida where as often happens with introduced species it could become a pest.

In Maltese it is called dubbiena tal-għajnejn irrigati.

The lesser drone-fly is very similar to another very common species known simply as drone-fly, dubbiena dakar in Maltese. The drone fly is slightly larger than the lesser drone-fly and does not have its distinctive striped eyes.

These two species belong to the hoverfly family. This family consists of about six thousand species found throughout most of the world. They can be found in most terrestrial and aquatic habitats.

In the Maltese islands the family is represented by no less than thirty species.

 Many of these species live on or near flowers and are usually brightly coloured. Many species defend themselves by mimicking bees and wasps. They look like these poisonous species and many spend a lot of time hovering like them in front of flowers. Their mimicry is so effective that they often fool most people who are not familiar with them.

Adult hoverfly feed mostly on nectar and pollen but their larvae have a totally different menu. While the larvae of some species feed on decaying vegetable matter several species feed on aphids and other plant-sucking insects and are considered as very important agents of biological pest control.  

Hover flies are also important pollinators. Some species are generalists. They visit the flowers of many species of plants while others are specialists and visit a limited number of often closely related species. Hoverflies use vision to locate flower. They prefer to visit white or yellow flowers but sometimes they use olfactory clues to locate flowers especially if they are not white or yellow.

This article was published in the Times of Malta on 29 October 2013.





A striped spider

The banded argiope was first recorded in the Maltese islands in 2003. The first specimen was found in Gozo but since then it has been found in Malta and nowadays seems to have established itself firmly on the two islands although it is nowhere common.

It is a cosmopolitan species. In Europe it was restricted to several archipelagos of the southern Atlantic including Madeira and the Canary Islands. In the early eighties it was recorded in south-eastern Spain and later in southern Portugal and the Balearic Islands.

Since then it has continued to expand its range and has now been recorded from Sardinia, Sicily and Malta.

In America where it is widespread throughout most of the continent, it is sometimes called the banded garden spider or the garden spider. In Maltese it has been named brimba rrigata.
The banded argiope is large and impressive but it is not the only large spider one can find in the Maltese islands. The most common is the lobed argiope, known in Maltese as brimba kbira tal-widien. This species is found in valleys and in wooded areas including gardens.

Another species known scientifically as Argiope bruennichi is now extinct from the Maltese islands. One of the last individuals of this species was found at Buskett in 1976.

The scientific name argiope is Latin for “with bright face”.

The argiope family consists of 78 species. Members of this family can be found on all continents except Antarctica.

The argiopes are well known for their large webs which are often decorated with a zigzag band of silk called stabilimentum. This feature makes the web more visible which might reduce the number of insects that are caught in it but studies have shown that the stabilimentum also reduces the number of birds flying through the web. This gives spiders which build more visible webs an advantage over others which do not, as they do not have to rebuild a new web every time it is damaged or destroyed.  

This article was published in the Times of Malta on 23 October 2013



A green gem of a moth

The Etruscan emerald is a beautiful green gem of a moth that often spends the daylight hours resting on green leaves on which it is well camouflaged and difficult to spot. With luck you might find one that, probably because it had no other option, landed on a wall on which it becomes very visible.

This moth is relatively large. A female can have a wingspan of just over 23 centimetres. This species is found in southern Europe and Central Asia. The caterpillar has been recorded feeding on several species of plants including fennel. Adult moths can be seen flying from June to October.

The scientific name of the Etruscan emerald is Chlorissa etruscaria from which Maltese lepidopterists coined the Maltese name klorissa Etruska. Two other closely related species can be found in the Maltese islands. Both are rare and it would be difficult for somebody who is not a lepidopterist to find and identify them.

The small grass emerald, known in Maltese as klorissa ħadra is very rare. It has been recorded in Malta only three times. The latest record dates back to 1982. The other species does not seem to have an English name. In Maltese it has been called the klorissa tar-risq. Its scientific name is Chlorissa faustinata. This species has been recorded in European Mediterranean countries, in North Africa as well as in Syria.

These three species belong to the Geomitridae family. The family got its name because the caterpillars of moths belonging to this family move by using their front legs to hold to the ground and pulling the rest of their body forward by forming a loop giving the impression that they are measuring the ground. Another name for members of this family is inchworms. Only one other species from this family has been recorded in the Maltese islands. 

