scholarly journals Negative Fitness Consequences and Transmission Dynamics of a Heritable Fungal Symbiont of a Parasitic Wasp

2009 ◽  
Vol 75 (10) ◽  
pp. 3115-3119 ◽  
Author(s):  
Cara M. Gibson ◽  
Martha S. Hunter
Keyword(s):  
Competitive Ability ◽  
Horizontal Transmission ◽  
Parasitic Wasp ◽  
Experimental Tests ◽  
Bacterial Symbionts ◽  
Fitness Costs ◽  
Fungal Symbiont ◽  
Fitness Consequences ◽  
Single Host ◽  
Host Ecology

ABSTRACT Heritable bacterial symbionts are widespread in insects and can have many important effects on host ecology and fitness. Fungal symbionts are also important in shaping their hosts' behavior, interactions, and evolution, but they have been largely overlooked. Experimental tests to determine the relevance of fungal symbionts to their insect hosts are currently extremely rare, and to our knowledge, there have been no such tests for strictly predacious insects. We investigated the fitness consequences for a parasitic wasp (Comperia merceti) of an inherited fungal symbiont in the Saccharomycotina (Ascomycota) that was long presumed to be a mutualist. In comparisons of wasp lines with and without this symbiont, we found no evidence of mutualism. Instead, there were significant fitness costs to the wasps in the presence of the yeast; infected wasps attacked fewer hosts and had longer development times. We also examined the relative competitive abilities of the larval progeny of infected and uninfected mothers, as well as horizontal transmission of the fungal symbiont among larval wasps that shared a single host cockroach egg case. We found no difference in larval competitive ability when larvae whose infection status differed shared a single host. We did find high rates of horizontal transmission of the fungus, and we suggest that this transmission is likely responsible for the maintenance of this infection in wasp populations.

scholarly journals Inbred burying beetles suffer fitness costs from making poor decisions

2018 ◽  
Vol 285 (1881) ◽  
pp. 20180419 ◽  
Author(s):  
Jon Richardson ◽  
Pauline Comin ◽  
Per T. Smiseth
Keyword(s):  
Decision Making ◽  
Inbreeding Depression ◽  
Resource Availability ◽  
Environmental Conditions ◽  
Fitness Costs ◽  
Individual Decision ◽  
Burying Beetle ◽  
Individual Decision Making ◽  
Fitness Consequences ◽  
Nicrophorus Vespilloides

There is growing interest in how environmental conditions, such as resource availability, can modify the severity of inbreeding depression. However, little is known about whether inbreeding depression is also associated with differences in individual decision-making. For example, decisions about how many offspring to produce are often based upon the prevailing environmental conditions, such as resource availability, and getting these decisions wrong may have important fitness consequences for both parents and offspring. We tested for effects of inbreeding on individual decision-making in the burying beetle Nicrophorus vespilloides, which uses the size of a carrion resource to make decisions about number of offspring. Both inbred and outbred females adjusted their initial decisions about number of eggs to lay based on carcass size. However, when we forced individuals to update this initial decision by providing them with a different-sized carcass partway through reproduction, inbred females failed to update their decision about how many larvae to cull. Consequently, inbred females reared too many larvae, resulting in negative fitness consequences in the form of smaller offspring and reduced female post-reproductive condition. Our study provides novel insights into the effects of inbreeding by showing that poor decision-making by inbred individuals can negatively affect fitness.

Transitions in symbiosis: evidence for environmental acquisition & social transmission within a clade of heritable symbionts

2020 ◽  
Author(s):  
Georgia C Drew ◽  
Giles E Budge ◽  
Crystal L Frost ◽  
Peter Neumann ◽  
Stefanos Siozios ◽  
...  
Keyword(s):  
Honey Bee ◽  
Honey Bees ◽  
Fluorescent In Situ Hybridization ◽  
Horizontal Transmission ◽  
Bacterial Symbionts ◽  
Free Living ◽  
Social Contacts ◽  
Obligate Mutualism ◽  
Environmental Microbes

AbstractA dynamic continuum exists from free-living environmental microbes to strict host associated symbionts that are vertically inherited. However, knowledge of the forces that drive transitions in the modes by which symbioses form is lacking. Arsenophonus is a diverse clade of bacterial symbionts, comprising reproductive parasites to coevolving obligate mutualists, in which the predominant mode of transmission is vertical. We describe a symbiosis between a member of the genus Arsenophonus and the Western honey bee. We then present multiple lines of evidence that this symbiont deviates from a heritable model of transmission. Field sampling uncovered marked spatial and seasonal dynamics in symbiont prevalence, and rapid infection loss events were observed in field colonies and individuals in the laboratory. Fluorescent in-situ hybridization showed Arsenophonus localised in the gut, and detection of the bacterium was rare in screens of early honey bee life stages. We directly show horizontal transmission of Arsenophonus between bees under varying social conditions. We conclude that honey bees acquire Arsenophonus through a combination of environmental exposure and social contacts. Together these findings uncover a key link in the Arsenophonus clades trajectory from free-living ancestral life to obligate mutualism, and provide a foundation for studying transitions in symbiotic lifestyle.

