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Deconstructing the brown ant

The brown ant (Lasius brunneus) is common in Europe from the Mediterranean area to the south of Great Britain, south Sweden and south Norway. Like all members of the Formicidae brown ants are social insects. The nests contain female workers, a queen, and the brood (eggs, larvae and pupae). The female workers are 2.5-4mm long, with yellow-brown legs and antennae. Their petiole (the part connecting the abdomen to the thorax – see diagram) consists of a broad scale-like segment. The opening of the cloaca at the tip of the gaster is surrounded by a ring of hairs. Female workers do not possess a stinger – to defend themselves they spray a liquid which contains formic acid. The dark-brown 6.5-8mm long queens possess wings which are brown coloured at the base. These wings are thrown off after copulation.

The brown ant is a monogyne ant species (each colony has only one queen). However, observations of some authors suggest multiple young queens may be accepted after the nuptial flight by an existing colony (polygyne). The black, ~4mm long males also develop once per year and die after the nuptial flight.


The females throw their wings off after the nuptial flight and copulation and create a nest chamber under the bark of standing trees, usually 3-12m above ground level. The first eggs are laid 1-4 weeks later and the queen takes care of the first offspring. During this time the female lives off her body fat and her flight musculature which is no longer needed. With the increasing size of the nest the colony moves down from the tree towards the soil. In the second year the colony can already contain several thousand individuals and after 10 years up to 100,000. Depending on their age, the workers have different tasks. The development from the egg to the adults takes five weeks under favourable conditions. During the swarming period which is mainly between June and July individual-rich swarms of queens and males leave the nest for the nuptial flight. The winged reproductive ants may already be present in May depending on the climatic conditions.


The brown ant occurs frequently in hardwood forests in rotten trunks, in dead roots and in decayed portions of trunks up to 4m high. Members of this species avoid shady coniferous forests, but it has no further special requirements in habitat. If the young queen finds decayed timbers with sufficient humidity at the front or inside a building, it may also settle there. Foundation of the nests occurs behind door frames, in partition walls made from gypsum board, insulation below the floor as well as in insulating material in close proximity to sources of humidity (e.g. cold and warm water pipes, underfloor heating and sewage drains).
Nest foundation in a building occurs usually after damage to the construction followed by the penetration of water into wood or stonework. Further causes of the establishment of ant colonies can be penetrating humidity through cracks in the external wall, defective water pipes within the building, leaky roofs etc. Brown ants act therefore as indicator species for any hidden moisture damage in the construction. The number of workers rise slowly in in the first years and workers generally avoid travelling over open surfaces. The infestation is therefore often noticed by the home owner 5 to 10 years after settlement of a brown ant queen, often when the first swarms of the winged reproductives occur. Swarms may occur several metres from the nest, and in colonies within heated buildings, may occur at different of the year from those based outside.
At first only decayed wood or insulation material is used by the brown ant to create the nest. However the ants will begin to gnaw on sound wood, creating tunnels in softer new growth, with the surface usually remaining intact. The wood serves only as a harbourage and not as food. The ants obtain moisture via condensation from heaters, water pipes or other sources around the nest.
The workers take honey dew from aphids outdoors, and indoors they are attracted to high-sugar foods such as jam, fruit juices or honey. Temporarily protein is needed for the developing larvae, which mainly comes from captured arthropods. At this stage the workers from indoor colonies may consume cooked or raw meat. Bins and dishwashers are ideal food sources for foraging worker ants, who take food back to other workers in the nest which then feed the queen and the brood.
Ants are of particular concern in food processing and catering establishments due to contamination of food with pathogens. Also ant secretions (i.e. formic acid) can sometimes cause skin irritation.

In the past ten years ants have been seen more and more frequently within the insulation substrate of buildings. Besides the brown ant, various other native ant species are now frequently found in the insulation material of outer walls, particularly the black garden ant (Lasius niger) and the shining black wood ant (L. fuliginosus). Carpenter ant species are also found in insulation materials, especially C. ligniperdus and C. herculeanus. Another species which immigrates temporarily into buildings is the invasive ant species Lasius neglectus, which has spread over the past decades from southern Europe to southern England. This species is characterised by very individual-rich colonies with many queens.

