Choosing the Bug of the Month each month is a unilateral decision we make based on currency and interest. We are so thrilled with the web dialog that sprang up around this posting of the Florida Deepdigger Scarab Beetles, and since Floridians should be encountering them through January, and since there seems to be a dearth of information about them on the web, the decision this month was quite easy.
Beetle Mound Builders
December 30, 2009
Hi Bugman. I’ve got some kind of beetle building mounds all over the property. They do about 25 mounds a day. They might be dung beetles but I don’t know (I tried to match them up with pics online).
My concern is knowing if they are destructive (besides the annoying mounds). I want to do a large vegie garden and so I’m concerned both about the beetles and about insecticide.
A neighbor (I’m new here) said they live in the ground and only build their mounds during the winter but I don’t know if that is correct. I did first notice the mounds when it turned cold here.
They seem to do most of their work at night though I think they build during the day too.
The beetles are about the size of a quarter, maybe a little bigger. They are shiny black, almost bluish when I shine a light on them at night. They have long back legs.
I’ve enclosed a picture of the beetle, the mound and the series of mounds built in just one day.
Would appreciate identifying the type of beetle, knowing whether or not it is destructive and if so what is the best way to control this little lawn beast.
We believe this is a Florida Deepdigger Scarab Beetle, Peltotrupes profundus, a species of Earth Boring Dung Beetle, though we are going to request a second opinion from Eric Eaton. BugGuide only has two images posted from the genus and indicates they are endemic to Florida. We are also going to try to locate information on the mounds, and we are not sure if the Florida Deepdigger Scarab Beetle is really the party that is constructing them.
It is a most interesting question. Is your soil sandy? because BugGuide indicates they are found in sand scrub. Is the soil consistent with the coloration of the mounds? The Soil Science Society of America Journal has an online article entitled Soil Mixing by Scarab Beetles and Pocket Gophers in North-Central Florida, but there are no images.
Aren’t you guys wonderful! I just happened upon your website while trying to investigate this bug. Your info is very appreciated.
Yes, the soil here is quite sandy. There is a layer of some top soil but then it turns to an orangey/yellowish/reddish sand, the color of the mounds. I believe it gets darker red further down as the previous owner had some pvc pipe set up as ballards so when I removed them I had soil borings to examine.
Also, my neighbor was told, when digging his drainfield, that this type of sand is excellent for drainage. This area of Tampa is actually Temple Terrace, named for the then new hybrid temple oranges grown here. My property sits on an old orange grove, so there might be a bit of manure still in the top soil (just a guess; I don’t know).
What is strange is that these mound builders prefer just a few properties near my house, but a block away I don’t see them at all. There is one empty lot here, about an acre in size, and it looks like a moonscape of mounds.
Interesting the conversation at http://bugguide.net/node/view/39946 as it mentions that December is their active season, just now when I am experiencing the little critters.
Thank you so much for your good information. Please do let me know if you find out otherwise or additional from Mr. Eaton.
Eric Eaton forwards identification request to two experts
Florida + scarab = Eric is clueless. LOL! I’m sending a copy of my reply here to two eminent authorities on scarab beetles. Then I will learn something, too! Sorry I can’t be of more immediate help.
Arthur Evans forwards identification request to another expert
Would you please take a look at the pushups illustrated in the link below and let us all know what you think it is? Many thanks!
Happy holidays to everyone!
Confirmation from Paul E. Skelley
You’ve all had it correct. It is Peltotrupes profudus making the mounds. As a new commer to Florida, I am not surprised by Mr. ‘Bugged’ concerns. We get his exact questions several times every year.
The short answer they are really no problem at all. The mounding is temporary, and actually benefitial to the type of grasses we must grow in Florida. As with many related beetles, Peltotrupes is somewhat colonial. Where you find one, you may find many, and yet, none across the road. Some of this may have to do with their habits of provisioning their burrows with dead plant matter, acorns, etc. In fact, I believe there is a study or two that link these beetles with oaks and deep sand. I have never heard of any case of these beetles actually damaging a lawn or garden plants. Their eye-sore, nuisance mounds are easily knocked over and are washed away with a couple rains. Golf course grounds people will argue about the mounds being a problem, but the beetles pose no other problems that we are aware of.
As for control, I would not waste my time or money. The mound is spoils of a narrow burrow that goes straight down. These burrows are known to be 10 ft. deep and there is no way to put enough pesticide in the soil to kill the larvae in the bottom of the burrows. For a bit of fun, if you can quickly scrape the mound away and find an open burrow, then take a straight grass stalk or other long thin object and stick it down the hole. I occasionaly do this with my kids and have seen 3 ft. grass stalks simply disappear down the hole.
Inspite of them being hard to kill with pesticides, habitat destruction and mis-management are destroying many populations of these beetles. Plus, I have not seen them in heavily managed – irrigated lawns and suspect these yards do not provide the conditions or food needed for the beetles.
This is a non-pestiferous endemic part of native Florida, Mr. Bugged should be proud to have such an interesting insect in his yard. I wish I had them where I lived, but I live in an area with more clay in the soils.
Feel free to drop me additional questions if needed, Happy New Year!
Paul E. Skelley, Collections Manager
Florida State Collection of Arthropods
What a wonderful reply from Paul. Please thank him for me. Now of course I feel terrible (& poorer) for having applied insecticide which I will stop immediately and just hose down the mounds.
Thank you Daniel for your good work in this matter.
[no longer] bugged
ps, Paul is exactly correct where he references the preferred environment as there is deep sand here and I’ve a number of oak trees.
I’m very pleased to have this information and hope I did not damage the colony terribly with the poisoning I did prematurely.