scholarly journals Hot and sour: parasite adaptations to honey bee body temperature and pH

2021 ◽  
Author(s):  
Evan C Palmer-Young ◽  
Thomas R Raffel ◽  
Jay D Evans

Host temperature and gut chemistry can shape resistance to parasite infection. Heat and acidity can limit trypanosomatid infection in warm-blooded hosts, and could shape infection resistance in insects as well. The colony-level endothermy and acidic guts of social bees provide unique opportunities to study how temperature and acidity shape insect-parasite associations. We compared temperature and pH tolerance between three trypanosomatid parasites from social bees and a related trypanosomatid from poikilothermic mosquitoes, which have alkaline guts. Relative to the mosquito parasites, all three bee parasites had higher heat tolerance that reflected levels of endothermy in hosts. Heat tolerance of the honey bee parasite Crithidia mellificae was exceptional for its genus, implicating honey bee endothermy as a filter of parasite establishment. The lesser heat tolerance of the emerging Lotmaria passim suggests possible spillover from a less endothermic host. Whereas both honey bee parasites tolerated the acidic pH's found in bee intestines, mosquito parasites tolerated the alkaline conditions found in mosquito midguts, suggesting that both gut pH and temperature could structure host-parasite specificity. Elucidating how host temperature and gut pH affect infection—and corresponding parasite adaptations to these factors—could help explain trypanosomatids' distribution among insects and invasion of mammals. Keywords : thermal performance curve, metabolic theory of ecology, infectious disease ecology, thermoregulation, Apis mellifera, Leishmania

2021 ◽  
Vol 288 (1964) ◽  
Author(s):  
Evan C. Palmer-Young ◽  
Thomas R. Raffel ◽  
Jay D. Evans

Host temperature and gut chemistry can shape resistance to parasite infection. Heat and acidity can limit trypanosomatid infection in warm-blooded hosts and could shape infection resistance in insects as well. The colony-level endothermy and acidic guts of social bees provide unique opportunities to study how temperature and acidity shape insect–parasite associations. We compared temperature and pH tolerance between three trypanosomatid parasites from social bees and a related trypanosomatid from poikilothermic mosquitoes, which have alkaline guts. Relative to the mosquito parasites, all three bee parasites had higher heat tolerance that reflected body temperatures of hosts. Heat tolerance of the honeybee parasite Crithidia mellificae was exceptional for its genus, implicating honeybee endothermy as a plausible filter of parasite establishment. The lesser heat tolerance of the emerging Lotmaria passim suggests possible spillover from a less endothermic host. Whereas both honeybee parasites tolerated the acidic pH found in bee intestines, mosquito parasites tolerated the alkaline conditions found in mosquito midguts, suggesting that both gut pH and temperature could structure host–parasite specificity. Elucidating how host temperature and gut pH affect infection—and corresponding parasite adaptations to these factors—could help explain trypanosomatids' distribution among insects and invasion of mammals.


2017 ◽  
Vol 284 (1864) ◽  
pp. 20171066 ◽  
Author(s):  
Marian Hu ◽  
Yung-Che Tseng ◽  
Yi-Hsien Su ◽  
Etienne Lein ◽  
Hae-Gyeong Lee ◽  
...  

The unusual rate and extent of environmental changes due to human activities may exceed the capacity of marine organisms to deal with this phenomenon. The identification of physiological systems that set the tolerance limits and their potential for phenotypic buffering in the most vulnerable ontogenetic stages become increasingly important to make large-scale projections. Here, we demonstrate that the differential sensitivity of non-calcifying Ambulacraria (echinoderms and hemichordates) larvae towards simulated ocean acidification is dictated by the physiology of their digestive systems. Gastric pH regulation upon experimental ocean acidification was compared in six species of the superphylum Ambulacraria. We observed a strong correlation between sensitivity to ocean acidification and the ability to regulate gut pH. Surprisingly, species with tightly regulated gastric pH were more sensitive to ocean acidification. This study provides evidence that strict maintenance of highly alkaline conditions in the larval gut of Ambulacraria early life stages may dictate their sensitivity to decreases in seawater pH. These findings highlight the importance of identifying and understanding pH regulatory systems in marine larval stages that may contribute to substantial energetic challenges under near-future ocean acidification scenarios.