scholarly journals Wolbachia infection reduces sperm competitive ability in an insect

2006 ◽  
Vol 273 (1593) ◽  
pp. 1455-1458 ◽  
Author(s):  
Fleur E Champion de Crespigny ◽  
Nina Wedell
Keyword(s):  
Population Dynamics ◽  
Sperm Competition ◽  
Empirical Evidence ◽  
Reproductive Strategies ◽  
Competitive Ability ◽  
Cytoplasmic Incompatibility ◽  
Wolbachia Infection ◽  
Sperm Production ◽  
Fitness Costs ◽  
Wolbachia Pipientis

The maternally inherited bacterium Wolbachia pipientis imposes significant fitness costs on its hosts. One such cost is decreased sperm production resulting in reduced fertility of male Drosophila simulans infected with cytoplasmic incompatibility (CI) inducing Wolbachia . We tested the hypothesis that Wolbachia infection affects sperm competitive ability and found that Wolbachia infection is indeed associated with reduced success in sperm competition in non-virgin males. In the second male role, infected males sired 71% of the offspring whereas uninfected males sired 82% of offspring. This is the first empirical evidence indicating that Wolbachia infection deleteriously affects sperm competition and raises the possibility that polyandrous females can utilize differential sperm competitive ability to bias the paternity of broods and avoid the selfish manipulations of Wolbachia . This suggests a relationship between Wolbachia infection and host reproductive strategies. These findings also have important consequences for Wolbachia population dynamics because the transmission advantage of Wolbachia is likely to be undermined by sperm competition.

scholarly journals When more is less: the fitness consequences of predators attacking more unpalatable prey when more are presented

2010 ◽  
Vol 6 (6) ◽  
pp. 732-735 ◽  
Author(s):  
Hannah M. Rowland ◽  
Elizabeth Wiley ◽  
Graeme D. Ruxton ◽  
Johanna Mappes ◽  
Michael P. Speed
Keyword(s):  
Empirical Support ◽  
Warning Signal ◽  
Fixed Number ◽  
Visual Signal ◽  
Fitness Costs ◽  
Avian Predators ◽  
Fitness Consequences ◽  
Unpalatable Prey

In 1879, Fritz Müller hypothesized that mimetic resemblance in which defended prey display the same warning signal would share the costs of predator education. Although Müller argued that predators would need to ingest a fixed number of prey with a given visual signal when learning to avoid unpalatable prey, this assumption lacks empirical support. We report an experiment which shows that, as the number of unpalatable prey presented to them increased, avian predators attacked higher numbers of those prey. We calculated that, when predators increase attacks, the fitness costs incurred by unpalatable prey can be substantial. This suggests that the survival benefits of mimicry could be lower than Müller proposed. An important finding is, however, that these costs decline in importance as the total number of available prey increases.

scholarly journals The importance of environmentally-acquired bacterial symbionts for the squash bug (Anasa tristis), a significant agricultural pest

2021 ◽  
Author(s):  
Tarik S. Acevedo ◽  
Gregory P. Fricker ◽  
Justine R Garcia ◽  
Tiffany Alcaide ◽  
Aileen Berasategui ◽  
...  
Keyword(s):  
Horizontal Transmission ◽  
Development Stage ◽  
Bacterial Symbionts ◽  
Complete Understanding ◽  
Anasa Tristis ◽  
Squash Bug ◽  
The Family ◽  
Insect Symbionts ◽  
Midgut Crypts ◽  
Bacterial Plant Pathogen

Most insects maintain associations with microbes that shape their ecology and evolution. Such symbioses have important applied implications when the associated insects are pests or vectors of disease. The squash bug, Anasa tristis (Coreoidea: Coreidae), is a significant pest of human agriculture in its own right and also causes damage to crops due to its capacity to transmit a bacterial plant pathogen. Here, we demonstrate that complete understanding of these insects requires consideration of their association with bacterial symbionts in the family Burkholderiaceae. Isolation and sequencing of bacteria housed in midgut crypts in these insects indicates that these bacteria are consistent and dominant members of the crypt-associated bacterial communities. These symbionts are closely related to Caballeronia spp. associated other true bugs in the superfamiles Lygaeoidea and Coreoidea. Fitness assays with representative Burkholderiaceae strains indicate that the association can significantly increase survival and decrease development time, though strains do vary in the benefits that they confer to their hosts, with Caballeronia spp. providing the greatest benefit. Experiments designed to assess transmission mode indicate that unlike many other beneficial insect symbionts, the bacteria are not acquired from parents before or after hatching but are instead acquired from the environment after molting to a later development stage. The bacteria do, however, have the capacity to escape adults to be transmitted to later generations, leaving the possibility for a combination of indirect vertical and horizontal transmission.

