One of the surest ways to know that Spring is here is that ticks are back. Although ticks can feed year round, they ramp up their blood lust in April and May. Because of their increasing activity, I thought you’d like to know some biology which dictates their behavior. Ticks are interesting creatures.
Ticks’ life cycles are long and complex. Take the deer tick-let’s face it, that’s the one we’re most concerned with for the obvious reason that it carries Lyme disease. Ixodes scapularis, the eastern black legged tick, has a 2 year life cycle which involves multiple life stages. Egg, larva, nymph and adult each live on several mammalian host species, including mice, deer, domestic animals and humans. The female deer tick feeds to repletion-often taking several days to gorge, and then drops off to lay hundreds to thousands of eggs. Amazingly, Ixodes ticks can reach 10 times their unfed body weight. This tick captivates us because there is so much trouble in a tiny tick. Dangerously hungry nymphs are smaller than a pinhead, and are very difficult to see. Because of their size, nymphs feed on prey low to the ground such as mice and squirrels. Mature adults, on the other hand, in their quest for food, hover on taller grass-about 3 feet high. That’s where the deer are-as well as any other non-suspecting potential host. The questing method of prey seeking is a unique feeding behavior. In response to vibration in air currents, changes in CO2 concentrations or even smell in the air, ticks extend their forelimbs and wave them about in order to latch onto their prey. Lying in ambush, they thus expend very little energy in their search for food. And if no potential prey comes along, ticks have developed incredible adaptations to ensure their survival. They have a long starvation tolerance. They can tolerate drought conditions by entering diapause, a state of dormancy which can last months to years. Ticks survive through harsh winters by burrowing into leaf litter. Remarkably, diapause will end when triggered by favorable ground temperatures and lengthening light in the day.
Ticks have an ability to suppress a host’s immune response allowing the tick-or many ticks, to remain attached until feeding is complete. Their saliva contains an anticoagulant which permits continued blood flow while gorging. Mating can actually occur while the female tick is feeding so that she can expeditiously hatch her eggs soon after dropping off her host.
All of these biologic modifications ensure that ticks have superb survival strategies.
All coming to a field near you.
Protect yourselves and your pets now by calling your vet for the newest defense against these potent foes.
Celeste Conn, VMD
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