scholarly journals Parasites reduce food web robustness because they are sensitive to secondary extinction as illustrated by an invasive estuarine snail

2009 ◽  
Vol 364 (1524) ◽  
pp. 1659-1663 ◽  
Author(s):  
Kevin D. Lafferty ◽  
Armand M. Kuris
Keyword(s):  
Food Web ◽  
Trematode Species ◽  
Snail Species ◽  
Native Community ◽  
Free Living ◽  
Predator Prey ◽  
Living Species ◽  
Secondary Parasite ◽  
Disproportionate Number ◽  
Secondary Extinction

A robust food web is one in which few secondary extinctions occur after removing species. We investigated how parasites affected the robustness of the Carpinteria Salt Marsh food web by conducting random species removals and a hypothetical, but plausible, species invasion. Parasites were much more likely than free-living species to suffer secondary extinctions following the removal of a free-living species from the food web. For this reason, the food web was less robust with the inclusion of parasites. Removal of the horn snail, Cerithidea californica , resulted in a disproportionate number of secondary parasite extinctions. The exotic Japanese mud snail, Batillaria attramentaria , is the ecological analogue of the native California horn snail and can completely replace it following invasion. Owing to the similarities between the two snail species, the invasion had no effect on predator–prey interactions. However, because the native snail is host for 17 host-specific parasites, and the invader is host to only one, comparison of a food web that includes parasites showed significant effects of invasion on the native community. The hypothetical invasion also significantly reduced the connectance of the web because the loss of 17 native trematode species eliminated many links.

scholarly journals Untangling the roles of parasites in food webs with generative network models

2015 ◽  
Author(s):  
Abigail Z. Jacobs ◽  
Jennifer A. Dunne ◽  
Cristopher Moore ◽  
Aaron Clauset
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Statistical Physics ◽  
Network Models ◽  
Food Web Structure ◽  
Free Living ◽  
Web Structure ◽  
Living Species ◽  
Parasitic Interactions ◽  
The Impact

Food webs represent the set of consumer-resource interactions among a set of species that co-occur in a habitat, but most food web studies have omitted parasites and their interactions. Recent studies have provided conflicting evidence on whether including parasites changes food web structure, with some suggesting that parasitic interactions are structurally distinct from those among free-living species while others claim the opposite. Here, we describe a principled method for understanding food web structure that combines an efficient optimization algorithm from statistical physics called parallel tempering with a probabilistic generalization of the empirically well-supported food web niche model. This generative model approach allows us to rigorously estimate the degree to which interactions that involve parasites are statistically distinguishable from interactions among free-living species, whether parasite niches behave similarly to free-living niches, and the degree to which existing hypotheses about food web structure are naturally recovered. We apply this method to the well-studied Flensburg Fjord food web and show that while predation on parasites, concomitant predation of parasites, and parasitic intraguild trophic interactions are largely indistinguishable from free-living predation interactions, parasite-host interactions are different. These results provide a powerful new tool for evaluating the impact of classes of species and interactions on food web structure to shed new light on the roles of parasites in food webs.

scholarly journals A food web including parasites for kelp forests of the Santa Barbara Channel, California

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Dana N. Morton ◽  
Cristiana Y. Antonino ◽  
Farallon J. Broughton ◽  
Lauren N. Dykman ◽  
Armand M. Kuris ◽  
...  
Keyword(s):  
Food Web ◽  
Kelp Forest ◽  
Kelp Forests ◽  
Life Stages ◽  
Santa Barbara Channel ◽  
Santa Barbara ◽  
Free Living ◽  
Predator Prey ◽  
Research Questions ◽  
System Nodes

