Today I noticed a cluster of four or five dime-to-quarter-sized pits in dark soil beneath a burning bush shrub along our driveway in central Ohio. I believe they were dug by antlion larvae. Can someone recommend a gentle way to definitively ID the pits and observe one of the larvae? I can of course carefully dig away the soil in an attempt to expose the insect, but perhaps someone with experience has a less destructive suggestion.
You can start by taking some photos (with something for scale) and uploading them to iNat ;)
You will have to take the larva out of the pit, I do this by poking at the bottom of pit with a pine needle to get the larva to come up and try to attack the needle
I was told to use a plastic teaspoon to dig up at the bottom of the pit and lift the larva out gently.
Just a general question here: Can an antlion larva ‘redig’ a hole once its been taken out? Or do they emerge from an egg underground and construct the hole upwards after emerging? I guess I can wiki it!
The proper way to do this, as taught to me by my mother here in Texas, is to gently prod the bottom of the pit with a stick while singing…
Come out of your hole
Your house is on fire,
And your children will burn
I don’t know if they’re born underground but I know they re-dig.
When I was a kid we’d gently scoop them up with just our hands and watch them scuttle backwards across our palms. When we put them back on the ground they’d immediately hide back under the loose soil, wait a while, and then start constructing a new pit.
A time-honored method that my husband uses with his entomology students goes like this: slide a plastic card (like a gift card, credit card, or your driver’s license*) beneath the entire pit, from the side, aiming the lowest point of your “scoop” about a centimeter below the bottom of the cone. Balance the sand/soil on the card until you can dump it into a plastic tray (or just your palm) and sort through it gently to see if you can find the larva. In my experience, this works about 3/4 of the time, and if it’s carried out delicately, no harm comes to the larva other than the general disturbance of its day. You can return it to the substrate and it will quickly dig a new pit (which is a fun process to watch).
*Warning: do not walk off and leave your driver’s license sitting on a pile of sand at your antlion site…like I did.
Thank you, WeeCorbie and all for your helpful replies. WeeCorbie - I will try your method, which is much like using the spoon mentioned by susanhewitt. Maybe we can improve your 3:4 odds by singing “Doodlebug, doodlebug, Come out of your hole…” (Thank you Pfau_Tarlton for your anecdote!) I will experiment with a pine needle probe, also. Thank you again, everyone…Darrell
Thank you, trh_blue. I had posted a photo of three of the pits as an observation. The photo included a dime to show scale. I’m new to iNat and wasn’t sure whether I should post an image/observation of the pits, since it showed an object and not an organism. Thanks again for your comment. :)
Sure! Any evidence of an organism is acceptable. Eg scat, scratch marks, feathers.
Great! That is very helpful to know. Thanks again!
Not only can antlions re-dig their pit, the process only takes about 20 minutes and they have to do it any time a large insect crawls through the pit or whenever it rains or is sufficiently windy to mess up the dry, loose soil where they dig. So it’s really barely an interruption to briefly scoop them out.
As a follow-up: I did use the credit-card-capture method twice. The first attempt = no larva. For the second attempt, I used two cards. The first I shoved vertically into the ground at the one edge of the pit. Opposite that, I slipped a second card at an angle gently about a cm under the bottom of the pit until I reached it about reached the first card. I lifted the two cards together and deposited their soil into a shallow pan with a white bottom. Gently sorting through the soil revealed the larva, dark-gray, 1/4" or slightly less, which I photographed and added to iNat as an observation. Enlarged with a lens, antlion larvae are bristly, nasty looking creatures :) Thank you again for the suggestion!
Thank you polypody - As I scanned the small cluster of pits for my second attempt at a capture, I noticed tiny activity at the bottom of one of them. A few fine grains of soil were shifting. The sunlight revealed a tiny glint at the bottom of the pit. I thought maybe a small insect had been captured. That wasn’t it. Bits of an insect were being expelled. Knowing a larva was present, I attempted the successful capture.
I have been aware of antlions since childhood and the illustration in the Golden Guide to Insects. But over decades living in the Midwest, Oregon and now Ohio, for whatever reason, I never observed antlion pits in the environment…until spotting eight or 10 pits in black soil beneath a burning bush beside our driveway earlier this week. (My very first sighting of antlion pits was in 2009 in northern Zimbabwe, in fine sandy soil along a path at a remote hospital.) I wonder what it is about the soil beneath this burning bush that makes for good antlion habitat, and how did a female antlion discover it? You’re right about their ability to re-dig. Rain did wash out the pits one day, but they were back next morning. I hope to observe an adult one day.
What a life these creatures lead. What thrilling moments such tiny creatures can give us. And how great it is to have a community of people to share such small adventures with. Thanks, everyone, and thank you iNat!
Unfortunately, that wasn’t my suggestion. I was the person who just used my hands.
Oh yeah, that’s the other thing we used to do as kids to tell if a pit was “live” or not: sprinkle a few grains of sand in (or drop an ant in), and see if there was any activity before scooping up with our hands.
I’m so glad you found success with the credit-card method! These are such neat little creatures, and it’s a lot easier to find their larvae than wait for the occasional serendipitous encounter with an adult. Antlion pits are present in every dry spot in our landscaping beds (which are many, as the house has deep eaves). The larvae themselves have always reminded me of the mind-controlling “ear bug” from Ceti Alpha V in the Wrath of Khan.
While we’re on the subject, you might enjoy seeing this observation of the loveliest antlions I’ve ever seen; they were near a wall apiary in the Mani region of Greece, fluttering among the flowers like butterflies. https://www.inaturalist.org/observations/32125192
Those are gorgeous!
Wow, gorgeous is right. Thanks for providing this link!
The question of how female antlions find places to lay eggs is an interesting one. Around here, the landscape is dominated by moist forests and areas of loose, dry soil are relatively rare. I usually see antlion pits in places that are protected from rain, like around the edges of buildings or under picnic tables. Yet I also often see antlion pits in isolated patches of suitable habitat like in the sawdust around carpenter ant nests. They must have some mechanism of detecting places where the soil stays dry.