Currently viewing the category: "Water Beetles"
What's That Bug? does not endorse extermination

Subject:  Mystery Bug, Japan
Geographic location of the bug:  Northern Hyogo Prefecture, Japan
Date: 06/22/2019
Time: 07:13 AM EDT
Your letter to the bugman:  I found the strangest bug out on my run today. We’re in the middle of the rainy season right now (late June), and a massive downpour had just finished. I live in a pretty rural area and I found this guy on the road next to the rice paddies. At first I thought it was a caterpillar of some kind, but the way it was moving was a little off. Instead of the normal perstaltic motion it was kinda flopping around more like “the worm” dance, raising it’s head pretty significantly at the end of each movement. And when it flipped over while crawling I was surprised to see it had six legs! The skin looked pretty soft and covered in silt, and combined with the fact that it wasn’t very elegant moving around on land I guessed it was probably aquatic. When I got home I googled pictures for dragonfly larvae though, they don’t match at all! It was about 10 cms long, with a rather big and fat “tail”, six small legs, and small but noticable mandibles. What kind of bug could this be? I’ve never seen anything like this in the three years I’ve lived here. Thank you!
How you want your letter signed:  Justin

Larva Dorsal View

Dear Justin,
Had you only provided us with a dorsal view, we might have pondered this being a Soldier Fly pupa, but the legs and mandibles rule out that possibility.  We believe this is a Beetle larva.  We will continue to research this identification while having posted it as Unidentified.

Larva Ventral View

Update:  Cesar Crash believes this is a Water Scavenger Beetle larva in the family Hydrophylidae.

What's That Bug? does not endorse extermination

Subject:  biting swimmer in pool
Geographic location of the bug:  Queen Creek, AZ
Date: 06/08/2019
Time: 04:38 PM EDT
Your letter to the bugman:  We have found this type of bug in our Arizona pool (more than once). It swims very fast, it is not a water boatman, the legs are different and all go the same direction. Also it swims belly down. It has 6 legs, 2 small antennae, and it appears to use a bubble on its underside to help it go up to the surface and down again. It also bites (or stings), and if a person is in the pool nearby, it will make a beeline for them. Very aggressive for a little creature. (the 3rd photo is not 2 bugs, but a reflection on the side of the glass it was in).
Nobody seems to be able to identify it. Thank you in advance for your help!
How you want your letter signed:  Zonie Girl

Water Scavenger Beetle

Dear Zonie Girl,
Thank you for pointing out and for having documentary images showing the position of the legs while swimming.  The is a Beetle, and based on information on BugGuide, including “Aquatic forms may superficially resemble Dysticidae but can be easily distinguished by antennae. Many have keeled sterna. The adults come up for air head first, and move hind legs alternately (Dysticidae come up for air tail first and move hind legs together, like oars)”, we conclude this is a Water Scavenger Beetle in the family Hydrophilidae.  Though the bite might be an annoyance, we do not believe it poses any threat to humans.

Water Scavenger Beetle

Thank you for the quick response! I looked these up online, and yes, that is exactly what this bug is.

Water Scavenger Beetle

What's That Bug? does not endorse extermination

Subject:  Found multiple of the same type of Bug in pond.  What is it?
Geographic location of the bug:  Massachusetts
Date: 06/05/2019
Time: 07:57 PM EDT
Your letter to the bugman:  Found this in the pond in my backyard, no idea what it is.
How you want your letter signed:  Alexander

Water Tiger

Dear Alexander,
These are Water Tigers, the predatory larvae of a Predaceous Diving Beetle in the family Dytiscidae.

What's That Bug? does not endorse extermination

Subject:  Freshwater bug
Geographic location of the bug:  East Kootenay, British Columbia
Date: 06/03/2019
Time: 10:44 PM EDT
Your letter to the bugman:  Found this insect floating in a freshwater lake in late May.
6 legs, approximately 2” long.
Found another smaller specimen the next day.
Suspect type of dragon fly larva but never seen one with these mouth appendages
How you want your letter signed:  David

Water Tiger

Dear David,
This is a Water Tiger, the predatory larva of a Predaceous Diving Beetle.  It breathes air through a siphon at the tip of its abdomen which is why you found it floating.  Here is a BugGuide image for comparison.

Water Tiger

What's That Bug? does not endorse extermination

Subject:  Pool creature?
Geographic location of the bug:  Tennessee
Date: 05/12/2019
Time: 08:17 PM EDT
Your letter to the bugman:  My sister had me come look at her pool over these things eating the tadpole eggs in the filter.
How you want your letter signed:  Kitty

Water Tiger

Dear Kitty,
This is a Water Tiger, the predatory larva of a Predaceous Diving Beetle.  These larvae breathe through a siphon at the tip of the abdomen that breaks the surface of the water.

What's That Bug? does not endorse extermination

Subject:  Elongated bug in old pool water
Geographic location of the bug:  West central Alabama
Date: 04/26/2019
Time: 07:00 PM EDT
Your letter to the bugman:  I’ve began seeing these segmented, elongated bugs for the first time this year (beginning about March, when weather got warm) in the foot of nasty pool water left in our above ground pool. They swim leisurely, but can also dart very quickly.
How you want your letter signed:  Amanda In Alabama

Water Tiger

Dear Amanda in Alabama,
This is a Water Tiger, the aquatic larva of a Predaceous Diving Beetle.  Water Tigers are efficient predators that eat small aquatic insects and invertebrates as well as small fish and tadpoles.  Here is an image from Insects of Alberta.

Water Tiger

What's That Bug? does not endorse extermination