Several species of plants have leaves which are 'fenestrated' - i.e. have large holes in them (from Latin fenestra, window). Notable examples are the Monstera genus (Araceae) a.k.a. the Swiss Cheese Plant.

It's known that the holes form due to programmed cell-death in certain regions of the leaves. Evolutionary theory suggests that the holes must have some advantage for the plants, but there is currently no agreement about what those advantages might be.

There are several hypotheses on the potential adaptive value of the holes in Monstera plants, but no studies have been done to directly test these possible adaptive functions."

[Source link below]

Possible explanations include:

• As a means of avoiding wind damage
• A 'trick' to deter predators - which might assume that the leaves have already been part-eaten
• As a water conservation measure - to allow water to reach the roots.

See : The adaptive function of leaf fenestrations in Monstera spp (Araceae) a look at water, wind, and herbivory Tropical Ecology Collection, Monteverde Institute.