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| Subject: | | Giant water beetle |
| From: | |
Eggit
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posted
Sun, Sep 19 2004, 1:16pm
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A couple of years ago we had a pool you could barely call a pool. It was not kept up and was full of green alge and frogs and mosquitos and water beetles. The beetles I am talking about are these I always refered to them as "rowboat beetles" anyone familiar with them knows why. Anyways as can be seen in that picture they aren't much bigger than a centimeter. When I was out near the pool getting ready to drain it so I could get rid of it all I saw one fo the beetles dart up to the surface and then dart back down, only this one was the size of a silver dollar. I know what I saw and It definately moved with the same rowboat motion as the smaller ones. Anyways was this just a freak abnormality, a different yet similar species, or do these things actualy get that big? |
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| Subject: | | Re: Giant water beetle |
| From: | |
Ego
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posted
Sun, Sep 19 2004, 6:18pm
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What you describe & have pictured are called waterboatmen because of the rowing action as you said. The other beetle was probably a great diving beetle which may have looked similar in shape & colour especially if you just got a brief glimpse. These are not uncommon.
Ego- who knows pond life but doesnt know the size of a silver dollar!! |
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| Subject: | | Re: Giant water beetle |
| From: | |
Cricket
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posted
Mon, Sep 20 2004, 7:03am
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Actually, it's not a waterboatman. Waterboatmen are true bugs (Order: Hemiptera) whereas the photo shows a beetle (Order:Coleoptera). There are two major families of aquatic beetles: predaceous water beetles (Family: Dytiscidae) and the water scavenger beetles (Family:Hydrophilidae). They can be differentiated by several structural differences, one being the antennae. Hydrophilids have short clubbed antennae and dytiscids have long filiform antennae. Therefore, your photo is of a dytiscid. You can also tell them apart by how they "row". One kicks legs alternately, the other kicks them both at the same time (sorry, can't remember which is which).
Anyway, as to your silver dollar sized beetle. There are two water beetles that size. One is a hydrophilid and the other a dytiscid (at least here where I live in Florida, there may be more or less where you live). These large species are actually very common but usually get noticed much more so than their smaller cousins.
Hope this helped. |
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| Subject: | | Re: Giant water beetle |
| From: | |
Eggit
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posted
Mon, Sep 20 2004, 2:30pm
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Well the ones I saw (small and large) both rowed with both arms at the same time. I am not sure about antennae. Anyways seems like this was normal. |
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| Subject: | | Re: Giant water beetle |
| From: | |
Ego
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posted
Mon, Sep 20 2004, 4:59pm
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Cricket, there may be an oceanic impasse responsible here & as you sound very knowledgable I refuse to argue but the beetle shown are called waterboatmen in the UK, you may well use the term to describe some other critter so's I cannot correct you but from this side of the atlantic I am also confident of the views expressed, i'm no expert on US pond life tho. (as I try to avoid mentioning politics) |
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| Subject: | | Re: Giant water beetle |
| From: | |
Gerry Bacon
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posted
Mon, Sep 20 2004, 7:00pm
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Hey, watch it Ego. Our politicians may be pond scum but they're OUR pond scum.
Gerry - :0) |
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| Subject: | | Re: Giant water beetle |
| From: | |
Cricket
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posted
Tue, Sep 21 2004, 7:43am
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Fair enough.
Over here (across the pond) a waterboatman is a hemipteran (Corixidae)Water boatman
but I guess you guys might know something about the English language (even though WE invented it) so I'll cut you some slack.
Cricket - who knows the English language was invented by Thomas Edison in 1843 |
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| Subject: | | Re: Giant water beetle |
| From: | |
The_Scorpion
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posted
Mon, Sep 20 2004, 7:11pm
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it looks kind of like a kind of diving beetle its scientific name is Dytiscus marginalis or something |
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| Subject: | | Re: Giant water beetle |
| From: | |
DarthDoughnut
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posted
Fri, Jan 7 2005, 3:06pm
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Predacious diving beetles in the genus dytiscus or cybister regularly reach sizes equaling or surpassing a half dollars, and I find them more often than the small ones. Up here in the north, I've caught several female Cybister fimbriolatus larger than half dollars, a slightly smaller male, and a dytiscus harissi that looks like it could've given a musky a run for it's money when it was alive. ( a little longer than your average housekey) |
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