Facades insulated with polystyrene sheets and polyurethane foam also offers ants ideal conditions for nest foundation. Glass wool, rock wool and cellulose wool have no fixed structure and are rarely used by the ants as nesting sites. However, ants contaminate these materials with moisture and through gnawing and waste deposition from the nest.

Ant activity within buildings

The average householder will be unaware of brown ant activity because the ants move mostly hidden in cracks and crevices or behind baseboards, the infestation only becoming noticeable with the first annual flights. However, activity of the workers is signposted by small heaps of gnawed particles (wood, pupal cases, dead ants and the carcases of captured insects) on the ground, under insulating material and within timber constructions, the composition and colouring of the particles being dependent on the materials in which the nest was built. Because workers stay away from open areas, baiting with different food sources (proteins and sweets) or with a liquid ant gel is helpful to locate the nest. The measurement of moisture in the structure can also give an indication of the nest location, so a moisture meter is a helpful addition to any technician’s toolkit. The homeowner should be interviewed to ask about possible moisture damage during the past 10 years, as this may be the origin of ant infestation.

External insulation

Ant infestation within external insulation can be detected from the ant activity on the foundation surfaces, as well as by tracking worker ants, which enter the insulation layer through gaps and cracks. It is less likely to see the typical gnawed particles at the exits (tunnel ends) since they are blown away by wind or washed away by rain. Winged ants rarely stay on the outer facade.

To determine the extent of an ant infestation, the insulation must be removed in the infested area. Insulation boards damaged by ant activity may cause heat loss in the building. Cold spots on the wall inside the house combined with increased humidity and mould are an indicator for ant activity in external insulation.

Infestation prevention

Modern foam-based insulation is an excellent habitat for many organisms, therefore it is important to permanently shield such insulating layers from the outside. Reinforce the insulation surface using a gauze layer with one millimetre mesh size covering 100% of the insulation even around windows, doors and other potential openings to prevent ant penetration. The terminal edge of the insulation board to the foundation must be protected by a metal profile so that ants cannot penetrate the insulation from the soil. Ensure the façade does not allow growth of ivy or Virginia creeper which encourage ant activity. Bitumen sheets with glass fleece provide protection against the penetration of ants around the foundation of the building. Covering the insulated façade with thin clinker slices offers a good long-term protection against ants, but most ant invasion is via the foundation.


The first step to successful ant control in buildings is species identification and adjustment of the control strategy accordingly. Since the brown ant builds a colony indoors usually only in decayed wood or insulation with moisture damage, it is necessary to locate and remove the nest and the decayed wood or other moisture sources which facilitate the settlement of the ants (e.g. incorrectly repaired building damage, rotten wood within the foundation range or other sources of humidity). After the elimination of the nest, care must be taken to make good all damaged areas to avoid further settlement of brown ants. The remaining workers can be killed with sweet baits after the removal of the nest. Swarming ants which are found seasonally in large quantities at windows and on walls, should be eliminated by physical means using a vacuum cleaner.

Bee ready and bee right!

The mild winter and warm spring has caused an increase in bee activity, and a high volume of calls from concerned homeowners. But with all the confusion around the ethics and legalities of treating bees, we felt it would be useful to dispel some of the myths and advise on how best to deal with bees.

Identifying the suspects

As with any pest, correct identification is key to establishing the most appropriate course of action.

Bumble Bees

Bumblebees (Bombus) are not easily confused with any other bee. They are rounder, larger and furrier and come with a variety of coloured stripes across the end of their tails. Nesting sites are normally found in bird boxes, under the decking, or in the compost bin. If possible educate your customer to leave them alone as they are an important pollinator, rarely sting, and are under threat of extinction.

Solitary Bees

You’ll find these small bees popping in and out of the wall or very small holes in the ground. They have a reddish-brown bottom and black body. Solitary bees are harmless and, as their name suggests, live more or less alone so you will only really find them in small numbers. It’s unlikely you’ll receive a high volume of calls for this bee as one or two are unlikely to raise an alarm with your customer.

