Day 64 of #LMB365 shows a transparent nematode worm C. elegans (and eggs), with red and green fluorescence marking different tissues in the body, including neurons in the head (middle of image). The fluorescent markers indicate where signalling molecules acting via a particular neuropeptide (red) or dopamine (green) are expressed. Fluorescent tools like these help researchers to dissect which neurons make up circuits in the brain that control the animal’s behaviour. This was one of the winners in the 2018 Image Competition.