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Chlaenius emarginatus larva - Chlaenius emarginatus

Chlaenius emarginatus larva - Chlaenius emarginatus
Fauquier County, Virginia, USA
July 28, 2015
1st instar. A bad photo, but it shows the urogomphi coloration well. Unlike C. aestiv*us, there is only one pale stripe on each 'tail', and the 'tails' are also shorter and don't appear to be articulated.

I reared these easily from two adults I collected at night and brought home. The setup was similar to the one I used to rear C. aestiv*us(1).
The period from observed mating to larval emergence took exactly one week. Four days after mating, there were mud-cell-encased eggs in the container, and just three days after that the first larvae were found.

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Chlaenius emarginatus larva - Chlaenius emarginatus Chlaenius emarginatus larva - Chlaenius emarginatus

Awesome stuff man
I might just have to try breeding some of my local carabids again....

Please do!
Rearing carabids is a valuable thing to do.. so many have never been studied in the larval form, and larval characters could be useful for sorting out relationships in unclear genera. [edit: And it's fun!]

Chlaenius seem to be very easy to get larvae from, if my two casual attempts are any indication. It's nice that they lay eggs in mud cells, because you can be certain that oviposition has happened, and the adults are probably less likely to eat the eggs.
Getting them through pupation seems like a challenge, especially since it's unknown what conditions they seek out in their natural habitat. A more controlled temperature/light cycle would surely be helpful, rather than having them on a shelf in a bedroom like I did.

I was able to get eggs from two species...
Harpalus pensylvanicus and a Pterostichus sp, but was not able to rear either to adulthood. I did get one H.pensylvanicus to pupate, but it died after a few days. However, I just found some more H.pensylvanicus, and I will try again to breed them. The first instar larva of the Harpalus were quite cute, they had huge heads in comparison to their bodies.

In what manner did they lay the eggs? I'm curious how easy it is to notice carabid eggs of species that don't make distinctive mud cells. I've read that some Pterostichus make mud cells too..

They layed some eggs in the substrate
Which was coconut fiber. They layed their eggs at the bottom of their Tupperware, so they were easy to see. However, its seems that their favorite spot to lay eggs in was a milk cap with wet toilet paper in it. It was supposed to be a water bowl, and after a week I noticed small round holes drilled into the toilet paper. I softly ripped the toilet paper apart and found several eggs. The Harpalus laid much more eggs than the Pterostichus, and layed more eggs in the substrate than in the water bowl. None of my Pterostichus made mud cells, but then again, I never gave them mud to make cells out of...

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