Lucanus Elaphus habitat question

N

newbie007

L3
I've been blacklighting frequently for the past year, my main goal has been getting lucanus elaphus. But in this time I've become a little puzzled in where they seem to be common or not, and was wondering if anyone had some insight.

I had mainly been blacklighting in 2 locations (no sightings at other locations I've been to):

Location A:
This is a large forest, very dense. There have been several elaphus sightings in connected forests less than a mile away. In my entire time blacklighting here (probably 20+ nights) I've only gotten 1 elaphus.

The other insects that show up are mostly the same as the second location, seems to be a good number of tityus, a very large amount of capreolus, a few Dorcus paralellus and a few Ceruchus piceus.

Probably about a 25 sq mile area of forest (5 miles x 5 miles). There is no ambient lighting such as street lights.

Location B:
A small forested park. I catch 4+ elaphus quite frequently almost every night. I think there has only been one night I haven't gotten an elaphus here but it was raining a bit so that might be the reason.

There is way less capreolus here, maybe 1/5th of what I get in location A. Haven't seen too many tityus, but they might just be starting to come out. Probably same amount of dorsus and only have seen 1-2 cerichus.

This spot is about 1 sq mile of forest, but since it's a park maybe half of that is clearings. There is are also street lights (HPS) so a lot of light pollution.

I'm curious if anyone has any ideas why they are so rare in other spots? Are there specific trees they prefer? I have heard they like oak trees, location B has a ton of oaks, location A has few oaks but neither location seems to have particularly large amounts of oaks, in fact it seems to be more maples from what I can see (although I'm not great at IDing trees so could be wrong). I do love that I have a spot they are common, but would also be great if I could find other spots to blacklight in besides a single location.

 
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I did some more searching and found someone mentioning cervus needing clay soil, and that possibly applying to elaphus. I took a look NC since it has the most observations on iNat, and also looked up if NC had clay soil. According to my search, the center "Pledmont" region is known for it's clay soil. Comparing that orange region on the top map to the sightings on the bottom map, seems to correlate strongly.

I did go back to location B last night and did observe the ground was in fact a lot of clay. I am planning to visit location A tonight to hopefully find some tityus and compare the soil there, but if my memory is correct it's more muddy black soil.

This also reminded me when I was trying to rear elaphus larvae a few years ago, my larvae did not pupate for 2 years. I read a suggestion about putting a layer of clay on the bottom, and when I did that it instantly started building a pupa chamber. Not only that but I got the clay soil at the location I found the larvae, and I remember not having to look for it because it was everywhere.

So maybe I found my own answer, but I'm curious if anyone else still has any insight, or opinions on my theory.

north_carolina_soil.jpg

 
That explanation makes so much sense! Last summer I went to a small town near Western Choctaw county, Mississippi, and looked a bit for invertebrates. I found a dozen or so Elaphus larvae (which are now pupating) and a few dead Capreolus adults. It would make sense, since the area has clay beds! They are the only L. elaphus I have ever found, but I have only went once.

 
So quick update, the clay soil theory is a bust, I realized that everywhere around me is clay soil. However in my OP I mentioned Oaks, now that I have learned what oak tree leaves look like, actually the spot that I find a ton of elaphus has a lot of oaks. I wouldn't say it's a majority, but there is at least one oak tree every 30ft or so, if not more than one.

The spot where I didn't find them, I see barely any oaks, and some of the ones I found are just little young trees only 10-15ft tall.

I went to the spot where I originally found some elaphus in 2023, and that spot had an insane amount of oaks as well.

So my current theory is while I'm sure they aren't necessarily needed, if it's their favorite type of tree for feeding on sap as adults, I could see over time populations moving towards areas with heavy oaks and that's why I find them more frequently in those spots. I've been trying to explore forested spots in my area to see if I can find more spots with many oaks, so I can test next year, as elaphus season seems pretty much over.

 
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That makes sense, since many oak forests have been cleared out (Orin’s book). Still, there could be multiple variables in play, and perhaps there would be no elaphus in the area without clay.

 
Absolutely, did not mean to imply clay soil wasn't important. in fact it's probably mandatory, from my first experience trying to read an elephus larvae must have been going on 2 years refused to pupate until I added clay soil to the bottom. My observation was just that both areas had it so it wasn't a factor why they weren't as common in one area.

And completely agree it's probably multiple factors, could also be the amount of downed wood/logs, I know that was an issue for Cervus since apparently people used to clean up forests removing rotting wood.

 
Another funny thing I’ve heard and am doing myself is hibernating the L. elaphus, but winters don’t seem to get too cold where they are found. Perhaps it’s just a captivity thing, but I would love to find correlations to wild specimens.

 
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