scholarly journals Host manipulation as a parasite transmission strategy when manipulation is exploited by non-host predators

2008 ◽  
Vol 4 (6) ◽  
pp. 663-666 ◽  
Author(s):  
Otto Seppälä ◽  
Jukka Jokela
Keyword(s):  
Predation Risk ◽  
Transmission Probability ◽  
Parasite Transmission ◽  
Host Manipulation ◽  
Predator Species ◽  
Transmission Strategy ◽  
Adaptive Value ◽  
Parasite Populations ◽  
Manipulation Strategy ◽  
Increased Susceptibility

Trophically transmitted parasites often alter their intermediate host's phenotype, thereby predisposing hosts to increased predation. This is generally considered to be a parasite strategy evolved to enhance transmission to the next host. However, the adaptive value of host manipulation is not clear, as it may be associated with costs, such as increased susceptibility to predator species that are unsuitable next hosts for the parasites. Thus, it has been proposed that, to be adaptive, manipulation should be specific by predisposing hosts more strongly to predation by target hosts (next host in the life cycle) than to non-hosts. Here we formally evaluate this prediction, and show that manipulation does not have to be specific to be adaptive. However, when manipulation is nonspecific, it needs to effectively increase the overall predation risk of infected hosts if it is to increase the parasite transmission probability. Thus, when initial predation risk is low, even highly nonspecific manipulation strategies can be adaptive. However, when initial predation risk is high, manipulation needs to be more specific to increase parasite transmission success. Therefore, nonspecific host manipulation may evolve in nature, but the adaptive value of a certain manipulation strategy can vary among different parasite populations depending on the variation in initial predation risk.

scholarly journals Host manipulation by parasites in the world of dead-end predators: adaptation to enhance transmission?

2008 ◽  
Vol 275 (1643) ◽  
pp. 1611-1615 ◽  
Author(s):  
Otto Seppälä ◽  
E. Tellervo Valtonen ◽  
Daniel P Benesh
Keyword(s):  
Definitive Host ◽  
Host Manipulation ◽  
Transmission Success ◽  
Adaptive Value ◽  
Dead End ◽  
The World ◽  
Acanthocephalus Lucii ◽  
Trophically Transmitted Parasites ◽  
Benefits And Costs ◽  
Increased Susceptibility

Trophically transmitted parasites often alter their intermediate host's phenotype, thereby predisposing the hosts to increased predation. This is generally considered a parasite strategy evolved to enhance transmission to the next hosts. However, the adaptive value of host manipulation is not clear as it may be associated with costs, such as increased susceptibility to predators that are unsuitable next hosts for the parasites. We examined the ratio between the benefits and costs of host manipulation for transmission success of Acanthocephalus lucii (Acanthocephala), a parasite that alters the hiding behaviour and pigmentation of its isopod hosts. We experimentally compared the susceptibility of infected and uninfected isopods to predation by perch ( Perca fluvialis ; definitive host of the parasite) and dragonfly larvae (dead end). We found that the parasite predisposed the isopods to predation by both predators. However, the increased predation vulnerability of the infected isopods was higher towards perch. This suggests that, despite the costs due to non-host predation, host manipulation may still be advantageous for the parasite.

Pollutant-induced effects on immunological and physiological interactions in aquatic host–trematode systems: implications for parasite transmission

2006 ◽  
Vol 80 (2) ◽  
pp. 137-149 ◽  
Author(s):  
N.J. Morley ◽  
J.W. Lewis ◽  
D. Hoole
Keyword(s):  
Life Cycles ◽  
Economic Importance ◽  
Parasite Transmission ◽  
Combined Stress ◽  
Complex Life Cycles ◽  
Physiological Processes ◽  
Digenetic Trematodes ◽  
Functional Biology ◽  
Parasite Populations ◽  
Pathogenic Effects

AbstractUnder conditions of pollution both host and parasite are susceptible to the pathogenic effects of toxicants, which in turn may result in detrimental changes to their immunological and physiological processes. Digenetic trematodes, which encompass species of both medical and economic importance, possess complex life cycles and are common parasites of both vertebrates and molluscs. The combined stress induced by pollution and parasitism influences the physiology of the host which can have implications not only on host survival but also on the functional biology of resident parasite populations. The present paper reviews the effects of pollutants on the immunology and physiology in both vertebrate and molluscan host–trematode systems and the implications for parasite transmission.

Increased susceptibility of salmonids to the monogenean Gyrodactylus salaris following administration of hydrocortisone acetate

Parasitology ◽  
2000 ◽  
Vol 120 (1) ◽  
pp. 57-64 ◽  
Author(s):  
P. D. HARRIS ◽  
A. SOLENG ◽  
T. A. BAKKE
Keyword(s):  
Salmo Trutta ◽  
Salvelinus Fontinalis ◽  
Salvelinus Alpinus ◽  
Arctic Charr ◽  
Hydrocortisone Acetate ◽  
Hydrocortisone Administration ◽  
Resistant Group ◽  
Parasite Populations ◽  
Practical Level ◽  
Increased Susceptibility

Gyrodactylus salaris infects numerous salmonid species, ranging from the fully susceptible (Norwegian strains of Salmo salar), through species which, though initially susceptible, eventually eliminate their infections (Salvelinus alpinus and S. fontinalis) to entirely resistant (Salmo trutta) species. Here we describe experiments in which Salvelinus alpinus, S. fontinalis and Salmo trutta, implanted with hydrocortisone acetate to simulate stress-induced immunosuppression, were challenged with G. salaris. With previously uninfected Salvelinus fontinalis, G. salaris infections on fish treated with hydrocortisone acetate grew larger, and for longer, than on sham-treated controls. A similar result was obtained with S. trutta. Patterns of infection on Arctic charr, Salvelinus alpinus, were more complex, because individual fish varied from susceptible to highly resistant. Fish were therefore initially infected with G. salaris, and the most highly resistant group of individuals identified and disinfected. After 6 months recovery from this primary infection, hydrocortisone acetate was administered to half the fish, and all were challenged with G. salaris. Parasite populations on the hydrocortisone-treated individuals were consistently larger than those on the sham-treated controls, exceeding 30 parasites per fish after 5 weeks, in comparison with less than 10 parasites per fish on controls. These results indicate that hydrocortisone administration can lead to enhanced gyrodactylid populations on a range of salmonids. This suggests that the response to G. salaris is mediated by the immune system, and that the spectrum of responses observed in different species are, at least in part, due to the same mechanism. At a practical level, stress-induced immunosuppression during handling and transport of cultured salmonids may prove an important factor in the dissemination of G. salaris between watersheds.

scholarly journals Testing Whether Camera Presence Influences Habitat Specific Predation Pressure on Artificial Shorebird Nests in the Arctic

ARCTIC ◽  
2021 ◽  
Vol 74 (1) ◽  
pp. 22-29
Author(s):  
Kevin G. Young ◽  
Lisa V. Kennedy ◽  
Paul A. Smith ◽  
Erica Nol
Keyword(s):  
Predation Risk ◽  
Proportional Hazards Model ◽  
Habitat Type ◽  
Cox Proportional Hazards Model ◽  
The Arctic ◽  
Arctic Fox ◽  
Artificial Nests ◽  
Predator Species ◽  
Risk Of Predation ◽  
The Impact

When monitoring the breeding ecology of birds, the causes and times of nest failure can be difficult to determine. Cameras placed near nests allow for accurate monitoring of nest fate, but their presence may increase the risk of predation by attracting predators, leading to biased results. The relative influence of cameras on nest predation risk may also depend on habitat because predator numbers or behaviour can change in response to the availability or accessibility of nests. We evaluated the impact of camera presence on the predation rate of artificial nests placed within mesic tundra habitats used by Arctic-breeding shorebirds. We deployed 94 artificial nests, half with cameras and half without, during the shorebird-nesting season of 2015 in the East Bay Migratory Bird Sanctuary, Nunavut. Artificial nests were distributed evenly across sedge meadow and supratidal habitats typically used by nesting shorebirds. We used the Cox proportional hazards model to assess differential nest survival in relation to camera presence, habitat type, placement date, and all potential interactions. Artificial nests with cameras did not experience higher predation risk than those without cameras. Predation risk of artificial nests was related to an interaction between habitat type and placement date. Nests deployed in sedge meadows and in supratidal habitats later in the season were subject to a higher risk of predation than those deployed in supratidal habitats early in the season. These differences in predation risk are likely driven by the foraging behaviour of Arctic fox (Vulpes lagopus), a species that accounted for 81% of observed predation events in this study. Arctic fox prey primarily on Arvicoline prey and goose eggs at this site and take shorebird nests opportunistically, perhaps more often later in the season when their preferred prey becomes scarcer. This study demonstrates that, at this site, cameras used for nest monitoring do not influence predation risk. Evaluating the impact of cameras on predation risk is critical prior to their use, as individual study areas may differ in terms of predator species and behaviour.

Vulnerability To Predation in Baboon Populations

Behaviour ◽  
1994 ◽  
Vol 131 (3-4) ◽  
pp. 293-304 ◽  
Author(s):  
Guy Cowlishaw
Keyword(s):  
Predation Risk ◽  
Prey Capture ◽  
Prey Selection ◽  
Predator Species ◽  
Sleeping Sites

AbstractThis study investigates patterns of predation in Papio baboon populations across Africa. Using anecdotal reports collated from the primate and predator literature, the following analyses are conducted. First, the primary predators of baboons are identified. These are shown to be the terrestrial carnivores; in order of importance leopards, lions and hyena. Second, patterns of large felid predation on baboons are investigated in detail. In terms of prey selection, leopards are more likely to take (1) adults than juveniles and (2) males than females. While lion attacks are strictly diurnal, leopards will attack during both the day and night. However, both predators are usually limited to conducting attacks when and/or where visibility is limited. Leopards were about twice as successful as lions at hunting baboons. Nocturnal leopard hunts were more successful than diurnal hunts when twilight cases were excluded; in relation to this, leopard attacks at sleeping sites were more likely to end in prey capture than attacks at waterholes. Finally, patterns of baboon retaliation against predators revealed that males are more likely to retaliate than females and that such behaviour effectively deters predators. Males are particularly aggressive towards leopards, where in 4/11 cases the leopard was killed. These results may help to resolve a number of outstanding controversies regarding the nature of predation risk in baboons, indicating that diurnal predation is a substantial threat, that males are effective at deterring several predator species, particularly leopards, and that predators will successfully attack and capture males.

Is prey predation risk influenced more by increasing predator density or predator species richness in stream enclosures?

Oecologia ◽  
2004 ◽  
Vol 139 (1) ◽  
pp. 117-122 ◽  
Author(s):  
Heather D. Vance-Chalcraft ◽  
Daniel A. Soluk ◽  
Nicholas Ozburn
Keyword(s):  
Species Richness ◽  
Predation Risk ◽  
Predator Density ◽  
Predator Species

Susceptibility of eye fluke-infected fish to predation by bird hosts

Parasitology ◽  
2005 ◽  
Vol 132 (4) ◽  
pp. 575-579 ◽  
Author(s):  
O. SEPPÄLÄ ◽  
A. KARVONEN ◽  
E. T. VALTONEN
Keyword(s):  
Transmission Efficiency ◽  
Infected Fish ◽  
Parasite Transmission ◽  
Host Manipulation ◽  
Laboratory Studies ◽  
Intermediate Hosts ◽  
Diplostomum Spathaceum ◽  
In The Wild ◽  
Set Up ◽  
Eye Fluke

Host manipulation by trophically transmitted parasites may predispose infected hosts to predation and in this way enhance parasite transmission. In most study systems, however, the evidence comes from laboratory studies, and therefore knowledge of the effect of manipulation on parasite transmission efficiency in the wild is still limited. Here we examined the effect ofDiplostomum spathaceum(Trematoda) eye flukes on the susceptibility of fish intermediate hosts to predation by bird definitive hosts. Our earlier studies have shown that the parasite alters fish phenotype and increases their susceptibility to artificial predation under laboratory conditions. In the present field study, we allowed wild birds to feed on fish from cages placed into a lake, and found that predation vulnerability of infected fish did not differ from that of controls. However, we suggest that the experimental set-up likely affected the result because the cages allowed gulls, which caught most of the fish in the study, to feed on fish in an easy, unnatural manner by standing on the edges of the cages. Nevertheless, considerable predation was observed, which provides important initial evidence of how this question should be addressed in the wild.

scholarly journals Behavioral Responses of Wild Rodents to Owl Calls in an Austral Temperate Forest

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 428
Author(s):  
Mᵃ Carmen Hernández ◽  
Denise M. Jara-Stapfer ◽  
Ana Muñoz ◽  
Cristian Bonacic ◽  
Isabel Barja ◽  
...  
Keyword(s):  
Predation Risk ◽  
Temperate Forest ◽  
Rattus Rattus ◽  
Camera Traps ◽  
Rodent Species ◽  
Control Treatment ◽  
Feeding Time ◽  
Rodent Control ◽  
Wild Rodents ◽  
Predator Species

