scholarly journals Does Drosophila sechellia escape parasitoid attack by feeding on a toxic resource?

2020 ◽  
Author(s):  
Laura Salazar-Jaramillo ◽  
Bregje Wertheim
Keyword(s):  
Field Survey ◽  
Immunological Response ◽  
Morinda Citrifolia ◽  
Ecological Interactions ◽  
Closely Related Species ◽  
Host Shifts ◽  
Selective Pressures ◽  
Drosophila Sechellia ◽  
Seychelles Islands ◽  
Melanotic Encapsulation

ABSTRACTHost shifts can drastically change the selective pressures that animals experience from their environment. Drosophila sechellia is a species restricted to the Seychelles islands, where it specialized on the fruit Morinda citrifolia (noni). This fruit is known to be toxic to closely related Drosophila species, including D. melanogaster and D. simulans, releasing D. sechellia from interspecific competition when breeding on this substrate. Previously, we showed that D. sechellia is unable to mount an effective immunological response against wasp attack, while the closely-related species can defend themselves from parasitoid attack by melanotic encapsulation. We hypothesized that this inability constitutes a trait loss due to a reduced risk of parasitoid attack in noni. Here we present a field study aimed to test the hypothesis that specialization on noni has released D. sechellia from the antagonistic interaction with its larval parasitoids. Our results from the field survey indicate that D. sechellia was found in ripe noni, whereas another Drosophila species, D. malerkotliana, was present in unripe and rotting stages. Parasitic wasps of the species Leptopilina boulardi emerged from rotten noni, where D. malerkotliana was the most abundant host. These results indicate that the specialization of D. sechellia on noni has indeed drastically altered its ecological interactions, leading to a relaxation in the selection pressure to maintain parasitoid resistance.

scholarly journals Does Drosophila sechellia escape parasitoid attack by feeding on a toxic resource?

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10528
Author(s):  
Laura Salazar-Jaramillo ◽  
Bregje Wertheim
Keyword(s):  
Field Survey ◽  
Immunological Response ◽  
Morinda Citrifolia ◽  
Ecological Interactions ◽  
Lab Experiment ◽  
Closely Related Species ◽  
Host Shifts ◽  
Drosophila Sechellia ◽  
Seychelles Islands ◽  
Melanotic Encapsulation

Host shifts can drastically change the selective pressures that animals experience from their environment. Drosophila sechellia is a species restricted to the Seychelles islands, where it specializes on the fruit Morinda citrifolia (noni). This fruit is known to be toxic to closely related Drosophila species, including D. melanogaster and D. simulans, releasing D. sechellia from interspecific competition when breeding on this substrate. Previously, we showed that larvae of D. sechellia are unable to mount an effective immunological response against wasp attack, while larvae of closely-related species can defend themselves from parasitoid attack by melanotic encapsulation. We hypothesized that this inability constitutes a trait loss due to a reduced risk of parasitoid attack in noni. Here we present a lab experiment and field survey aimed to test the hypothesis that specialization on noni has released D. sechellia from the antagonistic interaction with its larval parasitoids. Our results from the lab experiment suggest that noni may be harmful to parasitoid wasps. Our results from the field survey indicate that D. sechellia was found in ripe noni, whereas another Drosophila species, D. malerkotliana, was present in unripe and overripe stages. Parasitic wasps of the species Leptopilina boulardi emerged from overripe noni, where D. malerkotliana was the most abundant host, but not from ripe noni. These results indicate that the specialization of D. sechellia on noni has indeed drastically altered its ecological interactions, leading to a relaxation in the selection pressure to maintain parasitoid resistance.

scholarly journals The genetics of resistance to Morinda fruit toxin during the postembryonic stages in Drosophila sechellia

2015 ◽  
Author(s):  
Yan Huang ◽  
Deniz Erezyilmaz
Keyword(s):  
Host Plant ◽  
Genetic Basis ◽  
Octanoic Acid ◽  
Major Effect ◽  
Morinda Citrifolia ◽  
Host Plant Specialization ◽  
Drosophila Sechellia ◽  
Single Host ◽  
High Resolution Analysis ◽  
Resolution Analysis

