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.

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.

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.

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.

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.

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.

Mechanisms of damage prevention, signalling and repair impact disease tolerance.

The insect gut is frequently exposed to pathogenic threats and must not only clear these potential infections, but also tolerate relatively high microbe loads. In contrast to the mechanisms that eliminate pathogens, we currently know less about the mechanisms of disease tolerance. We investigated how well-described mechanisms that prevent, signal, control or repair damage during infection contribute to the phenotype of disease tolerance.

Variation in mitochondrial DNA affects locomotor activity and sleep in Drosophila melanogaster.

Mitochondria are organelles that produce cellular energy in the form of ATP through oxidative phosphorylation, and this primary function is conserved among many taxa. Locomotion is a trait that is highly reliant on metabolic function and expected to be greatly affected by disruptions to mitochondrial performance. To this end, we aimed to examine how activity and sleep vary between Drosophila melanogaster strains with different geographic origins, how these patterns are affected by mitochondrial DNA (mtDNA) variation, and how breaking up co-evolved mito-nuclear gene combinations affect the studied activity traits.

Carry on caring: infected females maintain their parental care despite high mortality.

Parental care is a key component of an organism's reproductive strategy that is thought to trade-off with allocation toward immunity. Yet, it is unclear how caring parents respond to pathogens: do infected parents reduce care as a sickness behavior or simply from being ill or do they prioritize their offspring by maintaining high levels of care? To address this issue, we investigated the consequences of infection by the pathogen on mortality, time spent providing care, reproductive output, and expression of immune genes of female parents in the burying beetle . We compared untreated control females with infected females that were inoculated with live bacteria, immune-challenged females that were inoculated with heat-killed bacteria, and injured females that were injected with buffer.

Testing evolutionary explanations for the lifespan benefit of dietary restriction in fruit flies (Drosophila melanogaster).

Dietary restriction (DR), limiting calories or specific nutrients without malnutrition, extends lifespan across diverse taxa. Traditionally, this lifespan extension has been explained as a result of diet-mediated changes in the trade-off between lifespan and reproduction, with survival favored when resources are scarce. However, a recently proposed alternative suggests that the selective benefit of the response to DR is the maintenance of reproduction.

Navigating infection risk during oviposition and cannibalistic foraging in a holometabolous insect.

Deciding where to eat and raise offspring carries important fitness consequences for all animals, especially if foraging, feeding, and reproduction increase pathogen exposure. In insects with complete metamorphosis, foraging mainly occurs during the larval stage, while oviposition decisions are made by adult females. Selection for infection avoidance behaviors may therefore be developmentally uncoupled.

Oral Bacterial Infection and Shedding in Drosophila melanogaster.

The fruit fly Drosophila melanogaster is one of the best developed model systems of infection and innate immunity. While most work has focused on systemic infections, there has been a recent increase of interest in the mechanisms of gut immunocompetence to pathogens, which require methods to orally infect flies. Here we present a protocol to orally expose individual flies to an opportunistic bacterial pathogen (Pseudomonas aeruginosa) and a natural bacterial pathogen of D.

The route of infection determines antibacterial protection in .

Bacterial symbionts are widespread among metazoans and provide a range of beneficial functions. -mediated protection against viral infection has been extensively demonstrated in In mosquitoes that are artificially transinfected with (wMel), protection from both viral and bacterial infections has been demonstrated. However, no evidence for -mediated antibacterial protection has been demonstrated in to date.