Increased Parasite Abundance Associated with Reproductive Maturity of the Clam Anodonta piscinalis

1999 ◽  
Vol 85 (3) ◽  
pp. 588 ◽  
Author(s):  
J. Taskinen ◽  
M. Saarinen
1998 ◽  
Vol 151 (6) ◽  
pp. 497 ◽  
Author(s):  
Arneberg ◽  
Skorping ◽  
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Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 227
Author(s):  
Tessa Carrau ◽  
Carlos Martínez-Carrasco ◽  
María Magdalena Garijo ◽  
Francisco Alonso ◽  
Rocío Ruiz de Ybáñez ◽  
...  

In the analysis of a multi-host/multi-parasite system and its associated risk factors, it is particularly interesting to understand the natural dynamics among pathogens, their hosts, and the environment in wildlife populations. This analysis is particularly feasible in a scenario where multiple overlapping host populations are present in high densities, along with a complex community of parasites. We aimed to describe and analyze the naturally occurring lungworm polyparasitism in a wild ruminant community in Southeast Spain. The respiratory tracts of 250 specimens belonging to four different species (red deer, mouflon, Iberian ibex, and fallow deer) were studied. Almost half (48.0%) of the animals were infected with bronchopulmonary nematodes. Seven different nematodes were identified of which two genera (Protostrongylus spp. and Dictyocaulus spp.) and three additional species (Cystocaulus ocreatus, Muellerius capillaris, and Neostrongylus linearis) were recorded in at least two ruminants, with the mouflon as the commonest host. Our study shows a significant effect of host species and sampling area, plus a marginal effect of age, on parasite multivariate abundance at the host population level. Mouflon and adults of all hosts appear to carry the highest parasite load on average. From a spatial perspective, the highest parasite abundance was detected at the central part of the park.


1991 ◽  
Vol 40 (3-4) ◽  
pp. 269-289 ◽  
Author(s):  
P. Philippe

AbstractAn attempt has been made to apply Payami's models to maternal age-specific twin birth prevalences in several countries. The models disclose the heterogeneity of a cohort and spell out the risks to susceptible members (who will actually get the disease) according to age (or time). Payami's method specifies that the typical cohort of susceptibles is ascribed to two exposures: a potent and generalised exposure and a very low or no risk secondary exposure. The models have been adjusted to international data from current as well as old populations, of Occidental and Japanese origin. Results show that cohorts of twin-prone mothers aged 25 to 45 are homogeneous. A single dominant etiology is suggested which applies to both MZ and DZ twins. Heterogeneity, from 10% to 25%, is present in all countries whenever the 20-24 age group is involved. A separate study of illegitimate twin births from Denmark reduces the heterogeneity and shows that MZ illegitimate twin births are due to a secondary exposure responsible for a distinct twinning etiology. The age-specific risks of a MZ illegitimate twin birth are much higher than those of any comparison group, and are constant until age 35 years. This suggests a single-hit exposure akin to a neuroendocrine stimulus which short-cuts the usual age-dependent etiologic pathway. MZ and DZ twins both experience the same maternal age specific risks, an observation which underscores the common etiology of both types of twins. Risks increase with age from age 20 to 45 years. The pattern according to age varies among countries and time periods. Occidental populations have a pattern varying from an exponential to a more linear increase in old and recent populations, respectively. Only present-day Japan displays a logarithmic-like growth curve. The concept of “reproductive maturity” is introduced, and related to the secular trend of the DZ twin birth risk and to its variation across countries. Two new conclusions are drawn: a) The higher the rate of reproductive maturity, the less the DZ twin birth risk and, b) Reproductive maturity determines the maternal age-specific gonadotropin levels.


1983 ◽  
Vol 61 (1) ◽  
pp. 179-187 ◽  
Author(s):  
Mark P. Widrlechner

Through a review of floristic and taxonomic literature and an examination of over 1500 herbarium specimens, this report documents the rapid spread of Chaenorrhinum minus (L.) Lange along railroads across North America. The relationship between C. minus and railroads is described and phenological data on flowering and fruiting are presented. The combination of an effective dispersal mechanism and the rapid onset of reproductive maturity contributes to the species' adaptive success.


