scholarly journals Comparative demography elucidates the longevity of parasitic and symbiotic relationships

2018 ◽  
Author(s):  
Luke B.B. Hecht ◽  
Peter C. Thompson ◽  
Benjamin M. Rosenthal
Keyword(s):  
Trichinella Spiralis ◽  
Mosquito Vector ◽  
Potato Blight ◽  
Aiptasia Pallida ◽  
Symbiotic Relationships ◽  
Ecological Relationships ◽  
Energy Flows ◽  
Algal Symbiont ◽  
Comparative Demography ◽  
History Of

AbstractParasitic and symbiotic relationships govern vast nutrient and energy flows1,2, but controversy surrounds their longevity. Enduring relationships may engender parallel phylogenies among hosts and parasites3,4, but so may more ephemeral relationships when parasites disproportionately colonize related hosts5. When considering these relationships’ temporal durability, it would be useful to understand whether parasite and host populations have grown and contracted in concert. Here, we devised methods to compare demographic histories, derived from genomic data6. We used these methods to compare the historical growth of the agent of severe human malaria, Plasmodium falciparum, to human and primate histories7,8 and to that of their mosquito vector Anopheles gambiae9, thereby discerning long-term parallels and anthropogenic population explosions10,11. The growth history of Trichinella spiralis, a zoonotic parasite disseminated by swine domestication12,13, proved regionally-specific, paralleling distinctive growth histories for wild boar in Asia and Europe14. Parallel histories were inferred for an anemone and its algal symbiont (Aiptasia pallida15 and Symbiodinium minutum16). Concerted growth in potatoes and the agent of potato blight (Solanum tuberosum17 and Phytophthora infestans18) did not commence until the age of potato domestication, helping date the acquisition of this historically consequential fungal plant pathogen. Therefore, comparative historical demography provides a powerful new means by which to interrogate the history of myriad ecological relationships, enriching our understanding of their origins and durability.

scholarly journals Comparative demography elucidates the longevity of parasitic and symbiotic relationships

2018 ◽  
Vol 285 (1888) ◽  
pp. 20181032 ◽  
Author(s):  
Luke B. B. Hecht ◽  
Peter C. Thompson ◽  
Benjamin M. Rosenthal
Keyword(s):  
Trichinella Spiralis ◽  
Demographic History ◽  
Mosquito Vector ◽  
Potato Blight ◽  
Symbiotic Relationships ◽  
Ecological Relationships ◽  
Energy Flows ◽  
Algal Symbiont ◽  
Comparative Demography ◽  
History Of

Parasitic and symbiotic relationships govern vast nutrient and energy flows, yet controversy surrounds their longevity. Enduring relationships may engender parallel phylogenies among hosts and parasites, but so may ephemeral relationships when parasites colonize related hosts. An understanding of whether symbiont and host populations have grown and contracted in concert would be useful when considering the temporal durability of these relationships. Here, we devised methods to compare demographic histories derived from genomic data. We compared the historical growth of the agent of severe human malaria, Plasmodium falciparum , and its mosquito vector, Anopheles gambiae , to human and primate histories, thereby discerning long-term parallels and anthropogenic population explosions. The growth history of Trichinella spiralis , a zoonotic parasite disseminated by swine, proved regionally specific, paralleling distinctive growth histories for wild boar in Asia and Europe. Parallel histories were inferred for an anemone and its algal symbiont ( Exaiptasia pallida and Symbiodinium minutum ). Concerted growth in potatoes and the agent of potato blight ( Solanum tuberosum and Phytophthora infestans ) did not commence until the age of potato domestication. Through these examples, we illustrate the utility of comparative historical demography as a new exploratory tool by which to interrogate the origins and durability of myriad ecological relationships. To facilitate future use of this approach, we introduce a tool called C-PSMC to align and evaluate the similarity of demographic history curves.

scholarly journals Molecular Analysis of Targeted Insecticide Resistance Gene Mutations in Field-Caught Mosquitos of Medical Importance From Saudi Arabia

2021 ◽  
Author(s):  
Yuan Fang ◽  
Ernest Tambo ◽  
Jing-Bo Xue ◽  
Yi Zhang ◽  
Xiao-Nong Zhou ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Insecticide Resistance ◽  
Resistance Gene ◽  
Phylogenetic Analyses ◽  
Gene Mutations ◽  
Mosquito Vector ◽  
Dengue Disease ◽  
The Status ◽  
History Of ◽  
Exon 20

