The devil's coach-horse beetle

The devil's coach-horse beetle is common and widespread in the Maltese countryside but not often seen because it is mostly active at night. It is found in most of Europe and has also been introduced to the Americas and parts of Australasia.

It belongs to a large family of beetles known as the rove beetles. Members of this family have short forewings, which cover only half the abdomen. The exposed abdomen is protected by hardened plates.

The devil’s coach-horse beetle can and sometimes does fly but when threatened it prefers to raise its abdomen like a scorpion and to open its jaws. This explains its Maltese name Katarina għolli denbek. In English speaking countries it is sometimes also called cock-tail beetle.

The sting has no poison but it can give a painful bite with its strong jaws. It can also secrete a foul smelling liquid from a pair of glands found at the end of its abdomen.

It feeds on other invertebrates such as insects and spiders as well as on carrion.

The specimen I photographed early in the morning was feeding on the remains of a snail that had been trodden upon by somebody a few hours earlier. When feeding it cuts its prey into small pieces with its mandibles and moulds them into a spherical shape using its front legs. It then chews and swallows then regurgitates it covered in a brown liquid which digests the material. When the solid material is completely liquefied swallows it. The larvae have similar eating habits.

In many parts of Europe this beetle has been associated with the devil since the Middle Ages. In Ireland it was believed that the devil takes the form of this beetle to eat sinners. It was supposed to bring bad luck and people could turn this to their advantage to acquire power over others.

This article was published in The Times on 25 November 2009.

Beetle mania

Recently while taking some early morning pictures at Fiddien I found a species of black beetle that I had never seen before. A friend of mine, a specialist in beetles, identified it for me.

It was a nocturnal weevil known to entomologists as Otiorhynchus lugens but for which I could not find a common name.

Weevils are recognised by their long snout and small antennae which have small knobs at the end. They are plant feeders and are often found on or near their food plant.

The weevil family is very large. Over 40,000 species have been identified worldwide of which more than 120 species, including several endemics, are found in the Maltese islands.Most of the weevils I am familiar with are either a shade of brown or grey.

Being black and nocturnal this species made me think about the fact that although the most familiar beetles such as ladybirds and leaf beetles are brightly coloured, many beetles, many of which we do not often see, are black.

A study carried out about ten years ago in Brazil found that the body colour of beetles is strongly related to their daily activity pattern. In other words, nocturnal beetles are likely to be black while diurnal species are either brown or brightly coloured.

Bright colours are used to warn predators, especially birds, that that particular insect is either bad tasting, poisonous or that it can inflict a painful sting. Brown or grey colours camouflage them, making them difficult to see against their surroundings. On the other any brown or grey beetle would be easy to spot in the darkness so nocturnal beetles have evolved black bodies which makes them difficult to see at night.

This gives them an advantage over beetles that are not black, as, being more difficult to see there is a smaller chance that they are eaten by predators.

This article was published in The Times on 28.12.11

The leaf beetle family

Chrysolina variolosa

Leaf beetles are members of an insect family represented  by about sixty species in Malta. 

The one pictured with this article is known simply as a leaf beetle and in Maltese as żabbella a name that was used also for the ladybirds. The scientific name which distinguishes this beetle from all other leaf beetles is Chrysolina variolosa.

This species is frequent although not common. 

It is usually found on the spiny asparagus, (spraġġ in Maltese) as it probably eats its leaves.

But the specimen I photographed last Sunday at Mistra Bay was walking on rocks far from any asparagus plant.

The leaf beetle family is the largest and most commonly encountered beetle family. It is estimated that there are over 35,000 species in this family. Several species are of economic importance because of their impact on agricultural produce. 

Some have been used to control weeds biologically especially in Australia and in California.

But the greatest impact is probably that of another species - the Colorado potato beetle which can devastate entire crops of potato.

The Colorado potato beetle is indigenous to the Americas but it was not until 1840 that it started to become a pest of the potato plant. 

It appeared in Germany in Germany in 1877 but was soon eradicated from there. It reappeared in Europe sometime during World War I. It was first observed near American military bases in Bordeaux and from there it spread to Belgium, the Netherlands and Spain eating its way through potato fields.

Soon after the Colorado potato beetle started to spread in Europe the Maltese Government, prohibited the importation of crops from any areas where this beetle was present and managed to keep the Maltese islands free from this pest.

In 2008 the European Union issued a Directive by means of which Malta was declared a protected zone and was thus given special protection to be able to take measures such as plant quarantine to keep the Colorado potato beetle away from the islands. 

This article was published in The Times on 23.11.11)

Of gourd ladybirds and the squirting cucumbers

Many species of animals and plants are closely linked together. In some cases the relationship benefits one species only and in others both species benefit from the relationship. 

This relationship often means that if one species had to disappear the other would not be able to survive on its own and would cease to exist as well. 

One such relationship is that existing between the squirting cucumber (faqqus il-ħmir) and the gourd ladybird (nannakola tal-faqus il-ħmir).

