No ID, No Problem?

Almost every time I go out on the Sycamore Greenway, I find the most adorable bug I've ever seen. It is almost always a different bug, a new bug, spotted while photographing a bee or a flower. I catch sight of them sitting on a petal nearby, or clinging precariously to a blade of grass, and then I go into paparazzo-mode, circling my subject and slowly moving closer until I exhaust every angle (or it, fed up, flees).

I love these chance encounters with new critters. The problem? I can't always identify them. Oh, I try--I take to the guides both paper and online. I will google as many descriptive terms as I can and scroll pages of image results looking for something close. If I am desperate, I may post a shot to the fantastic bugguide.net or another online forum for help.

More often than not, I (or more accurately, the helpful community of online naturalists) can at least narrow the ID down to a genus. Sometimes, though...bubkes. Despite my best efforts my charming little bug remains a mystery, and I never get around to sharing it because without a name, it's just a thing. Occasionally I will sneak it into a Friday post with a quotation, if I can find something suitable. If it is just a bit too odd for that, I will plan to go back and keep trying...but eventually the season changes and it is too late and it remains on the island of forgotten photos.

Not this time! I don't know what this sweet little moth is, but it is too cute to consign to a photo archive, never to see the light of day. Spotted while photographing a bee on Rudbeckia hirta, I first noticed the gangly legs with what appeared to be spikes here and there. Then up to the cute little striped antennae and then...it's face! That fuzzy little upturned snout, like a nasal pompadour. What was it all for? What kind of a life does this moth live, that it has such features?

Alas, I may never know. But it is a comfort to remember the chance encounter with this individual and consider the extremely specific lifecycle it undergoes, along with the rest of its species, right here in the Greenway. It deserves a moment of notice, even if I don't know its name, or why it has long spiky legs and a weird, hairy face. I see it.

Free Nectar? Don't Mind If I Do!

Ants on Partridge Pea. The extrafloral nectaries are visible as small
red spots near the base of each leaflet

 

Most people are familiar with the mutually beneficial relationship between plants and pollinators: plants offer up nutritious nectar or pollen to entice insects, birds, or small mammals to assist in their (ahem) sexual reproduction. Sure, in some cases the plants cheat and trick a bee into "mating" with a flower that resembles a female bee with no nectar or pollen provided, or a tricky bee will snip into a flower's base to drink the nectar while avoiding its pollen-laden anthers.  But for the most part, it's a convenient system for both plants and pollinators.

Some plants, however, have a secret stash of nectaries tucked away on their stems or leaves. These little pots of sweetness offer up nectar to insects, apparently without a catch. Ants or flies may wander the leaves, sipping nectar, and going nowhere near the flowers. It's obvious what the insects get out of this--but how does it benefit the plant?

Assorted ants and flies visiting
Partridge Pea nectaries.

The most likely advantage plants derive from extrafloral nectaries is protection. Ants and other insects that avail themselves of the nectaries will, in the defense of their wonderfully nutritious and low-effort food source,  drive off or deter more harmful herbivores that may attempt to feed on the plants themselves.

I first learned of "extrafloral nectaries" when researching the partridge pea, which has fairly large nectaries on its leaves that are easily visible by the naked eye. Its foliage is often crawling with ants and other small insects, and if you watch closely you can see them pausing at the little nectar pots.

When I observed an ant on the leaves of Illinois bundleflower, another plant in the legume family like the partridge pea, I wondered if it, too, had extrafloral nectaries to lure insects as a protective squad. I examined the leaf but was unable to find any obvious pots like the partridge pea had. Research online confirmed that the Illinois bundleflower did indeed have extrafloral nectaries, so I was determined to find them.

A fly foraging on
Illinois Bundleflower.

First I staked out a patch of bundleflower on the Greenway and watched the ants and flies going about their business. They seemed to wander aimlessly up and down the stems and leaves, but often paused at the petioles, where the compound leaves joined the stem. Armed with an idea of where to focus my search, I collected a stem to bring home for a closer look (doing my best to de-ant it before bringing it inside, with limited success).

It didn't take long at all, with a little extra magnification, to find tiny little nectar pots right at the base of the leaves, where the ants had paused in their journeys. Just a tiny round opening with a drop of nectar within, there for the taking by any passing invertebrate, no questions asked.

What other plants on the Greenway are harboring these secret sweets? You can bet I will be keeping a closer eye out for ants among the leaves.

The minuscule nectary at the base of an
Illinois Bundleflower leaf.

Further reading/resources:

• Many Plants Have Extrafloral Nectaries Helpful to Beneficials
• The diversity, ecology and evolution of extrafloral nectaries: current perspectives and future challenges