When doing macro photography with moving things its always a bit of a tricky endeavour. The macro lens does its magic at very high f-stops and if there is any movement perpendicular to the sensor, the desired part of the image may be out of focus due to the very small depth of field. In this case a calm day and a bug that knows how to hold still are very important to success.
I messed around with the cropping on this one for quite a while until I was happy with it. You should also know that (read more)