This article was published in the Times of Malta on 16 October 2913.



Lady's tresses orchid

The autumn lady's-tresses, is an uncommon orchid that flowers in September or October a few weeks after the first heavy rains of the season. Its blooming coincides with the flowering of the autumn narcissus which in Maltese is known as narcis imwaħħar.  
The inflorescence consists of small flowers growing spirally on a small vertical stalk. You need to look very carefully to spot the flowers as the stalk is often very short –sometimes not more than five centimeters high. You would also need to go to the right place at the right time. In Malta the autumn lady’s-tresses is restricted to rocky arid habitats known as garigue. The best places to find it are at Buskett and at Pembroke. In none of these localities is it common.
To make itself more elusive the autumn lady’s tresses, like other species of orchids, does not flower every year as its flowering is determined by rainfall.
Its scientific name is Spiranthes spiralis, a combination of two words one Greek and one Latin both of which mean a spiral.
The autumn lady’s-tresses is indigenous in the Mediterranean region. Thousands of years ago it migrated north where it occupied close-cropped grasslands overlying chalk or limestone, habitats. These habitats were created by early man by removing trees to provide suitable pasture land.
The autumn lady’s tresses is now found in most of Europe (except in the north), and east towards the Western Himalayas.
The species is nowhere common and is absent from many suitable habitats.
In Maltese the autumn’s lady’s tresses is known as ħajja u mejta a name given to many species of orchids. The name refers to the plants tubers which grow in pairs. While one tuber is large and full of nutrients the other is small and shriveled.
This article was published in the Times of Malta on 9 October 2013.


A cockroach that looks like a beetle

The Egyptian cockroach is one of about seven species of cockroaches that occur in the Maltese islands. The males and females of this species are very different from each other and one would not be blamed for assuming that they are two different species.

The male looks like a black American cockroach (wirdiena ħamra) which is more common and familiar. The female on the other hand resembles a wingless black beetle.

In Maltese the Egyptian cockroach is known as wirdiena sewda but the male and female are often called patri and soru respectively. In English they would be monk and nun.

The Egyptian cockroach is found around the Mediterranean especially along the southern shores. It prefers warm, moist environments such as caves and cellars where it can find plenty of debris and organic matter on which it feeds.

In large territories it prefers to live in coastal areas but on a small island like Malta there would probably not be much difference in the number of cockroaches present between coastal areas and the central parts of the island.

About four thousand species of cockroaches have been described. Most live in tropical areas and feed on decaying wood and leaves and are important components of the ecosystem as they help to convert organic matter into nutrients. Thirty or so species live in association with man but of these only four can be considered as pests.

The Egyptian cockroach is one of the species that lives close to humans but it is not very common and most people never actually see one.
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Pest species such as the American cockroach usually become pests in countries where they are not indigenous. Despite its name the American cockroach is indigenous to Africa. It crossed the ocean on slave ships and in the past it was often associated with slaves. It has now travelled to other parts of the world and has become a cosmopolitan species. 

This article was published in the Times of Malta  on 2 October 2013.





 



Otala punctata

Otala punctata
Otala punctata is the scientific name of a snail indigenous in Spain but which a few years ago was discovered in the Maltese islands.

It does not seem to have an established name in English. In Spanish it is called la cabrilla which according to an online translator means the leopard. In a database it was referred to as the Spanish snail so for this article to avoid constantly using its scientific name I decided to call it the Spanish leopard. It has not yet been given a Maltese name.

This species can be found in eastern Spain, the Balearic Islands, Corsica, the south of France and northwestern Algeria. Nowadays it can also be found in the Americas including the United States, Argentina, Uruguay and Chile. In the United States it is being assumed that it could be a serious pest which could have negative effects on agriculture, and local biodiversity. In Europe it has been found also in Sardinia.

It appeared in Malta around 2003. It established itself in the areas surrounding a plant nursery in Mosta which indicates that it was probably imported accidentally with plants. Studies have shown that its range expanded slowly into the surrounding areas.

It was recently recorded in fields around Baħrija. No Spanish leopards were recorded between Baħrija and Mosta. This indicates that the snails in Baħrija were introduced there by humans. Although it is possible that this was an accidental introduction it could also have been introduced intentionally.

If this did happen it was a very irresponsible act as the introduction could have many negative consequences for the area.

