Subject: Black Larvae?
Location: Logan Village, Queensland, Australia
December 7, 2013 6:11 pm
Hi, I found these coming and going from a large crack in a concrete slab. They’re about 1.5 cm long and have a light green belly. Hoping you can identify them.
We have no idea what these creatures are. They might be beetle larvae, and then again, they may be more primitive insects or arthropods. We will continue to research this matter and perhaps one of our readers (AussiTrev are you out there???) might be able to assist in this identification.
P.S. When you stated “these coming and going” did you find more? How many? A colony?
Eric Eaton provides his opinion
I’d say it is probably a chrysomelid leaf beetle larva, but I’m not that great with Australian insects.
Hi Daniel, thanks for you quick reply.
The first time I saw them, earlier this year I think, there were probably a total of 100 or more. Sighted over a few days, coming out of the same crack in the concert slab. I was ‘removing’ them once or twice a day.
This time there was only about 30 and they seemed to be heading to the crack…from where, I could not determine. Perhaps they’d been out for the day and were returning home 😉 They definitely seem to be a colony, but where they’re based, I presume under the slab?, I can’t see.
Thanks so much for your help and hope to hear from you very soon.
We are still working on this. Here is what Eric Eaton has to say, but the fact that they appear to be a colony associated with a slab of concrete is not consistent with what we would expect from Leaf Beetle Larvae.
I may have been mistaken about the crack in the concrete. I’ve just taken another look and there are some loose bricks right next to the crack, and it appears they are coming/going from under or behind them. Please see attached. One photo is of the debris under the brick. I’m sure it’s not all a result of these larvae, but there does appear to be dead ones in amongst it, along with other insect bits and pieces. The second photo is of 2 approaching the crack and loose bricks.
Would it make sense that Leaf Beetle larvae would opt to make use of such an area?
Thanks for the update Nina. Though we still don’t have an answer for you, we are happy about some new clues. We do not believe these are Leaf Beetle Larvae and we believe Eric Eaton might agree with the new photos. The debris under the brick might hold clues regarding the anatomy of the adult beetles. Those appear to be brown beetle elytra or wing covers in the dirt.
We have made several other requests from knowledgeable folks who contribute to our site and we hope to eventually have an answer for you.
Update: Possibly Carrion Beetle Larva
Hi again Nina,
We are obsessed with this identification. The closest visual match that makes sense is a Carrion Beetle Larva. Carrion Beetles lay eggs on dead animals and the larvae feed on the putrefying flesh and the maggots that are attracted to the decomposition. Your beetles resemble this image of Carrion Beetle Larvae from our archives. We continued to dig and found this image of a Carrion Beetle Larva, Eusipha japonica, which is probably a Japanese species, on FlickR. The Calodema Supplementary Paper No. 79 (2008) mentions a species Ptomaphila perlata. We tried to find a photo of that larva and we found a drawing that looks very similar on Beetle Larvae of the World. We then found a photo on Alum Cliffs, Dec 2009 that looks very close to your larva, but you must scroll down the page to view it.
A Different Opinion
December 9, 2013 4:16 am
here another opinion. In my eyes this maybe the larva of a tenebrionid beetle, subfamily Lagriinae.
I found several pictures in the internet which are rather close. For instance here:
I could, owever, not find a picture that matches 100%.
larva of Lagriinae is, however, only a possibility, I am not sure…
Signature: Erwin Beyer
We also thought Darkling Beetles might be a possibility, but we couldn’t locate any matching larval images. Thanks for supplying a link.
It does look very similar to Carrion beetle larva Ptomaphila lacrymosa (Silphidae), except for the side pieces? where the legs are attached, which are more pronounced (larger and flatter) in your example.
The brick: Please note, that this brick has holes in it, which allows many insects to climb in/out and die in and under it. It hasn’t been moved in about 15 years or so. Therefore, it is probably a bit of a bug cemetery. I just turned over another larva and it wasn’t as lime green on the belly, as the one in my photo, more cream in colour.
There only appears to be a few crawling around now, so their obvious activity appears to only last a few days. I wish I could provide more information. Perhaps I should preserve one or two somehow?
More questions from Nina
Yes, the tenebrionid beetle larvae is VERY close! This is image is the closest I have found http://beetlesinthebush.wordpress.com/2011/02/14/answers-to-id-challenge-5-artropodes-em-casca-de-arvore-morta/
The fact that they live off and on dead trees? is a bit disconcerting, if they’re heading for my house. Although, I’m a tad paranoid after having battled termites for nearly 2 years.
If they’re in the larvae stage, I may seem an influx of a particular beetle soon? Being ignorant to the cycles of insects, how long would the larvae stage last?
Hi again Nina,
The link you provided does look very close. We don’t believe you need to worry about these larvae infesting your home. Most larvae live less than a year before metamorphosing into adults, but some may live several years in the immature stages. We are uncertain how long the larval stage of this creature will last.
Thanks for your efforts Daniel. I’m happy with the conclusion that it’s some type of beetle larvae. No doubt this will not be the last time I submit a bug for identification. We live on 5 acres of bushland, so there’s an abundant supply!
Enjoy your festive season and have a merry Christmas!