Why can ladybugs not eat acidic fruit?

Answer 1

That the internal acids can break down food reserves and function as a natural pesticide are reasons why a ladybug may not eat acidic fruit.

Specifically, the insect in question (Coccinellidaefamily) builds up energizing reserves for life-sustaining activities and for surviving inclement weather and prey-poor times. Such internal acids as citric acid can interfere with storage-building endeavors. They also function as inactive/inert ingredients in some pesticides.