The specific species of mangrove tree which attracts these fireflies is the berembang (sonneratia caseolaris). Firefly watching at Sungai Kerian is increasingly drawing visitors, and the firefly is an icon of Nibong Tebal. The fireflies emit light at the lower abdomen not only to attract mates but also to scare away predators. Their abdomens are filled with a chemical called lucibufagens. Sunset cruises and tours are offered.