Introduced species often do not have natural enemies and often increase in numbers to the detriment of local species. The Spanish leopard is very similar to the indigenous common garden snail, the species that is collected for cooking and could interact negatively with it.
It could also become a serious pest, creating more problems to the farmers of the area. This could lead to the use of even more snail poison with more negative consequences to the environment.

In Spain this species is cooked in a spicy tomato sauce and no harm would be done if it is also collected in Malta for consumption. 










 






The geranium bronze

Geranium bronze, Cacyreus marshalli,
The geranium bronze is a recent addition to the butterflies of the Maltese islands. It is native to South Africa where it feeds on wild pelargonium geraniums (sardinell in Maltese) which also originate in South Africa. This species is often is often considered a pest because of the damage it causes to the cultivated pelargonium.
The South African butterfly was first recorded in the Balearic Islands in about 1987. It was feeding on cultivated pelargonium geraniums. From there it was introduced to Spain, France and Portugal. In 1997 it arrived in the UK. In Malta it was recorded for the first time in spring 2007.
Once it arrived in Europe it spread quickly in Mediterranean countries mainly because of the popularity of its food plant as well as because parts of South Africa have a Mediterranean climate. It thus found the right conditions to survive and expand its range.
At present it is restricted mainly to Mediterranean Europe but its range might expand further north as is happening with other species. Studies have shown that as a result of global warming and climate change, the range of several species of butterflies is moving north. At the same time some species are disappearing from their former range as the climate becomes too warm for them.
As butterflies disappear in one area new species appear in areas where they had not been recorded before. It is assumed that this is also happening with other insects such as moths, flies and bees, which are not as easy to record and monitor as butterflies.
On continental land masses this is a continuous process but on islands such as Malta insects might disappear because of these changes but new ones are added more slowly as potential invaders might find it difficult to cross the sea separating the Maltese islands from North Africa. 



The eucalyptus tree

Most of the 700 or so species of eucalyptus trees are native to Australia. A small number of them are native to New Guinea and Indonesia and one species is found in the Philippines. Several of these species have been planted in other parts of the world. At least three species have been planted in the Maltese countryside, often to the detriment of local flora.

The roots of many species of eucalyptus are able to draw up water very efficiently and can dominate the flora in arid zones. In many countries they were planted to drain marshes.

In the 1930s Mussolini planted thousands of eucalyptus trees in the marshes around Rome as part of an attempt to drain them and create new agricultural land and destroy the habitat of the anopheles mosquito which transmits malaria.  

In Malta eucalyptus trees are often planted by bird hunters because they are fast growing and within a few years they are large enough to lure migrating birds within range of the waiting hunters. In Maltese eucalyptus trees are known as ewkaliptu but many hunters use the name siġra tal-gamiem meaning the bird of the turtle doves.

The three species of eucalyptus that have been planted in the Maltese islands flower at the end of summer. The flowers of the commonest species, the red gum eucalyptus consist of an ovary surrounded by a large number of stamens topped by pollen-carrying anthers.

The flowers are rich in nectar and pollen and attract large numbers of bees. Many Maltese apiarists nowadays depend on the presence of these trees to harvest honey during autumn. For some apiarists eucalyptus trees have become so important that they protested when eucalyptus trees were cut down. They even appealed for more eucalyptus trees to be planted.    

Eucalyptus trees are still being planted by hunters in the Maltese countryside. This practice should stop and trees that have already been planted should be replaced by indigenous species such as Holm oak (siġra tal-ballut) and Aleppo pine (siġra taż-żnuber). Eucalyptus trees in built areas could be kept and perhaps more could be planted to provide bees with nectar when few if any other sources of nectar are available.

This article was published in the Times of Malta on 11 September 2013.




