scholarly journals A carbohydrate-rich diet increases social immunity in ants

2014 ◽  
Vol 281 (1778) ◽  
pp. 20132374 ◽  
Author(s):  
Adam D. Kay ◽  
Abbie J. Bruning ◽  
Andy van Alst ◽  
Tyler T. Abrahamson ◽  
W. O. H. Hughes ◽  
...  
Keyword(s):  
Disease Transmission ◽  
High Protein Diet ◽  
Resistance Mechanisms ◽  
Parasitic Fungus ◽  
Social Immunity ◽  
Potential Mediator ◽  
Social Grouping ◽  
Metapleural Glands ◽  
Group Members ◽  
Ecological Dominance

Increased potential for disease transmission among nest-mates means living in groups has inherent costs. This increased potential is predicted to select for disease resistance mechanisms that are enhanced by cooperative exchanges among group members, a phenomenon known as social immunity. One potential mediator of social immunity is diet nutritional balance because traits underlying immunity can require different nutritional mixtures. Here, we show how dietary protein–carbohydrate balance affects social immunity in ants. When challenged with a parasitic fungus Metarhizium anisopliae , workers reared on a high-carbohydrate diet survived approximately 2.8× longer in worker groups than in solitary conditions, whereas workers reared on an isocaloric, high-protein diet survived only approximately 1.3× longer in worker groups versus solitary conditions. Nutrition had little effect on social grooming, a potential mechanism for social immunity. However, experimentally blocking metapleural glands, which secrete antibiotics, completely eliminated effects of social grouping and nutrition on immunity, suggesting a causal role for secretion exchange. A carbohydrate-rich diet also reduced worker mortality rates when whole colonies were challenged with Metarhizium . These results provide a novel mechanism by which carbohydrate exploitation could contribute to the ecological dominance of ants and other social groups.

scholarly journals Feeder density enhances house finch disease transmission in experimental epidemics

2018 ◽  
Vol 373 (1745) ◽  
pp. 20170090 ◽  
Author(s):  
Sahnzi C. Moyers ◽  
James S. Adelman ◽  
Damien R. Farine ◽  
Courtney A. Thomason ◽  
Dana M. Hawley
Keyword(s):  
Radio Frequency Identification ◽  
Disease Transmission ◽  
Bacterial Pathogen ◽  
Pathogen Transmission ◽  
House Finch ◽  
Resource Subsidies ◽  
House Finches ◽  
Bird Feeders ◽  
Group Members ◽  
Radio Frequency Identification Devices

Anthropogenic food provisioning of wildlife can alter the frequency of contacts among hosts and between hosts and environmental sources of pathogens. Despite the popularity of garden bird feeding, few studies have addressed how feeders influence host contact rates and disease dynamics. We experimentally manipulated feeder density in replicate aviaries containing captive, pathogen-naive, groups of house finches ( Haemorhous mexicanus ) and continuously tracked behaviours at feeders using radio-frequency identification devices. We then inoculated one bird per group with Mycoplasma gallisepticum (Mg), a common bacterial pathogen for which feeders are fomites of transmission, and assessed effects of feeder density on house finch behaviour and pathogen transmission. We found that pathogen transmission was significantly higher in groups with the highest density of bird feeders, despite a significantly lower rate of intraspecific aggressive interactions relative to the low feeder density groups. Conversely, among naive group members that never showed signs of disease, we saw significantly higher concentrations of Mg-specific antibodies in low feeder density groups, suggesting that birds in low feeder density treatments had exposure to subclinical doses of Mg. We discuss ways in which the density of garden bird feeders could play an important role in mediating the intensity of Mg epidemics. This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife'.

