Effect of Host Distribution on the Reproduction of Encarsia formosa Gahan (Hymenoptera: Chalcidoidea)

1958 ◽  
Vol 90 (3) ◽  
pp. 179-191 ◽  
Author(s):  
T. Burnett
Keyword(s):  
Physical Environment ◽  
Host Selection ◽  
Parasite Species ◽  
Insect Pests ◽  
Host Density ◽  
Host Population ◽  
Average Density ◽  
General Consideration ◽  
Encarsia Formosa ◽  
Host Parasite

That insect parasites regulate and, in the case of newly introduced species, sometimes reduce the average density of insect pests has led to an exmination of the properties of parasites in general. Consideration has been given to the manner in which parasites select hosts for oviposition and to the physiological and psychological basis of this selection. The distribution of parasite progeny among suitable hosts has been analysed in many cases, for the fewer the hostS that are superparasitized for any given number of parasite eggs laid the greater the efficiency of the parasite in reducing host density. It is obvious that before the factors of host selection and superparasitism become important in host-parasite interaction the parasite must find the host individuals. When the hosts are confined to a relatively small area the potential oviposition of the parasite, subject to discrimination among hosts and restraint in oviposition, often determines the level of parasitism. As distance between individuals of the host population becomes greater, however, it is necessary for the parasite to search the environment more extensively. Therefore, the ability of the parasite to find hosts is a factor of prime importance in determining its influence on the density of its host. The success with which a parasite discovers hosts in relation to host density is determined, of course, by several characteristics of the parasite species and by the modification of these characteristics through variations in the physical environment.

scholarly journals Occurrence and influence of bopyrid parasites on female penaeid prawns from coastal waters of central Queensland (Australia)

1991 ◽  
Vol 42 (6) ◽  
pp. 615 ◽  
Author(s):  
AJ Courtney
Keyword(s):  
Coastal Waters ◽  
Parasite Species ◽  
Habitat Preferences ◽  
Species Group ◽  
Host Population ◽  
Trawl Fishery ◽  
Specific Host ◽  
Low Prevalence ◽  
Host Parasite ◽  
First Time

The prevalence of bopyrid isopods, parasitic on penaeid prawn hosts, is recorded for the first time from a central Queensland prawn trawl fishery. The bopyrid parasite Parapenaeon prox. expansus has been recorded for the first time from the red spot king prawn, Penaeus longistylus, and the blue-legged king prawn, Penaeus latisulcatus. Previous unpublished reports of Parapenaeon japonicum parasitizing P. longistylus have also been substantiated. Parasite species were not randomly associated with all prawn species but rather were associated with a single prawn host species or species group. The factors that give rise to such specific host-parasite associations, particularly the host-selective behaviour of the parasite and the habitat preferences of the juvenile prawns, are discussed. Bopyrids had no significant effect on the weight of the prawns, but they did have a significant effect on ovary weight and histology, causing sterility in their hosts. High levels of infestation have been recorded from other fisheries (resulting in reduced spawning potential of the host population), but the low prevalence (0.32%) of bopyrid parasites in central Queensland prawns appears to be so low as not to present a concern at present.

scholarly journals Within-host interference competition can prevent invasion of rare parasites

Parasitology ◽  
2017 ◽  
Vol 145 (6) ◽  
pp. 770-774 ◽  
Author(s):  
Benjamin J. Z. Quigley ◽  
Sam P. Brown ◽  
Helen C. Leggett ◽  
Pauline D. Scanlan ◽  
Angus Buckling
Keyword(s):  
Parasite Species ◽  
Interference Competition ◽  
Host Population ◽  
Priority Effect ◽  
Parasite Genotype ◽  
New Host ◽  
Parasite Ecology ◽  
The Common ◽  
The Cost ◽  
Host Parasite

AbstractCompetition between parasite species or genotypes can play an important role in the establishment of parasites in new host populations. Here, we investigate a mechanism by which a rare parasite is unable to establish itself in a host population if a common resident parasite is already present (a ‘priority effect’). We develop a simple epidemiological model and show that a rare parasite genotype is unable to invade if coinfecting parasite genotypes inhibit each other's transmission more than expected from simple resource partitioning. This is because a rare parasite is more likely to be in multiply-infected hosts than the common genotype, and hence more likely to pay the cost of reduced transmission. Experiments competing interfering clones of bacteriophage infecting a bacterium support the model prediction that the clones are unable to invade each other from rare. We briefly discuss the implications of these results for host-parasite ecology and (co)evolution.

scholarly journals Host selection by Microplectron fuscipennis , Zett. (Chalcididae, Hymenoptera)

