Insects are generally quite small creatures. A photographer must consequently approach them closely with a lens of sufficient magnification to more or less fill the frame with the subject. Many subjects also move quite fast, so in some cases relatively high shutter speeds may be required to freeze the action. These factors add up to the need for a macro lens with a wide maximum aperture of at least f/2 or f/2.8. The Nikon Micro 105mm f2.8 lens is a useful piece of kit. The other basic requirement is good light. This can be bright sunlight, flash or some form of lamp.