Predatory Stink Bug Eggs

We had a new neighbor Cyrus in 2018, who is on the lookout for nature.  His toddler daughter was excited to release the spicebush swallowtails that were emerging from chrysalises we had given him, and the whole family has been nurturing her interests in the natural world.  He shared with us a leaf from a newly planted spicebush that had some tiny bumps.  A macro photograph revealed the hidden beauty of insect eggs.

Eggs with a ballpoint pen - REK

The eggs were roughly 1 mm in diameter with a crown of spikes, with long projections around the top that are quite distinctive.  They were diagnostic of Podisus spp. of predatory stink bugs.  The most common species in our area is Podisus maculiventris, the spined soldier bug (SSB).

Spined soldier bug - Entnemdept.ufl.edu

SSB are generalist predators, attacking over 90 species of insects.  For that reason they have been introduced to many other countries as a biological control agent (BCA) for agricultural pests.  They are considered beneficial although monarchs might disagree.  For some reason they are attracted to butterfly milkweed where they will attack the occasional innocent monarch caterpillar.

First instar - entnemdept.ufl.edu

I saved the eggs expecting to hatch a cluster of brightly colored larvae to photograph.  They go through five colorful instars, each with its own distinctive pattern before becoming very boring brown adults, all shown here at Entemdept.ufl.  Two weeks later I found tiny specks on the bottom of the bug box.  The hatchlings weren't the little bright red 1mm SSBs I expected.  Instead they were tiny chalcid wasps, parasitoids that had been living in the eggs, protected and fed by their unwitting hosts.

Chalcid wasps are hymenoptera, related to other wasps, bees and ants. They are in the superfamily Chalcidoidea with 22,500 known species worldwide that are constantly undergoing taxonomic debates so I didn't try to identify them further.  Many species have been imported as a biological control agent (BCA) to control plant pests.  In this case a BCA attacking another BCA.

These wasps were the product of smaller eggs carefully placed on the 1mm SSB eggs.  I am constantly amazed at how much life is out there that we never notice.  Here was a complete food cycle flying under the radar until exposed by a fellow nature nerd's curiosity about bumps on a leaf. 

Now 8-12-2021

I  saw a smudge on our storm door glass turned out to be SSB eggs.  Two days later they hatched and were crawling about, probably discussing where to find a juicy caterpillar for breakfast.  You can see them here crawling around a 2" section of window.

They have a tenacious grip on smooth surfaces.  I had to pry them off one at a time from the glass and again from the plastic bug box to release them in the garden.   Please don't ask me why.