Why are there no any spider web or insects in historical mosques?

We do we not meet any spider in Selatin Mosques which are among the most important masterpieces of Ottoman architecture?

Our ancestors have discovered that odor of ostrich egg disturbed spiders and similar small insects and used this in our architecture.

They have mixed inside egg in mortar and placed shell of egg into candle basins. Therefore no spider or similar insect grow inside mosques.

Do you know that Kanuni Sultan Suleiman has ordered tens of ostrich eggs from Africa even during construction of Süleymaniye Mosque as semiskilled work of Mimar Sinan?