Intriguing and somewhat misunderstood, scorpions are a relatively uncommon pest but remain one that we pest managers should know how to effectively manage.

We as humans tend to be scared of things we don’t understand or know a great deal about. So unsurprisingly, scorpions are definitely the stuff of nightmares, with their cryptic behaviour and combative appearance. It’s no wonder the average homeowner can get a bit panicky and perhaps overreact at the first sign of a scorpion within their home.

Scorpions (which are arachnids, of the order Scorpiones) are certainly not something we as pest managers treat for every day, but they are an accidental invader most of us will eventually cross paths with and should know how to respond to.

I personally have probably had a little bit more to do with scorpions than the average person, having had an almost obsessive fascination for these critters since I was a teenager. I have kept and collected many species of scorpions for the most part of the last 30 years. Travelling the countryside in search of different species has taken me to some of the remotest parts of Australia including Lake Eyre SA, the Pilbara WA, Palm Valley NT, Broken Hill NSW and Cape York, QLD. But to be honest the more I have learnt about these arachnids the more I have learnt how much I don’t know.

Scorpions in Australia are studied to a relatively poor degree but what we do know is this: there are currently more than 40 recognised species of scorpions in Australia with realistic estimates of there being in excess of 100 different species. Scorpions occur in all types of habitats, including dry desert areas, rainforest areas, open woodland areas and even on our coastlines. Some species are sit-and-wait ambushers while others are active hunters. All Australian scorpions are nocturnal hunters.

Buchar's scorpion
Buchar’s scorpion (Lychas buchari) grows to only 5cm and inhabits sand dunes throughout SA and WA

By far the most commonly asked question about scorpions is ‘How deadly are they?’ Australia has no medically important species to deal with. However, having said that – as with anything that can inject venom much like bees, wasps and ants – a severe immune reaction is always a possibility. In fact, there have been two suspected deaths from scorpion stings in Australia, but both were toddlers and details were sketchy.

Venom oozing from the aculeus (stinger) of an aggressive Urodacus hoplurus (Credit: Nick Volpe)

There is an old theory that scorpions with smaller pincers have more toxic venom. To some degree this is true, having personally been stung several hundred times by multiple species I can certainly confirm the smaller species do tend to pack more of a punch. However the most I have ever experienced is a localised burning sensation and slight swelling with the irritating itchiness that follows most stings.

Of the 40-plus species of scorpions in Australia, only a handful of species are likely to be encountered by homeowners. Scorpions do not enter homes deliberately –  it is purely accidental and, in fact, scorpions will typically desiccate and perish in a short period of time in a dry household environment. Scorpions can be accidentally carried in with firewood but mostly they wander in beneath our doors if not sealed properly. Scorpions will often wander in search of food, a mate or even somewhere drier during or after heavy rain. Although some scorpions are quite adept at climbing they are not likely to climb into a household roof and then drop out of the downlights as some homeowners would believe.

The wood scorpion (Cercophonius squama) has been found in suburban gardens in the Melbourne region (Credit: Nick Volpe)

By far the most long-term management method of scorpions is ensuring all doorways have good seals, which includes the garage doors as well. The effects of pesticides on scorpions is not well known, however I personally suspect they are quiet sensitive to pesticides due to their behaviour of combing the ground with their pectines to detect chemical pheromones. A quick search of APVMA’s PubCRIS database doesn’t list any products with scorpions specifically listed on their labels, however a few recent products do have the very handy definition ‘crawling insects’ included on their label. Certainly a good general pest treatment – a very broad horizontal residual treated zone around the perimeter of the home along with a dusting of any weep holes – is likely to slow them down.

The marbled scorpion (Lychas marmoreus) is found throughout southern Australia and will occasionally enter people’s houses (Credit: Nick Volpe)

As professional pest managers there is an expectation by the public that we should know how to control virtually anything that creeps, crawls or flies. In reality this is a big task. We can, however, gradually spend a bit of time learning about the biology of many different critters so that if we are ever faced with this type of pest scenario we can at least live up to that expectation and keep being the professionals that we really are!

Jay Turner, Laguna Pest Control, Pest Manager of the Year 2017

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