Being smelled out

 Theophrastus, the ancient biologist, suggested that our noses are above our mouths so that they can be used to test food before we eat it.

It seems like such an obvious principle I tend to forget the rest of the story. As Roy Bedichek said, nature has done a lot of experimenting. The olfactory organs of many insects are in their antennae. The “noses” of ticks — they are called Haller’s organs — are in their feet.

I was thinking of Bedichek’s observation because the ticks are out.

And although I know that my theory that all ticks lurk in blackberry vines when the berries are ripe is an example of observer bias, I found ticks on blackberry vines almost immediately.

When a large animal such as a man with an interest in natural history is near, the tick on the blackberry vine extends her forelegs and waves them. The Haller’s organs are in the forelegs, and the tick is combing the air for compounds such as pheromones and carbon dioxide that will allow her to find her host.

It’s the equivalent of a dog putting its nose to the wind.

It’s hard for me to imagine. Like Theophrastus’s thinking, mine is conditioned by my sensory system, which favors sight and hearing over smell. It’s hard for me to understand forms of life in which smell — or what we think of as smell — comes first.

• Sources: Roy Bedichek, The Sense of Smell; London: Michael Joseph, 1960.

Meredith Swett Walker, “An Up-Close Look at the Tiny Sensory Pits That Ticks Use to Smell”; Entomology Today,” Jan. 16, 2018. It’s here:
http://entomologytoday.org/2018/01/16/up-close-look-tiny-sensory-pits-ticks-use-smell/