You cannot effectively drown a grasshopper by simply holding its head underwater. This is because insects, including grasshoppers, possess a respiratory system fundamentally different from that of mammals, which does not rely on a head-based breathing apparatus.
Grasshopper Respiration
Air enters their bodies through small openings along their sides, known as spiracles. Typically, a grasshopper has ten pairs of spiracles, with one pair located on its thorax and the remaining eight pairs distributed along its abdomen.
These spiracles act as entry points to a complex network of internal tubes called tracheae, which branch into progressively finer tubes called tracheoles. This extensive system delivers oxygen directly to the grasshopper’s tissues and cells, bypassing the need for a blood-based oxygen transport system like that found in humans. Unlike mammalian lungs, which are centralized organs, the insect tracheal system provides a decentralized and efficient method for gas exchange throughout the body.
Spiracles are equipped with valve-like structures that allow the grasshopper to open and close them. This control helps regulate gas exchange and, significantly, minimizes water loss, which is crucial for terrestrial insects. Small hairs surrounding the spiracles also act as filters, preventing dust particles from entering the respiratory system.
Insect Drowning Mechanism
While submerging a grasshopper’s head alone will not drown it, insects can indeed drown when water enters their spiracles and blocks the flow of oxygen to their tracheal system. Drowning in insects is, therefore, more accurately described as suffocation due to the physical obstruction of their respiratory tubes by water, rather than a failure of lung function as seen in mammals.
Insects possess various adaptations that can delay drowning, even when fully submerged. Their spiracles can close to prevent water from entering, and many insects have hydrophobic, or water-repelling, surfaces around these openings. These features, along with their ability to perform discontinuous gas exchange, allow some insects to survive for extended periods underwater. For instance, adult grasshoppers have been observed to survive immersion in water for a range of 7.5 to 21 hours, while nymphs can endure for 3 to 13 hours. This resilience means that even if fully submerged, it can take a considerable amount of time for a grasshopper to suffocate.