PPC124 | OPINION

Are we the problem? PPC picks the brains of some rodent behaviour experts to explore why some rodents avoid traps, bait stations and monitoring devices, and whether our own control methods could be helping them learn what to avoid.

The discussion covers neophobia, behavioural resistance, bait and trap avoidance, customer expectations, and the practical changes pest professionals can make when rodents refuse to play by the rules.

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Speakers:
PPC Niall Gallagher, BPCA Technical Manager
SM Shane McKenna, Verus Environmental
AM Anthony Murphy, SETU and RRAG
NE Nick Eddy, Pesttrain
NB Nicholas Blaszkowicz, Representing the CRRU Best Practice Working Group

What is neophobia?

PPC Today’s debate is titled: are our control methods fuelling neophobia in rats?

It’s a topic that comes up quite a lot and I’m sure most people have probably come across neophobia in some form or another during their career. From a control standpoint, what’s going on when rats and mice avoid our traps, avoid our baits, avoid our monitoring devices, and how can we adapt when rodents are adapting alongside us?

We use the term neophobia, but it’s not actually covered that much in training. So, what do we think neophobia is?

AM If you’re trying to control rodents on a particular site and you’re experiencing difficulties, you can probably classify the basic problems into three broad categories: ecological, genetic or behavioural resistance. Ecological is where you’re getting invasions from outside so quickly that it appears you’re not managing control. In actual fact, you might be managing control, it’s just that your invasions are so quick.

The second one is genetic resistance. Hopefully you’re all familiar with the CRRU scheme around testing for the VKORC1 mutations, which can mean that even if a rodent consumes poisonous bait, they’re not actually killed by it.

The one we’re talking about today is behavioural resistance. This is when the rodents’ behaviour leads them to avoid consuming bait that appears to be both palatable and available.

When we talk about neophobia, neo means new and phobia means fear. So it basically means fear of new things.

In relation to rats and mice, it generally relates to fear of objects rather than food. That’s why we use permanent bait stations to try to overcome that fear.

We’ve been waging this war for thousands of years, so what we have is a pretty wary set of animals. They vary widely in terms of their behaviour, both as individuals and as groups, depending on their history of control.

Behaviour can be learned, in terms of experiences animals might have on a particular site, or it can be instinctive, because of that long history of these animals being chased by predators and by man.

NE It’s quite easy to talk about neophobia and end up talking about learned behavioural resistance. They’re definitely linked, but I would say neophobia is the natural instinct of the rat to avoid new things.

Behavioural resistance is the learned, over time, avoidance of traps or baits or whatever.

If you’ve gone to a site where the previous pest controller has done loads and loads of work, you might be experiencing behavioural resistance from the previous controller rather than instinctive resistance to new things.

How does it show up on site?

PPC If we’re looking at that learned behaviour, what are we typically seeing when it comes to neophobia?

NE The key one I see in my day-to-day job mainly affects pest control companies doing one-off jobs.

They might not have the luxury of having external boxes or internal boxes down 24/7.

People who sell three to five-part riddances need to be explaining to their customers that, for the first one to two weeks, we might have a neophobic response from the rats and decreased acceptance of baits.

Managing that expectation can manage the customer’s expectations of your work. You actually show yourself as a bit of a behavioural scientist as well as a pest controller.

SM I’d jump in on the back of what Nick said about taking over other sites, particularly where the previous pest controller has hit a brick wall.

That’s probably the reason you’re there, to try and resolve the issue in a more effective way.

Sometimes they’ve just run out of ideas. They’ve not been persistent or experimental with their approach. They’ve just been one-track minded.

The rats and mice have got used to the treatment a lot of the time, and they’ve never changed it up. Which is a shame really. They should be trying different things, in my opinion.

Should we pre-bait?

PPC Nick mentioned resistance or neophobia for a couple of weeks potentially. Some textbooks quote much longer periods as well.

As we move from old school pest control into a newer style of pest control, what can we do to help combat neophobia? Is there an element of pre-baiting, especially for one-off jobs?

NE My view on pre-baiting is that it’s a luxury that some people don’t have.

If you’re selling, especially on the cheaper end of the market, you might not have the margin to spend one week not necessarily doing anything, especially if you’ve got the type of customer who’s looking over your shoulder.

The counterpoint is: will your treatment be more effective and therefore quicker in the longer run?

