Sometimes insects help plants, but other times insects are only using plants for their own creepy purposes. 

As many a caterpillar would tell you, plants serve as delicious meals, but plants also offer protection to insects. 

Some insects hide from predators, like birds and small mammals, by pretending to be a part of the plant:

 

    

While other inventive insects have figured out how to take over the plant's own hormones and create little safety pockets within leaf tissue. These abnormal growths on plants caused by insects are called galls. Some galls are beautiful, like these pink galls on a maple tree leaf. 

 

 

Some galls have inspired the imagination and appear to be a certain shape while other galls are much more discrete. 

 

 

 

 

 

Whatever your feelings on the shapes & sizes, it's hard to argue that insects have created a home by manipulating plants on the molecular level!

More info on galls: Brandeis University (MA, USA)