The squirting cucumber is a common plant with large leaves and yellow flowers. The fruit are oval and when ripe they shoot out the seeds. The seeds emerge with such force that they can land up to one metre away from the parent plant thus helping the plant to disperse. 

The squirting cucumber grows in disturbed habitats along country lanes and in urban areas.

Whenever you find a squirting cucumber you are also likely to find the gourd ladybird. This species of ladybird spends its entire life on the squirting cucumber. Ladybirds are known to be predators. 

Most feed on insects especially aphids but I have never seen this species eating other insects. I have often seen the adults in the flower of the squirting cucumber probably eating pollen. 

Adult ladybirds often carry a sprinkling of pollen on their wings which indicates that they could be transferring pollen from one flower to another thus aiding pollination.

The eggs are laid on the plant and the larvae spend their entire life on it. I have not found any literature on the life cycle of this species but I have seen small parts of the surface of the leaf on which a larva of this ladybird is living eaten away which indicates that the larvae feed on the leaves on which they live.

My observations indicate that the relationship between these two species is beneficial to both species. The plant provides the food for the larvae and adults while the adult ladybirds help to pollinate the flowers. 

This article was published in The Times on 16.11.11

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

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

Insect diversity

Last Sunday I photographed a soft-winged flower beetle at Wied Qirda. This is a small shiny green beetle known in Maltese as ħadranija tal-ward. 

It is a common species often seen on yellow flowers such as the Cape sorrel (ħaxixa Ngliża) and the crown daisy (lellux). The beetle I photographed on Sunday was spotted by my three year old son.

 I did not see it myself because it was walking on the stem of a grass about 10 cm from the ground and out of my line of vision. Children have a different perspective of their surroundings and often manage to see things which grownups miss. 

I often encountered adults who say that they remember seeing more flowers and insects when they were young. They remember more than anything the gourd ladybird (nannakola tal-faqqus il-ħmir) an insect that lives on the squirting cucumber (faqqus il-ħmir). Both the squirting cucumber and the ladybird are still common in the Maltese countryside. These people fail to see them because they do not know where and how to look.

This does not mean that insect numbers have not gone down. The amount of countryside has shrunk drastically during the last 50 years and it continues to be gobbled up at an alarming rate in spite of the fact that we are more aware about the need to conserve it. 

Changes in agriculture, especially the use of pesticides have had their toll as well. Pesticides kill insects and many kill indiscriminately. They kill pests as well as other species some of which are beneficial such as bees especially if they are used indiscriminately. 

For several decades farmers have been urged to spray their crops. As the pests became immune to the pesticides stronger pesticides in larger doses had to be used. Now they are being told to stop using them and many are confused. Some have been spraying their crops throughout their whole life and do not know otherwise. 

Although many are now realising that something is wrong they find it hard to accept that what they have been told for the past thirty or forty years was not exactly right and find it hard to change. A small number are now starting to practice more environment friendly agriculture and more should do so for the benefit of everybody including nature.

This article was published in The Times on 03.03.2010 

The destructive red palm weevil

The red palm weevil has been in the news since it appeared in Malta about three and a half years ago. It is a large rusty-red beetle that lives on palm trees and can kill the host plant. It is a strong flier. 

Last week one flew through my bedroom window in a locality where there are no palm trees within a radius of several hundred metres.

The red palm weevil, which has been given the Maltese name bumunqar aħmar tal-palm, came from tropical Asia from where it spread to Africa and Europe. It reached the Mediterranean in the 1980s and was first recorded in Spain in 1994. In 2006 it was found in France and in 2007 it was recorded from Malta.
The adult weevil damages palm trees through feeding but it is the larva that kills it by burrowing into the trunk.

The cause of the high rate of spread of this pest is human intervention, by transporting infested young or adult date palm trees and offshoots from contaminated to uninfected areas.

Information on Red Palm Weevil was first published in 1891 in India. This pest was first described as a serious pest of the coconut palm in 1906, while in 1917 it was described as a serious pest in the date palm in the Punjab, India.

It is considered as the most serious pest of palm trees in the world. Control is mainly through the use of pesticides although other measures such as attracting the adult insect into traps by means of pheromones are sometimes used. Pheromones are chemicals released by females to attract males.

It has been found that the most effective way to apply pesticides directly into the trees by injecting it directly into the trunk. As happens whenever pesticides are used there can be serious negative consequences to the environment. 

These chemicals leach into the soil and water killing other organisms. In other countries experiments are being carried out to assess the effectiveness of biological methods of control.

One such method is by the use of nematodes that attack the insect killing it within three days but what is effective in the laboratory does not necessarily work in nature.

This is not the only pest that arrived in Malta in the past few years. Another pest which has had serious negative consequences is the tomato leaf miner which last summer destroyed a large percentage of the tomato crop.

This article appeared in The Times 17.03.2010