Invasive plants supporting invasive bees

Male Bee feeding on Spotted Knapweed

A male Bee feeding on Spotted Knapweed


Male bee resting on Virginia Creeper

Male bee resting on Virginia Creeper

I have been collecting insects since 2005 and I collected almost anything unique to the eye. A majority of my collection was Coleoptera and Hymenoptera. In 2008, I started collecting native bees when I was using bowl traps for the Pennsylvania Department of Agriculture. My collecting was concentrated in Montgomery, Chester and Lehigh County.

Around this time the department was working on locating an invasive species by the name of Lithurgus chrysurus or the Mediterranean wood boring bee. The females cause damage to wood structures by burrowing into wood to nest. Overwintering of this bee occurs as prepupae inside a cocoon and they are univoltine, like numerous insects, where there is only one generation of brood in a year. This wood-boring bee was first found in PA in 2007. As soon as I heard about this bee I was intrigued and started looking for it. There are images to the right and above of the male, note the color variation.

After a few months of working I found this invasive species in my parent’s back yard and I discovered it on the biennial spotted knapweed. Ironically, spotted knapweed is also an invasive species and it produces chemicals that inhibit the growth of other plant species. This plant can cause quite a decline in biodiversity over time. I took many photographs and collected some specimens to make a positive identification on this bee and plant.

While observing the females I noticed they were very territorial and aggressive towards each other. There are some images below of some of the behavior I noticed. You can see in one image a bee that had been knocked down off the flower onto a leaf on its back.

Female collecting provisions on spotted Knapweed, note the full pollen load on the scopa of the underside of the abdomen.

Here a female is collecting provisions on spotted Knapweed, note the full pollen load on the scopa of the underside of the abdomen.

This Image demonstrates the aggressive nature of these females protecting their territory.

In this image you see the aggressive nature of these bees protecting their territory.

Here you see the aftermath of being knocked off a flower by another female.

Here you see the aftermath of a female being knocked off a flower onto its back.

Note the burnt red color on the T6 of this female, this is a key characteristic of this species

Note the burnt red color on the T6 of this female, this is a key characteristic of this species

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About Rob Snyder

I currently work out of the Butte County Cooperative Extension in Oroville, CA as a Crop Protection Agent. I received my B.S. in biology from Delaware Valley College, PA. There I attained a majority of my entomological knowledge from Dr. Chris Tipping and Dr. Robert Berthold. After graduation, I was an apiary inspector for 2 years at the Department of Agriculture in Pennsylvania. In my third year there, I still inspected some colonies but I mainly focused on The Pennsylvania Native Bee Survey (PANBS) where I pinned, labeled, entered data and identified native bees to genus species. Leo Donavall assisted me in learning the basics on positive Identifications of the native bees. Around the same time I began working on coordinating kit construction and distribution for the APHIS National Honey Bee Survey. I was also fortunate to conduct many of these surveys with fellow co-worker Mike Andree and Nathan Rice of USDA/ARS throughout California. All of these experiences have led me to where I am today, working to assist beekeepers in maintaining genetic diverse colonies resistant to parasites while reducing the use of chemical treatments in colonies. The BIP Diagnostic Lab at the University of MD is in an integral part of this process by generating reports in which we can track change and report to beekeepers vital information in a timely manner which may influence their treatment decisions.

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