AbstractWe built a high-resolution topological food web for the kelp forests of the Santa Barbara Channel, California, USA that includes parasites and significantly improves resolution compared to previous webs. The 1,098 nodes and 21,956 links in the web describe an economically, socially, and ecologically vital system. Nodes are broken into life-stages, with 549 free-living life-stages (492 species from 21 Phyla) and 549 parasitic life-stages (450 species from 10 Phyla). Links represent three kinds of trophic interactions, with 9,352 predator-prey links, 2,733 parasite-host links and 9,871 predator-parasite links. All decisions for including nodes and links are documented, and extensive metadata in the node list allows users to filter the node list to suit their research questions. The kelp-forest food web is more species-rich than any other published food web with parasites, and it has the largest proportion of parasites. Our food web may be used to predict how kelp forests may respond to change, will advance our understanding of parasites in ecosystems, and fosters development of theory that incorporates large networks.

scholarly journals Biodiversity loss decreases parasite diversity: theory and patterns

2012 ◽  
Vol 367 (1604) ◽  
pp. 2814-2827 ◽  
Author(s):  
Kevin D. Lafferty
Keyword(s):  
Species Richness ◽  
Food Web ◽  
Biodiversity Loss ◽  
Parasite Diversity ◽  
Free Living ◽  
Parasite Richness ◽  
Living Species ◽  
Host Parasite ◽  
Food Web Complexity ◽  
The Relationship

Past models have suggested host–parasite coextinction could lead to linear, or concave down relationships between free-living species richness and parasite richness. I explored several models for the relationship between parasite richness and biodiversity loss. Life cycle complexity, low generality of parasites and sensitivity of hosts reduced the robustness of parasite species to the loss of free-living species diversity. Food-web complexity and the ordering of extinctions altered these relationships in unpredictable ways. Each disassembly of a food web resulted in a unique relationship between parasite richness and the richness of free-living species, because the extinction trajectory of parasites was sensitive to the order of extinctions of free-living species. However, the average of many disassemblies tended to approximate an analytical model. Parasites of specialist hosts and hosts higher on food chains were more likely to go extinct in food-web models. Furthermore, correlated extinctions between hosts and parasites (e.g. if parasites share a host with a specialist predator) led to steeper declines in parasite richness with biodiversity loss. In empirical food webs with random removals of free-living species, the relationship between free-living species richness and parasite richness was, on average, quasi-linear, suggesting biodiversity loss reduces parasite diversity more than previously thought.

scholarly journals Misinformation tactics protect rare birds from problem predators

2021 ◽  
Vol 7 (11) ◽  
pp. eabe4164
Author(s):  
Grant L. Norbury ◽  
Catherine J. Price ◽  
M. Cecilia Latham ◽  
Samantha J. Brown ◽  
A. David M. Latham ◽  
...  
Keyword(s):  
Decision Making ◽  
Threatened Species ◽  
Prey Availability ◽  
Free Living ◽  
Bird Populations ◽  
New Information ◽  
Mammalian Predators ◽  
Decision Making Processes ◽  
Living Species ◽  
Information Reliability

Efficient decision-making integrates previous experience with new information. Tactical use of misinformation can alter choice in humans. Whether misinformation affects decision-making in other free-living species, including problem species, is unknown. Here, we show that sensory misinformation tactics can reduce the impacts of predators on vulnerable bird populations as effectively as lethal control. We repeatedly exposed invasive mammalian predators to unprofitable bird odors for 5 weeks before native shorebirds arrived for nesting and for 8 weeks thereafter. Chick production increased 1.7-fold at odor-treated sites over 25 to 35 days, with doubled or tripled odds of successful hatching, resulting in a 127% increase in modeled population size in 25 years. We demonstrate that decision-making processes that respond to changes in information reliability are vulnerable to tactical manipulation by misinformation. Altering perceptions of prey availability offers an innovative, nonlethal approach to managing problem predators and improving conservation outcomes for threatened species.

scholarly journals Draft Genome Sequence of Piscirickettsia litoralis , Isolated from Seawater

2016 ◽  
Vol 4 (6) ◽  
Author(s):  
Xuehua Wan ◽  
Alex J. Lee ◽  
Shaobin Hou ◽  
Blake Ushijima ◽  
Yen P. Nguyen ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Draft Genome ◽  
Salmonid Fish ◽  
Draft Genome Sequence ◽  
Free Living ◽  
Living Species

One species of Piscirickettsia , a pathogen of salmonid fish, has been described. The genome sequence of a putative second and free-living species may provide insights into the evolution of pathogenicity in the genus.

scholarly journals What factors explain the geographical range of mammalian parasites?

