The role of neuronal protein <scp>NOS</scp> in regulation of magnetic orientation in the subterranean termite <i>Odontotermes formosanus</i>

Magnetic orientation is essential for subterranean termites during foraging and homing. Although neuronal mechanisms are known to be central to magnetoreception, the specific regulatory proteins involved in this process remain unclear. Here, we report that the expression of the neuronal protein nitric oxide synthase (NOS) in the subterranean termite Odontotermes formosanus was significantly reduced under a strong magnetic field (0.1 mT) and upon elimination of the horizontal component of the geomagnetic field. RNA interference-mediated silencing of NOS led to significant downregulation of the magnetoreception gene Cryptochrome 2 (Cry2) and disrupted magnetic orientation in O. formosanus, indicating that NOS is integral to magnetoreception. Consistently, pharmacological inhibition of NOS by L-NAME decreased nitric oxide (NO) levels and abolished magnetic orientation. Together, our behavioural and molecular evidences suggest that NOS plays a critical regulatory role in termite magnetic orientation, which provides new insights into the molecular mechanisms underlying insect magnetoreception.