1936 ◽  
Vol 120 (817) ◽  
pp. 253-291 ◽  
Keyword(s):  
Physical Environment ◽  
Host Selection ◽  
Present Writer ◽  
Host Material ◽  
Stage Larva ◽  
European Species

Microplectron fuscipennis , Zett., appears to be restricted for its host material to the European species of the Tenthredinid genus Diprion , Schrank. It has been recorded from D. sertifer , Geoffr., D. pini , L., D. pallidus , Kl., and, recently, from D. polytomum , Htg. The resting stage larva within the cocoon is attacked, oviposition occurring after the host has been paralysed. The present paper is an account of part of a more extensive programme of work on Microplectron which is being undertaken in view of the promising nature of the parasite and of its introduction into Canada. The biology of the species has been dealt with by Morris and Cameron (1935) and its reactions to changes in the physical environment by the present writer (Ullyett, 1936).

Do different parasite species interact in their effects on host fitness? A case study on parasites of the amphipod Paracalliope fluviatilis

Parasitology ◽  
2011 ◽  
Vol 138 (9) ◽  
pp. 1176-1182 ◽  
Author(s):  
C. A. RAUQUE ◽  
R. A. PATERSON ◽  
R. POULIN ◽  
D. M. TOMPKINS
Keyword(s):  
Parasite Species ◽  
Low Frequency ◽  
Host Population ◽  
Interactive Effects ◽  
Population Means ◽  
Significant Relationships ◽  
Coitocaecum Parvum ◽  
Paracalliope Fluviatilis ◽  
Generally True

SUMMARYThere is a gap in our understanding of the relative and interactive effects of different parasite species on the same host population. Here we examine the effects of the acanthocephalan Acanthocephalus galaxii, an unidentified cyclophyllidean cestode, and the trematodes Coitocaecum parvum and Microphallus sp. on several fitness components of the amphipod Paracalliope fluviatilis, using a combination of infection surveys and both survival and behavioural trials. In addition to significant relationships between specific parasites and measures of amphipod survival, maturity, mating success and behaviour, interactions between parasite species with respect to amphipod photophilia were also significant. While infection by either A. galaxii or C. parvum was associated with increased photophilia, such increases were negated by co-infection with Microphallus sp. We hypothesize that this is due to the more subtle manipulative effect of A. galaxii and C. parvum being impaired by Microphallus sp. We conclude that the low frequency at which such double infections occur in our sampled population means that such interactions are unlikely to be important beyond the scale of the host individual. Whether or not this is generally true, implying that parasitological models and theory based on single parasite species studies do generally hold, requires cross-species meta-analytical studies.

The effect of the acanthocephalan Pomphorhynchus laevis upon the respiration of its intermediate host, Gammarus pulex

Parasitology ◽  
1974 ◽  
Vol 68 (2) ◽  
pp. 271-284 ◽  
Author(s):  
A. E. Rumpus ◽  
C. R. Kennedy
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Host Population ◽  
Gammarus Pulex ◽  
Multiple Infections ◽  
Pomphorhynchus Laevis ◽  
Respiration Rates ◽  
Physiological Processes ◽  
Stage Of Development ◽  
Host Parasite

The respiration rates of individual Gammarus pulex infected by larval Pomphorhynchus laevis were investigated with particular reference to the stage of development of the host and parasite and to the water temperature. At 20°C the oxygen consumption of Gammarus of all sizes was reduced by an average of 19·3 % by the presence of cystacanths of the parasite, but was unaffected by the presence of acanthellae. It is considered that the small size of this larval stage, in relation to that of its host, is responsible for the failure to detect an effect. Multiple infections did not exert any greater effect upon host respiration than single cystacanths, nor did it appear that the parasite had different effects upon hosts of different sexes. At 10°C no significant differences were observed between the respiration rates of infected and uninfected gammarids. The parasite was probably still depressing the host respiration rate at this temperature, but the oxygen uptake of G. pulex is so low that the differences between infected and uninfected individuals were too small to be detected. The parasite has a direct effect upon the physiological processes of the host, but neither the mechanism of this nor the reasons for the different effects found in different host-parasite systems are yet understood. Despite the pronounced effect of P. laevis on respiration of individual hosts, its effect upon the oxygen consumption of a natural host population is small since only a small proportion of the population carries infections and water temperatures remain below 10°C for over half the year.

