Red-orange bugs by the thousands in Southeastern Brazil, 800 m. asl
Mon, Feb 23, 2009 at 5:01 AM
Our garden in Petropolis (Rio de Janeiro, Southeastern Brazil, 22º22’S 43º06’W), in the Serra do Mar, about 800 meters asl) is now filled with tens of thousands of these little red-orange bugs, with size varying from one millimeter to a centimeter. They apparently do not cause any damage to the plants, but seem to be associated with the red fruits of a nearby tree, which are all over the ground at this time of the year.
Eduardo Viveiros de Castro
Serra do Mar, Rio de Janeiro, Brazil (22S43W)
You were quite accurate in calling these bugs. They appear to be immature Hemipterans, probably True Bugs. Since they are immature, they may change in appearance as they mature. Mature Hemipterans usually have wings. There are many North American species of Hemipterans that form large aggregations like the ones depicted in your image. One of the most common is the Boxelder Bug. We are going to post your images in the hope that one of our readers can locate an accurate identification for you.
Many immature True Bugs are quite similar in appearance and it may be very difficult to get an exact species identification without seeing an adult insect.
Update: Aggregation of Unknown Red Hemipterans in Brazil
Tue, Feb 24, 2009 at 3:26 PM
Hemipteran nymphs are always difficult to identify, but I believe the ones posted by Eduardo are probably in the family Lygaeidae (chinch bugs and seed bugs). They really look very similar to early instar Large Milkweed Bugs (Oncopeltus fasciatus), which range from the southern USA to Brazil. I don’t think that that’s quite it, however, for a variety of reasons (no mention of any sort of milkweed; the larger juveniles would be showing some black markings; Eduardo’s nymphs clearly have white-tipped antennae). It could be some other Oncopeltus species or it could be a related species – there are plenty to choose from in Brazil. Regards.