Spatial distribution of the intertidal snail Ilyanassa obsoleta in relation to parasitism by two species of trematodes

2000 ◽  
Vol 78 (7) ◽  
pp. 1137-1143 ◽  
Author(s):  
Dean G McCurdy ◽  
J Sherman Boates ◽  
Mark R Forbes
Keyword(s):  
Spatial Distribution ◽  
Intertidal Zone ◽  
Bay Of Fundy ◽  
Spatial Distributions ◽  
Ilyanassa Obsoleta ◽  
Intermediate Hosts ◽  
Corophium Volutator ◽  
Vertical Distributions ◽  
Second Intermediate Host ◽  
Intertidal Snail

We studied the spatial distributions of mud snails (Ilyanassa obsoleta) infected by two trematodes, Lepocreadium setiferoides and Gynaecotyla adunca, on a macrotidal mudflat in the Minas Basin, Bay of Fundy. Snails, as first intermediate hosts, were castrated by both parasites, and we found no evidence of sex differences in parasitism. Similar to previous work, prevalence of L. setiferoides in I. obsoleta increased exponentially with host size (and age). Unexpectedly, prevalence of G. adunca decreased over the largest size classes of snails, a result that may be due to several causes. Distributions of both parasites across the intertidal zone differed from previous accounts in that snails infected with L. setiferoides were found only in the middle of the intertidal zone, whereas prevalence of G. adunca increased exponentially moving seaward. Several species of polychaetes could be infected by L. setiferoides in the laboratory and may act as appropriate second intermediate hosts, whereas only the amphipod Corophium volutator served as a second intermediate host for G. adunca. Finally, the vertical distributions of I. obsoleta infected by either species of trematode overlap with distributions of apparent or known second intermediate hosts.

Behaviour and ecological importance of a mud snail (Ilyanassa obsoleta) population in a temperate macrotidal estuary

1988 ◽  
Vol 66 (2) ◽  
pp. 459-466 ◽  
Author(s):  
Peter J. Cranford
Keyword(s):  
Intertidal Zone ◽  
Standing Stock ◽  
Bay Of Fundy ◽  
Subtidal Zone ◽  
Ilyanassa Obsoleta ◽  
Energy Reserves ◽  
Nutrient Regeneration ◽  
Southern Bight ◽  
Mud Flat ◽  
Ecological Importance

A population of Ilyanassa obsoleta was sampled during the 8-month period when they are present in the intertidal zone in the Southern Bight of Minas Basin, Bay of Fundy. Mud snails were first observed in April, and spawning took place in late May and early June. Flesh weight increased between May and November, with the highest growth rates recorded during August and September. During November the population returned to the subtidal zone, where energy reserves are partially utilized during winter. Clustering and differential habitat selection (salt marsh or mud flat) within size classes resulted in large spatial variations in density, standing stock, and production. Production by I. obsoleta averaged 1.1 g C∙m−2 during their stay in the intertidal zone. The supply of carbon from epibenthic microalgae is insufficient to meet the requirements of this population. Detritus derived from Spartina is believed to be an important additional source of carbon. Ilyanassa obsoleta is not a major prey item of any of the better known predators in this region. Their importance to the intertidal community results from the direct (predation) and indirect (competition, disturbance, nutrient regeneration, and bioturbation) influence of their presence on sedimentary microbial processes and the resident benthic flora and fauna.

scholarly journals Climate influences parasite-mediated competitive release

Parasitology ◽  
2011 ◽  
Vol 138 (11) ◽  
pp. 1436-1441 ◽  
Author(s):  
MARTIN H. LARSEN ◽  
K. THOMAS JENSEN ◽  
KIM N. MOURITSEN
Keyword(s):  
North Atlantic ◽  
Elevated Temperatures ◽  
Intermediate Hosts ◽  
Intertidal Habitat ◽  
Corophium Volutator ◽  
The North ◽  
Competitive Release ◽  
Second Intermediate Host ◽  
North Atlantic Climate ◽  
Climate Influences

SUMMARYParasitism is believed to play an important role in maintaining species diversity, for instance by facilitating coexistence between competing host species. However, the possibility that environmental factors may govern the outcome of parasite-mediated competition has rarely been considered. The closely related amphipods Corophium volutator and Corophium arenarium both serve as second intermediate host for detrimental trematodes. Corophium volutator is the superior competitor of the two, but also suffers from higher mortality when exposed to infective trematode stages. Here, we report parasite-mediated competitive release of C. arenarium in an intertidal habitat, in part triggered by unusually high temperatures linked to the North Atlantic climate oscillation (NAO). The elevated temperatures accelerated the transmission of cercariae from sympatric first intermediate hosts (mud snails) to amphipods, causing a local collapse of the parasite-sensitive C. volutator population and concordant increase in the abundance of the competitively inferior C. arenarium.

