Zachary M. Portman

Zachary M. Portman
University of Minnesota Twin Cities | UMN · Department of Entomology

PhD - Ecology

About

35
Publications
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224
Citations
Introduction
Skills and Expertise

Publications

Publications (35)
Article
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Reversing biodiversity declines requires a better understanding of organismal mobility, as movement processes dictate the scale at which species interact with the environment. Previous studies have demonstrated that species foraging ranges, and therefore, habitat use increases with body size. Yet, foraging ranges are also affected by other life‐his...
Preprint
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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 clarif...
Article
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Life-history traits, which are physical traits or behaviours that affect growth, survivorship and reproduction, could play an important role in how well organisms respond to environmental change. By looking for trait-based responses within groups, we can gain a mechanistic understanding of why environmental change might favour or penalize certain s...
Article
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Female and male bees forage for different reasons: females provision nests with pollen appropriate for larval development and consume nectar for energy while males need only fuel their own energetic requirements. The expectation, therefore, is that females should visit fewer floral resource species than males, due to females’ focus on host plant sp...
Article
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Nectar is one of the most important resources used by bees. It has long been known that some bees concentrate nectar externally with their mouthparts, including honey bees and stingless bees. However, observations of this behavior in disparate bee groups suggest this behavior is widespread. Here, we combine accounts and images from publications, co...
Article
Full-text available
1. Grassland restoration is an important tool for conserving bee biodiversity within agricultural landscapes. Restorations foster increases in local bee abundance and α‐diversity, however, these measures are insufficient for understanding if remnant communities are being conserved. We compared native bee α‐diversity, β‐diversity, and community comp...
Preprint
Full-text available
The ability to transport pollen from flowers back to the nest represents a key innovation in the evolution of bees from predatory wasp ancestors. Currently, the origin and evolution of pollen transport remains unsettled. Older hypotheses proposed that crop transport was the original mode of pollen transport, but more recent molecular phylogenies ha...
Article
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Fire and grazing are historic ecosystem drivers of tallgrass prairie and both are used for restoration management today. The effects of these drivers on animal taxa are still incompletely resolved, especially for wild bees, a growing conservation and restoration priority. Fire and grazing could affect wild bee communities through structural changes...
Article
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• Continued reports of bee declines have prompted repeated calls for a national monitoring programme in the United States. Here, we argue that such a large-scale surveillance monitoring programme would consume inordinate resources without providing the sought-after data in a meaningful time period. • Surveillance monitoring cannot provide reliable...
Article
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Network analyses rarely include fitness components, such as germination, to tie invasive plants to population‐level effects on the natives. We address this limitation in a previously studied network of flower visitors around a suite of native and invasive plants that includes an endemic plant at Badlands National Park, South Dakota, USA. Eriogonum...
Preprint
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The turfgrass lawn is a common feature of urban and suburban communities, often accounting for the largest green spaces by area in these landscapes. Flowering species within turfgrass lawns have the potential to serve as a source of forage for bee pollinators in urban and suburban areas. We intentionally introduced low-growing flowers to turfgrass...
Article
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Andrena (Micrandrena) ziziae Robertson, 1891 (Hymenoptera: 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...
Article
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Grassland ecosystems are imperiled by agricultural activity worldwide. Restoring grassland habitat is important to conserving grassland fauna and preserving ecosystem services, but more knowledge is needed on the impact that local and landscape factors have on patterns of diversity. We focused on whether prairie grassland restorations along a gradi...
Article
Full-text available
Effective monitoring is necessary to provide robust detection of bee declines. In the United States and worldwide, bowl traps have been increasingly used to monitor native bees and purportedly detect declines. However, bowl traps have a suite of flaws that make them poorly equipped to monitor bees. We outline the drawbacks of bowl traps, as well as...
Article
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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 rece...
Article
Full-text available
We report the first records of Pseudoanthidium nanum (Mocsáry) (Hymenoptera: Megachilidae) 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...
Article
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Pollen is the primary protein and nutrient source for bees and they employ many different behaviors to gather it. Numerous terms have been coined to describe pollen gathering behaviors, creating confusion as many are not clearly-defined or overlap with existing terms. There is a need for a clear yet flexible classification that enables accurate, su...
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Article
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Body size is an integral functional trait that underlies pollination‐related ecological processes, yet it is often impractical to measure directly. Allometric scaling laws have been used to overcome this problem. However, most existing models rely upon small sample sizes, geographically restricted sampling and have limited applicability for non‐bee...
Article
Full-text available
• The Mojave Desert of the southwestern U.S. is home to two protected species of poppy in the genus Arctomecon Torr. & Frém. (Papaveraceae). A pollinator of these species is the specialist bee Perdita meconis Griswold (Andrenidae) a specialist on poppy pollen. • Recently, the easternmost population of P. meconis, which was associated with A. humili...
Preprint
Full-text available
Body size is an integral functional trait that underlies pollination-related ecological processes, yet it is often impractical to measure directly. Allometric scaling laws have been used to overcome this problem. However, most existing models rely upon small sample sizes, geographically restricted sampling and have limited applicability for non-bee...
Article
Full-text available
Twenty-five years ago, Arctomecon humilis, a pollinator-dependent, endangered poppy globally restricted to the extreme northeastern Mojave Desert in southwestern Utah, was pollinated by native bee species and the European honey bee. Follow-up studies beginning in 2012 failed to find the two most important native bee pollinator species, one of which...
Article
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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) brach...
Article
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Purposeful transport of pollen represents a key innovation in the evolution of bees from predatory wasps. Most bees transport pollen on specialized hairs on the hind legs or ventral metasoma in one of three ways: moist, dry, or “glazed,” which combines dry and moist transport. The evolutionary pathway among these three transport modes is unclear, t...
Article
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Perdita subgenus Heteroperdita Timberlake, a distinctive subgenus of 22 species from the southwestern United States and adjacent Mexico, all specialists on Tiquilia (Boraginaceae), is revised. Nine new species are described: Perdita (Heteroperdita) desdemona Portman, sp. n., P. (H.) exusta Portman & Griswold, sp. n., P. (H.) hippolyta Portman & Gri...
Article
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The monotypic Perdita subgenus Xeromacrotera Timberlake is currently known only from the male sex. Here, the female of Perdita (Xeromacrotera) cephalotes (Cresson, 1878) is associated, resulting in two new junior synonyms of P. (X.) ce-phalotes: Perdita (Procockerellia) excellens Timberlake, 1958, new synonym and Perdita (Cockerellia) autumnalis Ti...
Article
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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. Much has been le...
Conference Paper
One of the great debates among pollination biology is how bees specialize on their floral hosts. Currently, the conventional wisdom is that specialist bees largely lack morphological adaptations for harvesting pollen. Instead, recent hypotheses have emphasized behavioral and dietary specialization. A survey of bee taxa has uncovered the pervasive o...
Chapter
Although not often discrete, the canopy (i.e., the organization of branches, shoot systems and their extent) remains the most definable and useful unit of function in bryophytes. Chambers used for gas exchange provide an integrated summary of canopy photosynthetic function. However, other techniques can provide more information on spatial variation...
Conference Paper
Bee species have a wide diversity in color, ranging from entirely black to entirely white or yellow. Differences in coloration are thought to play a role in temperature regulation, camouflage, or aposematism. In the speciose Nearctic genus Perdita Smith 1853 (>633 species), entire yellow coloration has evolved at least seven times in more than 25 s...

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