This is not entirely accurate. While it is true that there is a size limit for geckos' ability to stick to walls, this limit is much larger than a human. The largest gecko species, the Tokay gecko, can weigh up to 0.5 kg and has a body length of up to 35 cm. This means that a human would need to be much larger than a Tokay gecko in order to be unable to stick to walls.

In fact, there are several factors that determine an animal's ability to stick to walls, including the size and shape of its feet, the surface roughness of the wall, and the animal's weight. Spiders have a number of adaptations that allow them to stick to walls, including:

* Hairy feet: Spiders' feet are covered in tiny hairs called setae. These setae are incredibly thin and flexible, and they allow spiders to create a strong bond with the surface of the wall.

* Sticky pads: Some spiders also have sticky pads on their feet. These pads are made of a material called tarsal silk, which is a strong and adhesive protein.

* Claws: Spiders also have claws that they can use to grip onto rough surfaces.

These adaptations allow spiders to stick to walls even if they are much larger than geckos. In fact, some spiders can even stick to upside-down surfaces, such as the ceiling.

So, while there is a size limit for geckos' ability to stick to walls, this limit does not apply to spiders. Spiders have a number of adaptations that allow them to stick to walls even if they are much larger than geckos.