What’s Afoot in the AB Winter: 8-legged Moose Nightmare

Male Winter Tick

As a general rule, I don’t like ticks. Actually, that is an understatement: I loathe ticks! But it is winter and, even during this unusually mild version, there are few arthropods around to enliven the out-of-doors. Here’s an exception that showed up with the New Year, a bit earlier than expected, but a real live winter arthropod and not unattractive at that. My appreciation of this rather large (6.6. mm long) blood-sucking 8-legged fiend is influenced by the knowledge that it probably wouldn’t bite me: it is a male Winter Tick, Dermacentor albipictus (Packard, 1869).

Winter Tick-infested Moose - 3:12 AM
trail camera shot

 Winter Ticks appear to prefer to suck the blood of moose and their relatives (Cervidae – moose, elk, deer, caribou). Moose can be very heavily infested - the average load in late winter is 30,000 ticks (see Samuel* 2004 p. 31). Heavily infested moose spend more time rubbing up against trees and the like trying to remove the itchy ticks than feeding. The result is a Ghost Moose – skinny, with ragged coats, open sores, and a grey-white colour. Many such moose will die overwinter, but if they can last until May, most of the ticks will have dropped off and they have a chance to recover.

Ghost Moose at Dawn

 Winter Ticks are the only ticks you are likely to find in Alberta in the winter, so identification is not too challenging. The adults are ornate ticks, i.e. the dorsal plate (covering the whole body in the male, but only the part just behind the ‘head’ in females) is patterned and they have 11 posterior festoons (the tooth-like grin at the rear). A pair of small eyes on the margins of the plate and a spiracular plate with large ‘goblet cells’ (unless you know what small goblet cells look like, this isn’t a great character) completes the identification. Males also have a distinctively formed spur on the base of the first pair of legs. Adult males are not above wandering around looking for females, so you or your dog may pick-up one of these ticks while on a winter hike on a mild day. Usually, they would keep wandering until they found a moose with female ticks, but if they are more hungry than horny, the males may bite (or at least I was brought a Winter Tick male that someone claimed bit them near their eye).

Winter Ticks have eyes too (arrow)

 Most hard ticks (Ixodidae - the family that includes the Winter Tick) have three different hosts during their life cycle – one of the reasons they are so likely to pick-up and transmit a disease causing pathogen. Each life stage - larva, nymph, and adult – attaches to and feeds on the blood of a host until full and then drops off. Winter Ticks, however, usually spend most of their lives on the same host. The best place to learn about the fascinating story of the Winter Tick is Bill Samuel’s book (see below*), and SRD kindly provides a good factsheet, but I’ll give a quick overview of the highlights.

Mouthparts (upper) and coxal spur (lower)

 From late winter until early spring, you can find female Winter Ticks as blood-filled blobs (to ~1.5 cm diameter) attached to moose and other members of the Cervidae (deer, elk, moose, caribou), and rarely on other large herbivores (bison, cattle, horses) or smaller mammals (coyotes). Males feed a bit, but do not bloat, and wander the moose looking for females to mate. Once the females have dropped off to lay their eggs (about 5000 each), you might come across them on the ground or in the litter around moose wallows and the like. Some of these female ticks may have been buried in the litter by magpies – which will also eat the ticks directly off the moose. 

Magpies - boreal tick birds

Tick eggs lie dormant until late summer to early fall when they hatch into tiny (<1mm) seed ticks (larvae – with only 3 pairs of legs). Seed ticks hunt moose, usually by hanging on to low vegetation and grabbing a moose when it walks by. Sometimes larvae get on people by mistake, as we, much to our horror, found out one September, but they don't attach. The larva wanders the moose until it finds a good site to bite through the skin, suck blood, and then shed its skin to become a nymph. Nymphs hang out and wait for things to get cold before sucking enough blood to moult into adults.

Moose Fly - the business end

 You’d think that Winter Tick would be all the parasite nastiness that any animal should have to endure, but Mother Nature has a summer surprise for moose too - Haematobosca alcis (Snow, 1891), the Moose Fly. Just as the moose is beginning to recover its condition in early summer, these housefly-sized pests start to appear. The flies hang out on the back legs of moose, pierce the skin with their long proboscis, and cause large, open sores from which they feed.

Sores from Moose Fly bites

 If you notice a cloud of flies around the rear of a moose in summer, especially if there are sores on the hind legs, you are likely seeing Moose Flies. The flies lay their eggs in moose dropping, the larval food, so moose give these pests pretty much everything they need. The sores don't heal until frost kills off the adult flies but tend not to fester either. So, it seems likely that the flies introduce a substance that protects the sores from bacteria. You can read all the gory details at  another SRD factsheet and see better pictures of the sores than we have here. Next time I’m feeling persecuted by the mozzies, I think I’ll reflect on the life of the moose, and not complain so much.