2020 ◽  
Author(s):  
Hannah E. Brown ◽  
Calla L. Telzrow ◽  
Joseph W. Saelens ◽  
Larissa Fernandes ◽  
J. Andrew Alspaugh

AbstractThe ability for cells to maintain homeostasis in the presence of extracellular stress is essential for their survival. Stress adaptations are especially important for microbial pathogens to respond to rapidly changing conditions, such as those encountered during the transition from the environment to the infected host. Many fungal pathogens have acquired the ability to quickly adapt to changes in extracellular pH to promote their survival in the various micro-environments encountered during a host infection. For example, the fungal-specific Rim/Pal alkaline response pathway has been well characterized in many fungal pathogens, including Cryptococcus neoformans. However, alternative mechanisms for sensing and responding to host pH have yet to be extensively studied. Recent observations from a genetic screen suggest that the C. neoformans sterol homeostasis pathway is required for growth at elevated pH. This work explores interactions among mechanisms of membrane homeostasis, alkaline pH tolerance, and Rim pathway activation. We find that the sterol homeostasis pathway is necessary for growth in an alkaline environment, and that an elevated pH is sufficient to induce Sre1 activation. This pH-mediated activation of the Sre1 transcription factor is linked to the biosynthesis of ergosterol, but is not dependent on Rim pathway signaling, suggesting that these two pathways are responding to alkaline pH independently. Furthermore, we discover that C. neoformans is more susceptible to membrane-targeting antifungals in alkaline conditions highlighting the impact of micro-environmental pH on the treatment of invasive fungal infections. Together, these findings further connect membrane integrity and composition with the fungal pH response and pathogenesis.


Disease ecology is an interdisciplinary field that recognizes that the host–parasite interaction is shaped by the environment and can affect and be affected by the processes that occur across all levels of ecological organization. This book focuses on the dynamics of infectious diseases for wild avian hosts across different scales of biological organization—from within-host processes to landscape-level patterns. Parasite–bird interactions are both influenced by and have consequences for every level of ecological hierarchy, from the physiology, behavior, and evolution of individual hosts up to the complex biotic and abiotic interactions occurring within biological communities and ecosystems. As the most diverse group of extant vertebrates, birds have evolved to utilize every ecological niche on earth, giving them the capacity to serve as a host of pathogens in every part of the world. The diversity of birds is outmatched only by the diversity of the parasite fauna infecting them. Given the overwhelming diversity of both avian hosts and their parasites, we have only scratched the surface regarding the role that pathogens play in avian biology and the role that birds play in the maintenance and spread of zoonotic pathogens. In addition to this understudied diversity, parasite–bird interactions are increasingly occurring in rapidly changing global environments—thus, their ecology is changing—and this shapes the complex ways by which parasites influence the interconnected health of birds, humans, and shared ecosystems. The chapters in this book illustrate that the understanding of these complex and multiscale interactions requires an inherently integrative approach.


2020 ◽  
Author(s):  
Maxwell J. Farrell ◽  
Mohamad Elmasri ◽  
David Stephens ◽  
T. Jonathan Davies

Parasites that infect multiple species cause major health burdens globally, but for many, the full suite of susceptible hosts is unknown. Proactive disease surveillance involves gathering host-parasite association data, predicting missing links, and targeting efforts towards the most likely undocumented interactions. Using the largest global network of mammal host-parasite interactions amalgamated to date (>29,000 interactions), we predict undocumented links and conduct targeted literature searches. We find evidence for many of the top “missing” links, including parasites of humans, domesticated animals, and endangered wildlife, and identify regions such as tropical and central America as likely hotspots of undocumented associations. This approach of iterated prediction and targeted surveillance can efficiently guide the collection of host-parasite interaction data critical for developing broad-scale theories in disease ecology and evolution, help to identify previously undocumented hosts, and inform predictions of future host-parasite interactions.


2021 ◽  
Vol 376 (1837) ◽  
pp. 20200351 ◽  
Author(s):  
Maxwell J. Farrell ◽  
Andrew W. Park ◽  
Clayton E. Cressler ◽  
Tad Dallas ◽  
Shan Huang ◽  
...  

