Insects are the most diverse group of animals on the planet. There are approximately 6 to 10 million species still in existence worldwide, a number that exceeds the total of all other animal species combined.
In our daily lives, it is not difficult to see various insect species around us; however, understanding them and their developmental forms is not something everyone knows. It is estimated that over 1 million insect species inhabit every environment, from volcanoes and deserts to swamps and glaciers.
Typically, animals and insects tend to sink when they enter the water. So, why can some insect species easily walk on water?
The force exerted by insect legs on the ‘tension membrane’ is lower than the surface tension.
Water has a unique property. What is it?
Each water molecule experiences forces from surrounding water molecules in all directions (molecular attraction), except for the molecules located on the surface. Since there are no water molecules outside of those at the surface, they experience stronger attraction from within, which creates surface tension, turning every water surface into an invisible “tension membrane.”
Meanwhile, some insects, such as water striders and spider beetles, have very light weights. Therefore, the force exerted by their legs on the “tension membrane” is lower than the surface tension.
Additionally, insects always spread their legs when walking on water, which allows their weight to be distributed and dispersed across each leg. As a result, their legs do not sink but instead create a “depression” on the surface, enabling the insects to move across the water.
