scholarly journals Role of the Andean uplift as an asymmetrical barrier to gene flow in the neotropical leaf‐cutting ant Atta cephalotes

Biotropica ◽  
2021 ◽  
Author(s):  
Vanessa Muñoz‐Valencia ◽  
Glever Alexander Vélez‐Matínez ◽  
James Montoya‐Lerma ◽  
Fernando Díaz
Keyword(s):  
Gene Flow ◽  
Atta Cephalotes ◽  
Andean Uplift ◽  
Leaf Cutting

scholarly journals The role of the Andean uplift as an asymmetrical barrier to gene flow in the Neotropical leaf-cutting ant Atta cephalotes

2021 ◽  
Author(s):  
Vanessa Muñoz-Valencia ◽  
Glever Alexander Velez-Matinez ◽  
James Montoya-Lerma ◽  
Fernando Diaz
Keyword(s):  
Gene Flow ◽  
South America ◽  
Management Strategies ◽  
Atta Cephalotes ◽  
Geographical Barrier ◽  
History Of ◽  
Andean Uplift ◽  
Leaf Cutting ◽  
And Migration

Neotropical diversification by the Andean uplift is typically addressed on a large evolutionary scale (e.g. speciation), even though many species are still distributed in both sides of the mountains. The three parallel mountain ranges in the northern Andes (Colombia) impose a major geographical barrier to species' migration from South to Central America. How important these barriers are for conspecific diversification of cross-Andean species such as the leaf-cutting ants remains largely unknown. To answer this question, we studied the mtCOI gene of Atta cephalotes, the most widely distributed leaf-cutting ant species. Our hierarchical analyzes evidenced substantial genetic structure among regions and populations, suggesting a more complex biogeographical history of Andean populations than previously thought. These mountains seem to isolate Central American and Western Colombian populations from the rest of A. cephalotes in South America. Population and migration modelling are consistent with the origin of this species in South America and a major role of the Eastern cordillera as a geographical barrier to historical gene flow, restricting dispersion from north to south. These findings provide insights into the role of the Andean uplift as barrier to gene flow and, eventually, implications for monitoring and designing management strategies for leaf-cutting ants.

scholarly journals Immunity and survival response of Atta cephalotes (Hymenoptera: Myrmicinae) workers to Metarhizium anisopliae infection: Potential role of their associated microbiota

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247545
Author(s):  
Sandra Milena Valencia-Giraldo ◽  
Andrea Niño-Castro ◽  
Andrea López-Peña ◽  
Danna Trejos-Vidal ◽  
Odair Correa-Bueno ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Potential Role ◽  
Atta Cephalotes ◽  
Multiple Parameters ◽  
Defensive Role ◽  
Bacterial Microbiota ◽  
Bacterial Microbiome ◽  
Leaf Cutting ◽  
The Individual

Leaf-cutting ants of the genera Atta and Acromyrmex are at constant risk of epizootics due to their dense living conditions and frequent social interactions between genetically related individuals. To help mitigate the risk of epizootics, these ants display individual and collective immune responses, including associations with symbiotic bacteria that can enhance their resistance to pathogenic infections. For example, Acromyrmex spp. harbor actinobacteria that control infection by Escovopsis in their fungal gardens. Although Atta spp. do not maintain symbiosis with protective actinobacteria, the evidence suggests that these insects are colonized by bacterial microbiota that may play a role in their defense against pathogens. The potential role of the bacterial microbiome of Atta workers in enhancing host immunity remains unexplored. We evaluated multiple parameters of the individual immunity of Atta cephalotes (Linnaeus, 1758) workers, including hemocyte count, encapsulation response, and the antimicrobial activity of the hemolymph in the presence or absence of bacterial microbiota. Experiments were performed on ants reared under standard conditions as well as on ants previously exposed to the entomopathogenic fungus Metharrizium anisopliae. Furthermore, the effects of the presence/absence of bacteria on the survival of workers exposed to M. anisopliae were evaluated. The bacterial microbiota associated with A. cephalotes workers does not modulate the number of hemocytes under control conditions or under conditions of exposure to the fungal pathogen. In addition, infection by M. anisopliae, but not microbiota, increases the encapsulation response. Similarly, the exposure of workers to this fungus led to increased hemolymph antimicrobial activity. Conversely, the removal of bacterial microbiota did not have a significant impact on the survival of workers with M. anisopliae. Our results suggest that the bacterial microbiota associated with the cuticle of A. cephalotes workers does not play a role as a modulator of innate immunity, either at baseline or after exposure to the entomopathogen M. anisopliae. Further, upon infection, workers rely on mechanisms of humoral immunity to respond to this threat. Overall, our findings indicate that the bacterial microbiota associated with A. cephalotes workers does not play a defensive role.

