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Entomology (Study of Bugs)/boring in concrete slab


who done it
who done it  
Hello Ed:
I have attached a picture of boring in my concrete porch slab.
It appears as if someone drilled a perfect hole - but no one did.
Is it possible that an insect could have done this?
Thank You.

Dear Sharon - If you are absolutely certain that human activity was not responsible for this hole, about the only possibility that comes to mind is a carpenter bee. These bees, which resemble bumble bees, normally construct their tunnel nests in dead wood (including unfinished lumber). However, I have seen anecdotal (but not proven) reports of them boring into concrete/mortar on occasion. Keep your eyes peeled for bees that look like bumble bees but that exhibit different behavior - male carpenter bees (which are stingless) literally will get into your face when they are 'guarding' nest sites.

Hope this helps,

Entomology (Study of Bugs)

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Ed Saugstad


Will accept most questions in general entomology, including those related to medical entomology, taxonomy, ecology, arthropod surveillance, and pest management. If you are requesting a 'mystery bug' identification, PLEASE either attach an image to your question, or post an image on a web page (such as Flickr) so that I can look at it, as verbal descriptions frequently are insufficient for a definitive identification.


21 years in the U.S. Army as a medical entomologist; duties varied from surveillance of pest populations (including mosquitoes, cockroaches, ticks, and stored products pests) to conducting research on mosquito-virus ecological relationships and mosquito faunal studies. Ten years as a civilian analyst for the Department of Defense, primarily on distribution of vector-borne diseases worldwide. Limited experience on surveillance of agricultural insects in North Dakota and Indiana.

Entomological Society of America, West Virginia Entomological Society, Society for Vector Ecology, National Speleological Society, West Virginia Association for Cave Studies.

American Journal of Public Health, Contributions of the American Entomological Institute, Japanese Journal of Sanitary Zoology, Journal of Economic Entomology, Mosquito News, and Mosquito Systematics.

B.S. in entomology from North Dakota State University in 1963, M.S. in entomology from Purdue University in 1967.

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