Does anyone know how you tell the difference between greater and lesser water boatmen?

I have heard that the greater boatman will eat other things in the ponds including tadpoles and that the lesser are vegetarian. I would like to know mainly out of interest which type we have in our pond, but also because I don't really like the idea of the tadpoles being eaten, although I'm sure it is poerfectly natural.

The greater water boatman swims on it's back, looking like a little rowboat. The saliva of the GWB is toxic, and that is how it kills prey. It also may hurt quite a bit if one bites you! They do eat tadpoles.

The lesser water boatman swims 'front down'. It's not actually related to the greater water boatman. The LWB eats algae.

So what kind have you got?

Kingfisher

I wouldn't worry too much about the water boatman eating the tadpoles, frogs make huge numbers to make sure even though a lot get eaten by water boatmen and many other things some always survive.

Ah ok thanks Kingfisher, I have lesser then as they are definitely swimming face down, so nothing to worry about anyway.

Your LWBs are probably helping keep your pond a bit less green looking if they are doing their job properly .

Kingfisher

It can be useful to have some greaters also, they eat water fleas and mites which you might not want in your pond.

What kind of mites, Bill?

Kingfisher

Unfortunately, I have no idea what kind of mites. *Looks embarrassed*

I know because I did some research into this same question a while ago for myself, and found that the greater can be very useful in much the same way is ladybids are to gardeners.

I will have to do some research, then.

Kingfisher

They will also eat small fish, although I don't know which kind. Greaters also act as food sources for newts and other small mammals, so they have many more positives than negatives.

Sounds like I should get myself some greater water boatman after all!

On a side note, I haven't seen any of either type in the pond for the last few weeks.