Are Ticks Active in the Winter?
By Chris Williams on March 2, 2016.
John Maher: Hi, I’m John Maher, and today I’m here with Tim Chase of Colonial Pest Control. Tim is an entomologist and a pest control technician, and today our topic is are ticks active in the winter? Welcome Tim.
Tim Chase: Good morning, John.
Are Ticks Active in the Winter?
John: So Tim, what times of the year are ticks the most active?
Tim: Well, it sometimes depends a little bit on the species. We’ve got 3 species here in New England that we really consider of note. The American Dog Tick, the Black Legged Tick (we used to call it the deer tick). He’s known for his little black legs and that’s the one that carries Lyme Disease, Babesiosis, and ehrlichosis. [These are] some of the nastier diseases that ticks carry. The other ticks are also vectors of some of these diseases, but at a much lower level. Then we’ve got the Brown Dog Tick, so those are the 3 ticks that we usually run into. These are all in the family Ixodes, or what we would call hard ticks, so they’ve got a relatively hard front of the body, also known as the cephalothorax. Their abdominal section comes out behind that, and that’s the part of the tick that expands as it engorges with blood. As the tick feeds, this part gets really big. An important part of understanding when ticks are active is their actual life cycle.
A tick’s life cycle begins with the egg, which is usually laid in the springtime after the female has overwintered on the host and has obtained enough blood to produce her massive eggs. Depending on the species, it can be several thousand eggs that are laid. It takes a few weeks for those eggs to hatch, and then a very small larval tick will develop. These things are about the size of the head of a pin for the Black Legged Tick, while some of the other species are a little bit larger.
These ticks are very, very active in the springtime. They need to get a blood meal so they can change into the nymph stage. So, these little six legged guys are very actively seeking a host and generally, feed on smaller animals like mice, chipmunks, squirrels, and in some cases, birds. It’s very important for them to find a host, and that first feeding is one of their first potential times to pick up some of the disease bacteria that can spread Lyme disease and some of the other diseases that ticks carry.
Tim: As the development progresses, once the tick has its first meal, it drops off and changes into the nymph, which now has eight legs like the adult. The nymph is also a very aggressive feeders. Both larvae and nymphs are chiefly down in the lower layers of the leaf litter and in the grass. These guys are very sensitive to desiccation and sunlight, so they’re going to be down in the lower areas. That’s where most of their hosts live, the smaller animals like mice, chipmunks, voles, and things of that nature.
Once they’ve had a second blood meal, which is their second opportunity to pick up the organisms that cause Lyme disease or some of the other diseases we’ve talked about, they’ve got to drop off the host and do a complete metamorphosis into the adult, so they can mate. In the case of the Black Legged Tick, the most activity for the ticks is generally the early spring and in the mid-summer. That sort of wanes a little bit as we get into the fall and early winter. That’s where the adults of the Black Legged Tick and the American Dog Tick are most active outside.
The adults have gone through the two different earlier stages of their life cycle, and now they’re actively seeking an adult host. The adult ticks generally feed on larger animals, so they’re less susceptible to desiccation and they’re a little bit more mobile. What they’ll do is they’ll crawl up to the edge of a bridge or a blade of grass or something along the trail and they’ll stick their front legs out and as soon as a host comes by, they start waving their arms madly in hopes of contacting that host. In the case of the Black Legged Tick, it takes almost a full two years to develop. The first year, we’ve got the nymphs and the larvae feeding on smaller animals, and then the female overwinters on the host, where she mates with the male, and then in the springtime, she drops off and lays her eggs and that cycle continues again. So, it takes about a year or two for the whole cycle of the Black Legged Tick to actually take place.
Now with global warming, today it’s 45-46 degrees out and it’s going to be in the 50s.
John: Right, we’re in the middle of December now.
Tim: We can expect these adult ticks will be seeking out hosts and actively feeding on hosts. Again, the larvae and the nymphs are chiefly more busy in the early spring and mid-summer and then the adults are actively seeking their hosts right now. So, it’s a very busy time right now.
John: Right, so that late fall and early winter is a busy time for the ticks.
Tim: Sure, and on warm days throughout the whole winter, if the temperature goes up a little bit above freezing, most of these ticks can come out and actively look for hosts. So they are active during the winter on nice, warm days.
John: So I don’t really think of going for a hike in the winter in the woods or something like that. I’m not watching out for ticks because I think of those as being more of a spring and summer thing, or even a fall thing.
John: But you do have to be a little careful.