Abstract Gene mutations on target sites can be a valuable indicator of the status of insecticide resistance. Jeddah, a global commercial and major port-of-entry city, is bearing the brunt of dengue disease burden in Saudi Arabia. In the current study, six genotypes of three codon combinations (989, 1016, and 1534) were observed on voltage-gated sodium channel (VGSC) gene in Jeddah’s Aedes aegypti population, with PGF/PGC as the dominant one. Two types of introns between exon 20 and 21 on VGSC have been identified for the first time in Ae. aegypti in Saudi Arabia. Statistical and phylogenetic analyses showed that the intron type was significantly associated with the 1016 allele and may reflect the history of insecticide treatment in different continents. In addition, fixation of the L1014F allele on VGSC and G119S on acetylcholinesterase 1 gene was detected in local Culex quinquefasciatus populations, with frequencies of 95.24 and 100%, respectively. To the best of our knowledge, this is the first report of resistant-associated mutations in field-caught Cx. quinquefasciatus in Saudi Arabia. The high prevalence of insecticide resistance gene mutations in local primary mosquito vector species highlights the urgent need to carry out comprehensive insecticide resistance surveillance in Saudi Arabia.

Symbiotic relationships between worms and solitary rugose corals in the Late Ordovician

Paleobiology ◽  
1986 ◽  
Vol 12 (1) ◽  
pp. 32-45 ◽  
Author(s):  
Robert J. Elias
Keyword(s):  
North American ◽  
Direct Evidence ◽  
Indirect Evidence ◽  
Late Ordovician ◽  
Physical Contact ◽  
Taxonomic Affinity ◽  
External Wall ◽  
Symbiotic Relationships ◽  
Rugose Corals ◽  
History Of

Symbiotic relationships involving physical contact between worms and solitary rugosan polyps are recorded by the following structures in North American Late Ordovician corals: (1) Trypanites borings enclosed within septal swellings in two specimens, (2) vermiform grooves and openings along the external wall of one corallum, and (3) a chamber containing a unique brown tube within one individual. These features are indicative, respectively, of commensal boring polychaete annelids that penetrated through coralla, commensal epizoic worms of unknown taxonomic affinity that attached to the side of a polyp, and a tubicolous worm (possibly a polychaete) that was likely a parasitic endozoan. Symbionts comparable to the latter two types are also known from two specimens of Devonian solitary rugose corals.Indirect evidence suggests that symbioses between solitary rugosans and the worms that produced Trypanites borings as dwelling structures in the sides of coralla were relatively common. However, direct evidence that the hosts were alive has been found in only two corals. In both cases, worms bored through septa within the calices and came into contact with basal surfaces of the polyps, which secreted skeletal material that sealed off the intruders. The rarity of such structures suggests that the encounters were inadvertent. If boring worms favored upcurrent portions of objects in order to maximize feeding benefits and avoid sedimentation, their locations indicate that the concave sides of curved coralla faced toward prevailing currents when in life positions.“Opportunistic” worms are known to have attached to the sides of polyps only in rare instances when the hosts became temporarily exposed as a result of accidents or abnormalities. This indicates that coralla normally served to shield polyps from colonization by nonboring epizoans.Worms that apparently extended up through openings in basal surfaces of polyps likely obtained sustenance parasitically within the central cavities. They could have entered the hosts through their mouths, or via the calices when parts of the polyps detached from their coralla and contracted radially. The rarity of this type of relationship in solitary Rugosa suggests that the worms entered inadvertently.Symbioses involving physical contact between worms and polyps seem to have been rare throughout the history of solitary rugose corals. Both groups apparently tolerated such associations when they did occur, although the rugosans secreted structures in their coralla that served to isolate the symbionts. In doing so, they recorded the presence of worms not likely to be preserved as body fossils. The interpretation of such features provides information on the physiology and ethology of both organisms, on the history of symbiotic relationships, and on the diversity of soft-bodied organisms in ancient environments.

scholarly journals The rediscovery of the Red-tailed Newtonia Newtonia fanovanae in south-eastern Madagascar with notes on the natural history of the genus Newtonia

1991 ◽  
Vol 1 (1) ◽  
pp. 33-45 ◽  
Author(s):  
Steven M. Goodman ◽  
Thomas S. Schulenberg
Keyword(s):  
Natural History ◽  
Sympatric Species ◽  
The Other ◽  
Single Specimen ◽  
The South ◽  
Humid Forest ◽  
Ecological Relationships ◽  
South Eastern ◽  
History Of ◽  
Morphological Differences

