How heatwaves affect pest control
It’s hot for us all, and that’s the truth, as we sweltered through the June heatwave, with all of us silently wondering how long it could go on for, and exactly how much hotter would it get, it shouldn’t surprise you that we’re not the only ones having these thoughts.
Because this extreme heat affects every living thing around us; we saw last year how the trees which were denied water during the drought and went into a shocked preservation mode of creating more fruit and seeds as a defence mechanism.
The heat stressed all animals and insects and so that feeling of being unable to cope in the heat is the same for all our pests, they’re behaviour will change because of the heatwave and here’s how.
Bee's and wasps
Our main insect pest during the summer are wasps and hornets, I will mention bee’s in this blog because they’re behavioural changes really highlight the stress that all insects are under in heatwaves, but we should never regard bee’s as pests.
Now bees really struggle with heat through a double whammy of exhaustion from trying to keep the colony cool and starvation as many flowers will stop producing nectar and pollen, whether bumblebees or honeybees they really have a hard time when temperatures climb above 30 degrees centigrade.
Now wasps go through the same physical stresses as bees with dehydration and the additional workload keeping the colony cool, and they also suffer from having an irresistible sugar craving. You see, in the early stages of colony growth when there’s an abundance of larvae in the nest, the adult wasps feed off a sugary secretion produced after feeding those larvae.
When a heatwave occurs, due to the two additional factors of a lack of water and an increase in work, the laying of eggs and production of larvae inside the colony will drop, this cuts off the adults from their usual food supply.
Adult wasps now need to fly off and forage for their own food, and this is on top of bringing in insects for any remaining larvae still inside the nest, and remember that the flowers are drying up and not producing sufficient nectar which, in this case, would be the wasps alternative food supply.
Thios means that you will come into contact with hungry and aggressive wasps more frequently in hotter weather and if this is the case, try to avoid lashing out with your hands because this can provoke an attack; keep sweet and sticky foodstuffs secure and away from any patrolling wasps.
The only good thing about the heat, as temperatures climb over 38 degrees centigrade, the wasps quickly become exhausted and they will avoid flying; so remind yourself of this fact when you’re next melting into a puddle of sweat, and for additional comfort, if you can take any comfort from this, if temperatures get as high as 40 degrees, wasps will start to die off and now that’s what I call “a look forward”.
Bee's will be more active at dawn and dusk
Wasps and bee's will have to cool their nests
Wasps will need to find alternative food source
Garden ants and flies
Our black garden ant becomes a major pest when they get inside the kitchen but generally these are amazing insects that are so beneficial to the environment, and its beyond belief what they add to any ecosystem.
The black garden ant, Lasius niger has shown in studies that they can withstand heatwaves to some degree by changing their foraging periods from daytime to nighttime, they can adjust the ant nest structure to disperse heat more effectively and even when pressed, they’ll relocate the entire colony to someplace cooler.
Overall, as the soil dries out and heats up life becomes more difficult for those established colonies, but for new Queens that have to single handedly build a new colony, heatwaves present an insurmountable problem where nearly half will die off due to heat stress.
Ants maybe the losers during a heatwave, but houseflies take the podium as they are definitely the winners throughout the summer; as the heat rises household waste decomposes quicker and quicker, with extended periods between Council waste collections, from either two weeks or up to three weeks, the flies have a greater supply of food, and more food means more flies.
Houseflies like all insects are cold blooded but they use the high temperatures to their advantage, seeing egg incubation times cut in half to just 8 hours, added to this, the hot weather means that houses have more windows open, and open for longer periods and don’t forget, we are trying to make the interior of our homes as cool as possible, so a tempting place for houseflies that have hatched.
Houseflies will come in through open windows
Ants may have to relocate their entire nests
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House flies will breed much quicker in a heatwave
Rats
It’s not just insects that get affected by the heat, it’s also rats and like many mammals, they lack sweat glands to help keep them cool, we all know, or we should know, how dangerous it is for dogs to be out in high temperatures, well it’s the same for rats.
They don’t like temperatures above 32 degrees centigrade which cause heat stress and a temporary infertility in females, when the thermometer climbs up above 30 degrees, rats will seek cooler areas, which may, or may not mean inside your home.
