Biology subjects

Rovenolt, F.

Publications and source records attributed to Rovenolt, F..

3 recordsLinked to original sources

bioRxiv2025

Pace of life predicts parasite resistance and fecundity tolerance, but not mortality tolerance, among Trinidadian guppies, Poecilia reticulata

Host defence against parasites can include limiting parasite growth, resistance, limiting the mortality cost of infection, mortality tolerance, and limiting the reproductive cost of infection, fecundity tolerance. Theoretically, these three host strategies have very different epidemiological and evolutionary outcomes. In particular, because mortality tolerance increases parasite population size, it is under strong positive frequency-dependent selection and may therefore be less variable between populations than either resistance or fecundity tolerance. Additionally, host investment in each strategy can be expected to differ between populations that experience different ecological conditions. Here, we tested how populations of Trinidadian guppies Poecilia reticulata from the upper and lower courses of three rivers responded to experimental infection with a novel strain of Gyrodactylus turnbulli. In line with theoretical predictions, we found that lower course populations, previously shown to have faster paces of life, invested less in resistance and fecundity tolerance - but not mortality tolerance - than the upper course populations with slower paces of life. Our results indicate that this host-parasite interaction both conforms to evolutionary-epidemiological theoretical predictions, and is shaped by broader ecological conditions.

evolutionary biology↗

bioRxiv2023

Infection affects guppy reproductive fitness and offspring parasite resistance

O_LIInfection imposes energetic costs on hosts. Hosts typically respond by shifting resources, potentially affecting the quantity and quality of offspring they produce. As the sexes differ in their optimal reproductive strategies, infection of mothers versus fathers may affect offspring quantity and quality in different ways. C_LIO_LIHere, we test how experimental infection of guppies Poecilia reticulata with the ectoparasite Gyrodactylus turnbulli affects parental reproductive fitness and offspring parasite resistance. We compared breeding pairs in which one or neither parent had previously been infected. C_LIO_LIIn terms of reproductive fitness, parental infection experience did not affect the size, body condition, or number of offspring produced, but fathers who experienced the heaviest infections produced offspring [~]55 days sooner than average. This result may represent terminal investment by the males most affected by infection, or may indicate that these males have a faster pace of life, investing in reproduction at the expense of parasite defence. C_LIO_LIWe found that offspring age, parental infection experience, and parental infection severity together strongly predicted offspring parasite resistance. Only among pairs in which one parent had been infected, older offspring, which were those born soonest after the parents infection, tended to experience heavier infections. This result may therefore reflect temporary infection-induced reductions in parental investment in offspring quality. Beyond this effect of offspring age, offspring of infected mothers experienced 105 fewer worm days than those of infected fathers: fathers, but not mothers, that experienced heavy infections themselves produced offspring that also experienced heavy infections. The parent-offspring regression for infected fathers is therefore consistent with previous evidence that parasite resistance is heritable in this system, and yields a narrow sense heritability estimate of 0.69{+/-}0.13. By contrast, the mother-offspring regression (slope: -0.13{+/-}0.17) provides novel insight that mothers may engage in transgenerational immune priming. C_LIO_LIOverall, our results suggest that the sexes strike a different balance between offspring quantity and quality when faced with infection, with potentially broad implications for disease and host-parasite coevolutionary dynamics in nature. C_LI

ecology↗

bioRxiv2021

Social hosts evade predation but have deadlier parasites

Parasites exploit hosts to replicate and transmit, but overexploitation kills host and parasite (1): predators may shift this cost-benefit balance by consuming hosts (2-4) or changing host behavior, but the strength of these effects remains unclear. Modeling both, we find a primary, strong effect: hosts group to defend against predators (5), increasing parasite transmission, thus multiple infections, and therefore favoring more exploitative, virulent, parasites (6). Indeed, among 18 Trinidadian Gyrodactyus spp. parasite lines, those collected from high predation guppy populations were more virulent in common garden than those from low predation populations. Our model accurately predicted this result when parametrized with our experimentally demonstrated virulence-transmission trade-off, implicating the behavioral effects of predation. Broadly, our results indicate that reduced social contact selects against parasite virulence. One-Sentence SummaryOur theory and data show predators cause increased host social grouping; the resulting transmission favors parasite virulence.

ecology↗