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.

.

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.