Documenting Bombus nevadensis in Minnesota, with Some Notes on Discerning It from B. auricomus (Hymenoptera: Apidae)

In the face of well-documented declines in multiple bumblebee species, it is important to accurately identify species and properly delineate species ranges. Here, we document the range of Bombus auricomus (Robertson) and B. nevadensis Cresson in Minnesota, with particular reference to the unexpected discovery of B. nevadensis in St. Paul. We clarify the relative ranges of these two species and provide additional information on how to reliably identify them in Minnesota using color patterns and morphology, including differences in male genitalia. Our results support the consensus that B. auricomus and B. nevadensis are distinct species. Community science records were integral to fully documenting the range of B. nevadensis in Minnesota. Our findings demonstrate the value of community science data, though it highlights the need for experts to check the data and to be mindful of biases in observations around population centers

Megachile (Megachile) montivaga (Hymenoptera: Megachilidae) nesting in live thistle (Asteraceae: Cirsium)

Although Megachile Latreille (leafcutter bees) are well known for their diverse nesting habits, records of the genus nesting in live plants are rare.  Here, we report the widespread Megachile (Megachile) montivaga Cresson nesting in live thistle (Cirsium neomexicanum Gray), the first explicit record of this behavior in the Nearctic

Timing of Invasion by Africanized Bees Coincides with Local Extinction of a Specialized Pollinator of a Rare Poppy in Utah, USA

The introduction of exotic species can have profound impacts on mutualisms between native species in invaded areas. However, determining whether a new invader has impacted native species depends on accurately reconstructing the invasion timing. The arrival of Africanized honey bees (AHB) in southern Utah at some point between 1994 and 2011 has recently been implicated in the local extinction of Perdita meconis, a native specialist pollinator of an endangered poppy, Arctomecon humilis. Although AHBs were purportedly first detected in southern Utah in 2008, their presence in nearby Nevada, Arizona, and New Mexico by 1998–2001 suggests that they may have been present in Utah much earlier. We refined the arrival date of AHBs in southern Utah by using a molecular marker to determine maternal ancestry of museum specimens collected between 2000 and 2008. We found that AHBs were present in southern Utah from 2000 onwards, advancing the arrival date of this invader by at least 8 years. This lends credence to the hypothesis that AHBs played a critical role in the local extinction of P. meconis in Utah. This work also highlights the importance of vouchering even common species such as honey bees in museum collections to serve future research needs

First Records of the Adventive Pseudoanthidium nanum (Mocsáry) (Hymenoptera: Megachilidae) in Illinois and Minnesota, with Notes on its Identification and Taxonomy

We report the first records of Pseudoanthidium nanum (Mocsáry) in Illinois and Minnesota in 2016 and 2018, respectively. This represents a relatively rapid expansion since P. nanum was first detected in New Jersey in 2008. In order to help monitor the spread of this bee, we provide information on how to identify P. nanum and provide images of the general habitus, diagnostic features, and male genitalia. Finally, we confirm the taxonomic identity of P. nanum in the United States and highlight potential impacts on native anthidiines

Reinstatement of Andrena vernalis Mitchell (Hymenoptera: Andrenidae) from synonymy with A. ziziae Robertson

Andrena (Micrandrena) ziziae Robertson, 1891 (Andrenidae) is a well-known species found in a variety of habitats in the eastern and central United States and adjacent southern Canada. Andrena (Micrandrena) vernalis Mitchell, 1960 was described from five female specimens in the eastern United States and was synonymized with A. ziziae by Ribble in 1968. Recently collected specimens from throughout Minnesota have revealed that A. ziziae sensu Ribble is actually two species, one of which matches A. vernalis. Here, we reinstate A. vernalis as a valid species and describe the previously unknown male. We provide diagnostic characters that separate A. ziziae and A. vernalis, as well as data on the geographic range and floral preferences of both species in Minnesota. Andrena vernalis appears to be restricted to high-quality remnant habitats, making it a species of potential conservation concern. These changes will require that previous work on A. ziziae be revisited to determine if A. vernalis is also present

First Records of the Adventive Pseudoanthidium nanum (Mocsáry) (Hymenoptera: Megachilidae) in Illinois and Minnesota, with Notes on its Identification and Taxonomy

We report the first records of Pseudoanthidium nanum (Mocsáry) in Illinois and Minnesota in 2016 and 2018, respectively. This represents a relatively rapid expansion since P. nanum was first detected in New Jersey in 2008. In order to help monitor the spread of this bee, we provide information on how to identify P. nanum and provide images of the general habitus, diagnostic features, and male genitalia. Finally, we confirm the taxonomic identity of P. nanum in the United States and highlight potential impacts on native anthidiines

Abundance and diversity of bees visiting flowering pennycress, a new oilseed crop in the midwestern USA