Ecologically based rodent management strategies are arising as a sustainable approach to rodent control, allowing us to preserve biodiversity while safeguarding human economic activities. Despite predator signals being known to generally repel rodents, few field-based studies have compared the behavioral effects of several predators on different prey species, especially in Neotropical ecosystems. Here, we used camera traps to study the behavior of rodent species native to the Chilean temperate forest (Abrothrix spp., long-tailed pygmy rice rat Oligoryzomys longicaudatus) and an introduced rodent (black rat Rattus rattus). Using playbacks of raptor calls, we experimentally exposed rodents to three predation risk treatments: austral pygmy owl calls (Glaucidium nana), rufous-legged owl calls (Strix rufipes) and a control treatment (absence of owl calls). We evaluated the effects of the treatments on the time allocated to three behaviors: feeding time, locomotor activity and vigilance. Moonlight and vegetation cover were also considered in the analyses, as they can modify perceived predation risk. Results showed that predator calls and environmental factors modified prey behavior depending not only on the predator species, but also on the rodent species. Consequently, owl playbacks could be regarded as a promising rodent control tool, knowing that future studies would be critical to deeply understand differences between species in order to select the most effective predator cues.

scholarly journals Tricking Parents: A Review of Mechanisms and Signals of Host Manipulation by Brood-Parasitic Young

2021 ◽  
Vol 9 ◽  
Author(s):  
Juan M. Rojas Ripari ◽  
Cynthia A. Ursino ◽  
Juan C. Reboreda ◽  
María C. De Mársico
Keyword(s):  
Parental Care ◽  
Communication Systems ◽  
Parental Behavior ◽  
Future Research ◽  
Host Manipulation ◽  
Sensory Exploitation ◽  
Brood Parasites ◽  
The Past ◽  
Adaptive Value ◽  
Parental Feeding

Obligate avian brood parasites depend entirely on heterospecific hosts for rearing their offspring. From hatching until independence, the young parasites must deal with the challenge of obtaining sufficient parental care from foster parents that are attuned to provisioning their own offspring. Parent-offspring communication is mediated by complex begging displays in which nestlings and fledglings exhibit visual (e.g., gaping and postures) and vocal (e.g., begging calls) traits that serve as signals to parents to adjust and allocate parental effort. Parasites can manipulate host parental behavior by exploiting these stable parent-offspring communication systems in their favor. During the past 30 years, the study of host exploitation by parasitic chicks has yielded important insights into the function and evolution of manipulative signals in brood parasites. However, despite these major advances, there are still important gaps in our knowledge about how parasitic nestling and fledglings tune into the host’s communication channels and the adaptive value of the visual and acoustic signals they exhibit. Here we review the literature pertaining to host manipulation by parasitic young, focusing on four non-mutually exclusive mechanisms (i.e., host chick mimicry, begging exaggeration, host-attuned begging calls, and sensory exploitation) and the function and evolution of the signals involved, with the aim to summarize and discuss putative adaptations for stimulating parental feeding and escaping host discrimination. Finally, we bring some concluding remarks and suggest directions for future research on the ways in which brood parasites adapt to the communication systems of other birds to exploit the necessary parental care.

Specificity of theToxoplasma gondii-altered behaviour to definitive versus non-definitive host predation risk

Parasitology ◽  
2008 ◽  
Vol 135 (10) ◽  
pp. 1143-1150 ◽  
Author(s):  
P. H. L. LAMBERTON ◽  
C. A. DONNELLY ◽  
J. P. WEBSTER
Keyword(s):  
Toxoplasma Gondii ◽  
Drug Treatment ◽  
Predation Risk ◽  
Definitive Host ◽  
Predation Rate ◽  
Predator Species ◽  
Nest Box ◽  
Therapeutic Drugs ◽  
The Impact ◽  
Cognitive Alterations

SUMMARYThe hypothesis that the parasiteToxoplasma gondiimanipulates the behaviour of its intermediate rat host in order to increase its chance of being predated specifically by its feline definitive host, rather than a non-definitive host predator species, was tested. The impact of a range of therapeutic drugs, previously demonstrated to be effective in preventing the development ofT. gondii-associated behavioural and cognitive alterations in rats, on definitive-host predator specificity was also tested. Using a Y-shaped maze design, we demonstrated thatT. gondii-associated behavioural changes, apparently aimed to increase predation rate, do appear to be specific to that of the feline definitive host – there were significant and consistent differences between the (untreated) infected and uninfected rats groups whereT. gondii-infected rats tended to choose the definitive host feline-predator-associated maze arm and nest-box significantly more often than a maze arm or nest-box treated with non-definitive host predator (mink) odour. Drug treatment of infected rats prevented any such host-specificity from being displayed. We discuss our results in terms of their potential implications both forT. gondiiepidemiology and the evolution of parasite-altered behaviour.

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