scholarly journals Behavioral responses around conspecific corpses in adult eastern gorillas (Gorilla beringei spp.)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6655 ◽  
Author(s):  
Amy Porter ◽  
Winnie Eckardt ◽  
Veronica Vecellio ◽  
Katerina Guschanski ◽  
Peter Philip Niehoff ◽  
...  
Keyword(s):  
Social Relationships ◽  
Disease Transmission ◽  
National Park ◽  
Democratic Republic Of Congo ◽  
Behavioral Responses ◽  
Mountain Gorilla ◽  
Adult Females ◽  
Gorilla Beringei Beringei ◽  
Gorilla Beringei ◽  
Group Members

Humans were once considered unique in having a concept of death but a growing number of observations of animal responses to dying and dead conspecifics suggests otherwise. Complex arrays of behaviors have been described ranging from corpse removal and burial among social insects to quiet attendance and caregiving among elephants and primates. Less frequently described, however, are behavioral responses of individuals from different age/sex classes or social position toward the death of conspecifics. We describe behavioral responses of mountain gorillas (Gorilla beringei beringei) to the deaths of a dominant silverback and a dominant adult female from the same social group in Volcanoes National Park in Rwanda and the responses of Grauer’s gorillas (Gorilla b. graueri) to the corpse of an extra-group silverback in Kahuzi-Biega National Park, Democratic Republic of Congo. In gorillas, interactions between groups or with a lone silverback often result in avoidance or aggression. We predicted that: (i) more individuals should interact with the corpses of same-group members than with the corpse of the extra-group silverback; (ii) adult females with infants should avoid the corpse of the extra-group silverback; and (iii) in the mountain gorilla cases, individuals that shared close social relationships with the dead individual should spend more time with the corpse than other individuals in the group. We used a combination of detailed qualitative reports, photos, and videos to describe all occurrences of affiliative/investigative and agonistic behaviors observed at the corpses. We observed similar responses toward the corpses of group and extra-group individuals. Animals in all three cases showed a variety of affiliative/investigative and agonistic behaviors directed to the corpses. Animals of all age/sex classes interacted with the corpses in affiliative/investigative ways but there was a notable absence of all adult females at the corpse of the extra-group silverback. In all three cases, we observed only silverbacks and blackbacks being agonistic around and/or toward the corpses. In the mountain gorilla cases, the individuals who spent the most time with the corpses were animals who shared close social relationships with the deceased. We emphasize the similarity in the behavioral responses around the corpses of group and extra-group individuals, and suggest that the behavioral responses were influenced in part by close social relationships between the deceased and certain group members and by a general curiosity about death. We further discuss the implications close interactions with corpses have for disease transmission within and between gorilla social groups.

scholarly journals Opposing effects of allogrooming on disease transmission in ant societies

2015 ◽  
Vol 370 (1669) ◽  
pp. 20140108 ◽  
Author(s):  
Fabian J. Theis ◽  
Line V. Ugelvig ◽  
Carsten Marr ◽  
Sylvia Cremer
Keyword(s):  
Disease Transmission ◽  
Disease Risk ◽  
The Body ◽  
Disease Spread ◽  
Sis Model ◽  
Lasius Neglectus ◽  
Host Pathogen ◽  
Group Members ◽  
Risk Of Disease ◽  
Opposing Effects

To prevent epidemics, insect societies have evolved collective disease defences that are highly effective at curing exposed individuals and limiting disease transmission to healthy group members. Grooming is an important sanitary behaviour—either performed towards oneself (self-grooming) or towards others (allogrooming)—to remove infectious agents from the body surface of exposed individuals, but at the risk of disease contraction by the groomer. We use garden ants ( Lasius neglectus ) and the fungal pathogen Metarhizium as a model system to study how pathogen presence affects self-grooming and allogrooming between exposed and healthy individuals. We develop an epidemiological SIS model to explore how experimentally observed grooming patterns affect disease spread within the colony, thereby providing a direct link between the expression and direction of sanitary behaviours, and their effects on colony-level epidemiology. We find that fungus-exposed ants increase self-grooming, while simultaneously decreasing allogrooming. This behavioural modulation seems universally adaptive and is predicted to contain disease spread in a great variety of host–pathogen systems. In contrast, allogrooming directed towards pathogen-exposed individuals might both increase and decrease disease risk. Our model reveals that the effect of allogrooming depends on the balance between pathogen infectiousness and efficiency of social host defences, which are likely to vary across host–pathogen systems.