SummaryThe Red-tailed Newtonia Newtonia fanovanae, previously known from a single specimen from the eastern rainforest of central Madagascar, was rediscovered in October 1989 in the Marosohy Forest in the south-east of the island. In the study area, N. fanovanae occurs in the middle and upper section of the canopy of humid forest between 300 and 1,300 m. Ecological relationships with the other two sympatric Newtonia, amphichroa and brunneicauda, are discussed. The main morphological differences between fanovanae and the other two sympatric species are that the former has relatively long wings and short tarsi. The song of fanovanae is described and compared to other members of the genus. Our observations on the morphology, behaviour and vocalisations of N. fanovanae confirm its validity as a species.Le Newtonie à queue rouge Newtonia fanovanae jusqu'à presént uniquement connu d'un seul spécimen provenant de la partie orientale de la forêt tropicale du Madagascar central, fût redécouvert en octobre 1989 dans la forêt de Marosohy au sud-est de l'île. N. fanovanae fût rencontré dans les parties moyennes et supérieures du feuillage de la forêt humide entre 300 et 1,300 m d'altitude. Les relations écologiques avec les deux espèces sympatriques de Newtonia, amphichroa et brunneicauda sont discutées. Les différences morphologiques principales entre fanovanae et les deux espéces sympatriques sont que celle-ci a des ailes relativement longues et des tarses courts. Le chant de fanovanae est decrit et comparé avec celui d'autres membres du genre. Nos observations sur la morphologie, le comportement et les vocalizations de N. fanovanae confirment sa validité comme bonne espéce.

A History of Energy Flows

2019 ◽  
Author(s):  
Anthony N. Penna
Keyword(s):  
Energy Flows ◽  
History Of

THE USE OF VERSION SPACE CONTROLLED GENETIC ALGORITHMS TO SOLVE THE BOOLE PROBLEM

1993 ◽  
Vol 02 (02) ◽  
pp. 219-234 ◽  
Author(s):  
ROBERT G. REYNOLDS ◽  
JONATHAN I. MALETIC
Keyword(s):  
Genetic Algorithm ◽  
Genetic Algorithms ◽  
Decision Trees ◽  
General Framework ◽  
Performance History ◽  
New Members ◽  
Symbiotic Relationships ◽  
Version Space ◽  
History Of ◽  
Better Than

The Version Space Controlled Genetic Algorithms (VGA) uses the structure of the version space to cache generalizations about the performance history of chromosomes in the genetic algorithm. This cached experience is used to constrain the generation of new members of the genetic algorithms population. The VGA is shown to be a specific instantiation of a more general framework, Autonomous Learning Elements (ALE). The capabilities of the VGA system are demonstrated using the Boole problem suggested by Wilson [Wilson 1987]. The performance of the VGA is compared to that of decision trees and genetic algorithms. The results suggest that the VGA is able to exploit a certain set of symbiotic relationships between its components, so that the resulting system performs better than either component individually.

On the Life History of the Lungworm, Synthetocaulus abstrusus, hitherto confused with that of Ollulanus tricuspis in Cats

1926 ◽  
Vol 4 (2) ◽  
pp. 53-60 ◽  
Author(s):  
Thomas W. M. Cameron
Keyword(s):  
Life History ◽  
Intestinal Tract ◽  
Trichinella Spiralis ◽  
Posterior Extremity ◽  
Original Description ◽  
Domestic Cat ◽  
Internal Organs ◽  
Large Numbers ◽  
History Of ◽  
Enclosed Space

In 1865, Leuckart described from the stomach of the domestic cat, a minute bursate worm which he named Ollulanus tricuspis. His original description was somewhat scanty, but it was amplified in later years (1867–1876). As this work is scattered throughout many pages, the following is a brief resumé of Leuckart's theory.He was struck by the fact, that being viviparous in habit, it resembled Trichinella spiralis, but recognised that several fundamental differences existed between them. Ollulanus never produced more than three larvae at a time from relatively large eggs, about 60μ to 120μ long; whereas Trichinella produced numerous larvae with small eggs about 35μ long. He found what he believed were the free larvae of Ollulanus, which measured about 320μ long by 15μ wide, had a truncated oral extremity and a short tail which ended in a short S-shaped tip (Fig. 1, a). The oesophagus was between one third and one half of the total length of the intestine; several transparent vesicles could be seen at its clubshaped posterior extremity. Although there are seldom more than three embryos inside the female, larvae were usually, found in large numbers throughout the whole intestinal tract of the host, as well as encysted (in cysts ·15 to ·2 mm. in diameter) on various internal organs. The cyst wall had a connective tissue-like structure of such thickness that it might be three or four times the diameter of the enclosed space.

