There is growing evidence that insects in high‐density populations invest relatively more pathogen resistance than those low‐density (i.e. density‐dependent prophylaxis). Such increases are often accompanied by cuticular melanism, which characteristic of the form many phase polyphenic insects. Both melanism and involve prophenoloxidase enzyme system. In this paper link between resistance, phenoloxidase activity examined Spodoptera larvae. S. exempta , was positively correlated with cuticle,...

Summary 1. Diet and health are intimately linked recent studies have found that caloric restriction can affect immune function. However, when given a choice between diets differ in their macronutrient composition, pathogen–infected individuals select diet improves survival, suggesting the nutritional composition of diet, as well its calorie content, play role defence against disease. Moreover, change infected, it suggests is optimal for growth not immunity, leading to trade‐offs. 2....

Abstract Theory predicts that natural selection will erode additive genetic variation in fitness-related traits. However, numerous studies have found considerable heritable traits related to immune function, which should be closely linked fitness. This could due trade-offs maintaining these We used the Egyptian cotton leafworm, Spodoptera littoralis, as a model system examine quantitative genetics of insect function. estimated heritabilities several different measures innate immunity and...

1. Mounting an immune response is likely to be costly in terms of energy and nutrients, so it predicted that dietary intake should change infection offset these costs. The present study focuses on the interactions between a specialist grass-feeding caterpillar species, African armyworm Spodoptera exempta, opportunist bacterium, Bacillus subtilis. 2. main aims were (i) establish macronutrient costs insect host surviving systemic bacterial infection, (ii) determine relative importance protein...

It is well known that organisms defend their fitness against attack from parasites and pathogens by mounting a personal immune response. However, there increasing evidence diverse taxa also exhibit responses for the purpose of protecting other individuals as themselves. We argue any type immunity has consequences both challenged individual one or more recipients should be referred to ‘social immunity’. show social systems are widespread yet relatively neglected component immunity, ideal...

Summary Some animals change their feeding behaviour when infected with parasites, seeking out substances that enhance ability to overcome infection. This ‘self‐medication’ is typically considered involve the consumption of toxins, minerals or secondary compounds. However, recent studies have shown macronutrients can influence immune response and pathogen‐challenged individuals self‐medicate by choosing a diet rich in protein low carbohydrates. Infected might also reduce food intake (i.e....

Abstract Wild animals are used in scientific research a wide variety of contexts both situ and ex situ. Guidelines for best practice, where they exist, not always clearly linked to animal welfare may instead have their origins practicality. This is complicated by lack clarity about indicators wild animals, what extent researcher should intervene cases compromised welfare. Primer highlights discusses the broad topic ethics using research, controlled conditions. Throughout, we discuss issues...

Nutrition is vital to health and the availability of resources has long been acknowledged as a key factor in ability fight off parasites, investing immune system costly. Resources have typically considered something "black box", with quantity available food being used proxy for resource limitation. However, complex mixture macro- micronutrients, precise balance which determines an animal's fitness. Here we use state-space modelling approach, Geometric Framework (GFN), assess first time, how...

Like humans, animals use plants and other materials as medication against parasites. Recent decades have shown that the study of insects can greatly advance our understanding behaviors. The ease rearing under laboratory conditions has enabled controlled experiments to test critical hypotheses, while their spectrum reproductive strategies living arrangements – ranging from solitary eusocial communities revealed behaviors evolve maximize inclusive fitness through both direct indirect benefits....

Summary The risk of parasitism and infectious disease is expected to increase with population density as a consequence positive density‐dependent transmission rates. Therefore, species that encounter large fluctuations in are predicted exhibit plasticity their immune system, such investment costly defences adjusted match the probability exposure parasites pathogens (i.e. prophylaxis). Despite growing evidence insects high‐density populations show resistance certain pathogens, few studies...

Summary 1. A key component of parental care involves defending resources destined for offspring from a diverse array potential interspecific competitors, such as social parasites, fungi and bacteria. 2. Just with other aspects care, provisioning or brood defence, sexual conflict between parents may arise over how to share the costs this form care. There has been little previous work, however, investigate particular burden might be shared. 3. Here, we describe hitherto uncharacterized in...