2021 ◽  
Author(s):  
Benny Shalmon ◽  
Ping Sun ◽  
Torsten Wronski

AbstractThe Arabian gazelle (Gazella arabica) population in Israel has experienced a turbulent conservation history and repeatedly faced local extinction. Low fawn survival was considered the main cause for the constant decline. In our study, we analyzed instantaneous fawn mortality rates, using a binomial coding at three different developmental stages, i.e., mortality rates to 3 months after parturition (weaning age), to 5 months after parturition (male fawns leave their mothers), and to the age of reproductive maturity, i.e., recruitment (12 months). We used a dataset obtained from 20 individually discernible mothers and their fawns (49 females and 48 males) born between June 2006 and September 2019. To explore causes for the fawn mortality rates, parental- (age of the mother at parturition) and offspring-related attributes (offspring sex), year of birth, together with one weather variable (mean monthly maximum temperature) were included as independent variables into three independent mixed effects cox regression models. Out of 97 fawns, 92 survived to weaning age, 73 to the age of 5 months and only 7 to the age of reproductive maturity. Temperature had significant effects on instantaneous fawn mortality rates, suggesting that low temperatures were detrimental to the survival of fawns after weaning (4–5 months) and male dispersal age (6–12 months). Male offspring encountered a higher instantaneous mortality rate than female offspring at the age of 6–12 months. Moreover, fawns from less experienced mother (young age at parturition) experienced higher mortality. Our results were in line with previous studies on fawn mortality observed in other desert dwelling ungulates.


2015 ◽  
Vol 75 (3) ◽  
pp. 736-741 ◽  
Author(s):  
J Moreira ◽  
F Paschoal ◽  
AD Cezar ◽  
JL Luque

AbstractBetween March 2010 and August 2011 were necropsied 100 specimens of Sardinella brasiliensis (Steindachner, 1879), from the coast of the State of Rio de Janeiro, Brazil (22°51’S, 43°56’W), to study their community of metazoan parasites. All specimens of S. brasiliensis were parasitized by at least one species of metazoan parasite, with mean of 68.7 ± 71.2 parasites/fish. Eleven species were collected: 3 digeneans, 1 monogenean, 2 cestodes, 3 nematodes and 2 copepods. The digenean Myosaccium ecaude Montgomery was the most abundant, prevalent, and dominant species, representing 72.7% of metazoan parasites collected, showing positive correlation between host’s total length and parasite abundance. Total parasite abundance was positively correlated with host’s total length. Three pairs of adult endoparasites showed significant positive association and covariation. The parasite community of S. brasiliensis showed dominance by digeneans. Sardinella brasiliensis represents new host record for most found parasite species.


2020 ◽  
Vol 40 ◽  
pp. 109-129
Author(s):  
Tom Robin Olk ◽  
Ann-Cecilie Henriksen ◽  
Solveig Irene Dolven ◽  
Mathias Leithe Haukø ◽  
Espen Lydersen ◽  
...  

Time and spatial variations in macroparasite status were investigated in European perch, Perca fluviatilis, European whitefish, Coregonus lavaretus, and Arctic charr, Salvelinus alpinus in Lake Norsjø (Southern Norway), based on gillnet fishing in three locations in the spring, summer, and fall 2018. In addition, length, weigth, age, sex, δ13C, and δ15N were determined. Parasite abundance was modelled using negative binomial generalized linear models in relation to fish metrics, season, and sampling location. The most prevalent parasite species were determined by the diet and habitat of the host. European perch was mainly infected by acanthocephalans, European whitefish mainly infected by acanthocephalans and cestodes, and Arctic charr mainly infected by cestodes. The most prevalent parasites in European perch are transmitted by benthic animals. Parasites in European whitefish are transmitted by both benthic animals and copepods, while the most prevalent parasites in Arctic charr are copepod transmitted. This corresponds well with the δ13C signatures in the three species, indicating that European perch primarily fed in the littoral zone (δ13C: -24.9 ± 2.5 ‰), Arctic charr in the pelagic and profundal zone (δ13C: -29.4 ± 1.1 ‰), while European whitefish both fed in the littoral and pelagic zone (δ13C: -28.3 ± 2.3 ‰) of Lake Norsjø. Individual abundances of parasites depended on host age, length, sex, δ15N, and season. Positive correlations between parasite abundance and host age, length, or trophic level measured as δ15N were most common, and occurred in all three host species. Many parasites accumulate with age, and larger hosts provide more diverse habitats for parasites.


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