Many phytophagous insect species are ecologic specialists that have adapted to utilize a single host plant. Drosophila sechellia is a specialist that utilizes the ripe fruit of Morinda citrifolia, which is toxic to its sibling species, D. simulans. Here we apply multiplexed shotgun genotyping and QTL analysis to examine the genetic basis of resistance to M. citrifolia fruit toxin in interspecific hybrids. We find that at least four dominant and four recessive loci interact additively to confer resistance to the M. citrifolia fruit toxin. These QTL include a dominant locus of large effect on the third chromosome (QTL-IIIsima) that was not detected in previous analyses. The small-effect loci that we identify overlap with regions that were identified in selection experiments with D. simulans on octanoic acid and in QTL analyses of adult resistance to octanoic acid. Our high-resolution analysis sheds new light upon the complexity of M. citrifolia resistance, and suggests that partial resistance to lower levels of M. citrifolia toxin could be passed through introgression from D. sechellia to D. simulans in nature. The identification of a locus of major effect, QTL-IIIsima, is an important step towards identifying the molecular basis of host plant specialization by D. sechellia.

scholarly journals Host shifts result in parallel genetic changes when viruses evolve in closely related species

2018 ◽  
Vol 14 (4) ◽  
pp. e1006951 ◽  
Author(s):  
Ben Longdon ◽  
Jonathan P. Day ◽  
Joel M. Alves ◽  
Sophia C. L. Smith ◽  
Thomas M. Houslay ◽  
...  
Keyword(s):  
Related Species ◽  
Closely Related Species ◽  
Genetic Changes ◽  
Host Shifts

scholarly journals Rock-paper-scissors: Engineered population dynamics increase genetic stability

Science ◽  
2019 ◽  
Vol 365 (6457) ◽  
pp. 1045-1049 ◽  
Author(s):  
Michael J. Liao ◽  
M. Omar Din ◽  
Lev Tsimring ◽  
Jeff Hasty
Keyword(s):  
Population Control ◽  
Single Cells ◽  
Fixation Time ◽  
Ecological Interactions ◽  
Gene Circuits ◽  
Selective Pressures ◽  
Complementary Approach ◽  
Common Strategy ◽  
The Stability ◽  
Engineered Bacteria

Advances in synthetic biology have led to an arsenal of proof-of-principle bacterial circuits that can be leveraged for applications ranging from therapeutics to bioproduction. A unifying challenge for most applications is the presence of selective pressures that lead to high mutation rates for engineered bacteria. A common strategy is to develop cloning technologies aimed at increasing the fixation time for deleterious mutations in single cells. We adopt a complementary approach that is guided by ecological interactions, whereby cyclical population control is engineered to stabilize the functionality of intracellular gene circuits. Three strains of Escherichia coli were designed such that each strain could kill or be killed by one of the other two strains. The resulting “rock-paper-scissors” dynamic demonstrates rapid cycling of strains in microfluidic devices and leads to an increase in the stability of gene circuit functionality in cell culture.

On the role of enemies in divergence and diversification of prey: a review and synthesis

2005 ◽  
Vol 83 (7) ◽  
pp. 894-910 ◽  
Author(s):  
Steven M Vamosi
Keyword(s):  
Visual Cues ◽  
Phenotypic Diversity ◽  
Theoretical Models ◽  
Ecological Interactions ◽  
Closely Related Species ◽  
Diversification Rates ◽  
Extinction Rates ◽  
Phenotypic Divergence ◽  
Experimental Approaches

Understanding the contribution of ecological interactions to the origin and maintenance of diversity is a fundamental challenge for ecologists and evolutionary biologists, and one that is currently receiving a great deal of attention. Natural enemies (e.g., predators, parasites, and herbivores) are ubiquitous in food webs and are predicted to have significant impacts on phenotypic diversity and on speciation, and extinction rates of their prey. Spurred by the development of a theoretical framework beginning in the late 1970s, there is now a growing body of literature that addresses the effects of enemy–prey interactions on the evolution of prey. A number of theoretical models predict that enemies can produce phenotypic divergence between closely related species, even in the absence of interspecific competition for resources. Effects on diversification of prey are more variable, and enemies may either enhance or depress speciation and extinction rates of their prey. Empirical evidences from a number of study systems, notably those involving predators and prey in aquatic environments and interactions between insects and flowering plants, confirm both predictions. There is now considerable evidence for the role of enemies, especially those that are size-selective or use visual cues when identifying suitable prey, on phenotypic divergence of sympatric and allopatric taxa. Enemies may spur diversification rates in certain groups under some circumstances, and hinder diversification rates in other cases. I suggest that further research should focus on the role of enemies in diversification of prey, with significant insights likely to be the product of applying traditional experimental approaches and emerging comparative phylogenetic methods.