References:

*Bill Samuel. 2004. "White as a Ghost: Winter Ticks & Moose" Federation of Alberta Naturalists.

Alberta Sustainable Resource Development. 2004. Winter Tick - Fact Sheet #21. http://srd.alberta.ca/fishwildlife/WildlifeDiseases/documents/Winter_ticks.pdf

Alberta Sustainable Resource Development. 2010. Moose Flies - Fact Sheet #30. 

http://www.srd.alberta.ca/fishwildlife/WildlifeDiseases/documents/MooseFliesFactSheet-Aug2010.pdf

What if and What is it? Mystery Beetles of the Moose Pasture

Gray and chilly this morning in Edmonton, only a week until the end of calendar winter. Of course, here in central Alberta, the calendar is never more than theory until May, a wistful picture over a grid of snow white blocks. Alberta Bugs has had rumours of insects in flight in Calgary, but not even a Mourning Cloak has shown up here. Still, the snow cover is in retreat, the southern exposures are becoming exposed, and one can always hope that El Niño will grant us an early Spring.

But Spring isn’t here and An Inordinate Fondness is all set for its second issue. Alas, I seem to have plundered most of our digital beetle collection for previous postings, leaving little new to add. But, when the facts are inconvenient, it is time to turn to theory, and the theory of the Home Bug Garden (HBG) is that I can create an oasis of biological diversity in urban Edmonton. As a test of how well I have succeeded to date, lets compare the HBG diversity to – well, the Moose Pasture. This seems appropriate since the Moose Pasture is our theoretical escape in the country, a quarter section of bush land near Elk Island National Park where we take our bugpersons’ holidays, putter around appreciating the biological diversity of central Alberta, and daydream that some day we will do more than putter. Sometimes we can even put a name on a beetle, like this wasp-mimicking long-horned beetle Clytus ruricola (Olivier) that probably uses some of our aspen or birch logs as a larva (thanks to Eric Eaton and Kenn Kaufman in the Kaufman Field Guide for the information that they breed in decaying deciduous trees).

You may recall from the When Alien meets Alien: De gustibus ... posting, the HBG claimed 339 species of animals identified from its environs including 28 beetles. Not bad for a quarter acre urban lot, but not really a strong showing for the beetles. I am happy to say this total has risen in the last month to 362 species of animals – but, alas, the beetles have failed to budge. In fact, almost all the increase has been due to moths, thanks to Feralia – the annual celebration of Lepidoptera identification, music, and the usual shenanigans hosted by John Acorn in February. In comparison, our Moose Pasture ‘boasts’ 492 identified animal species including – what, only 31 beetle species! Well, our Inordinate Fondness obviously needs some work and we don’t have a beetle equivalent to Feralia. But, we do have a beetle carnival to appeal to and perhaps its readers can shed some light on a few Moose Pasture mystery beetles.

Here’s one example (with Ted MacRae in mind), a beetle we have labeled Dicerca possibly tenebrosa (Kirby). However, we note that the Strickland Entomological Museum says “Dicerca tenebrosa is easily confused with other Dicerca species” (e.g. Dicerca crassicollis LeConte (Kirby)) and that one character for this species is “a short second segment on the antennae”. Characters like this always make me ask - How short and in comparison to what? Since both of the bupers above bore in conifers, I wonder if we aren’t on the wrong track? The Moose Pasture is full of aspen but has only a handful of spruce (I think most burned up in the early 1900s when the last large fire swept through the Beaver Hills Region), so I wonder if this may not be the Bronze Aspen Borer Dicerca callosa Casey? In case this flat headed borer is too easy, here is a mystery weevil that has no guess at all.

We would be especially pleased with an id on the weevil, but we know there are lots of them and they tend to look alike. So, how about a few of the more colourful Chrysomelidae. Below are a few guesses and one we just don’t know.

Carrying on with the colourful – a few gay beetles on a gray winter day – here’s one Scarabaeidae we think we know and one we don’t.

Well, the sun seems to be trying to peep through the clouds, the temperature is above zero, and if I don’t get outside, then I won’t have any chance to see my first Mourning Cloak, Ring-billed Gull, or other hopeful sign of Spring. One thing that I have noticed in pouring over our Moose Pasture insects is that from the few we have identified, there isn’t much overlap with the Home Bug Garden fauna, and the two sites are a mere 53 km (33 miles) apart. I think this has implications for what I am trying to achieve, but that is something I will need to think about. In the meantime, it seems most appropriate to end, not with a beetle, but with an eponymous Moose Pasture beastie. When the thaw does come, there will be lots of reminders of this animal dotting the landscape - and ones that some scarabs will no doubt find attractive.