Felix and a number of other Characters responded positively when I gave them an Insect for the first time. It came as a shock to me, therefore, when I gave Felix a Butterfly and he responded rather sadly that: 'I don't actually like this. I'm a little disappointed.'
I wondered then if I had made a mistake in my Guide, when I logged his response to an Insect as: 'Oh, how nice. Thank you, Freyja.'
In fact, different varieties of Insects like Flowers can elicit different responses when given as a Gift to any Character. As with Flowers, some Characters love or detest ALL Flowers and Insects and some differentiate between different types of each. I tested this with Felix by giving him a Tree Frog. His response: Oh, how nice. Thank you, Freyja.'
After a bit of testing, I found that Felix appreciates the Gift of any Frog, Grasshopper or Locust, but views any Butterfly with distaste. Freya loves Butterflies.
In most cases, you will find that Characters who differentiate between different varieties of any Item either respond positively to all or negatively to all and it is simply a question of degree of liking or dislike. For example, Angelo LOVES Moondrop Flower but simply likes other Flowers. Lloyd LOVES Blue Magic Flower but simply likes other Flowers. Sherry loves Moondrop Flower and Antoinette loves Magic Blue Flower. You will not find a Flower to excite Dirk until Autumn when you will discover that he LOVES Magic Red Flower. Both Daisy and Ivan love all Flowers. Felix's negative response to one type of Insect and his positive responses to others is more unusual.
For a Guide Writer, this means I shall have to do far more research than usual in my gift-giving. Thanks to other players for posting their findings as well.