Tree Bees

The tree bumblebee (B. Hypnorum) is a recent addition to the UK’s fauna. Despite this it will already be familiar to many householders and pest controllers in the UK, as it can be the cause of most phone calls – “Help, there’s a bees’ nest in my house!”. The tree bumblebee banding is unique amongst the UK species. The thorax is tawny to reddish brown, the abdomen is black and tail is white. Fresh drones have a patch of yellowish facial fur, but this wears off with time. Queens vary significantly in size, and workers are normally quite small.
Some traits of tree bees can be the cause of worried calls to pest controllers as they commonly establish a nest in bird boxes, or in parts of buildings. Apparent high level of nest flight activity due to ‘nest surveillance’ by drones, and the sound of bee chatter/activity heard through the ceiling are all signs of activity. However, by the time a colony has become obvious (due to this action) its activity will be about to decline naturally. Colonies formed in spring usually decline naturally by late July, if not sooner. Educating the customer about these facts may prevent them from taking any further action.

Honey Bees

Honey bees are small and vary in colour from golden brown to almost black. The most common scenario in which you’ll receive calls for honeybees is when they swarm. Typically these intimidating swarms will first set up a temporary camp somewhere nearby, such as a tree branch, fence post or even a car (pictured above)! At this point it is best to contact a local beekeeper to collect the swarm, and in the majority of cases this works well. The British Bee Keepers’ Association (BBKA) website has a handy search function you can use to find your local beekeeper. However in almost all cases the swarm will take off again within a day or two to occupy a more suitable permanent home elsewhere. If the use of a beekeeper doesn’t work then we recommend you try to convince the customer to wait a day or two, by which time it will have gone away. Swarms of honey bees can usually be safely removed by a suitably qualified and experienced beekeeper if they are contacted in time. If the honey bees have left their post/swarming clustering place, and taken up residence in the fabric of a building, that can be more difficult (if not impossible) to be safely dealt with by a beekeeper, so time is of the essence.

Treating bees

All bees can be treated, but we’d always recommend you explore all other avenues before considering eradication. Use the step by step guide below:

Leave Them Alone

Educating the customer is key. Bee species in a property won’t usually cause any damage, or be considered a significant risk to the customer, so it’s always best to inform the customer of this before agreeing to take the job. If the customer is adamant that they want them gone, then make sure you or another professional company take the job. If you don’t then they will go elsewhere and may possibly find a ‘cowboy’ who will automatically treat using biocides without considering all the options like a professional would. From an ethical standpoint, if your company won’t have anything to do with bees then please refer the customer to find someone else via the BPCA website or set up an arrangement with a local competitor to give them your unwanted bee work – who knows, they may even pass some other work back to you!


If a nest is outside or underground then there shouldn’t be a reason to really move it. However your customer may not see it this way. For underground nests, you’ll need to dig it out and retrieve it, but be careful and wear protective clothing as you’ll create a considerable amount of disturbance (and thus distress pheromone) as you dig down to the nest.
In more conventional and accessible places such as bushes, trees and sheds, to move a nest safely it is best to do it in the dark, when all of the bees will be in the nest and docile. They might buzz a bit, but they won’t fly in the dark so it’s safest to do it then. Bees also don’t see red light well, so if you need to see what you’re doing, put some red plastic film/acetate over your torch or alternately use a red LED light to reduce likelihood of attacks. Simply lift the hive and slowly place it in a sealable plastic box, securely closing the lid for transportation.
Some bumblebees (especially tree bees) like to nest in bird boxes. To move a colony in a bird nest box, wait until all or most of the workers have returned. When activity quietens down, bung the entrance hole with flexible foam (e.g. from a sponge or scouring pad), and seal up any holes you find around the box using tape, as bumblebees can easily use these to escape from the box when it is being moved. Take the box down carefully and without tipping it over, and place it in a secure sealable plastic box for transport. Carefully move the box to its new location and attach it to a surface that is not liable to vibration, as this can disturb the bees.
If possible relocate the bees close to their original nesting point. However, if this isn’t possible, keep the box upright and somewhere cool and dark overnight while they are shut in. Situate the box at least a mile or more from the original location to prevent the bees from returning. Remove the bung the next day and release the bees; they will re-orientate. It is best to leave it until after midday to remove the bung. At the original location, a few bees might return, but these will soon diminish. Make sure the customer knows this is normal and not a problem.
Obviously if the nest is located in an inaccessible location such as cavity walls or a chimney then relocation will not be possible, and eradication will be only viable option. If you do not feel competent to move a bee colony contact the BPCA to find a member who has experience in this area.


