Genetic Variation in Trophic Avoidance Behaviour Shows Fruit Flies are Generally Attracted to Bacterial Substrates.

Pathogen avoidance behaviours are often assumed to be an adaptive host defence. However, there is limited experimental data on heritable, intrapopulation phenotypic variation for avoidance, a strong prerequisite for adaptive responses to selection. We investigated trophic pathogen avoidance in 122 inbred lines, and in a derived outbred population.

A naturally occurring mitochondrial genome variant confers broad protection from infection in Drosophila.

The role of mitochondria in immunity is increasingly recognized, but it is unclear how variation in mitochondrial DNA (mtDNA) contributes to variable infection outcomes. To quantify the effect of mtDNA variation on humoral and cell-mediated innate immune responses, we utilized a panel of fruit fly Drosophila melanogaster cytoplasmic hybrids (cybrids), where unique mtDNAs (mitotypes) were introgressed into a controlled isogenic nuclear background. We observed substantial heterogeneity in infection outcomes within the cybrid panel upon bacterial, viral and parasitoid infections, driven by the mitotype.

Mitochondrial background can explain variable costs of immune deployment.

Organismal health and survival depend on the ability to mount an effective immune response against infection. Yet immune defence may be energy-demanding, resulting in fitness costs if investment in immune function deprives other physiological processes of resources. While evidence of costly immunity resulting in reduced longevity and reproduction is common, the role of energy-producing mitochondria on the magnitude of these costs is unknown.

Plasma-derived product recipients' views on the acceptability of implementing a programme of plasma donation for fractionation from men who have sex with men.

Background And Objectives: Over the past few years in Québec, Canada, exclusion criteria for blood donation and plasma donation for fractionation have been modified. Héma-Québec, the institution responsible for blood products, has made changes to allow more inclusive access to blood and plasma donation, in accordance with evolving scientific data concerning donation safety. The study, conducted before those changes were implemented, aimed to assess acceptability of recipients and parents of recipients of plasma-derived products for men who have sex with men (MSM) to become eligible to donate plasma for fractionation.

Infection-nutrition feedbacks: fat supports pathogen clearance but pathogens reduce fat in a wild mammal.

Though far less obvious than direct effects (clinical disease or mortality), the indirect influences of pathogens are difficult to estimate but may hold fitness consequences. Here, we disentangle the directional relationships between infection and energetic reserves, evaluating the hypotheses that energetic reserves influence infection status of the host and that infection elicits costs to energetic reserves. Using repeated measures of fat reserves and infection status in individual bighorn sheep () in the Greater Yellowstone Ecosystem, we documented that fat influenced ability to clear pathogens () and infection with respiratory pathogens was costly to fat reserves.

IMD-mediated innate immune priming increases Drosophila survival and reduces pathogen transmission.

Invertebrates lack the immune machinery underlying vertebrate-like acquired immunity. However, in many insects past infection by the same pathogen can 'prime' the immune response, resulting in improved survival upon reinfection. Here, we investigated the mechanistic basis and epidemiological consequences of innate immune priming in the fruit fly Drosophila melanogaster when infected with the gram-negative bacterial pathogen Providencia rettgeri.

Chronic wasting disease alters the movement behavior and habitat use of mule deer during clinical stages of infection.

Integrating host movement and pathogen data is a central issue in wildlife disease ecology that will allow for a better understanding of disease transmission. We examined how adult female mule deer () responded behaviorally to infection with chronic wasting disease (CWD). We compared movement and habitat use of CWD-infected deer ( = 18) to those that succumbed to starvation (and were CWD-negative by ELISA and IHC;  = 8) and others in which CWD was not detected ( = 111, including animals that survived the duration of the study) using GPS collar data from two distinct populations collared in central Wyoming, USA during 2018-2022.

Migratory behaviours are risk-sensitive to physiological state in an elevational migrant.

Accretion of body fat by animals is an important physiological adaptation that may underpin seasonal behaviours, especially where it modulates risk associated with a particular behaviour. Using movement data from male Sierra Nevada bighorn sheep (), we tested the hypothesis that migratory behaviours were risk-sensitive to physiological state (indexed by body fat). Sierra bighorn face severe winter conditions at high elevations and higher predation risk at lower elevations.