scholarly journals The Importance of Environmentally Acquired Bacterial Symbionts for the Squash Bug (Anasa tristis), a Significant Agricultural Pest

2021 ◽  
Vol 12 ◽  
Author(s):  
Tarik S. Acevedo ◽  
Gregory P. Fricker ◽  
Justine R. Garcia ◽  
Tiffanie Alcaide ◽  
Aileen Berasategui ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Horizontal Transmission ◽  
Bacterial Symbionts ◽  
Complete Understanding ◽  
Anasa Tristis ◽  
Squash Bug ◽  
The Family ◽  
Insect Symbionts ◽  
Midgut Crypts ◽  
Bacterial Plant Pathogen

Most insects maintain associations with microbes that shape their ecology and evolution. Such symbioses have important applied implications when the associated insects are pests or vectors of disease. The squash bug, Anasa tristis (Coreoidea: Coreidae), is a significant pest of human agriculture in its own right and also causes damage to crops due to its capacity to transmit a bacterial plant pathogen. Here, we demonstrate that complete understanding of these insects requires consideration of their association with bacterial symbionts in the family Burkholderiaceae. Isolation and sequencing of bacteria housed in the insects’ midgut crypts indicates that these bacteria are consistent and dominant members of the crypt-associated bacterial communities. These symbionts are closely related to Caballeronia spp. associated with other true bugs in the superfamilies Lygaeoidea and Coreoidea. Fitness assays with representative Burkholderiaceae strains indicate that the association can significantly increase survival and decrease development time, though strains do vary in the benefits that they confer to their hosts, with Caballeronia spp. providing the greatest benefit. Experiments designed to assess transmission mode indicate that, unlike many other beneficial insect symbionts, the bacteria are not acquired from parents before or after hatching but are instead acquired from the environment after molting to a later developmental stage. The bacteria do, however, have the capacity to escape adults to be transmitted to later generations, leaving the possibility for a combination of indirect vertical and horizontal transmission.

scholarly journals Strong Environment-Genotype Interactions Determine the Fitness Costs of Antibiotic Resistance In Vitro and in an Insect Model of Infection

2020 ◽  
Vol 64 (10) ◽  
Author(s):  
C. James Manktelow ◽  
Elitsa Penkova ◽  
Lucy Scott ◽  
Andrew C. Matthews ◽  
Ben Raymond
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Mutations ◽  
Fitness Costs ◽  
Mechanisms Of Resistance ◽  
Content Type ◽  
Poor Predictor ◽  
Fitness Consequences ◽  
Rifampin Resistance

ABSTRACT The acquisition of antibiotic resistance commonly imposes fitness costs, a reduction in the fitness of bacteria in the absence of drugs. These costs have been quantified primarily using in vitro experiments and a small number of in vivo studies in mice, and it is commonly assumed that these diverse methods are consistent. Here, we used an insect model of infection to compare the fitness costs of antibiotic resistance in vivo to those in vitro. Experiments explored diverse mechanisms of resistance in a Gram-positive pathogen, Bacillus thuringiensis, and a Gram-negative intestinal symbiont, Enterobacter cloacae. Rifampin resistance in B. thuringiensis showed fitness costs that were typically elevated in vivo, although these were modulated by genotype-environment interactions. In contrast, resistance to cefotaxime via derepression of AmpC β-lactamase in E. cloacae resulted in no detectable costs in vivo or in vitro, while spontaneous resistance to nalidixic acid, and carriage of the IncP plasmid RP4, imposed costs that increased in vivo. Overall, fitness costs in vitro were a poor predictor of fitness costs in vivo because of strong genotype-environment interactions throughout this study. Insect infections provide a cheap and accessible means of assessing the fitness consequences of resistance mutations, data that are important for understanding the evolution and spread of resistance. This study emphasizes that the fitness costs imposed by particular mutations or different modes of resistance are extremely variable and that only a subset of these mutations is likely to be prevalent outside the laboratory.

scholarly journals Bacterial symbionts in insects or the story of communities affecting communities

