Bees are an ecologically and economically important, diverse group of insect pollinators. Recent studies show that populations of some bee species are declining around the world. However, most regions lack baseline data for the species composition of bee communities, which makes detecting changes in species’ ranges and populations over time challenging. Thus, documenting the diversity of bee communities is critical for detecting these changes, as well as shifts in species’ phenology, ecology, and conservation needs.

Checklists provide information about the species found in a defined region and serve as baselines for detecting species range expansions, contractions, or introductions. Here, we present information and species lists for each of the six bee families recorded in Pennsylvania, based on records openly-accessible in the recently-updated state checklist [1]. At least 437 bee species occur in Pennsylvania. Phenology and county-level distribution information for each species is also available [see 1]. A total of 23 species are not native to North America. Over 80% of the species on the checklist have been collected or observed in the state between 2000-2018. However, at least five species are of conservation concern: endangered, declining, or rare within their ranges. For lists of non-native species and species of conservation concern, please visit the checklist [1] or the family pages linked below.

The updated checklist contributes to our knowledge about bees in the state, and will inform future ecology and conservation research. If you have any questions, or records you would like to contribute to this website and future checklist updates, please contact us using one of the methods below.

Want to learn more about the bees in Pennsylvania?

Click on each family below!​


Connect with and follow our project on social media:

  1. Create your post on social media (FacebookTwitter, and/or Instagram)
  2. Add the hashtag #BeesOfPA
  3. Tag our lab using @LopezUribeLab

Have a question, update to a species record, or website feedback?

Please contact Shelby Kilpatrick ( Thank you for your interest! 


Penn State Center for Pollinator Research: Group of faculty, postdocs, and students who are developing and implementing integrative, multidisciplinary approaches and resources for improving pollinator health, conservation, management, and education.

Pennsylvania Pollinator Protection Plan (P4): Outlines best management practices for supporting and expanding pollinator populations in Pennsylvania including pesticide use, forage, and habitat.

Bees in Pennsylvania: Diversity, Ecology, and Importance: Penn State Extension article featuring information about how bees in the state are classified, their lifestyles, and the value of documenting these pollinators in the state (3-page PDF download available). 

Pollinator Series – Bee Biodiversity in PennsylvaniaPenn State Extension webinar recording featuring information about how bee species are different from each other, what Pennsylvanian species are native to North America, and how you can help conserve bees.

Penn State Extension: Additional articles, guides, videos, webinars, and other resources for information about bees in the state.

Pollinating Insects & Bees in Pennsylvania: Guide and activity sheet for identifying, observing, and learning about common pollinator groups (2-page PDF).

PolliNation Podcast Episode 146 – Shelby Kilpatrick – Checklist of Pennsylvania Bees: Oregon State University Extension Service podcast, featuring discussion about how checklists are created and the results of the recently-updated Pennsylvania bee checklist.

Penn State Insect Identification: Free service from Penn State for insect identification.

Checklist of Pa. bees documents 49 new species and some that may be endangered: Penn State News press release on the updated checklist.


  1. Kilpatrick SK, Gibbs J, Mikulas MM, Spichiger S-E, Ostiguy N, Biddinger DJ, López-Uribe MM (2020) An updated checklist of the bees (Hymenoptera, Apoidea, Anthophila) of Pennsylvania, United States of America. Journal of Hymenoptera Research 77: 1–86.

Pie Chart Photo Credit
USGS Bee Inventory and Monitoring Lab

How to Cite this Webpage
Kilpatrick SK, López-Uribe MM (2020) Checklist of the Bees of Pennsylvania.

Updated 27 July 2020