The Aerial Photography of Potato Blight Epidemics

1966 ◽  
Vol 70 (672) ◽  
pp. 1082-1086 ◽  
Author(s):  
G. H. Brenchley
Keyword(s):  
Aerial Photography ◽  
Full Potential ◽  
Potential Yield ◽  
Potato Blight ◽  
History Of ◽  
Improved Methods ◽  
Methods Of Application ◽  
Better Than ◽  
Growing Crop

In spite of more active fungicides and improved methods of application, including the use of aircraft, the control of potato blight is not very much better than it was thirty years ago. The basic weakness appears to be the impossibility of achieving and maintaining anything like a complete fungicide cover on the foliage of a growing crop of potatoes. In every season in which the weather favours the parasite a time comes when the number of blight spores is so great that many of the gaps in the fungicide defence cover are bound to be penetrated. Once a number of infections have thus been established in a crop, the progress of the disease is only a matter of time and weather, for each of the new infections normally becomes an ineradicable centre for further spread. If this diagnosis is essentially correct, the chances of major improvements in blight control with our present methods are small. It is therefore desirable to examine the history of blight epidemics in detail, to see if there is any possibility of delaying the build-up of the spore inoculum. This would give the protective fungicides a better chance of holding off the attack until the crop had produced its full potential yield.

The Sponge Family Guadalupiidae in the Texas Permian

2010 ◽  
Vol 84 (5) ◽  
pp. 821-847 ◽  
Author(s):  
Robert M. Finks
Keyword(s):  
Evolutionary History ◽  
Growth Patterns ◽  
New Genera ◽  
The West ◽  
Entire Family ◽  
Ecological Relationships ◽  
West Texas ◽  
The Family ◽  
History Of ◽  
Almost All

New and old species and genera of the family Guadalupiidae (spherulitic hypercalcified demosponges of the order Agelasida) are described or redescribed from the West Texas Permian. The entire family is reviewed and observations are made on the epibionts, growth patterns, functional morphology, ecological relationships, morphologic variability, modular structure, and evolutionary history of these largely reef-dwelling sponges. The stratigraphic distribution of species is also noted; many are limited and can define zones. The new genera Exovasa and Incisimura and the new species Guadalupia auricula, G. cupulosa, G. ramescens, G. microcamera, G. vasa, Cystothalamia megacysta, Lemonea simplex, Incisimura bella, and Exovasa cystauletoides are described. Almost all previously published taxa are redescribed and in some cases redefined. The Guadalupiidae are unique among hypercalcified sponges in having a modular thalamid layer (thalamidarium) covered on the exhalant surface by a non-modular stromatoporoid-like layer (trabecularium).

Ecology and natural history of the protochordates

2005 ◽  
Vol 83 (1) ◽  
pp. 34-50 ◽  
Author(s):  
Gretchen Lambert
Keyword(s):  
Natural History ◽  
New Caledonia ◽  
Feeding Strategies ◽  
Antarctic Species ◽  
Predator Prey ◽  
Marine Communities ◽  
Ecological Relationships ◽  
History Of ◽  
Nonself Recognition ◽  
Environmental Tolerances

The last comprehensive reviews of ecology and natural history of ascidians were included in the excellent 1971 publication by Millar on the biology of ascidians and the 1991 treatise on New Caledonia ascidians by Monniot, Monniot, and Laboute. Several hundred papers have been published since that time, greatly expanding our knowledge of environmental tolerances and responses to increasing levels of anthropogenically derived toxins in marine waters, energetics and feeding strategies, predator–prey relationships, competition both intra- and inter-specific that include many studies of self–nonself recognition in colonial species, modes and environmental regulation of reproduction and development, symbionts, natural-product chemistry as antifouling and antipredator defenses, and dispersal mechanisms. The relatively new field of molecular genetics is revealing the presence of cryptic species and is helping to determine the origin of anthropogenically transported individuals, an important and growing problem that affects natural ecological relationships in marine communities worldwide. We are learning more about the difficult-to-study abyssal and Antarctic species. There have been great advances in our understanding of the importance in open-ocean food webs of the planktonic Appendicularia and Thaliacea. Also included in this review is a brief discussion of recent work on the Cephalochordata and Hemichordata.

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