scholarly journals Susceptibility to insecticides and resistance mechanisms in three populations of Aedes aegypti from Peru

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Jesus Pinto ◽  
Miriam Palomino ◽  
Leonardo Mendoza-Uribe ◽  
Carmen Sinti ◽  
Kelly A. Liebman ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Disease Transmission ◽  
Molecular Mechanisms ◽  
Mosquito Control ◽  
Resistance Mechanisms ◽  
Activity Levels ◽  
Metabolic Resistance ◽  
Glutathione S Transferases ◽  
Target Site Resistance

Abstract Background Epidemics of dengue, chikungunya and Zika are a growing threat to areas where Aedes aegypti are present. The efficacy of chemical control of Ae. aegypti is threatened by the increasing frequency of insecticide resistance. The objective of this study was to determine the susceptibility status as well as the biochemical and molecular mechanisms underlying insecticide resistance in three populations of Ae. aegypti in high risk areas of dengue, chikungunya, and Zika in Peru. Methods Bioassays were conducted on adult Ae. aegypti to evaluate their susceptibility to insecticides used currently or historically for mosquito control in Peru, including six pyrethroids, three organophosphates and one organochlorine, in populations of Ae. aegypti from the districts of Chosica (Department of Lima), Punchana (Department of Loreto) and Piura (Department of Piura). Resistance mechanisms were determined by biochemical assays to assess activity levels of key detoxification enzyme groups (nonspecific esterases, multi-function oxidases, glutathione S-transferases and insensitive acetylcholinesterase). Real-time PCR assays were used to detect two kdr mutations (V1016I and F1534C) on the voltage-gated sodium channel gene. Results Resistance to DDT was detected in all three populations, and resistance to pyrethroids was detected in all populations except the population from Chosica, which still exhibited susceptibility to deltamethrin. Resistance to organophosphates was also detected, with the exception of populations from Punchana and Piura, which still demonstrated susceptibility to malathion. In general, no increase or alteration of activity of any enzyme group was detected. Both 1016I and 1534C alleles were detected in Punchana and Piura, while only the 1534C allele was detected in Chosica. Conclusions The results suggest that resistance to multiple classes of insecticides exist in areas important to Ae. aegypti-borne disease transmission in Peru. The F1534C mutation was present in all 3 populations and the V1016I mutation was present in 2 populations. To our knowledge, this is the first report of the presence of 1016I and 1534C in Ae. aegypti in Peru. The absence of highly elevated enzymatic activity suggests that target site resistance is a key mechanism underlying insecticide resistance in these populations, although further research is needed to fully understand the role of metabolic resistance mechanisms in these populations.

scholarly journals Investment in chemical signalling glands facilitates the evolution of sociality in lizards

2021 ◽  
Vol 288 (1945) ◽  
pp. 20202438
Author(s):  
Simon Baeckens ◽  
Martin J. Whiting
Keyword(s):  
Information Transfer ◽  
Social Conflict ◽  
Group Living ◽  
Comparative Approach ◽  
Lizard Species ◽  
Chemical Signalling ◽  
Social Grouping ◽  
Evolution Of Sociality ◽  
Group Members ◽  
Epidermal Glands

