can someone ID this critter?

[maggiepie]

This is the fourth one of these I have seen lately. I squished the first 3 but don't want to kill them if they are beneficial critters.
They are over an inch long and a black/irridescent blue in colour, they seem to have very soft bodies.
They look like a giant ant of some sort from the front. Have never seen these before.
Have to admit they freak me out a bit.
Oh and when I caught this one in a couple of cups it played dead until my back was turned then took off.
Don't think they have wings.
Maybe they have just hatched, I don't have a clue.
Sorry I couldn't get better pics.

[WimB]

Hmmm,

it looks like a rove beetle (family Staphylinidae). I don't know which species of this family are native to North America, here in Europe we have amongst others the "Devil's coach horse beetle" (Ocypus olens).

[TheOnionMan]

Are they good bugs or bad bugs?

[maggiepie]

Wim, I spent hours with google this morning trying to ID it, I did see a rove beetle that was a bit like this but couldn't find an irridescent blue one anywhere.
Also, I've never seen a soft shelled beetle. Do you think it could have just hatched and the shell hasn't had time to harden ?

[maggiepie]

These pics might be a little better.

[maggiepie]

Think I found it.

This is a flightless Blister Beetle, Meloe sp., beetle family Meloidae.  They are parasitic as larvae in the nests of ground-dwelling solitary bees. Jim McClarin


http://pestcontrolcanada.com/Questions/What%20i2357.jpg

Scroll down to 1577 for more info, am off to squish it!!!

http://pestcontrolcanada.com/Questions/pest_photos1501.htm

Here's another link with much better pics.

Scroll down.

http://natural-japan.net/?m=200511

[WimB]

It's an ugly critter, that's for sure. I think you're correct, Helen. If it's parasitic on solitary bees, you should kill them.

[Anthony Darby]

These beetles are not common and are called oil beetles in the UK. In fact, being parasites of solitary bees, by their very nature, they are rare and I object to people killing them when they are not pests.

[WimB]

These beetles are not common and are called oil beetles in the UK. In fact, being parasites of solitary bees, by their very nature, they are rare and I object to people killing them when they are not pests.

Anthony, after reading that they do not kill the bees most of the time but just eat some of the provisions of the bees and that they are rare, I have to agree .
I thought they were heavy parasites on bees (...think varroa (which is also a disease vector)). Should learn to read more about a subject before I judge.  
And the cantharidin they produce is interesting too...  

[maggiepie]

Anthony, I respect your viewpoint but I have solitary bees here and I like having them. Find them very interesting. If the larvae eat the solitary bee eggs then to me they are pests.

[Anthony Darby]

Like most parasites, they will have little or no effect on the solitary bee population, upon which they depend. Killing a specialist parasite, on the other hand, could not only reduce the number of oil beetles, but ultimately reduce the solitary be population if one of their control measures disappears. As an ecologist, I find killing one form of wildlife because they feed on another, which they deem more desirable, unhelpful at best. Many years ago a dentist who lived in Callander, Perthshire and bred ducks in his back garden went to war on collard doves. These birds were attracted to the duck feed in ones and twos. He gave up after shooting 200 in one year. His predating the collard doves had no effect on the population.

[maggiepie]

Anthony, the solitary bees have been  disappearing in New Brunswick.  I don't see how having a specialist parasite to go at the remaining ones will help.
The solitary bees are very important pollinators. I have been thinking of getting/making some beehouses for them.

[Anthony Darby]

The oil beetle wouldn't exist if the bee population was too low. Their larvae hatch from eggs laid on flowers and hitch a ride on a bee, so they rely on chance to find a food source. I'm afraid food webs are complex and take a lot of understanding. The knock on effect is amply demonstrated by many classic examples: extinction on the Large Blue butterfly in England caused by myxomatosis in rabbits; coastal erosion on the west coast of America caused by over hunting of sea otters.

[Rodger Whitlock]

I think Anthony is on the right track. As Darwin discussed in The Origin of Species the interactions and interconnections between different forms of life are so complex as to defy our understanding. It may be that this beetle is a predator of solitary bees, but it may also be that the bees derive some benefit from the beetle's presence and the loss of provisions is merely the price they pay for unknown benefits. You may be sure that solitary bees have been coping nicely with these beetles for, perhaps, millions of years, and managing to survive. In the absence of definite proof that this beetle is in some way responsible the decline of the solitary bee population in your area, I'd recommend a hands-off approach.

The decline in solitary bee populations is much more likely to be due to some damned fool nonsense that we humans are responsible for, and the poor beetle is merely an innocent bystander caught up in the fray.

PS: Re The Origin of Species: Anyone seriously interested in any aspect of biology, including ornamental horticulture, would do well to read Darwin's magnum opus. It's been endlessly reprinted and for those with limited budgets, cheap second hand copies abound. The text, though long and discursive (reminiscent of Dickens), never sails off into regions where understanding is impossible. Darwin was very down to earth and anyone of average intelligence can understand his arguments. It's really quite a remarkable book, very readable, very interesting, and very persuasive.

[Anthony Darby]

Rodger, it is amazing what a little bit of delving can reveal. I have heard anecdotal stories that in some parts of the USA natural selection is producing silent rattle snakes. The rattle, which normally signals danger to another animal, draws a human's attention and instant death to the rattler. Rattle snakes that are predisposed to remain silent live longer and are thus more successful breeders, passing on this characteristic to their offspring.