If the rats are engaging with your traps on week one and not getting caught, and on week two they’re all getting caught, that might be better.

If you’re using traps or bait, make sure you’ve got enough of both, and make sure they’re down in week one. We can’t keep adding to them, otherwise we’re just resetting that neophobic response.

SM It’s a little bit hit and miss regionally, and area-based as well. For me, up in the north west, I go to Liverpool or I go to a different town and they behave differently in different areas. If you’re working in your own town, you’ll know how those rats and mice behave. But if you’re travelling to different areas, you’ll find different things work.

That’s been going on for as long as I’ve been doing pest control. That’s the challenge we all have to overcome.

Are bait preferences local?

NE I came from Devon when I was doing pest control, and when I moved up to Oxford to manage the Oxford team, I did see a big difference in how behaviours changed, and bait preferences.

Personally, I found in countryside areas they preferred more chocolatey-based baits, and in the city centre they preferred more cereal-based baits, because that’s not what they had.

I’m sure other pest controllers have found completely the opposite in their local areas.

On a training level, if we can do more localised training based on what people are observing in their day-to-day jobs, or sharing on WhatsApp or Facebook groups, maybe we could have more success as an industry.

PPC It’s interesting when you look at formulations, because that inherent safe food they learn is pretty much built in from birth and weaning.

AM We have evidence that rats can show feeding preferences based on what their mother has been feeding on, and what other rats within the community are feeding on.

If animals return to a burrow and smell of a particular food source, you can see preference for that food source from other animals. The big thing is that, unfortunately, there isn’t a single universally acceptable bait or magic ingredient.

You really need to know your individual site. You need to understand the food source that is competing with your bait, and the way the animals are interacting with the environment.

NB One thing we talked about with HSE many years ago was using different formulations in the same bait station. If you’ve got the same active in that bait station and you’re not exceeding the bait point quantity, you could use two different formulations to understand feeding preference.

If the maximum is 200g in a bait point, you could use 100g of one formulation and 100g of another, as long as it’s the same active and you stay within the label guidelines.

SM You see all sorts when you’re out there.

You see rainbow baiting, where people have got lots of different actives, lots of different baits, traps in boxes, and all sorts going on.

But condition is a big thing as well. If they’re doing a treatment and the traps have got mouldy bait in, or mouldy lures in the traps, a rat’s not going to eat from it.

NE From an audit perspective, I’ve seen one active ingredient being placed on top of another.

But that clarification is interesting, because if you’re using the same active but different formulations, that can be useful.

I had an example with a seafood restaurant where they were using Nutella and not getting anywhere. Then they moved to bits of mussels because that was what the rodents were eating, and they caught them all within two or three weeks.

Should we change the hardware?

PPC As we move away from permanent toxic baiting, where it isn’t justified, we’re seeing more permanent monitoring and more trap-based systems. Do traps have a role here? And are they part of the neophobia problem?

NB Traps might have a place, but if you’re using permanent traps, they need checking frequently, or they need electronic monitoring.

I’d be cautious about permanent snap traps in external boxes on long visit cycles. The other issue is non-toxic monitoring bait. 

If you condition non-targets to enter a bait station, then later introduce toxic bait, you may expose those non-targets.

The key with everything is to document what you’re doing and why. Then you’re giving your own justification.

NE I would advise against having permanent snap traps in an external box on a six or eight-week visit cycle. That’s not because traps are wrong. It’s because they need checking frequently. And frequently is open to interpretation.

The other thing is that some companies have one bait box or one trap and use it 100% of the time in every situation.

If you’re going onto a site with previous control pressure, maybe you need different trap designs, different trap actions and different approaches.

SM I’m doing a small trial myself looking at plastic versus metal traps.

What I’ve found is that certain plastic traps, like the L-shaped tombstone-style trap or generic snap traps, the rats seem to avoid. The full metal traps, heavier traps, seem to be more successful in certain strategic locations.

That’s just what I’ve been seeing, but I do think there’s room for more innovation in trap design. Different styles, materials and ways of constructing them.

PPC BPCA is doing some behavioural resistance work looking at trap types and lure types, so if anyone wants to get involved, let us know.

Are bait boxes always the right answer?

SM I very rarely get mice or rats going into bait boxes, especially in city centres like Manchester.

Pest controllers don’t use bait boxes anymore, or externals. They don’t go in them.

