Re‐weighing the 5% tagging recommendation: assessing the potential impacts of tags on the behaviour and body condition of bats

Considerable advances and breakthroughs in wildlife tracking technology have occurred in recent years, allowing researchers to gain insights into the movements and behaviours of a broad range of animals. Considering the accessibility and increase in use of tracking devices in wildlife studies, it is important to better understand the effects on these on animals. Our endeavour revisits a guideline established in 1988, which proposes that bats may encounter body condition or health problems and alter their behaviour when carrying tags weighing more than 5% of their body mass. Through a systematic literature review, we conducted a meta‐analysis to identify the impacts of tags on bats, including 367 papers from 1976 to 2023 that discussed, mentioned, employed, or quantified tagging of bats. We noted that the proportion of studies exceeding the 5% rule has not changed in recent years. However, the impact of tags was quantified in few studies for behaviour (n = 7) and body condition (n = 10) of bats. We were unable to assess whether tags weighing less or more than 5% of the bat's body mass impacted bats, but our meta‐analysis did identify that tags, irrespective of mass, affect the behaviour and body condition of bats. Although the overall magnitude of measured effects of tags on bats was small, progress has been made to advance our understanding of tag mass on bats. Naturally, there is a bias in reporting of significant results, illustrating the need of reporting results when there is no apparent effect of tags on bats. Our findings highlight the need for rigorous reporting of behaviour and body condition data associated with tagging of animals and illustrate the importance for studies comparing how tracking devices of different dimensions and masses may impact bat species to ensure research meets rigorous ethical standards

Big Data: Managing the Future\u27s Agriculture and Natural Resource Systems

Big Data: Managing the Future\u27s Agriculture and Natural Resource Systems Big data is the incredible flow of information that surrounds each of us, every day. Big data tools identify patterns and habits, not only in research, but in manufacturing, logistics–even ordering items online

DW-MRI as a Biomarker to Compare Therapeutic Outcomes in Radiotherapy Regimens Incorporating Temozolomide or Gemcitabine in Glioblastoma

The effectiveness of the radiosensitizer gemcitabine (GEM) was evaluated in a mouse glioma along with the imaging biomarker diffusion-weighted magnetic resonance imaging (DW-MRI) for early detection of treatment effects. A genetically engineered murine GBM model [Ink4a-Arf−/− PtenloxP/loxP/Ntv-a RCAS/PDGF(+)/Cre(+)] was treated with gemcitabine (GEM), temozolomide (TMZ) +/− ionizing radiation (IR). Therapeutic efficacy was quantified by contrast-enhanced MRI and DW-MRI for growth rate and tumor cellularity, respectively. Mice treated with GEM, TMZ and radiation showed a significant reduction in growth rates as early as three days post-treatment initiation. Both combination treatments (GEM/IR and TMZ/IR) resulted in improved survival over single therapies. Tumor diffusion values increased prior to detectable changes in tumor volume growth rates following administration of therapies. Concomitant GEM/IR and TMZ/IR was active and well tolerated in this GBM model and similarly prolonged median survival of tumor bearing mice. DW-MRI provided early changes to radiosensitization treatment warranting evaluation of this imaging biomarker in clinical trials

Supplementary Video 1 from Inconspicuous echolocation in hoary bats (<i>Lasiurus cinereus</i>)

A hoary bat (Lasiurus cinereus) flies into a fine mist-net obstacle. Note the abrupt buzz-like sequence of calls that is produced just before collision with the obstacle. Audio and video have been slowed to 12.5% of the original speed

Supplementary Video 2 from Inconspicuous echolocation in hoary bats (<i>Lasiurus cinereus</i>)

A hoary bat (Lasiurus cinereus) pursues, and makes contact with a second hoary bat. Note the echolocation calls that begin just as the first bat (which enters from the left) begins pursuing the second bat (which enters from the right and is initially difficult to see). Also note that the first bat makes direct contact with the second bat 20 s into the video. Audio and video have been slowed to 12.5% of the original speed

Supplementary Video 3 from Inconspicuous echolocation in hoary bats (<i>Lasiurus cinereus</i>)

A hoary bat (Lasiurus cinereus) circles a speaker that is broadcasting normal hoary bat echolocation calls (the broadcast has been removed from the audio). The video is played twice, first at real speed without audio, and then at 12.5% of the original speed with audio from the microphone that is nearest to the speaker

Supplentary materials from Inconspicuous echolocation in hoary bats (<i>Lasiurus cinereus</i>)

Includes Supplementary Methods, Results, and Supplementary Figure

Data from: Minimally invasive collection of adipose tissue facilitates the study of eco-physiology in small-bodied mammals

Adipose tissue is the primary fuel storage for vertebrates and is an important component of energy budgets during periods of peak energetic demands. Investigating the composition of adipose tissue can provide information about energetics, migration, reproduction and other life-history traits. Until now, most field methods for sampling adipose tissue of small-bodied vertebrates have been destructive. Therefore, investigations of adipose tissue in small-bodied vertebrates have been limited in their broadscale application. We developed a field-ready micro-adipose biopsy method for sampling adipose tissue of small-bodied vertebrates, by adopting fine-needle adipose aspiration. We applied the method to silver-haired bats (Lasionycteris noctivagans) and then quantified the resulting fatty acid signatures of a summer group and an autumn group to demonstrate one possible application of the method. We successfully obtained interpretable fatty acid signatures from 74·5% of micro-adipose biopsy attempts, with success positively correlated with body mass index. Summer and autumn groups of bats had different fatty acid signatures likely representing varied available dietary compositions at resident sites (the habitat where adipose deposits are accumulated prior to migration). The fatty acid profile of autumn silver-haired bats was largely characterized by 16:0, 18:1 and 14:0, and the summer group was characterized by 16:0, 16:1 and 18:0. Our results suggest that fatty acid signatures have the potential to characterize the origins of migrating individuals, or the number of unique subpopulations being supported by a migration route. This field-ready fine-needle adipose aspiration method can be used on small-bodied mammals and modified for application to other small-bodied vertebrates. This non-destructive approach to sampling adipose tissue has great value because it allows for robust sample sizes, longitudinal studies of the same individuals across space and time, and sampling of rare, threatened and endangered species

First Direct Evidence of Long-distance Seasonal Movements and Hibernation in a Migratory Bat

Understanding of migration in small bats has been constrained by limitations of techniques that were labor-intensive, provided coarse levels of resolution, or were limited to population-level inferences. Knowledge of movements and behaviors of individual bats have been unknowable because of limitations in size of tracking devices and methods to attach them for long periods. We used sutures to attach miniature global positioning system (GPS) tags and data loggers that recorded light levels, activity, and temperature to male hoary bats (Lasiurus cinereus). Results from recovered GPS tags illustrated profound differences among movement patterns by individuals, including one that completed a \u3e1000 km round-trip journey during October 2014. Data loggers allowed us to record sub-hourly patterns of activity and torpor use, in one case over a period of 224 days that spanned an entire winter. In this latter bat, we documented 5 torpor bouts that lasted ≥16 days and a flightless period that lasted 40 nights. These first uses of miniature tags on small bats allowed us to discover that male hoary bats can make multi-directional movements during the migratory season and sometimes hibernate for an entire winter