scholarly journals Impact of Bee Species and Plant Density on Alfalfa Pollination and Potential for Gene Flow

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Johanne Brunet ◽  
Christy M. Stewart
Keyword(s):  
Gene Flow ◽  
Seed Production ◽  
Plant Density ◽  
Bumble Bee ◽  
Solitary Bee ◽  
Relative Contribution ◽  
Transgene Escape ◽  
Alfalfa Seed ◽  
Leaf Cutting

In outcrossing crops like alfalfa, various bee species can contribute to pollination and gene flow in seed production fields. With the increasing use of transgenic crops, it becomes important to determine the role of these distinct pollinators on alfalfa pollination and gene flow. The current study examines the relative contribution of honeybees, three bumble bee species, and three solitary bee species to pollination and gene flow in alfalfa. Two wild solitary bee species and one wild bumble bee species were best at tripping flowers, while the two managed pollinators commonly used in alfalfa seed production, honeybees and leaf cutting bees, had the lowest tripping rate. Honeybees had the greatest potential for gene flow and risk of transgene escape relative to the other pollinators. For honeybees, gene flow and risk of transgene escape were not affected by plant density although for the three bumble bee species gene flow and risk of transgene escape were the greatest in high-density fields.

Traffic Dynamics of the Leaf-Cutting Ant, Atta cephalotes

2002 ◽  
Vol 159 (3) ◽  
pp. 283
Author(s):  
Burd ◽  
Archer ◽  
Aranwela ◽  
Stradling
Keyword(s):  
Atta Cephalotes ◽  
Traffic Dynamics ◽  
Leaf Cutting

scholarly journals Premating barriers in young sympatric snail species

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Arina L. Maltseva ◽  
Marina A. Varfolomeeva ◽  
Arseniy A. Lobov ◽  
Polina O. Tikanova ◽  
Egor A. Repkin ◽  
...  
Keyword(s):  
Gene Flow ◽  
Snail Species ◽  
Sympatric Populations ◽  
Gastropod Species ◽  
Shell Size ◽  
Closely Related Species ◽  
Partial Canonical Correspondence Analysis ◽  
In The Wild ◽  
Isolation Index

AbstractSympatric coexistence of recently diverged species raises the question of barriers restricting the gene flow between them. Reproductive isolation may be implemented at several levels, and the weakening of some, e.g. premating, barriers may require the strengthening of the others, e.g. postcopulatory ones. We analysed mating patterns and shell size of mates in recently diverged closely related species of the subgenus Littorina Neritrema (Littorinidae, Caenogastropoda) in order to assess the role of premating reproductive barriers between them. We compared mating frequencies observed in the wild with those expected based on relative densities using partial canonical correspondence analysis. We introduced the fidelity index (FI) to estimate the relative accuracy of mating with conspecific females and precopulatory isolation index (IPC) to characterize the strength of premating barriers. The species under study, with the exception of L. arcana, clearly demonstrated preferential mating with conspecifics. According to FI and IPC, L. fabalis and L. compressa appeared reliably isolated from their closest relatives within Neritrema. Individuals of these two species tend to be smaller than those of the others, highlighting the importance of shell size changes in gastropod species divergence. L. arcana males were often found in pairs with L. saxatilis females, and no interspecific size differences were revealed in this sibling species pair. We discuss the lack of discriminative mate choice in the sympatric populations of L. arcana and L. saxatilis, and possible additional mechanisms restricting gene flow between them.

