Hi Otavio,
As a 'first attempt' these are still pretty good - as I have come to expect from you
My favourite is #2, the ant because of the background.
For me #1 is spoilt by the harsh bokeh in the water drops - my 70-300mm isn't much better at f/5.6, but improves considerably by f/11, so another reason to stop down.
Also in number one, there's a double image of some parts, so I suspect the fly twitched within the 1/500s and caused movement of the leaf.
As Geoff says, they would be improved with greater DoF.
Cheers,