Revision, phylogeny and natural history of Cotithene Voss (Coleoptera: Curculionidae)

Zootaxa ◽  
2008 ◽  
Vol 1782 (1) ◽  
pp. 1 ◽  
Author(s):  
NICO M. FRANZ
Keyword(s):  
Costa Rica ◽  
Natural History ◽  
Morphological Traits ◽  
Anterior Margin ◽  
Narrow Range ◽  
Cladistic Analysis ◽  
Morphological Characters ◽  
Closely Related Species ◽  
Host Shifts ◽  
History Of

Cotithene Voss, a previously monotypic genus of Neotropical derelomine flower weevils (Curculionidae: Derelomini), is revised, with provision of a key to the species, cladistic analysis and notes on its natural history. The following six new species are described: C. anaphalanta (Costa Rica), C. dicranopygia (Costa Rica), C. leptorhamphis (Costa Rica, Panama), C. melanoptera (Venezuela), C. stratiotricha (Costa Rica) and C. trigaea (Costa Rica). The monophyly of Cotithene is supported by the characters of a dorsomedially expanded, carinate rostrum, ventrally angulate head, long and anteriorly directed setation on the anterior margin of the prosternum and an apicodorsally expanded aedeagus with paired sclerites in the male, and subcontiguous to separated procoxal cavities in the female. Particularly the males of several species have intriguing and allometrically scaled modifications on the head (triangular projections, long setae) and pronotum (expansion, tumescences), which possibly play a role in male-to-male conflicts. Cotithene species are specialized to visit and reproduce on a narrow range of typically closely related species of Cyclanthaceae. The adults do not function as pollinators, and the herbivorous larvae develop in the fruiting organs of their hosts, frequently triggering the abortion of infructescences. An analysis of 12 taxa (5 outgroup, 7 ingroup) and 32 morphological characters yielded a single most parsimonious cladogram (L = 38, CI = 89, RI = 93) with the topology (C. dicranopygia, (C. stratiotricha, ((C. leptorhamphis, C. trigaea), (C. globulicollis Voss, (C. anaphalanta, C. melanoptera))))). The evolution of morphological traits and host shifts is examined in light of the proposed phylogeny.

scholarly journals The genetic basis of larval resistance to a host plant toxin in Drosophila sechellia

2001 ◽  
Vol 78 (3) ◽  
pp. 225-233 ◽  
Author(s):  
CORBIN D. JONES
Keyword(s):  
Host Plant ◽  
Genetic Basis ◽  
Octanoic Acid ◽  
Morinda Citrifolia ◽  
Fourth Chromosome ◽  
Plant Toxin ◽  
Factors Affecting ◽  
Resistance Factors ◽  
Drosophila Sechellia ◽  
Close Relatives

The larvae of Drosophila sechellia are highly resistant to octanoic acid, a toxin found in D. sechellia's host plant, Morinda citrifolia. In contrast, close relatives of D. sechellia, D. simulans and D. melanogaster, are not resistant. In a series of interspecific backcrosses, 11 genetic markers were used to map factors affecting egg-to-adult (‘larval’) resistance in D. sechellia. The third chromosome harbours at least one partially dominant resistance factor. The second chromosome carries at least two mostly dominant resistance factors but no recessive factors. However, neither the X chromosome – which contains 20% of D. sechellia's genome – nor the fourth chromosome appear to affect resistance. These data suggest that larval resistance to Morinda toxin may involve only a handful of genes. These results, when compared with a previous analysis of adult resistance to Morinda toxin in D. sechellia, suggest that larval resistance may involve a subset of the genes underlying adult resistance.

scholarly journals A potential role for the gut microbiota in the specialisation of Drosophila sechellia to its toxic host noni (Morinda citrifolia)

2019 ◽  
Author(s):  
Chloe Heys ◽  
Adam M Fisher ◽  
Andrea D Dewhurst ◽  
Zenobia Lewis ◽  
Anne Lize
Keyword(s):  
Gut Microbiota ◽  
Host Plant ◽  
Lactobacillus Plantarum ◽  
Potential Role ◽  
Octanoic Acid ◽  
Acid Resistance ◽  
Morinda Citrifolia ◽  
Risk Of Death ◽  
Drosophila Sechellia ◽  
Series Of Experiments

