scholarly journals Host allometry influences the evolution of parasite host-generalism: theory and meta-analysis

2017 ◽  
Vol 372 (1719) ◽  
pp. 20160089 ◽  
Author(s):  
Josephine G. Walker ◽  
Amy Hurford ◽  
Jo Cable ◽  
Amy R. Ellison ◽  
Stephen J. Price ◽  
...  
Keyword(s):  
Body Size ◽  
Host Species ◽  
Meta Analysis ◽  
Transmission Risk ◽  
New Host ◽  
Host Body ◽  
Biological Interest ◽  
Single Host ◽  
Future Work ◽  
Host Body Size

Parasites vary widely in the diversity of hosts they infect: some parasite species are specialists—infecting just a single host species, while others are generalists, capable of infecting many. Understanding the factors that drive parasite host-generalism is of basic biological interest, but also directly relevant to predicting disease emergence in new host species, identifying parasites that are likely to have unidentified additional hosts, and assessing transmission risk. Here, we use mathematical models to investigate how variation in host body size and environmental temperature affect the evolution of parasite host-generalism. We predict that parasites are more likely to evolve a generalist strategy when hosts are large-bodied, when variation in host body size is large, and in cooler environments. We then explore these predictions using a newly updated database of over 20 000 fish–macroparasite associations. Within the database we see some evidence supporting these predictions, but also highlight mismatches between theory and data. By combining these two approaches, we establish a theoretical basis for interpreting empirical data on parasites' host specificity and identify key areas for future work that will help untangle the drivers of parasite host-generalism. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’.

scholarly journals Raillietiella mottae (Pentastomida: Raillietiellidae) parasitizing four species of Gekkota lizards (Gekkonidae and Phyllodactylidae) in the Brazilian Caatinga

2018 ◽  
Vol 55 (2) ◽  
pp. 140-145 ◽  
Author(s):  
V. F. Lima ◽  
S. V. Brito ◽  
J. A. Araujo Filho ◽  
D. A. Teles ◽  
S. C. Ribeiro ◽  
...  
Keyword(s):  
Body Size ◽  
New Host ◽  
Parasite Abundance ◽  
Host Body ◽  
Host Sex ◽  
New Host Records ◽  
Host Body Size

Summary We tested the role of sex, size, and mass of the lizards Phyllopezus pollicaris, Gymnodactylus geckoides, Hemidactylus agrius, Lygodactylus klugei, and Hemidactylus brasilianus on the rates of pentastomid infection in the Brazilian Caatinga. We collected 355 individuals of these five species, of which four (prevalence of infection: P. pollicaris 15.9 %, G. geckoides 1.4 %, H. agrius 28.57 %, and H. brasilianus 4.16 %) were infected by Raillietiella mottae. Parasite abundance was influenced by host body size and mass only in P. pollicaris. Host sex did not influence the abundance of parasites in any species. Hemidactylus agrius, G. geckoides, and H. brasilianus are three new host records for pentastomids.

Explaining variability in parasite aggregation levels among host samples

Parasitology ◽  
2013 ◽  
Vol 140 (4) ◽  
pp. 541-546 ◽  
Author(s):  
ROBERT POULIN
Keyword(s):  
Body Size ◽  
Strong Relationship ◽  
Host Susceptibility ◽  
Helminth Parasites ◽  
Susceptibility To Infection ◽  
Host Body ◽  
Parasite Aggregation ◽  
Using Data ◽  
Species Specific ◽  
Host Body Size

SUMMARYAggregated distributions among individual hosts are a defining feature of metazoan parasite populations. Heterogeneity among host individuals in exposure to parasites or in susceptibility to infection is thought to be the main factor generating aggregation, with properties of parasites themselves explaining some of the variability in aggregation levels observed among species. Here, using data from 410 samples of helminth parasites on fish hosts, I tested the contribution of (i) within-sample variation in host body size, taken as a proxy for variability in host susceptibility, and (ii) parasite taxon and developmental stage, to the aggregated distribution of parasites. Log-transformed variance in numbers of parasites per host was regressed against log mean number across all samples; the strong relationship (r2 = 0·88) indicated that aggregation levels are tightly constrained by mean infection levels, and that only a small proportion of the observed variability in parasite aggregation levels remains to be accounted for by other factors. Using the residuals of this regression as measures of ‘unexplained’ aggregation, a mixed effects model revealed no significant effect of within-sample variation in host body size or of parasite taxon or stage (i.e. juvenile versus adult) on parasite aggregation level within a sample. However, much of the remaining variability in parasite aggregation levels among samples was accounted for by the number of individual hosts examined per sample, and species-specific and study-specific effects reflecting idiosyncrasies of particular systems. This suggests that with most differences in aggregation among samples already explained, there may be little point in seeking universal causes for the remaining variation.

