They don’t like heat? That seems incorrect. If true, Then why are they a huge problem in TX and other southerly areas, and are only now spreading north?
Different species I belive. Ticks in Texas are differnent from ticks in Ottowa. Most lyme disease in the US is concentrated in the northeast and northern great lakes states and into Canada (though it is spreading over the past few decades).
Texas has the 'Lone star Tick' primarily. But in Michigan for example we've had the Blacklegged tick (which is the main species known to carry Lyme in our state...) for a looong time.
The black-legged tick season in Ottawa is March through June and again September through November. Summer (deerfly season) is just too hot for them and they go to ground.
We do all the best camping in January and February. Why, you might ask, when it's usually colder than -20 C? No ticks. Also no mosquitos, blackflies, or deerflies but mostly no ticks.
They seem to be much less active on hot days compared to cooler days in my experience - though I can't say why. I've definitely observed a difference over the years though.
That said, whether it is hotter or cooler doesn't make much of a difference in terms of how you go about your day - you pretty much have to assume you can encounter them regardless.
It's the length and depth of cold days in the winter that can potentially limit their breeding populations, is my understanding. So the issue is that more northerly areas are getting much more variance in temperature and lacking long deep consistent cold periods.
Up and down cycles in temperature have always been a thing on the North American continent but climate change has made it even more variable. We will still get places where it gets very very cold but not for the consistent chunks of time it takes to set back tick populations significantly.
TLDR I don't think it's the heat or cold per se but the variance.
And yes climate change is absolutely the prime factor in their spread. Into places where they were not ever a threat before.
I’ve seen a tick in Wisconsin every month of the year over the past five years or so. That is I’ve seen a January tick one year, February tick that same year or another year, etc. Whenever there is a bit of a warm spell they appear. Presumably small upward trends in temperature allows such warm spells to happen more frequently.
Ticks have always been around Ottawa, and even in 2011? I recall -40C for well over a week, and obviously cold temps around that week.
Insects lay eggs, and also go dormant under fallen leaves typically. The snow + leaves insulates them, it's how live insects survive the winter.
If you watch robins in the spring, before the ground thaws, you'll see them flipping over leaves. They're eating loads of insects hiding, most still torpid from the cold.
-40C isn't a problem for ticks to live through in this way.
In terms of population, everything follows predator/prey cycles. Nothing is static. It's normal for populations to "explode", eventually predators will grow in numbers too.
I see it with noseeums here, and dragonflies. There are almost no noseeums this year, but loads of dragonflies, which means the dragonfly population will collapse, and soon (couple of years) the noseemums will be relentless. But then the dragonflies will grow in numbers, with plentiful food, and the cycle will repeat.
It's natural.
Global warming may shift habitats, but these ticks are normally here. They're not new.
If there was more diversity in predators and prey, the population cycles would have smaller amplitudes. The large swings are often symptoms of a collapsing ecosystem.
The lowest recorded temperature in Ottawa in the last 40 years was -33.1c in 1996. It hasn't been down to -40 since like 1911.
You might be recalling wind chill temperatures, which would not be relevant here. They're subjective perceived temperatures for hairless apes.
However it does occasionally get to (real) -40C ish in Edmonton area, and they now have populations of blacklegged ticks. But very small populations.
Like I said above, the issue is not the absolute lows or highs, it's durations of cold, which impact their ability to recover and produce large quantities of eggs in the spring. This was literally in an article I was reading about ticks the other day, don't make me hunt for it.
Black legged ticks are not new to Ontario, but they absolutely are to places like central Alberta. And the Lone Star tick is moving north for similar reasons and will be established here in Ontario shortly as well.
I live in the Ottawa region, and it was indeed -40C for a week where I live. My Jetta screaming "warning extreme cold!" at start, and the kitchen window thermometer I have doubly validate that.
I'm also 20 minutes to downtown, outside of rush hour, so I stand by the ease of saying "Ottawa".
No you don't get my address, but temperatures in cities and at airports are warmer than rural areas in winter. Where I live, I'm also higher up by several hundred feet, and it all matters. I don't blame you for checking, but the city of Ottawa encompasses a lot of rural land.
It can rain torrents in part of southern Ottawa, but Ottawa weather stations could remain dry.
My point about snow and leaves, is that if there is snow cover, they're completely happy, insulated, nestled in the leaves.
I don't doubt you read an article, and from a reputable source, I just don't buy their assertions. Lack of snow cover would be a bigger predictor than overall temp.
Dude, weather stations record actual temperatures both in and outside the city. Environment Canada peppers the whole province with them. There's nowhere in southern or eastern Ontario that gets as cold as -40C. It simply doesn't happen. -35C is the lower bound and that is extreme.
I know this because I farm and grow grapes and have meticulously poured over weather charts for the whole province. (Survival cut off for hybrid and wild grapes is really around -32C or so. Vinifera... maybe -20C)
https://www.cdc.gov/lyme/data-research/facts-stats/lyme-dise...