Several insect species show an increase in cuticular melanism response to high densities. In some species, there is evidence that this correlated with up-regulation of certain immune system components, particularly phenoloxidase (PO) activity, and the down-regulation lysozyme suggesting a trade-off between two traits. As has genetic component, we selected both melanic nonmelanic lines phase-polyphenic lepidopteran, Spodoptera littoralis, order test for causative link melanism, PO activity...

1. How much should an individual invest in reproduction as it grows older? Answering this question involves determining whether individuals measure their age the time left for future or rate of deterioration state. Theory suggests that former case increase allocation resources to opportunities breeding dwindle, and terminally when they breed last time. In latter reduce investment with age, either through adaptive reproductive restraint a passive by-product senescence. 2. Here we present...

Tolerance and resistance are the two ways in which hosts can lessen effects of infection. aims to minimize fitness resulting from incumbent pathogen populations, whereas reduce population size within host. While environmental impacts on have been extensively, recorded their variation tolerance virtually unexplored. Here, we ask how environment, namely host diet, influences capacity an organism tolerate resist infection, using a model host-parasite system, burying beetle, Nicrophorus...

Abstract Nutrition is vital to health, but while the link between diet and body nutritional composition well explored in humans other vertebrates, this information not understood insects, despite roles they play ecosystems, their increasing use as experimental models. Here we used Nutritional Geometry explore rapid physiological response ingested nutrients haemolymph profile of Spodoptera littoralis caterpillars. We ask whether blood are maintained homeostatically face variable intake, or if...

Ecology Letters (2010) 13: 1114–1123 Abstract Social immune systems comprise defences mounted by individuals for the benefit of others ( sensu Cotter & Kilner 2010a ). Just as with other forms immunity, mounting a social response is expected to be costly but so far these fitness costs are unknown. We measured immunity in sub‐social burying beetle, species which two or more adults defend carrion breeding resource their young smearing flesh antibacterial anal exudates. Our experiments on...

Life-history theory suggests that offspring desertion can be an adaptive reproductive strategy, in which parents forgo the costly care of unprofitable current brood to save resources for future reproduction. In burying beetle, Nicrophorus vespilloides, commonly abandon their others, resulting female-only care, male-only parasitism, and sired by satellite males. Furthermore, when there is biparental males routinely desert before larval development complete, leaving females behind tend young....

Summary Recent work shows that organisms possess two strategies of immune response: personal immunity, which defends an individual, and social protects other individuals, such as kin. However, it is unclear how individuals divide their limited resources between protecting themselves others. Here, with experiments on female burying beetles, we challenged the system measured subsequent investment in immunity (antibacterial activity anal exudates). Our results show increased one aspect (wound...

Abstract Immunity and nutrition are two essential modulators of individual fitness. However, while the implications immune function on an individual's lifespan reproduction well established, interplay between feeding behaviour, infection remains poorly understood. Asking how ecological physiological factors affect responses resistance to infections is a central theme eco‐immunology. In this study, we used fruit fly, Drosophila melanogaster , investigate through septic injury modulates...

Abstract Aim The diversity of brood size across animal species exceeds the most other life‐history traits. In some environments, reproductive success increases with size, whereas in others it smaller broods. dominant hypothesis explaining such predicts that selection on varies along climatic gradients, creating latitudinal fecundity patterns. Another arises among adapted to different microhabitats within assemblages. A more recent concerned consequences these evolutionary processes era...

Abstract Aim Body size explains most of the variation in fitness within animal populations and is therefore under constant selection from ecological reproductive pressures, which often promote its evolution sex‐specific directions, leading to sexual dimorphism (SSD). Several hypotheses have been proposed explain vast diversity SSD across species. These emphasize: (a) mate competition benefits larger male (sexual selection); (b) female for fecundity (fecundity (c) simultaneous niche...