Harpalus pensylvanicus

[Hisserdude]

I had a topic on these a few years back, and was going to add some photos that i forgot to add, but it appears to be gone. Anyways, I guess I will kinda recreate it, with more info and photos.

I kept the adults in a 24 oz tupperware container, with moist coconut fiber as the substrate. I had about a dozen adults, which ate dog food and dead mealworms. I kept a milk cap filled with wet toilet paper in one corner, and i would pour water over it every week. One day, i went to replace the toilet paper in the cap, and found 3 or 4 eggs in the folds of the paper. I dug around the surrounding substrate, and found even more eggs. The surrounding substrate was very moist/wet. I separated the eggs to a small container with a thin layer of moist toilet paper. In about 4 days, I found 2 little larva crawling around. I separated the larva, and put them each in their own container. They ate dead mealworms (Eleodes larva). Over the next few days, more eggs hatched. The adults were laying eggs nonstop, every other day there would be another 4 eggs! Unfortunately, the larva were very weak, and prone to die off for no apparent reason. However, the adults were laying so much eggs that such losses were easily replaced. Eventually, I was starting to run out of food (I only had 1 or two darkling beetle species at the time, and no actual yellow mealworms). The adults had died of a fungal infection, due to having too much dog food in their diet. I released all but three mature larva. All but one died before pupation, and the one that did pupate died of unknown causes. A sad ending, but at least we know more than we did before. I may try again this year, if i can find some adults. Anyway, here are some pics!

Adults.

2 day old larva next to a dead Eleodes hispilabris larva.

Mature larva.

Pupa.

I hope my experience with this species can help others succeed where i could not. Hope you guys enjoy!

 

[Ratmosphere]

The different types of larvae and their process to adults is fascinating. Awesome pictures.

 

[Hisserdude]

Thanks! Yes, their life cycle is quite amazing, much more cool than mammals lol!

 

[pannaking22]

Very good information since not a lot seems to be known about rearing carabids successfully (or without difficulty anyways). You've given the hobby plenty of info and now I"m going to have to go out and try this lol

 

[Hisserdude]

Thank you! And good luck, I hope you can succeed!

 

[AlexW]

I think I have a theory why larvae were dying.

Remember the link on Creophilus maxillosus rearing I posted?

Not only more eggs were laid in wetter substrate, but the survival rate for larvae was higher too.

So maybe next time keep the larvae and pupae in dripping wet substrate so they don`t die from dehydration?

Just an idea.

 

[AlexW]

Also, here is how I keep my enclosures dry without causing beetle dessication:

For the enclosure shared by the Calathus and Coniontis, I put a moistened dog food piece in for them and take it out the day after. By then it will have dried up, and the same piece can be remoistened and reused over and over.

This saves a lot of dog food, since beetles can't eat the entire thing in one feeding.

 

[Hisserdude]

I actually kept the H.pensylvanicus larva very moist, one or two of the larva drowned in tiny little water puddles on the sand. However, the containers I kept them in had lots of holes, and I did not give them hides, so maybe they died of the air being too dry? Also, I wasn't able to read that article, I do not have an account on that site.

I leave the dog food in my darkling cages for a few days, and depending on the species, all or half of the food is gone. I remove it after a few days because of mites/mold. Yep, I get mold even in my dry containers, a mold that does not produce strands or gets poofy, it just makes the food white.