Tendy -
Since you are new to this, I hope you won't mind a few pointers on the use of DPP.
First, Canon recommends doing RAW editing primarily on the RAW tab. This is not to say that the RGB tab cannot be used, especially the curve editor which is very useful, but editing on the RAW tab is more straightforward. I have found this particularly true in handling color. In macro photography the emphasis is usually on accurate rather than artistic or impressionistic color. For this you need to get your white balance as accurate as possible for the actual light in which the subject was captured. Trying to do this by mucking about with the individual color curves is very difficult, precisely because they are curves and a proper balance in one range of tones can be accompanied by an improper one elsewhere. Moreover, moving the curves will affect the brightness or darkness in ways that are difficult to foresee. For this reason the color curves are best left for more artistic interpretations. The White Balance adjustment on the RAW tab is a linear adjustment, the same change is made throughout the tonal range from black to white. The best way to find an accurate WB is to use the eyedropper probe on a neutral grey or white object shot under the same light as the subject and the WB setting is than registered and applied to shots of the subject itself. In the case of the photo you posted above, assuming the bee is standing on a white paper, you have WB target and subject in one. After the basic WB is attained it can be tweaked using the color ball in the 'Tune' box.
Next, the slider that DPP calls 'Brightness' but which is generally called Exposure. This is also a linear adjustment, as you move it watch the entire histogram shift to one side or the other. Because of its linearity, its effect is similar to giving more or less exposure in the camera and is generally used to repair or at least tweak mistakes in the original exposure. The curve editor in RGB can then be used in its Luminance mode to change the tonal values of one range differently than another. For instance, the bee's tail can be lightened more than its head.
I have done an edit of your "before" view, although not in DPP because it is a jpg, not the original RAW:
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