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1. The Effects of Body Mass on Immune Cell Concentrations of Mammals

   https://doi.org/10.1086/706235  

   Downs, Cynthia J.; Dochtermann, Ned A.; Ball, Ray; Klasing, Kirk C.; Martin, Lynn B. (January 2020, The American Naturalist)
2. The impacts of body mass on immune cell concentrations in birds

   https://doi.org/10.1098/rspb.2020.0655  

   Ruhs, Emily Cornelius; Martin, Lynn B.; Downs, Cynthia J. (September 2020, Proceedings of the Royal Society B: Biological Sciences)

   null (Ed.)

   Body mass affects many biological traits, but its impacts on immune defences are fairly unknown. Recent research on mammals found that neutrophil concentrations disproportionately increased (scaled hypermetrically) with body mass, a result not predicted by any existing theory. Although the scaling relationship for mammals might predict how leucocyte concentrations scale with body mass in other vertebrates, vertebrate classes are distinct in many ways that might affect their current and historic interactions with parasites and hence the evolution of their immune systems. Subsequently, here, we asked which existing scaling hypothesis best-predicts relationships between body mass and lymphocyte, eosinophil and heterophil concentrations—the avian functional equivalent of neutrophils—among more than 100 species of birds. We then examined the predictive power of body mass relative to life-history variation, as extensive literature indicates that the timing of key life events has influenced immune system variation among species. Finally, we ask whether avian scaling patterns differ from the patterns we observed in mammals. We found that an intercept-only model best explained lymphocyte and eosinophil concentrations among birds, indicating that the concentrations of these cell types were both independent of body mass. For heterophils, however, body mass explained 31% of the variation in concentrations among species, much more than life-history variation (4%). As with mammalian neutrophils, avian heterophils scaled hypermetrically ( b = 0.19 ± 0.05), but more steeply than mammals (approx. 1.5 ×; 0.11 ± 0.03). As such, we discuss why birds might require more broadly protective cells compared to mammals of the same body size. Overall, body mass appears to have strong influences on the architecture of immune systems. 

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3. Foraging dive frequency predicts body mass gain in the Adélie penguin

   https://doi.org/10.1038/s41598-021-02451-4  

   Lescroël, Amélie; Schmidt, Annie; Elrod, Megan; Ainley, David G.; Ballard, Grant (December 2021, Scientific Reports)

   Abstract Quantifying food intake in wild animals is crucial to many ecological and evolutionary questions, yet it can be very challenging, especially in the marine environment. Because foraging behavior can be inferred from dive recordings in many marine creatures, we hypothesized that specific behavioral dive variables can indicate food intake. To test this hypothesis, we attached time-depth recorders to breeding Adélie penguins also implanted with RFID tags that crossed a weighbridge as they traveled to and from the ocean to feed their chicks. The weighbridge reported how much mass the penguin had gained during a foraging trip. The variables that explained a significant amount of the change in body mass while at sea were the number of foraging dives per hour (46%) and the number of undulations per hour (12%). Most importantly, every increment of 1 in the rate of foraging dives per hour equated to a penguin gaining an average 170 g of mass, over the course of a 6–60 h foraging trip. These results add to a growing understanding that different metrics of foraging success are likely appropriate for different species, and that assessing the types and frequencies of dives using time-depth recorders can yield valuable insights. 

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4. Numerical-relativity validation of effective-one-body waveforms in the intermediate-mass-ratio regime

   https://doi.org/10.1103/PhysRevD.105.124061  

   Nagar, Alessandro; Healy, James; Lousto, Carlos O.; Bernuzzi, Sebastiano; Albertini, Angelica (June 2022, Physical Review D)
5. Modeling the effects of Aedes aegypti’s larval environment on adult body mass at emergence

   https://doi.org/10.1371/journal.pcbi.1009102  

   Walker, Melody; Chandrasegaran, Karthikeyan; Vinauger, Clément; Robert, Michael A.; Childs, Lauren M. (November 2021, PLOS Computational Biology)

   Perkins, Alex (Ed.)

   Mosquitoes vector harmful pathogens that infect millions of people every year, and developing approaches to effectively control mosquitoes is a topic of great interest. However, the success of many control measures is highly dependent upon ecological, physiological, and life history traits of mosquito species. The behavior of mosquitoes and their potential to vector pathogens can also be impacted by these traits. One trait of interest is mosquito body mass, which depends upon many factors associated with the environment in which juvenile mosquitoes develop. Our experiments examined the impact of larval density on the body mass of Aedes aegypti mosquitoes, which are important vectors of dengue, Zika, yellow fever, and other pathogens. To investigate the interactions between the larval environment and mosquito body mass, we built a discrete time mathematical model that incorporates body mass, larval density, and food availability and fit the model to our experimental data. We considered three categories of model complexity informed by data, and selected the best model within each category using Akaike’s Information Criterion. We found that the larval environment is an important determinant of the body mass of mosquitoes upon emergence. Furthermore, we found that larval density has greater impact on body mass of adults at emergence than on development time, and that inclusion of density dependence in the survival of female aquatic stages in models is important. We discuss the implications of our results for the control of Aedes mosquitoes and on their potential to spread disease. 

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