By: Nicholas Cox
Some like to kill them in cold blood at first sight. Still few let them go unharmed, mostly due to a squeamish reaction to distance themselves as far and as quickly as possible. But have you ever stopped to ponder this monster, the tick?
There are over 800 species of ticks worldwide (1) though only 13 are commonly found in Minnesota. (2) Most of the ticks found in Minnesota (and worldwide) are known as "hard ticks" because of the hard shell (or scutum) on the top of their body. (2) Soft ticks are also found in Minnesota, and can be identified by their lack of scutum and their very small heads which appear to be missing to the naked eye. (2) The general life cycle of the tick occurs in four different stages: egg, larvae, nymph, and adult. Female ticks lay thousands of eggs at one time, and once hatched, the ticks typically require one meal of blood before molting, or moving on the the next stage. Some ticks can live up to 30 months without feeding depending on which stage of life they are in; adults are usually able to last longer and larvae shorter (although still from 2-15 months!). (3)
In Minnesota and the surrounding region, there are two ticks that can be found feeding on humans: the American Dog Tick (commonly the wood tick) and the Black Legged Tick (commonly the deer tick). (2) These ticks both survive Minnesota winters underground and typically take two or more years to complete their life cycle. (2) They can be found feeding on humans at all life stages; larvae can be identified by their smaller bodies and their six legs, nymphs are larger and have eight legs, and adults are the largest also with eight legs. Each feeding event lasts for a period of days.
Ticks are important worldwide because they are vectors for disease, transmitting protozoan, rickettsial and viral disease most problematic to livestock. In Minnesota, the deer tick is widely known to spread the organisms that cause Lyme disease, though it spreads less common disease-causing organisms as well. (2) Wood ticks are known to spread the organism that causes Rocky Mountain spotted fever in humans, but its occurrence is very uncommon in Minnesota. (2) The potential for a deer tick bite in Minnesota is great enough that people who spend any time in forests, tall grasses, or other deer tick habitat are recommended to take prevention measures. CCM field crews use multiple defenses, ranging from 20%+ DEET solutions to tucking pant legs into socks and duct taping to prevent ticks from getting inside of clothes. Combined with daily (or more frequently) tick checks, this has shown a very effective technique so far this year with zero reported instances of Lyme's symptoms (at this point I invite everyone to find some wood on which to knock). Some studies have shown 20% DEET solutions to provide 81%-85% effectiveness at deterring ticks while a chemical called permethrin is 89-100% effective. While showing the best results, permethrin is a bit more high maintenance as it can only be applied as a treatment to clothing and is only effective on unwashed clothes for up to one month. (3)
Would the world miss the tick? If my basic ecology education has taught me anything, the answer to this question is quite certainly a resounding YES. Population ecology, especially when considering disease vectors, hosts, and transmission can become very complicated very quickly. Ticks likely play a role in population control of the wildlife and livestock with which they've co-evolved, and their elimination or sudden population change could set off an avalanche of effects unforeseen by the casual observer. As part of a much more simple thought, ticks are a major food source for reptiles, birds, and amphibians. (3) So next time you find a tick who's climbed aboard your ship for a meal, take a second to ponder the wonders of life and its intricate ecosystems, then proceed as you will.
Disclaimer to potential tick activists: DO NOT allow said tick to enjoy said meal, they don't need any martyrs.
1. The Global Importance of Ticks. F. Jongejan and G. Uilenberg.
2.Ticks and Their Control. Jeffrey Hahn.
3. Integrated Pest Management Manual: Ticks. National Park Service.