2011 ◽  
Vol 366 (1569) ◽  
pp. 1389-1400 ◽  
Author(s):  
Julia Ferrari ◽  
Fabrice Vavre
Keyword(s):  
Bacterial Communities ◽  
Horizontal Transmission ◽  
Model Systems ◽  
Community Genetics ◽  
Bacterial Symbionts ◽  
Ideal Model ◽  
Host Genotype ◽  
Or Gene ◽  
Dynamic Communities ◽  
The Cost

Bacterial symbionts are widespread in insects and other animals. Most of them are predominantly vertically transmitted, along with their hosts' genes, and thus extend the heritable genetic variation present in one species. These passengers have a variety of repercussions on the host's phenotypes: besides the cost imposed on the host for maintaining the symbiont population, they can provide fitness advantages to the host or manipulate the host's reproduction. We argue that insect symbioses are ideal model systems for community genetics. First, bacterial symbionts directly or indirectly affect the interactions with other species within a community. Examples include their involvement in modifying the use of host plants by phytophagous insects, in providing resistance to natural enemies, but also in reducing the global genetic diversity or gene flow between populations within some species. Second, one emerging picture in insect symbioses is that many species are simultaneously infected with more than one symbiont, which permits studying the factors that shape bacterial communities; for example, horizontal transmission, interactions between host genotype, symbiont genotype and the environment and interactions among symbionts. One conclusion is that insects' symbiotic complements are dynamic communities that affect and are affected by the communities in which they are embedded.

scholarly journals Transitions in symbiosis: evidence for environmental acquisition and social transmission within a clade of heritable symbionts

2021 ◽  
Author(s):  
Georgia C. Drew ◽  
Giles E. Budge ◽  
Crystal L. Frost ◽  
Peter Neumann ◽  
Stefanos Siozios ◽  
...  
Keyword(s):  
Honey Bee ◽  
Horizontal Transmission ◽  
In Situ Hybridisation ◽  
Bacterial Symbionts ◽  
Free Living ◽  
Social Contacts ◽  
Obligate Mutualism ◽  
Metabolic Properties ◽  
Environmental Microbes

AbstractA dynamic continuum exists from free-living environmental microbes to strict host-associated symbionts that are vertically inherited. However, knowledge of the forces that drive transitions in symbiotic lifestyle and transmission mode is lacking. Arsenophonus is a diverse clade of bacterial symbionts, comprising reproductive parasites to coevolving obligate mutualists, in which the predominant mode of transmission is vertical. We describe a symbiosis between a member of the genus Arsenophonus and the Western honey bee. The symbiont shares common genomic and predicted metabolic properties with the male-killing symbiont Arsenophonus nasoniae, however we present multiple lines of evidence that the bee Arsenophonus deviates from a heritable model of transmission. Field sampling uncovered spatial and seasonal dynamics in symbiont prevalence, and rapid infection loss events were observed in field colonies and laboratory individuals. Fluorescent in situ hybridisation showed Arsenophonus localised in the gut, and detection was rare in screens of early honey bee life stages. We directly show horizontal transmission of Arsenophonus between bees under varying social conditions. We conclude that honey bees acquire Arsenophonus through a combination of environmental exposure and social contacts. These findings uncover a key link in the Arsenophonus clades trajectory from free-living ancestral life to obligate mutualism, and provide a foundation for studying transitions in symbiotic lifestyle.

scholarly journals A complex symbiosis involving within species variation in the response ofDictyosteliumamoebae toBurkholderiabacteria

2018 ◽  
Author(s):  
Longfei Shu ◽  
Debra A. Brock ◽  
Katherine S. Geista ◽  
Jacob W. Miller ◽  
David C. Queller ◽  
...  
Keyword(s):  
Dictyostelium Discoideum ◽  
Species Variation ◽  
Bacterial Symbionts ◽  
Disease Dynamics ◽  
Fitness Costs ◽  
Social Amoeba ◽  
Host Fitness ◽  
Symbiont Type ◽  
The Social

AbstractRecent symbioses, particularly facultative ones, are well suited for unravelling the evolutionary give and take between partners. Here we look at variation in wild-collected samples of the social amoebaDictyostelium discoideumand their relationships with bacterial symbionts,Burkholderia hayleyellaandBurkholderia agricolaris. Only about a third of field-collected amoebae carry a symbiont. We cured and cross-infectedD. discoideumhosts with different symbiont association histories and then compared the responses of the amoebae to each symbiont type. Before curing, field-collected clones did not vary significantly in overall fitness, but infected hosts produced morphologically different multicellular structures. After curing and re-infecting, host fitness declined overall. However, naturalB. hayleyellahosts suffered fewer fitness costs when re-infected withB. hayleyella,indicating that they have evolved mechanisms to tolerate their naturally acquired symbiont. Exploring relationships between endosymbionts and hosts that vary within species may also reveal much about disease dynamics.

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