Treatment for bees can be administered in exactly the same way as you would for wasps, the only difference being the need for post-
treatment activities. If you have to treat for bees you should consider the risk in terms of their location and access for post-treatment work. The decision to treat will depend if it is possible to close the entrance(s) to the nest after treatment. It may be possible to use extension lances to get the insecticide to the nest, but access equipment may be needed to close entrances safely. If the client is not prepared to pay to do the treatment properly, then you shouldn’t carry out the treatment under any circumstances, and should warn the client of their responsibilities under law if they choose to use an ‘alternative provider’.
Post treatment requirements will vary depending on the species of bees you are dealing with. For bumblebees and tree bees, blocking up access points will prevent non-target bees from entering and getting contaminated, as well as shortening the likelihood accessing the same area in the future.
For honey bees, it is essential you can either block all entrance points or remove all the honeycomb, but preferably both. If you fail to do this,robber bees will find the infected honey and take it back to their hive, contaminating it. This may lead to an investigation and prosecution by DEFRA. Also note that the smell of the honeycomb and the queen pheromone will be lingering, making the area more attractive to another swarm. It is therefore recommended that the smell be masked using a deodorising compound, but if unobtainable, creosote oil or Jeyes fluid are excellent substitutes. For more advice on dealing with feral honey bees, download the Pest Management Practice at

“If you do not feel competent to move a bee colony contact the BPCA to find a member who has experience in this area.”

Stay safe!

Bumblebees and tree bees are less likely to sting than honey bees and wasps. However, disturbing the nest can make them behave defensively, and precautions should be taken to prevent stings occurring. Also note it has been found that bees can become alerted to the presence of an intruder if they are breathed upon, so it is best to try to avoid breathing on the nest during removal. Bee stings are at best unpleasant and at worst can trigger potentially fatal anaphylactic shock or Kounis Syndrome. So always use protective equipment such as a bee veil/suit and gloves.

False Widow Spiders: Overhyped or Overlooked?

In late summer 2013 the false widow spider suddenly jumped onto centre stage. Within days the media and the public became very agitated about spiders, and reports of swollen limbs and terrified families were on the front page of national newspapers. We go into detail of the False Widow Spider and provide some much needed clarification on the matter.

Until the summer of 2013, most UK pest controllers were seldom involved in spider control. Spiders were a minor pest that the householder usually dealt with themselves without professional help, catching most pest controllers in the industry off balance when they suddenly reached prominence. Pest control training courses and publications do not cover UK spiders in any detail, and while a few pest control companies claimed to be busy on spider work, the rest were busy frantically researching on the internet or calling their trade association.

Tricky Identification

Spiders are of course arachnids, not insects, and are therefore more closely related to mites, ticks and scorpions. In the UK, we have around 650 native species of spiders, the vast majority of which live outdoors on vegetation or on the ground, although a few are regularly found in and around buildings. They are all predatory, feeding on other invertebrates. Some species use a silken web to entangle their prey, while others actively hunt down their food. Most spiders use venom to subdue their victim, but only a few spiders in the UK have sufficiently powerful mandibles to penetrate human skin. The spider causing the excitement in recent months was the false widow spider, Steatoda nobilis. This species is believed to have been introduced to Devon from the Canary Islands in the 1880s, and has gradually spread northward and eastwards, with most confirmed records lying south of a line from the Wash to Pembrokeshire. Although S. nobilis was introduced, there are also five other closely related false widow spider species that occur in the UK. S. grossa and S. bipunctata in particular are widespread and commonly found in sheds, outbuildings and porches as well as within homes. “For us, it has been tricky to identify the various false widow spiders with complete confidence, even using the online images. It would be helpful to have a proper spider identification guide” suggests Ian Miller of South London based Cleankill Environmental Services. Typically, the false widow spiders spin a loose tangle of webbing, with a tube of silk in one corner that leads into a crevice where the spider hides in the day. This web is often at least 1.5-2m above ground level, and sometimes higher. “The typical locations for us have been around window and door frames, and eaves,” adds Ian Miller, but they have been reported from a wide range of other locations, including walls, downpipes and gutters, waste pipes, porches, and outbuildings. The spiders of course increase in numbers during warmer months, but in late summer and autumn they may become particularly conspicuous as the males wander more extensively in search of a mate. “Certainly our requests for false widow work always peaks in October” confirms Brian Duffin of Hampshire-based Rokill Pest Control Services.