Silky yellow sea poppy

Glaucium flavum - Yellow-horned poppy - peprin isfar
The yellow horned poppy is one of the few indigenous plants that flowers during the summer. It is a biennial or a short-lived perennial. The flowers are similar in size and structure to those of the common poppy but are yellow instead of red.
The seeds are formed in a long thin pod.
The yellow horned poppies is native to many parts of Europe, Western Asia and North Africa. It was introduced in many parts of the United States and in some places it is considered as a weed.
In Malta it is most common along the north and east coast of Malta. It grows near the sea and is never found far inland. It prefers sandy areas but it can also be common in rocky areas especially in dust or soil-filled depressions.
In Maltese the yellow horned poppy is known as peprin isfar.
The leaves are thick and leathery, an adaptation to life close to the sea. The thick leaves store water in them and they are covered in a layer of wax which stops water from being lost through them.
The first flowers appear in late April, although it is not easy to find a plant in flower so early in the season as they start flowering in earnest in early June.
Like many other plants, the yellow horned poppy is both poisonous and medicinal. Every part of the plant is toxic and eating it can result in respiratory failure and even death. A clear yellow oil is obtained from the seeds. The plant’s main medicinal component is known as glaucine. This substance has properties similar to those of codeine. It is used in some countries as an antitussive but it can have side effects such as sedation, fatigue and can also bring about hallucinations. 
Thos article was published in the Times of Malta on 4 September 2013




Why cicadas only sing in summer

The continuous buzzing sound of the cicada is typical of Maltese summer days.

The cicada appears punctually during the second week of July. The larva digs its way out of the soil in it had lived for many years. It then climbs up the nearest vertical object which is usually the trunk of the tree of which it had been sucking juices. Occasionally instead of a tree it finds a wall or other stone structure.

Once it is high enough it expands slightly and this causes its external skeleton to break along a weak line at its back. It then pushes itself out of the exoskeleton and slowly walks away from it. This is a very vulnerable moment for the now adult insect. Its new external skeleton is still soft and in case of danger it is not able to fly.

The new external skeleton and the wings do not take long to harden and soon the male cicadas start singing while the females start their search for singing males.

When a pair of cicadas meets, they start courtship and then they mate. Courtship consists of repeated hugging and touching each other with their legs.

Soon after, the cicada lays its eggs in the soil close to the surface. The eggs hatch in late summer or early autumn in well enough time for the newly hatched larvae to dig their way further down into the soil where they will be spending the rest of their lives as larvae.

Once mating takes place and eggs are laid adult cicadas have no further need to stay alive and start dying. The number of singing cicadas has started to decrease and soon the last one will stop singing leaving behind a silence that indicates that the end of the summer season is fast approaching. 

This article was published in the Times of Malta on 28 August 2013.

Snapping nature at home

Nature photography is generally defined as the photographing of landscapes as well as plants and animals in their natural habitats. Purists do not consider any picture that includes man-made objects as a nature picture.
Some nature photography competitions stipulate that an image cannot be allowed to compete if it includes non-natural objects. This attitude would be commendable were it not for the fact that nowadays none of us live in untouched surroundings. Most of us live in towns and villages surrounded by buildings with little or no greenery.
For many the only nature they regularly come in contact is found in gardens and other man-made open spaces.  For them, nature consists of cultivated flowers, trees and nature programs on television.
On the other hand for those who are tuned to nature there is much more. As they walk through a street, they see wild plants growing wherever there is some soil. Wild plants grow even in cracks on pavements. Vegetation attracts wildlife and though we do not have large animals we have an interesting variety of insects and other arthropods. Some of which even enter buildings including our home.    
Sometimes unusual and interesting species such as the ant-lion end up in houses. Should one photograph an ant-lion on a wall? Yes, because although ant-lions normally spend the day resting on vegetation, the fact that it sometimes spends the day resting on a wall is of interest and worth recording.
This long-winged insect is active mostly in the evening and is more commonly found in sandy areas. The larva lives at the bottom of a funnel-like pit where it spends the day waiting for unwary ants to venture over the edge of the pit. The ants are unable climb out of the pit and fall to the bottom and are eaten by the ant-lion.
About 2,000 species of ant-lion are found world wide. 
This article was published in the Times of Malta on 21 August 2013



Tuesday, August 27, 2013

Caper flies

Caper fly Capparimyia savastani
The caper fly is one of several species of insects that lives on the caper plant. It is a small fly that lives exclusively on caper plants and if you want to see one you need to look for it only on this host species.

This fly species is found in some Mediterranean countries and in parts of Asia. It has been recorded in Italy, France, Tunisia, Algeria, Libya, Egypt, Israel, Jordan, Oman and Pakistan. In 2008 it was found in large numbers on wild and cultivated caper plants on the Greek island of Milos and was immediately considered as a pest because of the potential damage it could cause to the caper production industry.

