15 replies to this topic

[Daniel]

Hello All,

 

I keep a small colony of Hydrophilus triangularis that I thought I would share a few photos of. They are usually difficult to photograph because they are constantly active, but I caught this one relatively still while feeding on some lettuce. The adults are wonderfully entertaining to watch and very easy to keep.

 

I also just hatched some eggs from them and have about 100 hangry larvae that I am separating into individual containers before they all devour each other.  If anyone else keeps these and/or would be interested in some larvae let me know!

 

Cheers

 

 

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[bmb1bee]

What do they eat as larvae? These look pretty cool.

[ANTdrew]

This is quite fascinating. How do you care for these beetles?

[Daniel]

The larvae feed on other insects, both aquatic and terrestrial that fall in the water. I have been feeding them fruit flies that the larvae grab at the water surface. They are small, 1st instar larvae though. As they grow, I will try other insects like crickets and house flies. They are also cannibalistic.

The adults are detritivores and are much easier. I feed them vegetables, leafy greens, and algae wafers.

[Daniel]

This is quite fascinating. How do you care for these beetles?

I keep the adults communaly in a freshwater aquarium with a piece of wood and floating vegetation (sometimes just lettuce leaves that they eat) for them to haul out on. No substrate because it's easier to change the water that way.

They like to haul out of the water occasionally and just appear to be drying out for a while before jumping back in. I think it may be to replace the air bubble that they hold under their elytra. They are super active, always swimming around looking for food to scavenge. The adults have shown no aggression toward each other, but as I said earlier, the larvae are savage and need to be separated if you don't want to risk cannibalism.

[CheetoLord02]

Awesome! I've kept a few of these individuals in the past, but I've never gotten a pair at the same time. I love them, they're a ton of fun to keep, and I'd love to breed them in the future. It seems relatively straightforwards, but having someone else with a record of it seems very useful! Thanks for sharing!

[ANTdrew]

I’d be very interested in getting some of these for my classroom tank in a few weeks.

[Daniel]

Hello All,

I tried raising those larvae in individual setups but they all died, with only a couple making it to 2nd instar. I think this may have been due to poor water quality keeping them in such small containers.

Fortunately, another one of my females produced an ootheca recently and I decided to raise the larvae in a heavily vegetated communal setup. Although there has been some cannibalism, the growth has been much better, with all larvae currently in the 2nd or 3rd instar stage. Cannibalism has slowed down in the group and I expect a good number to fully develop.

Here are some photos of the current batch of larvae. They develop the darker coloring and wider heads when they reach 3rd instar.

They have done quite well on frozen/thawed bloodworms and feeder fish (and occasionally each other). The challenge now will be providing a way for them to pupate. They will need to leave the water and dig a pupal cell, so I will need to figure out a way to facilitate this. Suggestions are welcome!

Cheers,

Daniel

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[ANTdrew]

That is so cool. Maybe you could set their container in a larger outworld with soil?

[Daniel]

That is so cool. Maybe you could set their container in a larger outworld with soil?

Yes, I think this suggestion would be the most feasible. I will probably use a long plastic sweater box with a few inches of fine sandy clay or silty soil and bury the smaller wet container in it up to the brim. Then I will just drape a piece of carpet or fine mesh over one side to allow them to crawl out. Something like that.

[Daniel]

I think these two are getting close.

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[Daniel]

They've begun to pupate.

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[ANTdrew]

No way! I’d be interested to buy some if you’re selling.

[Daniel]

First pupa to eclose appears to be a male. I lost the first three pupae to mold in the dirt setup. So, I have switched all subsequent pupae over to artificial pupal cells that I made out of floral foam,which is a pretty common practice with terrestrial beetles.

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[bmb1bee]

No way! I’d be interested to buy some if you’re selling.

I second this! Rearing these sounds like it’ll be pretty interesting. Do you think they might be compatible with my Abedus water bugs?

[Daniel]

No way! I’d be interested to buy some if you’re selling.

I second this! Rearing these sounds like it’ll be pretty interesting. Do you think they might be compatible with my Abedus water bugs?

I think it would depend on the size of your Abedus, the size of your aquarium, and how well fed your Abedus are. These are pretty large and agile, so they may be able to coexist with Abedus.