2019 ◽  
Vol 286 (1903) ◽  
pp. 20190673 ◽  
Author(s):  
James E. Byers ◽  
J. P. Schmidt ◽  
Paula Pappalardo ◽  
Sarah E. Haas ◽  
Patrick R. Stephens
Keyword(s):  
Host Species ◽  
Parasite Species ◽  
Geographical Area ◽  
Complete Information ◽  
Sampling Effort ◽  
Free Living ◽  
Living Species ◽  
Habitat Breadth ◽  
Taxonomic Groups ◽  
Host Characteristics

Free-living species vary substantially in the extent of their spatial distributions. However, distributions of parasitic species have not been comprehensively compared in this context. We investigated which factors most influence the geographical extent of mammal parasites. Using the Global Mammal Parasite Database we analysed 17 818 individual geospatial records on 1806 parasite species (encompassing viruses, bacteria, protozoa, arthropods and helminths) that infect 396 carnivore, ungulate and primate host species. As a measure of the geographical extent of each parasite species we quantified the number and area of world ecoregions occupied by each. To evaluate the importance of variables influencing the summed area of ecoregions occupied by a parasite species, we used Bayesian network analysis of a subset ( n = 866) of the parasites in our database that had at least two host species and complete information on parasite traits. We found that parasites that covered more geographical area had a greater number of host species, higher average phylogenetic relatedness between host species and more sampling effort. Host and parasite taxonomic groups had weak and indirect effects on parasite ecoregion area; parasite transmission mode had virtually no effect. Mechanistically, a greater number of host species probably increases both the collective abundance and habitat breadth of hosts, providing more opportunities for a parasite to have an expansive range. Furthermore, even though mammals are one of the best-studied animal classes, the ecoregion area occupied by their parasites is strongly sensitive to sampling effort, implying mammal parasites are undersampled. Overall, our results support that parasite geographical extent is largely controlled by host characteristics, many of which are subsumed within host taxonomic identity.

Phase morphs and phoresy: New species of Antennoseius (Vitzthumia) mites (Acari: Mesostigmata: Ascidae) associated with pyrophilous carabids (Carabidae: Sericoda spp.) in Alberta, Canada

Zootaxa ◽  
2008 ◽  
Vol 1961 (1) ◽  
pp. 37-57 ◽  
Author(s):  
FRÉDÉRIC BEAULIEU ◽  
ANDREA D. DÉCHÊNE ◽  
DAVID E. WALTER
Keyword(s):  
New Species ◽  
North American ◽  
North American Species ◽  
Carabid Beetles ◽  
Free Living ◽  
Adult Females ◽  
As Species ◽  
Laboratory Cultures ◽  
Living Species ◽  
Mite Genus

The mite genus Antennoseius is composed of free-living species in soil and litter, as well as species that are phoretic on carabid beetles as adult females. Among approximately 60 described Antennoseius species, one North American species, A. janus, was found in laboratory cultures to have two female morphs: one granular, free-living morph, and one smooth, putatively phoretic morph. We here describe the adult females of A. perseus n. sp. and A. pyrophilus n. sp. collected from under the elytra of carabid beetles (Sericoda quadripunctata and S. bembidioides) associated with recently burned forests in Alberta, Canada. We also describe the female and male of a distinct, granular, non-phoretic morph of A. perseus, obtained from soil and by rearing the offspring of phoretic females. A key to the females of Antennoseius species having an ambulacrum on leg I (i.e. subgenus Vitzthumia) is provided.

