Benefits of fidelity: does host specialization impact nematode parasite life history and fecundity?

Koprivnikar, Janet; Randhawa, Haseeb S.

doi:10.1017/s0031182012002132

Cited by 9 publications

(8 citation statements)

References 85 publications

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“…When new hosts establish in a region, they may introduce new parasites to the residents (‘spillover’); however, resident species can also transmit novel parasites to introduced/non‐resident species (reviewed by Thompson ). In addition, migratory and resident birds may serve as competent hosts for each other's nematodes, thereby increasing the overall reservoir of infection (‘spillback’, Kelly et al ) but it will be important to determine nematode host specificity as this will impact transmission potential (Koprivnikar and Randhawa ).…”

Section: Discussionmentioning

confidence: 99%

Flying with diverse passengers: greater richness of parasitic nematodes in migratory birds

Koprivnikar

Leung

2014

Oikos

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Environmental changes are simultaneously affecting parasitic diseases and animal migrations, making it important to understand the disease dynamics of migratory species, including their range of infections and investment into defences. There is an urgent need for such knowledge because migratory animals, especially birds, are important for pathogen transmission and also particularly sensitive to environmental changes. Here we compare the nematode species richness and relative immune investment (via relative spleen size) of almost 200 migratory and non‐migratory species within three diverse groups of birds (Anseriformes, Accipitriformes and Turdidae) with worldwide distributions and varied ecology. Our results provide the first large‐scale demonstration that migratory birds face greater challenge from macroparasites as they have significantly dissimilar nematode fauna and higher nematode species richness compared to non‐migratory species. Even though birds with relatively large spleens had more nematode species, there was no difference in relative spleen size between migratory and non‐migratory bird species. The physiological stress of migration can be exacerbated by the potential range of pathologies induced by their richer nematode communities, particularly in combination with environmental perturbations. Altered migration stemming from global changes can also have important consequences for nematode transmission.

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Section: Discussionmentioning

confidence: 99%

Flying with diverse passengers: greater richness of parasitic nematodes in migratory birds

Koprivnikar

Leung

2014

Oikos

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“…Evidence for a cost of generalism in terms of a negative trade-off between host range width and parasite fitness is currently equivocal. For example, Koprivnikar & Randhawa (2013) found no general trade-off between host specificity and average prepatent period (time to first reproduction), female size, egg size or fecundity in nematodes. Ecological specialization is a complex topic that is still attracting conceptual clarification (e.g.…”

Section: Lateral Incorporation and The Generalist-specialist Problemmentioning

confidence: 93%

Evolution of complex life cycles in trophically transmitted helminths. I. Host incorporation and trophic ascent

Parker

Ball

Chubb

2015

J of Evolutionary Biology

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Links between parasites and food webs are evolutionarily ancient but dynamic: life history theory provides insights into helminth complex life cycle origins. Most adult helminths benefit by sexual reproduction in vertebrates, often high up food chains, but direct infection is commonly constrained by a trophic vacuum between free-living propagules and definitive hosts. Intermediate hosts fill this vacuum, facilitating transmission to definitive hosts. The central question concerns why sexual reproduction, and sometimes even larval growth, is suppressed in intermediate hosts, favouring growth arrest at larval maturity in intermediate hosts and reproductive suppression until transmission to definitive hosts? Increased longevity and higher growth in definitive hosts can generate selection for larger parasite body size and higher fecundity at sexual maturity. Life cycle length is increased by two evolutionary mechanisms, upward and downward incorporation, allowing simple (one-host) cycles to become complex (multihost). In downward incorporation, an intermediate host is added below the definitive host: models suggest that downward incorporation probably evolves only after ecological or evolutionary perturbations create a trophic vacuum. In upward incorporation, a new definitive host is added above the original definitive host, which subsequently becomes an intermediate host, again maintained by the trophic vacuum: theory suggests that this is plausible even under constant ecological/evolutionary conditions. The final cycle is similar irrespective of its origin (upward or downward). Insights about host incorporation are best gained by linking comparative phylogenetic analyses (describing evolutionary history) with evolutionary models (examining selective forces). Ascent of host trophic levels and evolution of optimal host taxa ranges are discussed.

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“…polyphylla suggest that R . regina is better adapted to this host [ 56 – 58 ]. Attributes such as virulence and immune evasion of R .…”

Section: Discussionmentioning

confidence: 99%

To live free or being a parasite: The optimal foraging behavior may favor the evolution of entomopathogenic nematodes

Trejo-Meléndez,

Contreras-Garduño

2024

PLoS ONE

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Facultative parasites can alternate between a free-living and a parasitic existence to complete their life cycle. Yet, it remains uncertain which lifestyle they prefer. The optimal foraging theory suggests that food preferences align with fitness benefits. To test this hypothesis, we investigated the facultative parasite nematode Rhabditis regina, assessing its host preference and the associated benefits. Two experiments were conducted using wild nematode populations collected from Phyllophaga polyphylla, their natural host. In the first experiment, we used a behavioral arena to assess host preference between the natural host and two experimental hosts: Spodoptera frugiperda which is an alternative host and dead Tenebrio molitor, which simulates a saprophytic environment. In the second experiment, we subjected wild nematodes to "experimental evolution" lasting 50 generations in S. frugiperda and 53 generations in T. molitor carcass. We then compared life history traits (the size, survival, number of larvae, and glycogen and triglycerides as energy reserves) of dauer larvae with those nematodes from P. polyphylla (control group). We found a significant preference for P. polyphylla, which correlated with higher values in the nematode’s life history traits. In contrast, the preference for S. frugiperda and the saprophytic environment was lower, resulting in less efficient life history traits. These findings align with the optimal foraging theory, as the nematode’s parasitic preferences are in line with maximizing fitness. This also indicates that R. regina exhibits specificity to P. polyphylla and is better adapted to a parasitic lifestyle than a free-living one, suggesting an evolutionary pathway towards parasitism.

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Benefits of fidelity: does host specialization impact nematode parasite life history and fecundity?

Cited by 9 publications

References 85 publications

Flying with diverse passengers: greater richness of parasitic nematodes in migratory birds

Flying with diverse passengers: greater richness of parasitic nematodes in migratory birds

Evolution of complex life cycles in trophically transmitted helminths. I. Host incorporation and trophic ascent

To live free or being a parasite: The optimal foraging behavior may favor the evolution of entomopathogenic nematodes

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