Tim: Yeah, exactly. One of the interesting ticks that we have in New England is called the Winter Tick. It’s mostly associated with moose and large animals that are hooved and live out in the forest. When hunters bag a big moose, sometimes they can find over 2,000 of these ticks. When a population of ticks gets that high on a host, it’s really not good for the animal.
Tim: It can cause stress, certain kinds of paralysis and even desalination or loss of blood on the animal. It can even lead to death, if there are enough ticks. So it does put a strain on the population. Mostly it’s a concern for hunters out there in the winter looking for moose and other large game. That being said, whenever you’re going into the woods at any time, you’re able to pick up ticks. Again, the most likely to give you disease would be the nymphs who have had two chances to potentially feed on a host, and then the adults who have had maybe their third chance to feed on an infected host.
Preventing Tick Bites
John: So those adults that are feeding on you in the late fall and early winter, that can be a problem [if they’re] a disease carrying kind of tick.
Tim: Sure. So considering that, one of the most important things is inspecting yourself after you’ve been out in the woods. It takes 36-48 hours for a tick that’s been on you to spread the two main diseases – Lyme Disease and Babesiosis. It can be under 24 hours for ehrlichosis. So, if you’ve come in from the woods, it’s imperative that you go over your whole body. Most of the nymphs are active in the spring, and those are the hardest ones to see because they’re so very small.
Tim: So they could actually be able to come through your sock at the bottom of your shoe.
Tim: There’s repellents and stuff that are very effective at potentially stopping the tick from biting you on the skin, but they’re not sure if it stops the tick from walking over your skin to find an untreated patch of skin or walking over your clothes. So just because you’re sprayed, that doesn’t mean it’s going to jump right off you. It might be able to walk over that repellent until it gets to a spot behind your ear, where it wants to go.
John: You’re not going to cover your entire body with insect repellent, that’s probably not a good idea.
Tim: And depending on the species of tick, you’ve got some that really want to find a nice warm, thin skinned place. The Brown Dog Tick doesn’t really care where it bites you, so it will go crawl right up and get on your back or something. It really doesn’t care.
Tim: Because ticks have a unique sort of anesthetizing properties, they work their mouth part into you. Most tick bites aren’t felt.
John: You don’t even notice.
Tim: You don’t even notice until there’s some kind of irritation a couple days later, where you might see the characteristic bullseye sort of mark on your body around irritation. Sometimes, [it can be] the size of a softball.
John: A rash of some kind.
Tim: The enzymes your body is interacting with the enzymes from the insect in a negative fashion.
Reducing Ticks in Your Yard and Around Your Home
John: Right. What are some of the things that people can do, maybe around their house, in the winter to prevent ticks in the spring or make them less common?
Tim: That’s a great question. When the female first lands in the spring, after she’s spent the winter on the host and she’s ready to lay those thousands of eggs, she’s going to want to get down into a nice, safe spot where it’s moist and dark, where these little eggs can hatch and the larvae and nymphs can be safe from the sunlight. So you’re talking about thick grass, wheat, leaf litter, areas under shrubs, and places like that. A good fall cleanup is great. A good spring cleanup is good too, so you’ve reduced a lot of those harbored spots where she wants to lay her eggs around your property. That can do a lot to help reduce [population of host animals]. [Pay special attention to] places where mice, shrews, voles, chipmunks and things live. If you’ve got lots of wood piles and habitat rock piles, you’re going to have more ticks just based on their gravitation towards those hosts.
We’ve all seen chipmunks living in stone walls. One of the suggestions that I just read yesterday was to point up all your stone wall, so you don’t have places where the chipmunks can live under and around your structure. We know that chipmunks are a part of the life cycle of these animals, we know the female [ticks] are going to lay their eggs where the animals are going to have access to a host. It just makes sense to remove the host population or reduce it as much as possible. Another consideration is, “Is my yard filled with deer?” Deer are one of the main end hosts for all of these ticks, so the adults of all species want to get on some of these larger animals, where they can spend the winter mating and just enjoying their time next to a nice, warm body. Then, in the springtime, they just drop right off and lay their eggs and the adults probably die at that point. Most of our tick species only last about a year, so you’re not getting multiple matings and breedings from that same tick. It’s pretty much a one way street to that egg laying at the end, as far as I’ve read in the literature.
John: Right. That’s really great information, Tim, thanks for speaking with me today.
Tim: Thank you so much.
John: For more information, you can call 1-800-525-8084.
Photo Credit : “American Dog Tick (Dermacentor variabilis)“| CC BY 2.0 via Wikimedia Commons.