First report of Gieysztoria falx Brusa, Damborenea & Noreña, 2003 (Platyhelminthes: Rhabdocoela) in southern Brazil

Zootaxa ◽  
2019 ◽  
Vol 4706 (3) ◽  
pp. 494-496
Author(s):  
JHOE REYES ◽  
DANIELA BINOW ◽  
ROGÉRIO T. VIANNA ◽  
SAMANTHA E. MARTINS
Keyword(s):  
Hot Spots ◽  
First Record ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Free Living ◽  
Similar Shape ◽  
Freshwater Habitats ◽  
Living Species ◽  
South Brazil ◽  
Shape And Size

Within Dalyelliidae Graff, 1905, Gieysztoria Ruebush & Hayes, 1939 is the most widely distributed and speciose genus, members of which live in marine, brackish, or freshwater habitats (Van Steenkiste et al., 2012). Gieysztoria is composed by ~97 free-living species (Tyler et al. 2016), and species identification is mainly made on the male copulatory system, which has an armed penis (stylet) with different configurations of spines (Noreña et al., 2016). The stylet configuration of Gieysztoria species is traditionally split into two groups: Aequales (spines of similar shape and size) and Inaequales (spines of different shape and size) (Luther, 1955). In the neotropics, specimens of Gieysztoria belong to both the Aequales and Inaequales group   and are well represented (Damborenea et al., 2005; Noreña et al., 2003). According to Braccini et al. (2016, 2017), there are 16 species of Gieysztoria in Brazil, mainly distributed in the southern region. South Brazil harbours a mosaic of wetlands that are considered hot spots of biodiversity, including the Taim Ecological Station (ESEC Taim) protected area that was designated as a Ramsar site (Ramsar, 2017). In the present study, Gieysztoria falx Brusa, Damborenea & Noreña, 2003 is registered in the ESEC Taim, located in Rio Grande do Sul. It represents the first record of G. falx in Brazil. Illustrations and comments on stylet configuration are given.

scholarly journals Distribution of Protein Folds in the Three Superkingdoms of Life

1999 ◽  
Vol 9 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Yuri I. Wolf ◽  
Steven E. Brenner ◽  
Paul A. Bash ◽  
Eugene V. Koonin
Keyword(s):  
Geometric Model ◽  
Protein Fold ◽  
Finite Sample ◽  
Multidomain Proteins ◽  
Free Living ◽  
Protein Fold Recognition ◽  
Protein Folds ◽  
Living Species ◽  
Simple Stochastic Model ◽  
Blast Program

A sensitive protein-fold recognition procedure was developed on the basis of iterative database search using the PSI-BLAST program. A collection of 1193 position-dependent weight matrices that can be used as fold identifiers was produced. In the completely sequenced genomes, folds could be automatically identified for 20%–30% of the proteins, with 3%–6% more detectable by additional analysis of conserved motifs. The distribution of the most common folds is very similar in bacteria and archaea but distinct in eukaryotes. Within the bacteria, this distribution differs between parasitic and free-living species. In all analyzed genomes, the P-loop NTPases are the most abundant fold. In bacteria and archaea, the next most common folds are ferredoxin-like domains, TIM-barrels, and methyltransferases, whereas in eukaryotes, the second to fourth places belong to protein kinases, β-propellers and TIM-barrels. The observed diversity of protein folds in different proteomes is approximately twice as high as it would be expected from a simple stochastic model describing a proteome as a finite sample from an infinite pool of proteins with an exponential distribution of the fold fractions. Distribution of the number of domains with different folds in one protein fits the geometric model, which is compatible with the evolution of multidomain proteins by random combination of domains.[Fold predictions for proteins from 14 proteomes are available on the World Wide Web atftp://ncbi.nlm.nih.gov/pub/koonin/FOLDS/index.html. The FIDs are available by anonymous ftp at the same location.]

scholarly journals Food‐web interaction strength distributions are conserved by greater variation between than within predator–prey pairs

Ecology ◽  
2019 ◽  
Vol 100 (10) ◽  
Author(s):  
Daniel L. Preston ◽  
Landon P. Falke ◽  
Jeremy S. Henderson ◽  
Mark Novak
Keyword(s):  
Food Web ◽  
Interaction Strength ◽  
Predator Prey ◽  
Strength Distributions
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