The evolution of sociality and traits that correlate with, or predict, sociality, have been the focus of considerable recent study. In order to reduce the social conflict that ultimately comes with group living, and foster social tolerance, individuals need reliable information about group members and potential rivals. Chemical signals are one such source of information and are widely used in many animal taxa, including lizards. Here, we take a phylogenetic comparative approach to test the hypothesis that social grouping correlates with investment in chemical signalling. We used the presence of epidermal glands as a proxy of chemical investment and considered social grouping as the occurrence of social groups containing both adults and juveniles. Based on a dataset of 911 lizard species, our models strongly supported correlated evolution between social grouping and chemical signalling glands. The rate of transition towards social grouping from a background of ‘epidermal glands present’ was an order of a magnitude higher than from a background of ‘no epidermal glands’. Our results highlight the potential importance of chemical signalling during the evolution of sociality and the need for more focused studies on the role of chemical communication in facilitating information transfer about individual and group identity, and ameliorating social conflict.

scholarly journals Social fluidity mobilizes contagion in human and animal populations

2017 ◽  
Author(s):  
Ewan Colman ◽  
Vittoria Colizza ◽  
Ephraim M. Hanks ◽  
David P. Hughes ◽  
Shweta Bansal
Keyword(s):  
Disease Transmission ◽  
Social Bonds ◽  
Group Living ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Animal Populations ◽  
Social Mixing ◽  
The Social ◽  
Group Members ◽  
Social Fluidity

Humans and other group-living animals tend to distribute their social effort disproportionately. Individuals predominantly interact with a small number of close companions while maintaining weaker social bonds with less familiar group members. By incorporating this behaviour into a mathematical model we find that a single parameter, which we refer to as social fluidity, controls the rate of social mixing within the group. We compare the social fluidity of 13 species by applying the model to empirical human and animal social interaction data. To investigate how social behavior influences the likelihood of an epidemic outbreak we derive an analytical expression of the relationship between social fluidity and the basic reproductive number of an infectious disease. For highly fluid social behaviour disease transmission is revealed to be density-dependent. For species that form more stable social bonds, the model describes frequency-dependent transmission that is sensitive to changes in social fluidity.

scholarly journals The effects of social environment and the metapleural gland on disease resistance in acorn ants

2021 ◽  
Author(s):  
Joseph T Scavetta ◽  
Sarah F. Senula ◽  
Daniel R. Crowell ◽  
Farzana Siddique ◽  
Jennifer F Segrest ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Pathogen Resistance ◽  
Living Conditions ◽  
Pathogen Transmission ◽  
High Rate ◽  
Social Immunity ◽  
Social Environments ◽  
Metapleural Glands ◽  
Group Environment ◽  
Series Of Experiments

Eusocial species differ in living conditions when compared to solitary species primarily due to the dense living conditions of genetically related individuals. Consequently, these crowded conditions can induce a high rate of pathogen transmission and pathogen susceptibility. To resist an epidemic, individuals rely on sets of behaviors, known as social immunity, to decrease pathogen transmission among nestmates. Alongside social immunity, ants have a pair of secretory metapleural glands (MG), thought to secrete antimicrobial compounds important for antisepsis, that are believed to be transferred among nestmates by social immune behaviors such as grooming. To investigate the effects of social immunity on pathogen resistance, we performed a series of experiments by inoculating acorn ants  Temnothorax curvispinosus  with a lethal spore concentration of the entomopathogenic fungus  Metarhizium brunneum . After inoculation ant survival was monitored in two environments: solitary and in groups. Additionally, the MG role in pathogen resistance was evaluated for both solitary and grouped living ants, by sealing the MG prior to inoculations. Individuals within a group environment had a higher survival compared to those in a solitary environment, and individuals with sealed glands had significantly decreased survival than ants with non-sealed-MG in both solitary and social environments. We observed the lowest survival for solitary-sealed-MG individuals. Although sealing the MG reduced survival probability, sealing the MG did not remove the benefits of grouped living. We show here that social living plays a crucial role in pathogen resistance and that the MG has an important role in pathogen resistance of individual  T. curvispinosus  ants. Although important for an individual's pathogen resistance, our data show that the MG does not play a strong role in social immunity as previously believed. Overall, this study provides insights into mechanisms of social immunity and the role of MG in disease resistance.