It is very similar to fruit flies such as the Mediterranean fruit fly (dubbiena tal-frott) which causes damage to fruit particularly oranges. It can be distinguished from the fruit flies by its yellow abdomen but the most important feature that would help you identify it from other flies is the fact that you will always find it resting on the leaves and flowers of the caper plant.

I have not found a Maltese name for the caper fly but dubbiena tal-kappar sounds like a good name for this species.

Female caper flies lay three to five eggs inside the buds and fruits of the caper plant. Once a fly has laid its eggs there is nothing to stop another fly from laying its eggs in the same bud or fruit and sometimes up to seven eggs can be found together in one bud or fruit.

The eggs hatch in two to ten days. The larva looks like a typical fruit-fly larva. The larva remains in the fruit or bud throughout its development which lasts from ten to eighteen days. When it is ready to pupate it emerges and falls onto the soil and digs itself in. The species probably has several broods per year. The adults can be seen only during the warmest months. It survives the winter as a pupa buried in the soil. 

This article was published in the Times of Malta on 14 August 2013.






White poplar

White poplar Populus alba
The white polar is the only native poplar of the Maltese islands. It is indigenous in southern and central Europe and to the east as far as Central Asia. It lives in moist habitats such as the sides of streams and rivers. In Malta it grows in valleys such as Chadwick Lakes and at Wied il-Luq which is Maltese for valley of the poplars.

In old English the white poplar was known as ‘Abele’ from the Latin albellus meaning white. Its scientific name is Populus alba which also means white polar.

The white poplar was introduced in North America in 1748. It is widely cultivated for its wood and in some areas it is considered as an invasive species. It is an invasive species also in many parts of Australia and in South Africa

The tree is easily recognised. The trunk is smooth greyish-white and the leaves appear white underneath. The white colour is a result of whitish-grey hair that grows on both sides of the leaves. The hair on the upper side of the leaves wears off uncovering the green surface of the leaves. That on the bottom remains on the leave until it falls off in late autumn.

In Ancient Greece the white poplar was dedicated to Hercules after he crowned himself with its branches to celebrate his victory over Cacus on Aventine Hill which was covered with white poplars. Those offering sacrifices to him bound their heads in a similar way as did those who conquered their enemies.

The white poplar is one of several species of poplars native to the Northern Hemisphere. The exact number of poplars is unknown mainly because of difficulties in distinguishing species and the existence of hybrids. It is believed that there are between twenty-five and thirty-five species.  

This article was published in the Times of Malta on 7 August 2013
 


Aggresive bulrush

Southern bulrush Typha domingensis
The lesser bulrush is a large aquatic plant found in southern Europe, North Africa and in many parts of Asia and the American continent.

It is rare in the Maltese islands because the aquatic habitat which it requires is very rare. One can see it in valleys behind man-made dams and in artificial ponds and pools.

About eleven species of bulrush can be found most of them restricted to the Northern Hemisphere. Only one of them occurs in the Maltese islands.

In Maltese the lesser bulrush is known as buda. In England bulrushes are also known as reedmace. In America they have several names including catnail and catninetail.

The plant grows from an underground rhizome. Above ground it consists of long sword-like leaves. The flowers consist of a thin vertical spike on which male flowers form. Beneath this is a thicker sausage-shaped inflorescence with female flowers. Female flowers form after the male flowers have shed their pollen, withered and died. This avoids self-fertilisation. 

In Turkey and some other countries the female inflorescence of the lesser bulrush is used to treat wounds. Recent studies have confirmed that these medicinal properties can be effective and are not just folk beliefs.

Bulrushes are aggressive, in some areas they can become the dominant species to the detriment of other plant species. Several species can grow in one area with the different species adapted to live at different depths.

The bulrush plant has many uses. It can be eaten, it has medicinal properties, and the leaves can be used as insulation for houses and to make decorative paper.


The plants’ rhizomes are rich in starch. They are edible and can be ground into a powder. Starchy remains of ground bulrush tubers have been found on prehistoric grinding stones suggesting that they have been consumed in Europe for as far back as 30,000 years ago. Other communities eat other parts of the plants. The developing flower-heads can be boiled and eaten like corn on the cob. The seeds are rich in linoleic acid and are used as cattle and chicken feed.

This article was published in The Times of Malta on 31 July 2013.