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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

Rain on a sunny day: Sharpshooters, Oncometopia sp.


A brown exoskeleton of the newly molted sharpshooter looks on while Oncometopia plans its next move.


Last week a Bug of the Week aficionado sent a wonderful image of a newly molted leafhopper resting near its freshly shed exoskeleton. This was not your run of the mill sucking insect. No, these large beautiful leafhoppers belong to a group called sharpshooters. A recent encounter with these guys helps explain their unusual nickname.

One lovely spring morning, while dining beneath a large shade tree in my back yard, I noticed fine droplets raining from above. This strange drizzle on a sunny day reminded me of the CCR lyric, “Have you ever seen the rain, Comin' down on a sunny day”, and led me to wonder why in the world a shade tree would be raining on my breakfast. The persistent drip, drip, drip took me to a branch about 10 feet above the patio. On a twig I discovered a very large member of the insect family known as Cicadellidae. These rascals feed by inserting soda straw-like mouthparts into a plant and tapping into its vascular system. The pipes they access are called xylem and, as plant tissues go, the xylem carries a fluid that is rather nutrient poor. As a result, sharpshooters remove large amounts of liquid to obtain requisite nutrients. The fluid is rapidly processed and the excess is forcefully excreted from the bug’s anus as liquid called honeydew. It is estimated that some sharpshooters process the equivalent of a human drinking nearly 400 gallons of water a day. No wonder a few of these buggers made it feel like it was raining!

The white chalky patch on the side of the sharpshooter contains brochosomes. They will be used to powder the area where the sharpshooter lays her eggs. This powdery substance may help protect the eggs from parasitic wasps.  

Determined to identify who was anointing me and my breakfast, I captured my six-legged friend and compared it to other specimens in our insect museum. It was clearly in the genus Oncometopia. It is not all that unusual to hear tales of rain on a sunny day while standing beneath trees. Several years ago I was fascinated by a curious inquiry about “raining trees” in the city of Baltimore. I did my best to investigate this strange phenomenon and removed several samples from the weeping trees with a long pole pruner. I was seeking evidence that some honeydew-producing insect such as soft scales or aphids like ones we met in previous episodes of Bug of the Week was behind this mysterious rain. I found no evidence of the sedentary scales and left the scene unfulfilled, my investigation inconclusive. A few weeks later, I received an envelope full of crushed bug remains from a concerned resident living nearby one of the “weeping trees”.  I compared my newly acquired Oncometopia to the specimens sent by the Baltimorean and found the remains from the weeping trees indistinguishable from the rainmaker I had collected above my patio.

Hind sight is usually nearly perfect and my failure to find sharpshooters in the tree canopies is not really surprising. I’m guessing that when the sharpshooters saw my pole pruner approaching, they simply took wing and were long gone before the excised branch hit the pavement. Sharpshooters have excellent eyesight and fly like F-14s. In the next few weeks if you encounter rain on a sunny day, follow the squirt back to the source and you might be rewarded with a glimpse of a sharpshooter.


We thank Heather Zindash for taking the great picture of the newly molted sharpshooter that provided inspiration for this Bug of the Week. To learn more about sharpshooters, please visit the following excellent web site: