Infestation intensity and prevalence of an ectosymbiotic midge under variable environmental and host conditions

2002 ◽  
Vol 80 (12) ◽  
pp. 2061-2071 ◽  
Author(s):  
C M Pennuto ◽  
C L Wooster-Brown ◽  
C A Belisle
Keyword(s):  
Population Dynamics ◽  
Attachment Site ◽  
Host Density ◽  
Host Population ◽  
Intraspecific Interactions ◽  
Abiotic Conditions ◽  
Host Interaction ◽  
Infestation Intensity ◽  
Obligate Symbiont ◽  
General Expectation

Host–symbiont theory suggests that the abundance of an obligate symbiont will correlate positively with the density and size of its host. We examined these expectations using an obligate chironomid ectosymbiont – host fishfly (Nanocladius (Plecopteracoluthus) sp. No. 5 – Nigronia serricornis) system in 13 streams of southern Maine over 2 years (1996–1998). In addition, we investigated field conditions and macroinvertebrate-community composition, to search for correlates with symbiont prevalence and mean infestation intensity. Prevalence and infestation intensity were high in both years of the study, but neither infestation intensity nor prevalence was correlated with host population density across sites. Within sites, prevalence increased significantly when host density declined, contrary to our expectation. Symbiont-infestation intensity was not related to host size. No symbiont-population attributes correlated with physicochemical conditions in either sample year but prevalence was positively correlated with infestation intensity. Ectosymbiotic midges exhibited a significant host and attachment-site bias. Collectively, these data suggest that this symbiont–host interaction is obligate and stable, but the dynamics in our streams do not support the general expectation of increasing symbiont-population size with either increasing host-population or body size. Intraspecific interactions between symbionts are thought to have a stronger influence on population dynamics than do host populations or abiotic conditions for this ectosymbiotic midge.

Monogenean parasites from fishes of the Vaal Dam, Gauteng Province, South Africa. I. Winter survey versus summer survey comparison from Labeo capensis (Smith, 1841) and Labeo umbratus (Smith, 1841) hosts

2014 ◽  
Vol 59 (1) ◽  
Author(s):  
Dionne Crafford ◽  
Wilmien Luus-Powell ◽  
Annemariè Avenant-Oldewage
Keyword(s):  
Population Dynamics ◽  
Large Scale ◽  
Experimental Studies ◽  
Attachment Site ◽  
Host Population ◽  
Site Preference ◽  
Gauteng Province ◽  
Active Choice ◽  
Vaal Dam ◽  
Intensive Aquaculture

AbstractIndigenous South African Labeo spp. show promise with regard to development of semi-intensive aquaculture, yet little research on their monogenean fauna has been conducted. Ecological aspects of monogenean fauna of the moggel Labeo umbratus (Smith 1841) and the Orange River mudfish Labeo capensis (Smith 1841), as recorded during both winter and summer sampling surveys, are reported here. Fish were collected using gill nets, euthanized and gills removed and examined to both quantify parasite numbers and distribution on the gills. Results obtained support the hypothesis that gill site preference is not due to active choice for a particular attachment site, but rather a result of water flow over gills during respiration in conjunction with fish behaviour and habitat use. Interaction between individual elements investigated (temperature effects, parasite population dynamics and host population dynamics) may be largely responsible for seasonal differences in infection statistics of monogenean parasites. Such interactions should be investigated in future large scale ecological studies, in combination with experimental studies, to further elucidate these effects.

scholarly journals Hybrid systems modeling of ecological population dynamics

2020 ◽  
Author(s):  
Abhyudai Singh ◽  
Brooks Emerick
Keyword(s):  
Population Dynamics ◽  
Discrete Time ◽  
Traditional Approach ◽  
Hybrid Approach ◽  
Host Density ◽  
Parasitoid Wasp ◽  
Host Population ◽  
Equilibrium Density ◽  
Reproduction Rate ◽  
Discrete Time Models

AbstractDiscrete-time models are the traditional approach for capturing population dynamics of insects living in the temperate regions of the world. These models are characterized by an update function that connects the population densities from one year to the next. We revisit classical discrete-time models used for modeling interactions between two insect species (a host and a parasitoid), and provide novel result on the stability of the population dynamics. In particular, for a class of models we show that the fixed point is stable, if and only if, the host equilibrium density is an increasing function of the host’s reproduction rate. We also introduce a hybrid approach for obtaining the update functions by solving ordinary differential equations that mechanistically capture the ecological interactions between the host and the parasitoid. This hybrid approach is used to study the suppression of host density by a parasitoid. Our analysis shows that when the parasitoid attacks the host at a constant rate, then the host density cannot by suppressed beyond a certain point without making the population dynamics unstable. In contrast, when the parasitoid’s attack rate increases with increasing host density, then the host population density can be suppressed to arbitrarily low levels. These results have important implications for biological control where a natural enemy, such as a parasitoid wasp, is introduced to eliminate a pest that is the host species for the parasitoid.

