A resurgence in populations of bed bugs, has been reported in Australia in recent years. The proliferation of bed bugs has been attributed to insecticide resistance, increased travel, limited availability of effective insecticides, and inadequate pest management procedures.
Australia has a unique role in the growing spread of bed bugs. With the current explosion in fly-in fly-out workers at the mines, conditions are perfect for repeated infestations of bed bugs.
Mine sites in Australia can have over 3,000 beds, constantly full of workers coming and going and severe infestations can lead to interrupted or disturbed sleep. The potential dangers for tired workers operating heavy machinery means companies are forced to find alternative accommodation.
A practical side effect of this is that companies can be forced to house workers in motels or accommodation in the closest town while the dongers or cabins are treated for infestations. This leads to extended travel time and costs per worker, which can rapidly increase due to the size of the workforce.
Biology
Bed bugs undergo an incomplete metamorphosis during which they pass through five nymphal instars. Each of these nymphal stages needs to feed on blood before it can moult into the next stage and eventually into the adult form. Adult males and females then need to continue to take regular blood meals for nutrition and the females to gain protein for egg production.
The total development process from egg to adult can take place in as little as 37 days, though often it might take much longer. In Australia, the adult bed bugs will typically live for about five months at average temperatures of 22oC, however in colder regions, they can live for much longer.
Bed bugs spend most of their life hidden in away in cracks and crevices where they will not be seen or disturbed. This lack of activity often prevents bed bugs from coming into contact with fresh insecticide residues. They usually feed every 3 – 7 days, so most of the time the population is hidden away digesting their previous meal.
Typically they will emerge between midnight and five in the morning, when people are in a deep sleep, in search of their blood meal. They are attracted by heat, carbon dioxide and other compounds given off by resting people, but usually they need to be close to the source to detect this.
We are also observing a modern trend with infestations occurring in shops, offices, hospitals, physician waiting rooms, and public transport systems.
The number of eggs that a female will lay is dependent on the number of blood meals she obtains and the ambient temperature. On average a female bed bug will lay between 1 – 7 eggs a day for up to ten days after each blood meal.
Bed bugs are wingless, flat insects. Adults are a reddish brown colour and to provide an idea of scale, an adult bed bug is about the same size as an apple seed. The earlier instars can be a little as 1 – 4 mm in length, and the eggs are a translucent white and just 1 mm in length, and the younger nymphs tend to be white.
Due to the nature of this pest, its increasing prevalence and its bites, they have been the subject of a great deal of research in the last five or so years. In Australia it has been well documented that most of our bed bug populations are resistant to the commonly used pyrethroid insecticides, which makes control more challenging.
This has led to the development of a Bed Bug Code of Practice. This Code was developed by Dr Stephen L. Doggett of the Department of Medical Entomology, Institute for Clinical Pathology & Medical Research, at Westmead Hospital; in association with a group of experts known as the Bed Bug Code of Practice Working Party, established by the Australian Environmental Pest Managers Association.
This document covers all aspects related to the management of bed bugs and should be followed by a professional pest manager when providing a bed bug treatment.
Treatment of bed bugs requires a thorough and detailed approach by all parties and a combination of chemical and non-chemical controls, together with hygiene and housekeeping measures.
Pest managers are a crucial component for ensuring the production and profitability of Australia's mining sector. The potential markets for our industry are expanding and the importance of our contribution is going to be recognised more and more.
Thanks to Steve Broadbent, Ensystex Australasia Pty Ltd for permission to use a paper prepared by him.