Older properties, typically from the late 1800’s and up to around 1930 with air bricks and voids beneath the floor, can suddenly find themselves with rats living under that same floor as the ground here will be very cool. The air bricks allow for a good flow of air through the space, and these spaces can be quite deep, I’ve had to use ladders to access the bottom on more than one occasion.
Warm to hot weather will always give rise to a breeding boom for rats but proper heatwaves means that they will only travel in the cool of the night. This effectively cuts down their foraging ability and so we may see a drop in the rat birth rate, however, for females already feeding a litter of young rats, the additional stress can make them more bolder and so, you may encounter rats for the first time as these rats are desperate for food.
Rats are unlike field mice that can get enough moisture from the food that they’re eating, so in a heatwave they will be irresistibly drawn to any source of water. Were you playing with the kids in the garden with a paddling pool, or a water play table? What do you think will happen when you go to bed at night, having left a few inches of water lying in the bottom? Yep, you’ll have rats climbing over the same toys that your children played with just a few hours ago, and are likely to play with again tomorrow, so to avoid anything unpleasant because rats carry diseases in their urine, empty and then shake out anything that holds water to deny a travelling rat a much needed drink.
The high temperatures will cause food to rot quickly and you know that from the awful smell, rats are more than happy to eat human faeces, so a wheelie bin or food waste bin of smelly, rotting kitchen waste is going to attract rats onto your property. Keep bin lids closed and even consider putting something heavy on the lid, especially for the food waste bins that tend to be very small and flimsy.
As an example: where I live, we have just gone over to wheelie bins and a two weekly collection cycle, the Council won’t take wheelie bins with kitchen waste inside, so we all must use these smaller bins as well. I’m now seeing so many bins attacked by rats and reports of rats in gardens throughout this area, that I can only conclude that the rats have found the smelly bins as an additional source of food.
Rats will breed much faster in warm weather
Female rats will have to work harder to feed their young
Rotting rubbish will become attractive to rats
Splooting squirrels
Squirrels are another typical summer pest for the reason that they have two breeding seasons, and one is now; usually in a “normal” British summer of rain and sunshine, followed by a lot more rain, squirrels are quite happy living inside the lofts of our houses.
They will gnaw holes through the fascia boards to gain more airflow and sit either in the gutter or, up on the roof tiles to keep cool (or alternatively, warm themselves up after all that rain), however when we get to a heatwave, just like rats and dogs they have to find ways to cool off.
Because the fur on a squirrel’s belly is quite thin, they will stretch out face down to bring their belly into contact with a cool surface, and this is called splooting. You will also see them draped across tree branches high up in the leaf canopy, taking advantage of the shade and any possible breeze.
Overall, they will adapt their lifestyle to become more active during dawn and dusk, resting up through the day, the problems with any heatwave is all down to the accessibility to drinking water, and any drought means that the squirrels’ autumn food production is going to be accelerated as these trees become stressed.
A heatwave combined with a drought, means that squirrels will need to harvest more food over a longer period as the winter food shortage period is stretched over more months, young squirrels born into this period will struggle to get their stocks built up, meaning come the late winter and early spring, they will be starving. We often see squirrels raiding bins and so you’d expect a higher proportion of squirrel to human conflict with bins being attacked.
The one piece of good news is that our native and massively under threat, red squirrel seems to not be affected by heatwaves in the same way as the grey squirrel. Grey squirrels both out compete and carry the harmful squirrel pox which is fatal to the smaller reds but given their range of habitat from lowland areas to highland forests, it’s believed that they can easily adapt to heatwaves whereas the greys can’t.
Splooting, how squirrels cool themselves down
They will spend more time lying about in trees
Heatwaves may be good news for the red squirrel
Final thoughts
A heatwave will like any extreme weather event, produce winners and losers, as we go into more turbulent times with the increasing threat of global warming it’s important for both businesses and residences to start forward planning for pest control.
Are there windows that could use fly screens?
Do we have or do we need an electronic fly killer machine?
What maintenance do we need to keep rats out of the building?
How can improve our waste storage and management?
And then, is there anything I can do to help beneficial insects like bees?
Climate change is going to present us with many challenges, and we should look at pest control in conjunction with wildlife support because we may not be unhappy with less rats but do we want to see a decline in ants and bee’s?
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