Here are some tips on how to lover the noise during recording:

0.) Bad connection of measurement electrodes and subject will produce high impedance between signal and amplifier and as a result amplifier is more susceptible to noise. 

1.) You can get noise (60hz) directly by connecting to your computer that is powered from mains. So if you are using computer for recording try using laptop that runs on battery. Disconnect it from power supply.

 2.) You can also have capacitive coupling with mains from different objects and conductors (image below depict human as a subject but same is valid for insect or any other subject). Try changing table or material under your setup.

Inline image 1

3.) Also you can have noise induced in measurement leads or insect from high frequency sources around you. It can be switching power supplies and transformers from electronics around you (for laptop, microscope or anything else on the table). Try cleaning your table from electronics that are not used in experiments.

4.) Some types of ceiling lights power supply circuit can emit "high" frequency electromagnetic noise (from 50kHz to 300kHz). Turn ON/OFF light and check does it make any difference for noise floor.

5.) Communication devices WiFi router, Bluetooth, mobile phones or any other radio emitter around you. 

6.) Also extension cords in vicinity of recording spot. Once we had huge noise because we were close extension cord reel. When we put reel out of the room noise dropped drastically. Generally you should try move away from any electronic and EM sources.

Also you can use filters in Config screen of PC/Mac application to filter out some of the types of noise.