Dead Monarch Butterflies

(Question)

I have had the same garden plants for at least 15 years. I have in the past had a lot of Monarchs in Aug and Sept. I have at least 3 dead Monarch this year. I picked up one and it looks like something ate the majority of the body!
I have 2 Rose of Sharon and 2 Bottle brush shrubs planted in a row and they are all at least 15 years old.
I noticed a new beetle in the Rose of Sharon plants.
Could these new beetles be killing the Monarch!
The beetles are black with blue and purple bodies.
I do not have any milkweed this year, so I know I do not have the wrong ones.
All ideas, suggestions welcome
Thank you

(Answer)

Thank you for contacting the Toronto Master Gardeners. According to my research there are a number of common predators of monarchs some of which include : wasps, ants, parasitic flies, birds, snakes, toads, rats, lizards, and dragonflies. Without a photo of the beetle it is difficult to determine whether this is the culprit.

Parasites and Natural Enemies is an excellent article from the University of Minnesota along with this article from the Journal of Lepidopterists’ Society.