Stink Bug Eats Stink Bug - Observation of the Week, 7/12/22

Our Observation of the Week is this bug-on-bug predation, seen in the United States by @denisewill!

“Like so many other iNat users I’ve been fascinated by insects since childhood,” says Denise Williams, a biology teacher who grew up on a farm in Virginia. Now living in North Carolina, she tells me she has a native plant garden and started it mostly to attract insects. 

I spend a great deal of time around my house photographing arthropods of all kinds that come to my plants. My principal interests rotate every few years. For the last several years, my main focus has been on bees and wasps, but I was already starting to take more interest in hemipterans, especially the leafhoppers and stink bugs. After this observation, my interest has grown even more.

While looking for bees to photograph in her yard, Denise noticed the bug duo photographed above.

At the time, I assumed they were different instars of the brown marmorated stink bug with the younger, smaller one simply standing behind the older, larger one. Brown marmorated stink bugs are a drab brown as adults, but they are quite colorful when they hatch, so they can appear as different species as they progress through their molts. They are also so common here that I might have ignored them both, but I went ahead and snapped a few photos thinking I could at least document the stink bugs in my yard. It wasn’t until I downloaded the photos that I could see the proboscis of the smaller bug had pierced the larger one and the larger one was in the process of being consumed!

I still assumed the smaller bug was a brown marmorated stink bug, and that maybe I had just captured a case of cannibalism, so I posted the photo on iNat with that ID. @trisha24 verified the larger bug as a brown marmorated stink bug and identified the smaller one as a species of Podisus, another common stink bug in my area, but one that is predatory rather than plant-eating. Another user, @lupoli_roland, pointed out that the discoloration of the larger bug was due to it being digested.

Bugs (Order Hemiptera) have proboscis that is used for sucking. Many bugs, like the brown marmorated stink bug, use theirs to ingest plant liquids, but there are quite a few species (such as the predatory stink bug here) that slurp up the innards of other animals.

Native to Asia, brown marmorated stinkbugs have become a noted agricultural pest in North America and other places where they have been introduced. A generalist when it comes to feeding, they’ve caused tens of millions of US dollars worth of damage to crops in the past few decades.

Denise (above) really got into iNat after participating in a bumblebee project in 2018, and she quickly realized it was a great tool for helping her learn. 

I’ve learned so much about my local flora and fauna because of it and I’ve become a better and more focused observer…

Without iNaturalist, I might not have bothered to take the photograph of these insects, I might not have had access to these experts who could identify the insects in my photo and explain what was happening, and I certainly would not have fully appreciated what I got the chance to observe.

- New Yorker staff writer Kathryn Schulz wrote an entertaining piece about brown marmorated stink bugs for the magazine back in 2018.

- Here’s an informative video about predatory stink bugs. 

Posted on July 13, 2022 02:47 AM by tiwane