Chinese Rose Beetles

The first flower on the 'oohai was promptly eaten overnight after blooming.  Nothing was left but the calyx (green sepals) at the base the next morning.  Some tiny ants were crawling around but I doubted they were responsible.  Above in the middle of the image is a picture of the second flower just before opening.  As I mentioned earlier the bloom is white but they open to a red flower. 

Here is the flower and a close up.

Again, the next morning this one was gone, removed down to the calyx. 

The yellow flowers on the nanea are also gone.  This (below) was taken before nightfall and in the morning nothing is there. 

I have noticed the ends of the shoots missing on the nanea, at the time I chalked it up to the pigeons and doves that have been in the backyard.  They dug out papaya seeds I tried to plant and ate them and I have seen them nipping at some other plants, but now I am not so sure.  There are several places where the leaves on the 'oohai have obviously been eaten. 

Also, on our hibiscus plants, the flowers are left alone but several of the leaves have holes chewed through them.

I have noticed beetles crawling out of the leaf litter underneath these plants when I water them.  And on at least one occasion a waiting brown anole grabbed one for a snack.

  I suspect the beetles are the culprits.  I managed to get a mug shot of one. 

I did some searching and they appear to be chinese rose beetles (Adoretus sinicus), and sure enough they are nocturnal and feed on plant leaves.  Originally from East Asia they are now common in Hawaii and have existed here for over 100 years.  (Here are some links; Garden Guy Hawaii and ExtEnto Knowledge Master).  According to their taxonomy they are in the scarab beetle family (Scarabaeidae).  I couldn't find much about other beetles within the genus, but the subfamily, monkey beetles (Rutelinae), often use flowers for food. People in the Eastern US are likely to be familiar with their invasive scarab beetle cousins, Japanese beetles (Popillia japonica), which also strip the leaves of certain types of plants. 

It appears that one option is to pick the beetles off of the plants around 1/2 and hour after sundown.  Since they are nocturnal they probably wouldn't work well for anoles, but maybe they can be fed to M's house geckos.

Update:  I went out to hand water some of the plants and took a plastic container with me to collect the beetles in.  They climb up out of the leaf litter under the plants when doused with water.  I didn't get any from under the 'oohai or nanea but quickly collected ~25 from under the pumpkin plants.(?)  There is no obvious sign of them feeding on the pumpkins, but they are close to the nanea and 'oohai.  I will keep collecting them for a while by hand while watering and see if it has an impact.