Can you see it? Ambush bugs are common inhabitants of Cornell campus, you can find them in open sunny areas sitting on flowers. They like hiding on the blossoms of Goldenrod plants (Solidago), waiting to catch any of the unsuspecting insects that are visiting the flowers. Sometimes you can see them sucking nectar from the flowers, but don’t get confuse, they are just taking some energy to wait for the prey . In the eastern United States, the nymphs start to appear in middle to late June, and the adults become more abundant in middle to late July and often are found through much of October . They are univoltine, which means they just complete one life cycle during the year.
How to recognize them? You can easily recognize them because they are yellow and black or brown, and they have raptorial forelegs with square and robust femora. You won’t want to meet one of them if you were a bee in a flower. To differentiate between males and females, you just have to look at the final part of their abdomen as shown in the following pictures. Keep in mind that there are large variations in size and color .
Males and females have two encounter behaviors: coupling and copulation. In coupling the male rides on the dorsum of the female. In this configuration, both may attack and take down prey too large for a single insect or each may take individual prey for consumption. In contrast, copulation occurs with the male clutching the side of the female with the terminalia united and heads diverging .
The ambush bugs are represented in the Nearctic region by 27 species in 3 genera. In this region there are two common species Phymata pennsylvanica and Phymata americana, with some specimens present in the Cornell insect collection. The easiest character to differentiate them is observing the edge of the abdomen (called connexiva) from a dorsal view and notice that Phymata pennsylvanica have the fourth segment distinctly angulate.
How do they kill their prey? Ambush bugs wait patiently hidden in the flowers until a confident visitor arrives, once the prey is trapped, it is capable of injecting paralyzing substances with its beak and then patiently suck all the internal juices of the dead insect. In this video you can see them in action at 3:45 minute...
References:  T. Yong, “Nectar-Feeding by a Predatory Ambush Bug ( Heteroptera : Phymatidae ) That Hunts on Flowers,” Ecology and population biology. Annals of the entomological society of America. Vol. 95 No. 5. pp. 643–651, 2003.  D. R. Swanson, “A Review of the Ambush Bugs ( Heteroptera : Reduviidae : Phymatinae ) of Michigan : Identification and Additional considerations for two common Eastern species” Gt. lake Entomol., vol. 46, no. July, pp. 154–164, 2014.  D. Punzalan and L. Rowe, “Concordance between stabilizing sexual selection , intraspecific variation , and interspecific divergence in Phymata,” Ecology and evolution. no. May, pp. 7997–8009, 2016.
Compiled by Diana Obregon, Ph.D. student at Cornell University. firstname.lastname@example.org