As Rand stated, you do not get credit for the first of any item in the collectables (butterflies, shells, beetles, pebbles). You do get tech points for any there after.

For example, you found the blue shell, a child takes it to the hut but you get no tech points. Now when you find a blue shell and a child takes it to the hut you will get 100 tech points. Now you find the orange butterfly, when the child takes the first one to the hut you will get no tech points but will get 100 tech points for any found thereafter.