# Predaceous Diving Beetle



## moosehooks (Apr 13, 2005)

A few weeks ago, a friend and I were in a parking lot in downtown Rochester, NY, when we came across what I originally thought was a shiny stone.  Turns out it was a large beetle, which I thought was pretty weird considering that it was very cold out and a lot of snow had only just melted away.  Anyway, we got it home and noticed that it had flipper-like appendages.  I was only used to the really tiny water beetles and such, so we decided to use a 'sink-or-swim' test to see if it was indeed a water beetle.  It swam like a champ.  

We didn't know what to feed it, but I knew that many water bugs were carnivorous, so we gave it a dead cricket, which it ate at some point during the night.  The next day, our roommate had some leftover feeder goldfish from a photoshoot, so we threw one in with the beetle.  I didn't expect what happened next:



















So after some searching, we've determined that we have a predaceous diving beetle.  It's constantly moving about, and will readily attack anything in its bowl.  Pretty awesome freebie!


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## Bayushi (Apr 13, 2005)

As soonas it warms up here(again), I'm going down to the flats and collecting some Diving beetles and if we can find any, some giant water bugs.  They are interesting to watch and feeder guppies are cheap so they make inexpensive pets.


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## Brian S (Apr 13, 2005)

Neato!! I use to keep these when I was a kid. We have several different species around here including the big one like in your pics. I also used to keep the larvae which is often called a "water tiger". The larvae is also a voracious predator. They are easy to sex. The males have like a "round pad" on the front legs which enables it to hold on to the female during mating. I think I see that in the last pic which it would be a male.


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## Wade (Apr 14, 2005)

They will also eat fish food flakes and they absolutely love reptomin turtle sticks.

Wade


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## Alex S. (Apr 21, 2005)

Very nice find. It's a predacious diving beetle (Family: _Dytiscidae_, approx. 3500 species worldwide) probably of the genus _Dytiscus_ or _Cybister_ (it’s hard to tell exactly from the photos alone). They are awesome predators that will often take down prey larger than themselves, which the photos show.

Alex S.


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## JJJoshua (Apr 21, 2005)

Wow, that's awesome, any tips on locating/catching them? From what I read they're seldom seen.


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## Wade (Apr 22, 2005)

The big ones are nocturnal, so it helps to collect them with a dip net at night. Sometimes you may get lucky by dip netting eep into the much during the day, but only rarely.

Wade


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## Malkavian (Apr 28, 2005)

JJJoshua said:
			
		

> Wow, that's awesome, any tips on locating/catching them? From what I read they're seldom seen.


In my experience usually you don't find one until it takes a shot at your little toe


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## orcrist (Apr 29, 2005)

Judging by the size in the pic with the fish, maybe D. harrissi? I have one of those in my collection, I first caught it when it landed on my trampoline in the night. At night they fly around out of the water, and are attracted to lights. Like the light that I was using to jump on the trampoline at night. It lived for a good while, and went into my collection when it died. By the way, it's a male. THe females have grooved elytra.


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## Randolph XX() (May 1, 2005)

they are more like scavengers than predators in my experience of Tw Cybister sp.


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