On Crepidostomum farionis O. F. Müll. (= Stephanophiala laureata Zeder), a Distome Parasite of the Trout and Grayling. I. The Life History

Parasitology ◽  
1927 ◽  
Vol 19 (1) ◽  
pp. 86-99 ◽  
Author(s):  
F. J. Brown
Keyword(s):  
Life History ◽  
Gall Bladder ◽  
Excretory Vesicle ◽  
Intermediate Hosts ◽  
Larval Trematode ◽  
Sphaerium Corneum ◽  
Two Generations ◽  
History Of ◽  
Second Intermediate Host ◽  
Ephemera Danica

1. Crepidostomum farionis inhabits the gall bladder, as well as the intestine and pyloric caeca, of the trout and grayling.2. The life history of Crepidostomum farionis has been worked out and is based on the similarity of organisation of the cercaria, encysted larval trematode and the adult.3. The first intermediate hosts in the life history of this trematode are Pisidium amnicum (Müll.) and Sphaerium corneum (L.) though the latter is unusual.4. The second intermediate host is the larva of the mayfly, Ephemera danica (Müll.).5. There are two generations of rediae, the first gives rise to daughter rediae, which in turn produce cercariae.6. The rediae are characterised by the absence of ambulatory processes and a functional intestine.7. The cercaria (n.sp.) possesses “eye spots,” stylet and gland cells (salivary?), and the excretory vesicle is tube-shaped.8. The excretory system of the redia and the cercaria has been worked out in detail.9. The relation of the parasites to their respective hosts is discussed. On account of the need for further observations definite conclusions are held over for a later paper.

scholarly journals Seasonal Variation in the Spatial Distribution of Basking Sharks (Cetorhinus maximus) in the Lower Bay of Fundy, Canada

PLoS ONE ◽  
2013 ◽  
Vol 8 (12) ◽  
pp. e82074 ◽  
Author(s):  
Zachary A. Siders ◽  
Andrew J. Westgate ◽  
David W. Johnston ◽  
Laurie D. Murison ◽  
Heather N. Koopman
Keyword(s):  
Spatial Distribution ◽  
Seasonal Variation ◽  
Bay Of Fundy ◽  
Cetorhinus Maximus

scholarly journals Use of negative binomial distribution to describe the presence of Anisakis in Thyrsites atun

2012 ◽  
Vol 21 (1) ◽  
pp. 78-80 ◽  
Author(s):  
Patricio Peña-Rehbein ◽  
Patricio De los Ríos-Escalante
Keyword(s):  
Spatial Distribution ◽  
Negative Binomial Distribution ◽  
Binomial Distribution ◽  
Negative Binomial ◽  
Marine Fishes ◽  
Intermediate Hosts ◽  
Distribution Models ◽  
Internal Organs ◽  
Fishery Resource

Nematodes of the genus Anisakis have marine fishes as intermediate hosts. One of these hosts is Thyrsites atun, an important fishery resource in Chile between 38 and 41° S. This paper describes the frequency and number of Anisakis nematodes in the internal organs of Thyrsites atun. An analysis based on spatial distribution models showed that the parasites tend to be clustered. The variation in the number of parasites per host could be described by the negative binomial distribution. The maximum observed number of parasites was nine parasites per host. The environmental and zoonotic aspects of the study are also discussed.

scholarly journals Effect of Droplet Size and Counterions on the Spatial Distribution of Ions

2019 ◽  
Author(s):  
Victor Kwan ◽  
Styliani Consta
Keyword(s):  
Spatial Distribution ◽  
Reaction Mechanisms ◽  
Charge Carriers ◽  
Transfer Reactions ◽  
Spatial Distributions ◽  
Hydronium Ions ◽  
Ionic Atmosphere ◽  
Droplet Sizes ◽  
Charge Transfer Reactions ◽  
First Time

Electrosprayed droplets have emerged as a new environment for accelerating chemical reactions by orders of magnitude relative to their bulk analogues. Nevertheless the reaction mechanisms are still unknown. Unraveling the ion spatial distribution is critical as to where charge transfer reactions are likely to take place and as to their effect on the ionic atmosphere of macroions. Here we investigate the ion spatial distributions in aqueous droplets with diameters in the range of 5 nm to 16 nm with and without counterions using molecular dynamics. The charge carriers are Na, Cl ions and model hydronium ions. For the first time droplet sizes that are accessible to experimental scrutiny are modeled atomistically. <br>

Population dynamics of two species of intestinal helminth in oystercatchers (Haematopus ostralegus)

1995 ◽  
Vol 73 (2) ◽  
pp. 296-308 ◽  
Author(s):  
C. P. Goater ◽  
J. D. Goss-Custard ◽  
C. R. Kennedy
Keyword(s):  
Paratenic Host ◽  
Feeding Preference ◽  
Host Population ◽  
Intestinal Helminth ◽  
Host Feeding ◽  
Intestinal Helminths ◽  
Host Age ◽  
Intermediate Hosts ◽  
Second Intermediate Host ◽  
Haematopus Ostralegus

The cestode Micrasomacanthus rectacantha and the trematode Psilostomum brevicolle are the two most common intestinal helminths of oystercatchers, Haematopus ostralegus, on the Exe estuary, England. Each was present in 57 of 60 birds, in numbers ranging from 1 to 9833 and from 1 to 182, respectively. Cockles (Cerastoderma edule) were used as paratenic host by M. rectacantha and as second intermediate host by P. brevicolle. Over 90% of the transmission of M. rectacantha from intermediate hosts occurred in winter, between cockles and juvenile birds. Exposure to M. rectacantha was highest in cockles from muddy sites, where up to 80% of older cockles were infected with 1–14 larvae. Exposure to P. brevicolle was similarly high at one sandy site. Juveniles also made up > 90% of the birds present on the estuary in summer, when significantly more worms were gravid. Estimates based on the numbers of uterine eggs per individual P. brevicolle showed that 8 % of the total Exe population of oystercatchers (ca. 200) contributed 51% of the eggs to the estuary. The results implicate host age, host feeding preference, and host population structure as important factors determining variation in helminth abundance in birds.

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