All stages (egg, larva, pupa and adult) are spent inside the palm itself and the life cycle cannot be completed elsewhere. The females deposit about 300 eggs in separate holes or injuries on the palm.
Eggs hatch in 2 to 5 days into legless grubs which bore into the tree’s interior moving by peristaltic muscular contractions of the body and feeding on the soft succulent tissues, discarding all fibrous material. The larval period varies from 1 to 3 months.
The grubs pupate in an elongate oval, cylindrical cocoon made out of fibrous strands. At the end of the pupation period (which lasts 14 to 21 days), the adult weevils emerge. Thus the life cycle is about 4 months and continues, pretty much relentlessly, throughout the year.
It used to be thought that weevils became dormant during the colder winter months, but as they’ve spread, they’ve changed their habits, and certainly in Portugal, weevils are known to stay active all through the winter.
Infestations within single palm trees can manifest over several generations until they reach hundreds of Weevils. Weevils will establish their home when there is sufficient live plant material on a palm, and feed and lay their eggs on it. Once they have exhausted the food source, the adults will disperse to find new plants to infect. Red Palm Weevils can be present on a palm all year round, although the adult weevils are more active during the warm summer months. Females will prefer to lay their eggs on palms that are diseased or in a bad condition.