Mitochondrial background can explain variable costs of immune deployment.

Organismal health and survival depend on the ability to mount an effective immune response against infection. Yet immune defence may be energy-demanding, resulting in fitness costs if investment in immune function deprives other physiological processes of resources. While evidence of costly immunity resulting in reduced longevity and reproduction is common, the role of energy-producing mitochondria on the magnitude of these costs is unknown.

Spatial prey availability and pulsed reproductive tactics: Encounter risk in a canid-ungulate system.

Predation risk is a function of spatiotemporal overlap between predator and prey, as well as behavioural responses during encounters. Dynamic factors (e.g.

Pathology of Chronic Mycoplasma ovipneumoniae Carriers in a Declining Bighorn Sheep (Ovis canadensis) Population.

Bighorn sheep (Ovis canadensis) across North America commonly experience population-limiting epizootics of respiratory disease. Although many cases of bighorn sheep pneumonia are polymicrobial, Mycoplasma ovipneumoniae is most frequently associated with all-age mortality events followed by years of low recruitment. Chronic carriage of M.

A test of the frost wave hypothesis in a temperate ungulate.

Growing evidence supports the hypothesis that temperate herbivores surf the green wave of emerging plants during spring migration. Despite the importance of autumn migration, few studies have conceptualized resource tracking of temperate herbivores during this critical season. We adapted the frost wave hypothesis (FWH), which posits that animals pace their autumn migration to reduce exposure to snow but increase acquisition of forage.

Role of fatty liver in the epidemic of advanced chronic liver disease among people with HIV: protocol for the Canadian LIVEHIV multicentre prospective cohort.

Introduction: Advanced chronic liver disease (ACLD) is a major cause of death for people with HIV (PWH). While viral hepatitis coinfections are largely responsible for this trend, metabolic dysfunction-associated steatotic liver disease (MASLD) is an emerging concern for PWH. We aimed to assess the contribution of MASLD to incident ACLD in PWH.

Duox and Jak/Stat signalling influence disease tolerance in Drosophila during Pseudomonas entomophila infection.

Disease tolerance describes an infected host's ability to maintain health independently of the ability to clear microbe loads. The Jak/Stat pathway plays a pivotal role in humoral innate immunity by detecting tissue damage and triggering cellular renewal, making it a candidate tolerance mechanism. Here, we find that in Drosophila melanogaster infected with Pseudomonas entomophila disrupting ROS-producing dual oxidase (duox) or the negative regulator of Jak/Stat Socs36E, render male flies less tolerant.

Behavioral responses of terrestrial mammals to COVID-19 lockdowns.

COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable with no change in average movements or road avoidance behavior, likely due to variable lockdown conditions.

Migrating mule deer compensate en route for phenological mismatches.

Billions of animals migrate to track seasonal pulses in resources. Optimally timing migration is a key strategy, yet the ability of animals to compensate for phenological mismatches en route is largely unknown. Using GPS movement data collected from 72 adult female deer over a 10-year duration, we study a population of mule deer (Odocoileus hemionus) in Wyoming that lack reliable cues on their desert winter range, causing them to start migration 70 days ahead to 52 days behind the wave of spring green-up.

Intraspecific genetic variation in host vigour, viral load and disease tolerance during Drosophila C virus infection.

Genetic variation for resistance and disease tolerance has been described in a range of species. In , genetic variation in mortality following systemic Drosophila C virus (DCV) infection is driven by large-effect polymorphisms in the restriction factor . However, it is unclear if contributes to disease tolerance.

Behavioural responses of a large, heat-sensitive mammal to climatic variation at multiple spatial scales.

Climate warming creates energetic challenges for endothermic species by increasing metabolic and hydric costs of thermoregulation. Although endotherms can invoke an array of behavioural and physiological strategies for maintaining homeostasis, the relative effectiveness of those strategies in a climate that is becoming both warmer and drier is not well understood. In accordance with the heat dissipation limit theory which suggests that allocation of energy to growth and reproduction by endotherms is constrained by the ability to dissipate heat, we expected that patterns of habitat use by large, heat-sensitive mammals across multiple scales are critical for behavioural thermoregulation during periods of potential heat stress and that they must invest a large portion of time to maintain heat balance.