Adaptation to a novel food source can have significant evolutionary advantages. The fruit fly, Drosophila sechellia, is a specialist of the toxic plant noni (Morinda citrifolia). Little is known as to how D. sechellia has become resistant to the toxins in the fruit - comprised predominantly of octanoic acid - but to date, the behavioural preferences for the fruit and genetic architecture underlying them, have been well studied. Here, we examine whether the gut microbiota could have played a role in adaptation to the fruit. In the first series of experiments, we examine the gut microbiota of wild-type, laboratory reared flies and characterise the gut microbiota when reared on the natural host plant, versus a standard Drosophila diet. We show a rapid transition in the core bacterial diversity and abundance within this species and discover sole precedence of Lactobacillus plantarum when reared on M. citrifolia. We also discover that flies reared on a laboratory diet are more likely to carry bacterial pathogens such as Bacillus cereus, although their function in Drosophila is unknown. Flies reared on a laboratory diet have a significantly reduced weight but with no impact on the risk of death before adulthood, when compared to the wild noni diet. In the second series of experiments, we examine the potential role of the gut microbiota in adaptation to octanoic acid resistance in this species and its sister species, Drosophila melanogaster, to which the fruit is usually fatal. We use a combination of methods to analyse resistance to octanoic acid by conducting life history analysis, behavioural assays and bacterial analysis in both D. sechellia and D. melanogaster. We find that by creating experimental evolution lines of D. melanogaster supplemented with gut microbiota from D. sechellia, we can decrease D. melanogaster aversion to octanoic acid, with the flies even preferring to feed on food supplemented with the acid. We suggest this represents the first step in the evolutionary and ecological specialisation of D. sechellia to its toxic host plant, and that the gut microbiota, Lactobacillus plantarum in particular, may have played a key role in host specialisation.

scholarly journals Recent host-shifts in ranaviruses: signatures of positive selection in the viral genome

2013 ◽  
Vol 94 (9) ◽  
pp. 2082-2093 ◽  
Author(s):  
A. Jeanine Abrams ◽  
David C. Cannatella ◽  
David M. Hillis ◽  
Sara L. Sawyer
Keyword(s):  
Positive Selection ◽  
Synonymous Substitution ◽  
Detection Methods ◽  
Host Switching ◽  
Synonymous Substitution Rate ◽  
Host Shifts ◽  
Selective Pressures ◽  
The Family ◽  
Viral Genes ◽  
Core Genes

Ranaviruses have been implicated in recent declines in global amphibian populations. Compared with the family Iridoviridae, to which the genus Ranavirus belongs, ranaviruses have a wide host range in that species/strains are known to infect fish, amphibians and reptiles, presumably due to recent host-switching events. We used eight sequenced ranavirus genomes and two selection-detection methods (site based and branch based) to identify genes that exhibited signatures of positive selection, potentially due to the selective pressures at play during host switching. We found evidence of positive selection acting on four genes via the site-based method, three of which were newly acquired genes unique to ranavirus genomes. Using the branch-based method, we identified eight additional candidate genes that exhibited signatures of dN /dS (non-synonymous/synonymous substitution rate) >1 in the clade where intense host switching had occurred. We found that these branch-specific patterns of elevated dN /dS were enriched in a small group of viral genes that have been acquired most recently in the ranavirus genome, compared with core genes that are shared among all members of the family Iridoviridae. Our results suggest that the group of newly acquired genes in the ranavirus genome may have undergone recent adaptive changes that have facilitated interspecies and interclass host switching.

scholarly journals Host shifts result in parallel genetic changes when viruses evolve in closely related species

2017 ◽  
Author(s):  
Ben Longdon ◽  
Jonathan P Day ◽  
Joel M Alves ◽  
Sophia CL Smith ◽  
Thomas M Houslay ◽  
...  
Keyword(s):  
Host Species ◽  
Related Species ◽  
Rna Virus ◽  
Parallel Evolution ◽  
Emerging Infectious Diseases ◽  
New Host ◽  
Closely Related Species ◽  
Genetic Changes ◽  
Host Shifts ◽  
Novel Host

AbstractHost shifts, where a pathogen invades and establishes in a new host species, are a major source of emerging infectious diseases. They frequently occur between related host species and often rely on the pathogen evolving adaptations that increase their fitness in the novel host species. To investigate genetic changes in novel hosts, we experimentally evolved replicate lineages of an RNA virus (Drosophila C Virus) in 19 different species of Drosophilidae and deep sequenced the viral genomes. We found a strong pattern of parallel evolution, where viral lineages from the same host were genetically more similar to each other than to lineages from other host species. When we compared viruses that had evolved in different host species, we found that parallel genetic changes were more likely to occur if the two host species were closely related. This suggests that when a virus adapts to one host it might also become better adapted to closely related host species. This may explain in part why host shifts tend to occur between related species, and may mean that when a new pathogen appears in a given species, closely related species may become vulnerable to the new disease.

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