Iowa Insect Information Notes

Bat Tick

Bat Tick

One species of soft tick occurs on bats in Iowa. This tick does not have a common name but has the scientific name Carios (formerly Ornithodoros) kelleyi. These ticks are widespread and common in Iowa, and are routinely found in houses and buildings that are infested with bats. They hide in cracks and crevices in bat roosting areas and feed on blood from the bats while they are roosting. If bats are present, these ticks usually do not wander far from them. However, if the bats abandon a roost, are removed, or if populations decline for some other reason, the ticks become hungry and start to wander in search of something to feed on. This is when they are usually noticed.

Bat ticks are a type of soft tick. Soft ticks prefer dry areas and are capable of living for years in the absence of a host to feed on. Few Iowans ever come in contact with soft ticks. Soft ticks do not look like the hard ticks, as a consequence most of us would not recognize them as ticks.

Family: Argasidae (Soft Ticks)

Scientific name: Carios kelleyi

Size: variable 1/7th to 3/8th of an inch depending on life stage

Color: dark to dirty gray to light black

Mouthparts: below the body; not visible when the tick is viewed from above

Feeding Behavior: do not engorge; considered to be intermittent feeders taking a blood meal several times a month

Bat ticks prefer to feed on bats but will feed on other animals, including humans, if bats are not available. Soft ticks are intermittent feeders taking small amounts of blood every few days. These ticks typically feed (bite) at night. They are reported to have a benign bite. In other words, most soft tick bites go unrecognized since they feeds only for a short time and does not cause a reaction in a person being bitten.  Soft ticks are not believed to be capable of transmitting the bacteria that cause Lyme disease.

Controlling bat ticks requires eliminating bats that are present in the home or building. This can only be accomplished by exclusion techniques that seal entrance cracks and holes (also known as "building them out"). There are no pesticides to control bats in attics. The best time to seal bats out of a building is late summer and fall.

In addition to eliminating the bats it may be necessary to directly control the ticks. This can be done by applying residual insecticides such as those commonly used for cockroaches to cracks and crevices in bat roosting areas and other places where ticks are observed. Spraying without eliminating the bats will probably provide short-term, temporary benefit but will not completely eliminate the bat ticks. Eliminating the bats and waiting for the ticks to starve to death is also not a likely possibility since these ticks have been known to survive months, and even years, without feeding.

In late 2003, we received a report of a house infested with Carios kelleyi in Bellveue, Iowa. It is my understanding that the home was bat proofed a couple of years ago. After several months of starvation the ticks probably left the attic, where the bats roosted, and spread throughout the house. Soft tick from above

Photo of Carios kelleyi, top view. Soft tick from below

Photo of Carios kelleyi, bottom view. Soft tick with dime

Photo of Carios kelleyi with dime for size comparison. QuickTime movie of Carios kelleyi (119k).

Updated 07/14/2005 - 12:34pm