'Good' but dangerous insects in our midst

GEORGE TOWN: They live among us but they are not outright pests. Let them in close proximity, and they will put us in a world of pain.

These four venomous or toxic insects serve vital roles in maintaining ecological balance and they have adapted to living in urban environments.

The large bi-coloured arboreal ant can sting, and if too many attack you or if you have allergies, you can go into anaphylactic shock, a severe allergic reaction which makes you faint, vomit and have trouble breathing.

The tiny paederus rove beetle has a toxin in its body fluids that is so virulent that if just a few microgrammes of it gets absorbed into your skin, you will suffer from large lesions, blisters and pustules for over 10 days.

Then comes the bee, perhaps the top pollinator of the world’s plants but can build hives in urban areas and put people at risk of being stung.

And there is the greater banded hornet or tebuan in Malay, which is able to repeatedly sting and inject venom into you that makes you feel like you are on fire.

“It is a sad case of these venomous insects being in the wrong place at the wrong time,” lamented entomologist or insect expert Associate Prof Dr Abdul Hafiz Ab Majid of Universiti Sains Malaysia (USM).

“We have to destroy them when they nest too close to human dwellings because of the pain they can cause, but I hope people understand how good they actually are for our ecology.”

Bi-coloured arboreal antIt stings instead of bites, and the sting of this ant is excruciating at best and life-threatening at worst.

If too many bite you at once, or if you have allergies, it can cause anaphylactic shock.

Abdul Hafiz said bi-coloured arboreal ants (Tetraponera rufonigra), locally called semut selangor or semut ipoh, are essential to the environment.

“They consume nectar and honeydew produced by insects and prey on many small insects and other invertebrates.

“They form mutualistic relationships with certain plants, protecting the plants in exchange for resources and shelter by keeping herbivores away and removing competing vegetation,” he said.

However, if they establish colonies in the trees at children’s playground and neighbourhood parks where many people frequent, Abdul Hafiz recommends removing them with insecticide out of public safety.

Paederus rove beetleIn the book Medical And Veterinary Entomology (2019), the body fluids of this beetle, called charlie in Malaysia, has a toxin that is “the most complex non-proteinaceous insect defensive secretion known”.

“They don’t bite or sting at all, but if a charlie lands on you – maybe on the back of your neck or under your knee where you don’t immediately see it – and you unknowingly brush it off and crush its soft body, then its body fluids smeared on your skin will cause days of irritation,” said Abdul Hafiz.

He said they are ecologically important insects because they feed on tiny herbivorous bugs which are destructive to plants.

“In agriculture, the charlie is a pivotal biological control agent because they feed on tiny aphids that destroy crops.

“But during padi harvesting season when the threshing machines work on the fields, the charlie can fly away by the thousands and at night, they are drawn to night lights especially in high-rise residential buildings.

“This is when they cause pain to human populations.”

Fortunately, Abdul Hafiz said the toxin does take many seconds to be absorbed through your skin, so if you discover that you have unwittingly smacked a charlie on yourself, quickly washing that area with soap and water will prevent its effects.

“But see a doctor if rashes and blisters develop to stop it from spreading,” he said.

Bee hives and hornet nests in the cityFor over 90% of the world population, a bee or hornet sting will yield no more than a few hours of burning pain at the stung spot.

But a few per cent will get a severely lowered blood pressure, a weak yet rapid pulse, extreme difficulty in breathing and loss of consciousness with risk of death.

Those who get stung dozens of times face the same risks.

As urban areas get closer to green belts and woodlands, and these insects themselves adapt to food sources in city gardens, urban farms and even food stalls serving sweet treats, Abdul Hafiz said it is becoming more common to find bee hives in cities.

“But if you can, don’t destroy bee hives. Bees are among the most efficient pollinators of plants in the world,” he urged.

He advised contacting Persatuan Penyelamat Lebah Malaysia (www.mybee savior.org) at 019-664 8081 and let experts check the beehives to see if they can be relocated.

But with hornets, even though they are highly efficient predators that keep the population of many other insects under control, he said the potential of being badly stung by them is high enough that if they build nests in urban areas, you should dial 999 and seek help to get rid of such nests.