Not Aggressive

False widow spiders are not aggressive, and will not launch an unprovoked attack on people. When bites do occur, it seems to be a result of accidental contact with a spider. The venom of S. nobilis can cause a short-lived reaction, described as similar to a wasp sting, but occasionally it is longer-lasting and extends beyond the site of the bite. In the UK, the recently publicised cases of serious reactions to so-called spider bites are unlikely to be a reaction to the venom itself, but are more likely to be the result of secondary infection of an initial skin lesion such as MRSA from hospital visits. Given that S. nobilis has been present in a large area of southern England for over a century, living in and around homes, the rarity of bites (around 10/year reported to the Natural History Museum, London) is an indication of the very low threat from this species. The threat is much less than that presented by wasp stings, or tick-borne Lyme disease, for example.

Customers and Spiders

We had a trickle of requests for control of false widows over the last few years, but in 2013 it became a flood. Most callers would report finding a spider that looked exactly like the one on our website, and were worried their family was at risk.. However in most cases, once we reassured our domestic callers that their lives were not in immediate danger, they were satisfied. However institutions such as schools clearly have a responsibility to their pupils, so with these customers we would often become more closely involved.

Prevention and Control

The CoSHH Regulations of course require us to consider non-chemical control options for pest problems. For customers that wanted something done, but were cautious about pesticide use, we would offer an inspection and a thorough vacuum clean of the affected area. Normally that seemed to be sufficient. In the longer term, then sealing potential harbourage points in high risk areas, such as in porches and conservatories, may further reduce the chance of contact with the spiders. However numbers of our domestic customers wanted to err on the side of caution, and have a pesticide applied, despite reassurances about the low risk from spiders. In su ch cases, where safe to do so, we would treat crevices and other likely harbourage areas with a residual pyrethroid or carbamate insecticide. In general, we find that spiders are even more susceptible than insects. However as the spiders are widespread across the areas where they do occur, we advise customers that insecticide treatment of a porch or garage is unlikely to give lasting and complete elimination. The spiders will gradually recolonise the treated area. In terms of choice of pesticide, remember that spiders are of course arachnids, so the ‘other crawling insects’ phrase often used on pesticide labels does not cover use against spiders. Pesticides which explicitly mention spiders on the label are relatively few, but include Pelgar’s Cimetrol and Bayer’s Ficam W. Spiders are likely to be found in situations where surfaces are porous, e.g. concrete, brick and wood, so formulations such as wettable powders and suspension concentrates are likely to give a longer-lasting effect. Regarding outdoor treatments, residual insecticides used in pest control are not approved for the treatment of foliage or garden plants and in the unlikely event that vegetation needs to be treated, this should be carried out with a pesticide explicitly approved for that use, typically a horticultural pesticide. In addition, users of such products must hold the PA1 and PA6 Certificates of Competence, as the RSPH exams which most pest control technicians undertake do not cover the use of horticultural pesticides.

Respect Beneficials

In the areas where false widow spiders occur, then there will almost certainly be a range of beneficial species present too, such as other spiders, hibernating ladybirds and lacewings. Before any treatment is carried out, whether it is chemical or non-chemical, then the potential impact on non-target species needs to be considered, and discussed with the customer. There is a balance between controlling what is actually a very low risk pest, and causing potential damage to organisms that are beneficial in the garden.

This Summer?

Fortunately, thanks to the internet, most pest control organisations are now much better informed about spiders than they were the last few summers. Hopefully those providing training, and responsible for training manuals, will also be able to update their material before long. So, looking ahead, how much spider work can we expect in 2016? Our view is that although spiders have definitely increased their range in recent years and the work has therefore increased too, the 2013 surge was largely driven by media coverage. Who knows what the media might latch onto this summer, it might even be Asian hornets!