Rates of growth of the food fungus of the leaf-cutting ant Atta cephalotes (L.) (Hymenoptera: Formicidae) on different substrates gathered by the ants

1979 ◽  
Vol 69 (1) ◽  
pp. 141-148 ◽  
Author(s):  
A. Mudd ◽  
G. L. Bateman
Keyword(s):  
Nutrient Availability ◽  
Plant Material ◽  
Growth Inhibitors ◽  
Atta Cephalotes ◽  
Leaf Extracts ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Foraging Preferences ◽  
Leaf Cutting ◽  
Rates Of Growth

AbstractGrowth of the food fungus of the leaf-cutting ant Atta cephalotes (L.) on extracts of plants selected by the ants was shown to be affected by the plant species, the pH of the extract, the concentration of the sap or plant extract and pretreatment of the substrate by the ants. It was not possible to establish an unambiguous relationship between the rate of growth of the fungus on leaf extracts and the foraging preferences of the ants for the leaves. There were indications, however, that the fungus grows most rapidly on extracts of plant material preferred by A. cephalotes. Relative growth rates of the fungus on different substrates may be related to the presence of growth inhibitors rather than to nutrient availability.

scholarly journals Molecular Signatures of Reticulate Evolution within the Complex of European Pine Taxa

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 489
Author(s):  
Bartosz Łabiszak ◽  
Witold Wachowiak
Keyword(s):  
Gene Flow ◽  
Reticulate Evolution ◽  
Modeling Framework ◽  
Closely Related Species ◽  
Interspecific Gene Flow ◽  
Nucleotide Sequence Variation ◽  
History Of ◽  
Best Fitting ◽  
Species Integrity

Speciation mechanisms, including the role of interspecific gene flow and introgression in the emergence of new species, are the major focus of evolutionary studies. Inference of taxonomic relationship between closely related species may be challenged by past hybridization events, but at the same time, it may provide new knowledge about mechanisms responsible for the maintenance of species integrity despite interspecific gene flow. Here, using nucleotide sequence variation and utilizing a coalescent modeling framework, we tested the role of hybridization and introgression in the evolutionary history of closely related pine taxa from the Pinus mugo complex and P. sylvestris. We compared the patterns of polymorphism and divergence between taxa and found a great overlap of neutral variation within the P. mugo complex. Our phylogeny reconstruction indicated multiple instances of reticulation events in the past, suggesting an important role of interspecific gene flow in the species divergence. The best-fitting model revealed P. mugo and P. uncinata as sister species with basal P. uliginosa and asymmetric migration between all investigated species after their divergence. The magnitude of interspecies gene flow differed greatly, and it was consistently stronger from representatives of P. mugo complex to P. sylvestris than in the opposite direction. The results indicate the prominent role of reticulation evolution in those forest trees and provide a genetic framework to study species integrity maintained by selection and local adaptation.

Introgression between non-sister species of honeyeaters (Aves: Meliphagidae) several million years after speciation

2019 ◽  
Vol 128 (3) ◽  
pp. 583-591
Author(s):  
Leo Joseph ◽  
Alex Drew ◽  
Ian J Mason ◽  
Jeffrey L Peters
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sex Chromosomes ◽  
Common Ancestor ◽  
Sister Species ◽  
Species Boundaries ◽  
North Eastern ◽  
The City

Abstract We reassessed whether two parapatric non-sister Australian honeyeater species (Aves: Meliphagidae), varied and mangrove honeyeaters (Gavicalis versicolor and G. fasciogularis, respectively), that diverged from a common ancestor c. 2.5 Mya intergrade in the Townsville area of north-eastern Queensland. Consistent with a previous specimen-based study, by using genomics methods we show one-way gene flow for autosomal but not Z-linked markers from varied into mangrove honeyeaters. Introgression barely extends south of the area of parapatry in and around the city of Townsville. While demonstrating the long-term porosity of species boundaries over several million years, our data also suggest a clear role of sex chromosomes in maintaining reproductive isolation.

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