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Pilophorus juniperi
Hemiptera: Miridae

"All warfare is based on deception."
—Sun Tzu, 6th century military strategist

It is unlikely Sun Tzu had insects in mind when he made this claim in his famous work, The Art of War, but this sentiment holds true in the most brutal manifestations of evolutionary battle. At first glance, you might have guessed this was an ant, but Pilophorus juniperi is in the family Miridae and in the order Hemiptera. Hence its specific epithet juniperi, it is commonly associated with native and ornamentally-planted Juniperus virginiana (Eastern redcedar). However, unlike many other mirids, this is not an exclusively phytophagous species, which is where things get interesting. 
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The semi-predatory behavior of this species is closely associated with its myrmecomorphy. Myrmecomorphy is the morphological mimicry of ants. Ants have often evolved symbiotic interactions with some members of the hemipteran suborder Sternorrhyncha, due to the production of honeydew, a sugar-rich substance secreted by aphids and scale insects which is very nutritious to ants. The aphids and scale insects benefit from this interaction because they receive protection from parasitoids and other predators for providing this tasty butt juice. This is one of the many drivers for the evolution of myrmecomorphy which has evolved independently at least 70 times, 10 times in the family Miridae alone (McIver and Stonedahl 1993). 

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​Pilophorus juniperi exploits this symbiotic interaction by pretending to be an ant, and like a Trojan Horse, it slides under the guard of the ants and wreaks havoc on the delicious resource of Carulaspis juniperi, the juniper scale insect and related juniper-feeding scale insects in the genus (Wheeler and Henry 1977). While this species is clearly a myrmecomorph, it is possible it also secretes chemical volatiles mimicking those of ants to further mask it from the ants defending this precious resource, but definitive behavioral or chemical studies have not been done.

Pilophorus juniperi is found associated with juniper throughout the Eastern United States. You can find this species at Cornell University among both ornamental and wild varieties of red cedar on the grounds of the Cornell Botanic Gardens. The Cornell University Insect Collection (CUIC) has 5 specimens, 2 of which were collected in Washington, D.C. by the author of the species, H.H. Knight.
References:
McIver, J.D., and Gary Stonedahl. (1993). Myrmecomorphy: Morphological and Behavioral Mimicry of Ants. 
Annual Review of Entomology​. 38: 351-379.

Wheeler, Jr., A.G., and Thomas Henry. (1977). Miridae Associated with Pennsylvania Conifers 1. Species on Arborvitae, False Cypress, and Juniper. ​Transactions of the American Entomological Society. 103 (4): 623-656.
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Collection information for specimen in photos: USA: NY: Greene Co. Freehold: Route 67 42.363 -74.055; 4 viii 2017; J.A. Gorneau; UV blacklight sheet under Juniperus virginiana

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Text and photos by Jacob Aaron Gorneau—Cornell University, Department of Entomology

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