Parasite infection and host dynamics in a naturally fluctuating rodent population

2012 ◽  
Vol 90 (9) ◽  
pp. 1149-1160 ◽  
Author(s):  
J.C. Winternitz ◽  
M.J. Yabsley ◽  
S.M. Altizer
Keyword(s):  
Population Density ◽  
Experimental Studies ◽  
Host Density ◽  
Positive Association ◽  
Population Cycles ◽  
Host Population ◽  
Reproductive Status ◽  
Vole Cycles ◽  
Host Infection ◽  
The Impact

Parasites can both influence and be affected by host population dynamics, and a growing number of case studies support a role for parasites in causing or amplifying host population cycles. In this study, we examined individual and population predictors of gastrointestinal parasitism on wild cyclic montane voles ( Microtus montanus (Peale, 1848)) to determine if evidence was consistent with theory implicating parasites in population cycles. We sampled three sites in central Colorado for the duration of a multiannual cycle and recorded the prevalence and intensity of directly transmitted Eimeria Schneider, 1875 and indirectly transmitted cestodes from a total of 267 voles. We found significant associations between host infection status, individual traits (sex, age, and reproductive status) and population variables (site, trapping period, and population density), including a positive association between host density and cestode prevalence, and a negative association between host density and Eimeria prevalence. Both cestode and Eimeria intensity correlated positively with host age, reproductive status, and population density, but neither parasite was associated with poorer host condition. Our findings suggest that parasites are common in this natural host, but determining their potential to influence montane vole cycles requires future experimental studies and long-term monitoring to determine the fitness consequences of infection and the impact of parasite removal on host dynamics.

scholarly journals Host-seeking efficiency can explain population dynamics of the tsetse fly Glossina morsitans morsitans in response to host density decline

2017 ◽  
Vol 11 (7) ◽  
pp. e0005730 ◽  
Author(s):  
Jennifer S. Lord ◽  
Zinhle Mthombothi ◽  
Vitalis K. Lagat ◽  
Fatumah Atuhaire ◽  
John W. Hargrove
Keyword(s):  
Population Dynamics ◽  
Host Density ◽  
Glossina Morsitans Morsitans ◽  
Tsetse Fly ◽  
Glossina Morsitans ◽  
Host Seeking

Effects of goldfish (Carassius auratus) population size and body condition on the transmission of Gyrodactylus kobayashii (Monogenea)

Parasitology ◽  
2017 ◽  
Vol 144 (9) ◽  
pp. 1221-1228 ◽  
Author(s):  
SHUN ZHOU ◽  
HONG ZOU ◽  
SHAN G. WU ◽  
GUI T. WANG ◽  
DAVID J. MARCOGLIESE ◽  
...  
Keyword(s):  
Population Size ◽  
Body Condition ◽  
Host Density ◽  
Host Population ◽  
Laboratory Model ◽  
Constant Density ◽  
Contact Rates ◽  
Effective Contact ◽  
Rate Of Increase ◽  
Population Sizes

SUMMARYField surveys indicate that host population size, rather than density, is the most important determinant of monogenean infection dynamics. To verify this prediction, epidemic parameters were monitored for 70 days at five host population sizes held at constant density using a goldfish – Gyrodactylus kobayashii laboratory model. During the first 20 days, the rate of increase of prevalence and mean abundance was faster in small host populations. Total mean prevalence and total mean abundance throughout the experiment were not significantly affected by host population sizes. Higher transmission rates were detected in larger host populations. However, there were no significant differences in effective contact rates among the five host populations on each sampling day during the first 20 days, implying that contact rates may be saturated at a sufficiently high host density. These results demonstrate that the epidemic occurs more quickly in smaller host populations at the beginning of the experiment. However, the epidemic is independent of the host population size due to the similar effective contact rates in the five population sizes. Significant negative influence of the initial body condition (Kn) of uninfected goldfish on total mean abundance of parasites suggests that susceptibility of hosts is also a determinant of parasite transmission.

scholarly journals Microfilarial distribution of Loa loa in the human host: population dynamics and epidemiological implications

Parasitology ◽  
2006 ◽  
Vol 133 (01) ◽  
pp. 101 ◽  
Author(s):  
S. D. S. PION ◽  
J. A. N. FILIPE ◽  
J. KAMGNO ◽  
J. GARDON ◽  
M.-G. BASÁÑEZ ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Host Population ◽  
Loa Loa ◽  
Human Host
Sign in / Sign up

Export Citation Format

Share Document