scholarly journals Variation in tolerance to parasites in natural Asian tiger mosquito populations and its effect on vectorial capacity

2018 ◽  
Author(s):  
Guha Dharmarajan ◽  
Kathryne D. Walker ◽  
Tovi Lehmann
Keyword(s):  
Disease Transmission ◽  
Disease Risk ◽  
Negative Relationship ◽  
Parasite Load ◽  
Parasite Prevalence ◽  
Resistance Mechanisms ◽  
Vectorial Capacity ◽  
Transmission Intensity ◽  
Population Variation ◽  
High Transmission

AbstractThe vectorial capacity of mosquitoes depends upon the magnitude of reduction of parasite load upon infection through resistance mechanisms (e.g., immune-mediated killing) and the ability of mosquitoes to offset infection-mediated costs through tolerance mechanisms (e.g., tissue repair). Here we use a common-garden experimental framework to measure variation in resistance and tolerance to dog heartworm (Dirofilaria immitis) between natural Aedes albopictus mosquito populations representing areas of low and high transmission intensity. Our data revealed that survival to the extrinsic incubation period, the earliest time point at which infective L3 larvae develop, significantly differed between populations (ranging from 10-60%) when mosquitoes infected with D. immitis at both the low (15 microfilaria/μl blood) and high (30 microfilaria/μl blood) infection dose (Dose: χ2 = 191.473; P < 0.001; Population: χ2 = 24.485; P = 0.001; Dose × Population: χ2 = 35.566; P = 0.001). Contrary to expectations, we found that mosquito populations with highest resistance (i.e., greatest reduction in parasite load) also exhibited highest mortality upon infection (F1,12 = 6.781, P = 0.023; Dose: F1,12 = 6.747; P = 0.023; Mortality × Dose: F1,12 = 0.111, P = 0.744). Expressing the effect of the number of killed (NKILLED) and live (NLIVE) parasite on survival of mosquitoes from the different population, we document a significant inter-population variation in the survival cost of additional parasite (i.e., tolerance to infection (NLIVE × Population: χ2 = 22.845; P = 0.002; NKILLED × Population: χ2 = 31.959; P = < 0.001; NLIVE × NKILLED × Population: χ2 = 22.266; P = 0.002), in conjunction with negative relationship between tolerance and resistance (Resistance: F1,12 = 11.870, P = 0.005; Dose: F1,12 = 16.0170, P = 0.002; Resistance × Dose: F1,12 = 9.699, P =0.009). Importantly, populations from areas with high transmission intensity (as measured by parasite prevalence in dogs) showed elevated tolerance (Prevalence: F1,12 = 9.5, P = 0.012; Prevalence2: F1,12 = 4.353, P = 0.064; Dose: F1,12 = 38.855, P = <0.001), and these populations were also associated with increased vectorial capacity (Tolerance: F1,12 = 8.175, P = 0.014; Dose: F1,12 = 0.005, P = 0.946; Tolerance × Dose: F1,12 = 0.920, P = 0.356). Consequently, our data indicate that spatial variation in disease transmission intensity is linked to the evolution of tolerance in natural mosquito populations, which in turn can feedback to impact disease risk.

The power of norms to sway fused group members

2018 ◽  
Vol 41 ◽  
Author(s):  
Winnifred R. Louis ◽  
Craig McGarty ◽  
Emma F. Thomas ◽  
Catherine E. Amiot ◽  
Fathali M. Moghaddam
Keyword(s):  
Evolutionary Anthropology ◽  
Normative Systems ◽  
Violent Extremism ◽  
Identity Fusion ◽  
Group Members

AbstractWhitehouse adapts insights from evolutionary anthropology to interpret extreme self-sacrifice through the concept of identity fusion. The model neglects the role of normative systems in shaping behaviors, especially in relation to violent extremism. In peaceful groups, increasing fusion will actually decrease extremism. Groups collectively appraise threats and opportunities, actively debate action options, and rarely choose violence toward self or others.

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