Composition:
I love this composition. It's a shiny little ladybug for sure! I think if you had shown more of what's around it though, the selective desaturation would've had more impact. As it is, the ladybug is the foreground, and desaturating doesn't change that fact. I wrote a post on choosing the right photo for selective desaturation, might be good for you to look over it.
Lighting:
The lighting in this photo is gorgeous. Specifically the reflection on the bug. Your exposure is spot on, no worries there.
Technical:
Someone said the ladybug is a little soft on the focus, and I can see their point, but I wouldn't say it's out by a lot.
Post-processing:
This is where your photo needs the most work. First of all there is still color in the entire photo. There is a greenish tint to all the plant material. I would've liked to see you just select the bug, and do a full desaturate. Since now you removed other colors from the bug that help define it's actual color. I'm not sure if you just forgot the green channel or what...
Overall:
This is a very cool macro bug shot. You just need to work on your desaturation technique.
I really like the clarity you were able to achieve on this photo. It looks like you desaturated by removing all colors except red, which left the ladybug a slightly odd brown color at the top. It might have been better to lasso the whole ladybug and desaturate everything else, which would retain the full color of the insect. But it's really nice like this as well - great shot.
Nice composition, you really got in there up close and personal. Would've liked a tad sharper focus on the ladybug, seems that thing it's sitting on stole the focus.