The Better To See You With

You may have noticed the long antennae of butterflies, or the sometimes very elaborate and feathery antenna of certain moths.
Male moths especially, like this Chickweed Geometer (Haematopis grataria), pick up the scent of female pheromones from great distances. Some beetles also have long antenna; c.f. the “long-horned beetles.”
But note how minor a dragonfly’s antenna are.
This is a Blue Dasher male. Blue Dashers are the most common dragonfly species in NYC. And yes, they definitely see you coming.
Here’s a female Great Blue Skimmer.
It’s only recently that Odonata antennae have been shown to have olfactory sensory pits on them. But a dragonfly’s main sensory receptors are its eyes. We humans, who bleat on and on how we are the top a-number-one Americans of the animal world, have three color-sensing proteins in our eyes. Dragonflies have from eleven to thirty, depending on the species (and for some, age). They see in “ultra-colour” as New Scientist puts it. There are as many as 30,000 facets on their compound eyes — along with bees, they have the largest eyes in the insect world — which can see in all directions at once.

Except obviously, their blind spot, which is behind and below. “They see the sky as a very bright background against which flying insects [their prey] stand out dramatically,” Dennis Paulson writes in his new natural history of odonates, which I will give more attention to shortly.

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