Population variation in the metabolic response of deer mice to infection with Capillaria hepatica (Nematoda)

2001 ◽  
Vol 79 (4) ◽  
pp. 554-561 ◽  
Author(s):  
Shawn Meagher ◽  
Timothy P O'Connor
Keyword(s):  
Cold Stress ◽  
Metabolic Response ◽  
Host Population ◽  
Population Variation ◽  
Deer Mice ◽  
Negative Consequences ◽  
Capillaria Hepatica ◽  
Generation Times ◽  
Stress Maximum ◽  
Host Parasite

The effects of parasites on their hosts can vary among host populations, but few studies have examined geographic variation in host-parasite interactions. We examined the effects of Capillaria hepatica (Nematoda) infection on deer mice (Peromyscus maniculatus gracilis) from two different populations. Specifically, we measured the basal metabolic rate (BMR), cold-stress maximum oxygen consumption (MRpeak), metabolic scope (MRpeak/BMR), and thermogenic endurance of infected and uninfected mice from one population with, and a second population without, a history with C. hepatica. Infection had no effect on BMR, but did have effects on cold-stress measures. A previous study documented a significant relationship between survival and MRpeak in wild deer mice; hence, the effects of infection on the parameters that we measured could influence fitness. Only mice that had no historical association with C. hepatica displayed negative consequences of infection, which suggests that the historical host population has evolved mechanisms to cope with infection. Models of the evolution of virulence should include evolutionary responses of both hosts and parasites, particularly when systems involve macroparasites that have long generation times.

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.

Sublethal effects of organophosphorus insecticide phoxim on patch time allocation and oviposition behavior in a parasitoid wasp Meteorus pulchricornis

2021 ◽  
pp. 1-10
Author(s):  
Sheng Sheng ◽  
Yan Song ◽  
Sheraz Ahmad ◽  
Jiao Wang ◽  
Ying Shao ◽  
...  
Keyword(s):  
Time Allocation ◽  
Sublethal Effects ◽  
Insect Pests ◽  
Oviposition Behavior ◽  
Host Density ◽  
Parasitoid Wasp ◽  
Patch Time Allocation ◽  
Meteorus Pulchricornis ◽  
Allocation Decisions ◽  
Patch Residence Time

Abstract Parasitoid wasps are key agents for controlling insect pests in integrated pest management programs. Although many studies have revealed that the behavior of parasitic wasps can be influenced by insecticides, the strategies of patch time allocation and oviposition have received less attention. In the present study, we forced the endoparasitoid Meteorus pulchricornis to phoxim exposure at the LC30 and tested the foraging behavior within patches with different densities of the host, the larvae of the tobacco cutworm Spodoptera litura. The results showed that phoxim treatment can significantly increase the patch-leaving tendency of female wasps, while host density had no impact. The number of oviposition and the number of previous patch visits also significantly influenced the patch time allocation decisions. The occurrence of oviposition behavior was negatively affected by phoxim exposure; however, progeny production was similar among patches with different host densities. Phoxim exposure shaped the offspring fitness correlates, including longer durations from cocoon to adult wasps, smaller body size, and shorter longevity. The findings of the present study highlight the sublethal effects that reduce the patch residence time and the fitness of parasitoid offspring, suggesting that the application of phoxim in association with M. pulchricornis should be carefully schemed in agroecosystems.

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 Assessing the direct and indirect effects of food provisioning and nutrient enrichment on wildlife infectious disease dynamics

2018 ◽  
Vol 373 (1745) ◽  
pp. 20170101 ◽  
Author(s):  
David J. Civitello ◽  
Brent E. Allman ◽  
Connor Morozumi ◽  
Jason R. Rohr
Keyword(s):  
Nutrient Enrichment ◽  
Management Strategies ◽  
Wildlife Disease ◽  
Host Population ◽  
Food Provisioning ◽  
Resource Subsidies ◽  
Predator Species ◽  
Interacting Species ◽  
Integrative View ◽  
Host Parasite

Anthropogenic resource supplementation can shape wildlife disease directly by altering the traits and densities of hosts and parasites or indirectly by stimulating prey, competitor or predator species. We first assess the direct epidemiological consequences of supplementation, highlighting the similarities and differences between food provisioning and two widespread forms of nutrient input: agricultural fertilization and aquatic nutrient enrichment. We then review an aquatic disease system and a general model to assess whether predator and competitor species can enhance or overturn the direct effects of enrichment. All forms of supplementation can directly affect epidemics by increasing host population size or altering parasite production within hosts, but food provisioning is most likely to aggregate hosts and increase parasite transmission. However, if predators or competitors increase in response to supplementation, they could alter resource-fuelled outbreaks in focal hosts. We recommend identifying the traits of hosts, parasites or interacting species that best predict epidemiological responses to supplementation and evaluating the relative importance of these direct and indirect mechanisms. Theory and experiments should examine the timing of behavioural, physiological and demographic changes for realistic, variable scenarios of supplementation. A more integrative view of resource supplementation and wildlife disease could yield broadly applicable disease management strategies. This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife’.

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