Renanthera monachica in Puerto Rico damaged by a native orchid weeveil Stethobaris polita

An intact flower for comparison.

Last week I was looking forward to enjoying the beauty of an inflorescence of Renanthera monachica with all its flowers open.  Distressingly, I found that something had damaged the open flowers and some of the buds.  But it was not obvious which animal was causing the damage.  I visited the flowers several times during the day and then found that the culprit for the damage was a native orchid beetle, Statobaris polita.  I checked all my other orchids and the only one that had beetles was the Renanthera.  I only use pesticides as a weapon of last resort.  What I do with these weevils is that when I find them in flowers, I put a small cup with a combination of detergent and alcohol under the flower and then I shake the flower gently.  The weevils will react by helpfully dropping into the cup and partaking of the detergent and the alcohol.  These weevils are a seasonal pest, months can go by without one showing on the flowers and then they start to appear, but never in large numbers.  At the peak of their infestation I can find five to ten a week in the flowers.  They had not been a problem before the exotic orchid Sphatoglottis plicata established large populations in the forest.  I saw the first Sphatoglottis plant in the forest, a white one, in 2004, now they are common and in some places downright abundant.

A hideous little pest of Bletia patula and other local orchids

The damage to the florar parts of Bletia patula flower betrays

 the handywork of a curculionid bettle that attacks the flowers of orchids.

Checking the flower shows that the bettle is hidden behind 

the lip of the flower, sometimes you find two bettles together.

If the bettle feels the flower is being handled, it tries to hide deeper between

 the lip and the petals.  If it is further annoyed it comes out of hiding and tries to flee.

If the bettle comes out of hiding, its usual strategy is to run to

 the end of a floral part and from there fall to the ground.

This particular flower bettle damages the flowers of many kinds of orchids in my garden.  Its local abundance varies seasonaly.  At certain times of the year I can find from one to five chewing in my flowers.  I think this might have to do with the peak of flower production by local plants, but this is just a guess.  Rather than use insecticide on them, I exploit their fleeing response by putting a cup with alcohol or dishwashing liquid under the flower and shaking the flower gently.  The usual result is that the bettle takes a dive into the liquid and then goes to the great orchid flower in the sky.  Thankfully for most of the year they are not present on the garden,    

These bettles are surprisingly hard for such a small insect.  It is not easy to crush them.   But if you are moved to squash them, they do produce a satisfying crunchy noise when crushed.  I have seen damaging flowers of Bulbophyllum, Cattleya, Dendrobium, Oncidium, Peristeria, Sphatoglottis and Bletia among others.