Oilseed pennycress (Thlaspi arvense) is a new, autumn-sown, “cash cover crop” for the Midwestern USA and elsewhere. Anthesis occurs in early spring when few other plants bloom, and its flowers attract early-emerging bees. However, the taxonomic composition of these bees was unknown. Consequently, we systematically captured and identified the genera and species of bees visiting pennycress flowers throughout anthesis at five site-years: two in Illinois and three in Minnesota. A cumulative total of 28 bee species were found across site-years. The most common genera were Andrena (10 species), Lasioglossum (12 species), and Halictus (2 species). Rarer genera were Apis, Ceratina, Hylaeus, and Nomada. Bee abundance and diversity were related closely and in a negative exponential manner with percent land area devoted to annual cropping. The inclusion of new early flowering crops, such as pennycress, may enhance bee abundance and diversity, especially if even small areas of uncropped land are nearby

Figure 9 from: Portman ZM, Griswold T (2017) Review of Perdita subgenus Procockerellia Timberlake (Hymenoptera, Andrenidae) and the first Perdita gynandromorph. ZooKeys 712: 87-111. https://doi.org/10.3897/zookeys.712.14736

A systematic study of Perdita subgenus Procockerellia Timberlake and the related subgenus Allomacrotera Timberlake results in the synonymy of the latter with the former, and two specific synonymies: Perdita (Hexaperdita) glamis Timberlake is a junior synonym of Perdita (Procockerellia) stephanomeriae Timberlake, while Perdita (Procockerellia) brachyglossa Timberlake is a junior synonym of Perdita (Cockerellia) imbellis Timberlake. Perdita (Procockerellia) moldenkei Timberlake is moved to subgenus Cockerellia Ashmead. A revised subgeneric diagnosis and key to the three included species are provided. Diagnoses of species are updated with novel characters; distributions and biological data are expanded. A gynandromorph of P. (Procockerellia) moabensis Timberlake, the first known in the genus Perdita, is reported

A 3-dimensional model of bryophyte canopy light interaction

While seemingly small and insignificant, bryophytes dominate a wide range of ecosystems such as boreal forests, rainforests, streams, wetlands, and bogs. Although rates of photosynthesis have been evaluated for a number of bryophyte species, there has been no evaluation of how variation in the three-dimensional structure of the canopy influences its function. To investigate this, I developed a 3D computer model of bryophyte canopy structure and modeled the light dynamics within the canopy. The liverwort species Bazzania trilobata was modeled due to both its ecological significance as well as its relatively simple branching structure. The model parameters were informed by measurements taken from actual B. trilobata specimens. Using the L-systems modeling approach, the model simulated a community of individual plants in order to create a holistic canopy structure. By altering structural features of individuals in the canopy, the relationship between canopy structure and function was explored. A nested radiosity algorithm previously implemented by third party open source software modeled the interactions of light within the canopy by simulating the scattering and transmission of light vertically within the canopy. The results from the model were validated against measured results of light attenuation in the canopies of living specimens of B. trilobata. The modeled canopy was found to have a much higher rate of light extinction in the canopy than the actual specimens. The source of this difference appears to be a faulty transmission function in the modeling software. However, despite a significant difference between the results from the model and the actual living specimens, the model was useful in exploring the unexpected intricacies of B. trilobata structure as well as highlighting the importance of transmission in the canopy. In the future, updates to the light modeling software may lead to a properly functioning canopy model, and eventually, the results of this research may lead to a canopy photosynthesis model to explore the connections between light intensity distribution and photosynthetic output

Foraging Behavior, Taxonomy, and Morphology of Bees (Hymenoptera: Apoidea), with an Emphasis on Perdita (Hymenoptera: Andrenidae)

Bees are the most important pollinators of flowering plants and are necessary for pollinating both wild plants and many of the crops that produce the food we eat. There are many different species of bees, with about 20,000 species worldwide and 4,000 species in the United States. Even though bees are important pollinators, there is still much we do not know about how many species there are and their biology. In order to better understand the species and their biology, I performed three projects that help fill these gaps by reviewing the species of a poorly known bee group, examining the different ways bees carry pollen, and then reviewing how bees gather pollen from flowers. To better understand bee diversity, I examined a group of species in the subgenus Heteroperdita in the genus Perdita (Andrenidae). I described nine species that were new to science, found the opposite sex of three species, and found that one species was a duplicate of a previously described species. This work increased the number of species in Heteroperdita to 22 and increased the number of species in the genus Perdita to 636. I then explored how pollen is carried back to the nest in two distantly-related bee groups, the genera Perdita and Hesperapis (Melittidae). I found that different species can carry pollen in one of three different ways: moist, dry, or glazed. Interestingly, how the bees carry pollen appears to depend on the shape and stickiness of the pollen grains that the bees prefer. I then reviewed how bees gather pollen from flowers. I combined previous research and my own observations of bees to classify the different pollen gathering behaviors into seven different types. I then examined why bees use different pollen gathering behaviors and provided a set terminology to refer to each behavior. Overall, this dissertation advances our knowledge of the diversity of bees and their relationships with flowers, which will support efforts to understand and conserve these important pollinators