DOI: 10.5061/dryad.xksn02vrk
title: Data from: Altitude sickness in pollinators: Skyward emigration holds consequences for a native bee

description: With the increasing severity of climate stressors, the elevational ranges
 of plant and animal species are pushing skyward. The channeling and
 redistribution of species is expected to increase in frequency and
 magnitude globally. However, any elevational gradient will be associated
 with decreasing air pressure, which will impose a degree of hypoxia on
 colonizing organisms. Insect species developing under depleted oxygen (O2)
 concentrations in controlled laboratory conditions are known to exhibit
 smaller adult sizes, reduced reproductive capacity, and lower survival
 rates, all of which represent major fitness consequences for insects. This
 begs the question as to whether altitudinal hypoxia might produce the same
 types of consequences as artificially reduced O2 in laboratory
 experiments. With this question in mind, we observed the development of a
 native bee species, Osmia lignaria across an elevational gradient
 in the Rocky Mountains, USA. Known commonly as the blue orchard bee, O.
 lignaria is a univoltine (single generation per year) solitary
 (non-social) bee that nests within hollow stems and reeds. Fully
 provisioned reeds were collected in the foothills of the Rocky
 Mountains in Salt Lake City, UT, and were distributed among three sites
 representing an elevational gradient: 1300 m, 1900 m, and 2500 m. The
 fully provisioned reeds were placed within unsealed plastic containers, in
 climate-controlled indoor spaces at each of the three elevations. Here we
 report a series of observations that reveal a surprising pattern of
 uneaten pollen-provisions, increased mortality, and markedly reduced sizes
 among the bees at higher elevations. The incidence of uneaten pollen
 increased with rising altitude, while pupal (or adult) weights declined
 with altitude, suggesting that with increasing altitude, the bee larvae
 ceased feeding prematurely, becoming smaller pupae/adults. As pollinator
 populations emigrate skyward, these communities will likely exhibit a
 diversity of responses to altitudinal hypoxia, with each species
 potentially experiencing its own ‘hypoxia ceiling.’ Given that bees are
 key players in the foundational mutualisms between microbes and flowering
 plants and that declining pollinator diversity has been linked to reduced
 plant diversity, the basic functioning of high-elevation ecosystems may be
 constrained by the ceilings imposed upon pollinator populations. 
description: # Altitude sickness in pollinators: Skyward emigration holds consequences
 for a native bee
 [https://doi.org/10.5061/dryad.xksn02vrk](https://doi.org/10.5061/dryad.xksn02vrk) ## Description of the data and file structure These data support the paper, "Altitude sickness in pollinators" (S.A. Steffan and P.S. Dharampal), published in Ecology (ECY24-0221). All data were derived from observations of wild \_Osmia lignaria\_ reared at positions along mountain slopes in northern Utah, USA. The bees are native to this range and were collected from local nests in 2023. The adult female bees had very recently provisioned hollow reeds with pollen and nectar for their young. The reeds were collected and then placed within indoor, controlled-environment structures along an elevational gradient (1300, 1900, 2500 m). After the bee larvae had completed their development (or died in the process), their adult size, mortality, and UPR were observed. These metrics represented evidence of how reduced ambient air pressure may be affecting native pollinators. ### Files and variables #### File: Osmia\_Dry-Weight\_\_ElevationGradient\_.csv **Description:** Bee mortality and body-size responses to elevation ##### Variables * Dry-weight and mortality of Osmia bees  * In the data file (Osmia_Dry-Weight_'ElevationGradient'.csv), the dry-weight of each bee specimen is presented in a column format. Each specimen (male, female) developed within a given reed at a specific altitude (1300, 1900, 2500 m). All units are milligrams (mg). * Also within this file are observations of larval mortality. If a larval bee survived to pupation or adulthood, it was designated with a "1" while if it died before reaching pupation/adulthood, it was designated with a "0." #### File: Osmia\_UnfinishedPollen-*ElevationGradient*.csv **Description:** Bee feeding behavior across an elevational gradient ##### Variables * Unfinished pollen rate (UPR) * In the data file (Osmia_UnfinishedPollen_'ElevationGradient'.csv), the UPR (unfinished pollen rate) was quantified for each reed. There were four reeds at the highest elevation (2500 m), three at the intermediate elevation (1900 m), and three at the lowest elevation (1300 m). ## Access information Data was derived from the following sources: * Observations (survival, weight, and feeding pattern) of wild bee specimens within nesting structures.