Host species of mistletoes (Loranthaceae and Viscaceae) in Australia

2020 ◽  
Vol 68 (1) ◽  
pp. 1
Author(s):  
Nicole F. Clark ◽  
Jen A. McComb ◽  
Andrew W. Taylor-Robinson
Keyword(s):  
Alien Species ◽  
Host Species ◽  
Current Knowledge ◽  
Sampling Effort ◽  
New Host ◽  
Host Family ◽  
Single Host ◽  
New Hosts ◽  
Host Families ◽  
New Host Species

In order to study the relationships between mistletoes and their host species, comprehensive collections of both mistletoes and hosts are needed. The effect of sampling effort on the estimation of mistletoe host range was demonstrated in a comparison of an inventory of host mistletoe interactions published by Downey in 1998 and a 2019 inventory presented here, which is based on data from collections in the Australian Virtual Herbarium and information in the literature. New hosts were recorded for 93% of the 90 Australian mistletoes. There were 338 previously known hosts recorded to be parasitised by additional mistletoe species, and 317 new host species that were not previously known as mistletoe hosts (25 being alien species). These were from 78 new host genera and 13 new host families. The total number of host species was 1186 within 327 genera from 92 host families. A total of 63% of all Australian mistletoes parasitise species of either Eucalyptus or Acacia or both these genera. The large rise in host species recorded in less than two decades between inventories suggests that current knowledge of hosts is still incomplete, such that further new hosts will be discovered in future. Some mistletoe species show a strong preference to one host family or genus but due to insufficient collecting it is premature to conclude that any of the three species known from a single host are host specific.

scholarly journals Costs of immune responses are related to host body size and lifespan

2017 ◽  
Vol 327 (5) ◽  
pp. 254-261 ◽  
Author(s):  
Amber J. Brace ◽  
Marc J. Lajeunesse ◽  
Daniel R. Ardia ◽  
Dana M. Hawley ◽  
James S. Adelman ◽  
...  
Keyword(s):  
Body Size ◽  
Immune Responses ◽  
Host Body ◽  
Host Body Size

Abundance of chewing lice (Phthiraptera: Amblycera and Ischnocera) increases with the body size of their host woodpeckers and sapsuckers (Aves: Piciformes: Picidae)

2017 ◽  
Vol 149 (4) ◽  
pp. 473-481 ◽  
Author(s):  
Terry D. Galloway ◽  
Robert J. Lamb
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Host Species ◽  
The Body ◽  
Louse Infestation ◽  
Mean Intensity ◽  
Chewing Lice ◽  
Host Body ◽  
Northern Flicker ◽  
Host Body Mass

AbstractSpecimens of five species of woodpeckers (Piciformes: Picidae) from Manitoba, Canada, were weighed and examined for chewing lice, 1998–2015: downy woodpecker (Picoides pubescens (Linnaeus), n=49), hairy woodpecker (Picoides villosus (Linnaeus), n=23), pileated woodpecker (Dryocopus pileatus (Linnaeus), n=10), northern flicker (Colaptes auratus (Linnaeus), n=170), and yellow-bellied sapsucker (Sphyrapicus varius (Linnaeus), n=239). The relationship between body mass of each host species and infestation by seven species of lice was analysed: Menacanthus pici (Denny) from all host species, Brueelia straminea (Denny) from Picoides Lacépède species, Penenirmus jungens (Kellogg) from northern flicker, Penenirmus auritus (Scopoli) from the other four hosts, Picicola porisma Dalgleish from northern flicker, Picicola snodgrassi (Kellogg) from Picoides species, and Picicola marginatulus (Harrison) from pileated woodpeckers. Mean abundance of lice increased with the mean mass of their host. Neither the species richness of lice nor the prevalence of lice were related to host body mass. Host body mass explained 98% of the variation in mean intensity of louse infestation among hosts. The positive association of mean intensity and body size was also detected for three genera of lice. Louse intensity also increased with body size for individual birds, more so for some species of lice and hosts than others. Body size matters, but the adaptations that allow higher mean intensity on larger host species remain to be determined.

scholarly journals Host body size and the diversity of tick assemblages on Neotropical vertebrates

2016 ◽  
Vol 5 (3) ◽  
pp. 295-304 ◽  
Author(s):  
Helen J. Esser ◽  
Janet E. Foley ◽  
Frans Bongers ◽  
Edward Allen Herre ◽  
Matthew J. Miller ◽  
...  
Keyword(s):  
Body Size ◽  
Host Body ◽  
Host Body Size

scholarly journals Consumer and host body size effects on the removal of trematode cercariae by ambient communities

Parasitology ◽  
2018 ◽  
Vol 146 (3) ◽  
pp. 342-347
Author(s):  
Jennifer E. Welsh ◽  
Anke Hempel ◽  
Mirjana Markovic ◽  
Jaap van der Meer ◽  
David W. Thieltges
Keyword(s):  
Body Size ◽  
Size Effects ◽  
Laboratory Experiments ◽  
Feeding Activity ◽  
Removal Rates ◽  
Host Interactions ◽  
Host Body ◽  
Species Specific ◽  
Host Body Size ◽  
Significant Mortality

AbstractParasite transmission can be altered via the removal of parasites by the ambient communities in which parasite–host interactions take place. However, the mechanisms driving parasite removal remain poorly understood. Using marine trematode cercariae as a model system, we investigated the effects of consumer and host body size on parasite removal rates. Laboratory experiments revealed that consumer or host body size significantly affected cercarial removal rates in crabs, oysters and cockles but not in shrimps. In general, cercarial removal rates increased with consumer (crabs and oysters) and host (cockles) body size. For the filter feeding oysters and cockles, the effects probably relate to their feeding activity which is known to correlate with bivalve size. Low infection levels found in cockle hosts suggest that parasite removal by hosts also leads to significant mortality of infective stages. The size effects of crab and shrimp predators on cercarial removal rates were more complex and did not show an expected size match-mismatch between predators and their cercarial prey, suggesting that parasite removal rates in predators are species-specific. We conclude that to have a comprehensive understanding of parasite removal by ambient communities, more research into the various mechanisms of cercarial removal is required.

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