A growing body of research is focused on the extinction of parasite species in response to host endangerment and declines. Beyond the loss of parasite species richness, host extinction can impact apparent parasite host specificity, as measured by host richness or the phylogenetic distances among hosts. Such impacts on the distribution of parasites across the host phylogeny can have knock-on effects that may reshape the adaptation of both hosts and parasites, ultimately shifting the evolutionary landscape underlying the potential for emergence and the evolution of virulence across hosts. Here, we examine how the reshaping of host phylogenies through extinction may impact the host specificity of parasites, and offer examples from historical extinctions, present-day endangerment, and future projections of biodiversity loss. We suggest that an improved understanding of the impact of host extinction on contemporary host–parasite interactions may shed light on core aspects of disease ecology, including comparative studies of host specificity, virulence evolution in multi-host parasite systems, and future trajectories for host and parasite biodiversity. This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.


2013 ◽  
Vol 3 (7) ◽  
pp. 2214-2222 ◽  
Author(s):  
Sophie E. F. Evison ◽  
Geraldine Fazio ◽  
Paula Chappell ◽  
Kirsten Foley ◽  
Annette B. Jensen ◽  
...  
Keyword(s):  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kelly Kulhanek ◽  
Andrew Garavito ◽  
Dennis vanEngelsdorp

AbstractA leading cause of managed honey bee colony mortality in the US, Varroa destructor populations typically exceed damaging levels in the fall. One explanation for rapid population increases is migration of mite carrying bees between colonies. Here, the degree to which bees from high and low mite donor colonies move between apiaries, and the effect visitation has on Varroa populations was monitored. More bees from low mite colonies (n = 37) were detected in receiver apiaries than bees from high mite colonies (n = 10, p < 0.001). Receiver colony Varroa population growth was associated with visitation by non-natal bees (p = 0.03), but not high mite bees alone (p = 0.19). Finally, colonies lacking robbing screens experienced faster Varroa population growth than screened neighbors (p = 0.01). Results indicate visiting non-natal bees may vector mites to receiver colonies. These results do not support the current two leading theories regarding mite immigration – the “mite bomb” theory (bees from high mite colonies emigrating to collapsing colonies), or the “robbing” theory (natal robbing bees return home with mites from collapsing colonies). Potential host-parasite effects to bee behavior, as well as important management implications both for Varroa treatment regimens and breeding Varroa resistant bees are discussed.


PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257701
Author(s):  
Gabriela M. Quinlan ◽  
Meghan O. Milbrath ◽  
Clint R. V. Otto ◽  
Rufus Isaacs

Agriculturally important commercially managed pollinators including honey bees (Apis mellifera L., 1758) and bumble bees (Bombus impatiens Cresson, 1863) rely on the surrounding landscape to fulfill their dietary needs. A previous study in Europe demonstrated that managed honey bee foragers and unmanaged native bumble bee foragers are associated with different land uses. However, it is unclear how response to land use compares between managed honey bees and a managed native bumble bee species in the United States, where honey bees are an imported species. Furthermore, to our knowledge, no such direct comparisons of bee responses to land use have been made at the colony level. To better understand how two different social bees respond to variation in land use, we monitored the weights of A. mellifera and B. impatiens colonies placed in 12 apiaries across a range of land use in Michigan, United States in 2017. Bombus impatiens colonies gained more weight and produced more drones when surrounded by diverse agricultural land (i.e., non-corn/soybean cropland such as tree fruits and grapes), while honey bee colonies gained more weight when surrounded by more grassland/pasture land. These findings add to our understanding of how different bee species respond to agricultural landscapes, highlighting the need for further species-specific land use studies to inform tailored land management.


2021 ◽  
Author(s):  
Maxwell Jenner Farrell ◽  
Andrew Park ◽  
Clay Cressler ◽  
Tad Dallas ◽  
Shan Huang ◽  
...  

A growing body of research is focused on the extinction of parasite species in response to host endangerment and declines. Beyond the loss of parasite species richness, host extinction can impact apparent parasite host specificity, as measured by host richness or the phylogenetic distances among hosts. Such impacts on the distribution of parasites across the host phylogeny can have knock-on effects that may reshape the adaptation of both hosts and parasites, ultimately shifting the evolutionary landscape underlying the potential for emergence and the evolution of virulence across hosts. Here we examine how the reshaping of host phylogenies through extinction may impact the host specificity of parasites, and offer examples from historical extinctions, present-day endangerment, and future projections of biodiversity loss. We suggest that an improved understanding of the impact of host extinction on contemporary host-parasite interactions may shed light on core aspects of disease ecology, including comparative studies of host specificity, virulence evolution in multi-host parasite systems, and future trajectories for host and parasite biodiversity.


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