NB There were historic trials comparing homemade wooden bait stations with plastic ones, and the results were pretty much 10 to one in favour of getting rats into homemade wooden bait stations.

When I’m doing trials on farms, the first thing I do is condition the bait station, removing the fresh plastic smell and the smell of human handling during manufacture.

PPC I’ve used mouse droppings before, rubbed into a box.

It’s similar with mole traps. People will weather them in soil before use.

NB You can use simple things in rural settings. An old tyre propped on bricks with a heavy dustbin lid on top. Or pipe runs with bait secured in the middle.

The important thing is securing bait where possible. The number of times we’ve seen blocks unsecured, and they just get taken away and cached. Farmers then move stuff at the end of the season and find 200 bait blocks behind a stack of hay bales.

SM That’s where the challenge is for technicians.

If you’re in an urban environment, you may not have a tyre, a pallet or a pipe. If you’re working for a larger company, you might have standard kit and standard training.

So, is it a training issue? Is it an experience issue? Technicians need to know they can think beyond “it’s got to go in the box,” while still working within the rules.

Does IPM reduce the need to fight neophobia?

NE If you can reduce competing food sources and nesting opportunities, you might not need to overcome every bit of neophobia. At some point, it’s got to eat.

So close bins. Remove food sources. Improve housekeeping. Get the customer to play their part.

AM Placement is critically important, particularly for trapping. If a rat has a safe food source of equal or higher value, you’re not going to move it off a run that it knows and trusts, where it’s going to get to that safe food source.

You need to get your trap placement correct.

In Ireland, we often find meat-based lures work better than peanut butter or chocolate. But again, it depends on the site.

Has the loss of glue boards changed the skill set?

PPC With glue boards now restricted or removed in parts of the UK, are we having to relearn some skills?

NE I think so. Glue boards could sometimes mask poor technique or poor placement. If other tools weren’t being interacted with, glue boards could still pick up activity and help end the job.

With that option reduced, technicians have to think more about why a control measure isn’t working.

How do we sell this to customers?

NE From my operational experience, when I was managing a team, we’d quite regularly sell three visits and then end up comping one or two extra visits to get on top of the problem.

We got to the point where we almost started selling a five-part rat riddance as standard.

That could be your upsell: pre-baiting in the first visits, or an extra visit to make sure you’re done at the end. Or if the customer wants it dead cheap, then they can have it in three.

SM I leave it open until I’ve done the initial survey. Always. I never put a tab on it: three visits, that’s it. Never do that, because you’ll get egg on your face at some point and you’ll end up doing extra visits for free.

Educate the customer. Tell them what you’ve found because you’ve done your survey. This issue is at this level, and this is what you feel you can achieve in a certain amount of time.

But if it doesn’t happen, you continue. Again, it’s education and letting customers know what’s going on.

What’s the one piece of advice?

PPC If you could give one piece of advice to pest controllers and business owners looking to tackle neophobia, what would it be?

NE Mine would be: experiment.

We tell our customers we’re dealing with animals and it’s not an exact science. Let’s treat it like that. Let’s try different traps, different active ingredients.

If you need to chat to your manager, chat to your manager. It’s all about experimentation.

SM Think outside the box, within the guidelines and within safety, obviously.

Try different things. Don’t have your blinkers on. Think outside the box and you’ll get there in the end.

NB I’m going back to my previous point: education.

Even leave customers with a copy of the CRRU Code of Best Practice. See if they want to read through that and educate themselves.

AM If you’re trapping, you’ve got one chance, one experience with a rat.

You need to make sure you use a trap that’s powerful enough, and that the rodent is going to interact with the trap in a way that you’re going to get a kill, not a miss.

A rat that has had a whack from a trap and escaped is going to be very hard to control afterwards.

You’re the person who knows the site. You know the behaviour of the animals on that site. 

You know the risks, and you know the owners of the property. You’re the person best placed to manage these challenges.

PPC That’s a good place to leave it.

Neophobia is not just a technical word. It’s what happens when a cautious animal meets a control programme that has not quite thought like an animal.

For pest professionals, the message is clear enough: survey properly, understand the site, vary the approach where needed, document your reasoning and keep the customer with you. And, as ever with rats, don’t assume they’ve read the method statement.

WATCH THE FULL DEBATE

Members can watch the full one-hour debate over on the BPCA website. bpca.org.uk/cpd-videos

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