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

Seed dispersal to germinate away from parent plant

Squirting cucumber (Ecballium elaterium)

Most plants have strategies to disperse their seeds which ensures that they germinate away from the parent plant. 

Seed dispersal is important because most plants have little or no mobility and thus would not be able to colonise new areas and habitats. 

Dispersal is also important as it takes seeds away from areas where they would face stiff competition from plants of the same species.

Plants use both internal and external forces to scatter their seeds far and wide. These include gravity, wind, water, explosive forces, and dispersion by animals including humans. Sometimes dispersal can be by more than one means thus a plant might allow a seed to fall onto the ground so that late it would be carried away by water. This often happens when coconuts fall to the ground along the coast and then carried away when the tide rises.

Some species can forcefully discharge their seeds long over large distances. The seed pods of the bear’s breaches (ħannewija) open with such force that they make a sound like a small pistol shot. 

The squirting cucumber, known in Maltese as faqqus il-ħmir, belongs to the cucumber family. During the summer months it forms a green-yellow fruit about the size of a large olive. 

It gets its name from the fact that when ripe the fruit ejects the seeds out together with a stream of thick liquid. When very ripe the slightest touch is enough for the fruit to explode. 

Children sometimes play with these fruit shooting the seeds and liquid at each other or throwing them in the direction of each other to see them explode and hitting each other with the seeds. 

The liquid that forms in the fruit is highly toxic but it has been used medicinally since classic times. It can act as a laxative and is known as a violent purgative. In parts of Cyprus and Turkey the juice is believed to cure cases of sinusitis, hepatitis and earache.

This article was published in The Times on 24.08.11