Natal-Host Environmental Effects on Juvenile Size, Transmission Success, and Operational Sex Ratio in the Entomopathogenic Nematode<i>Steinernema carpocapsae</i>

Therese, M. O.; Bashey, Farrah

doi:10.1645/ge-3069.1

Cited by 11 publications

(15 citation statements)

References 57 publications

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“…The emergence of IJs from the host cadaver often begins abruptly, peaks during the first few days, and involves tens or hundreds of thousands of IJs (e.g., Rolston, Griffin, & Downes, 2006). Certain traits of IJs vary predictably as the emergence progresses: early emerging IJs are typically larger and, in steinernematids, have either a more male-biased or female-biased sex ratio compared to later emerging IJs (Alsaiyah, Ebssa, Zenner, O'Callaghan, & Griffin, 2009;Nguyen & Smart, 1995;Therese & Bashey, 2012). The pattern of IJ emergence and certain characteristics of IJs could be associated with the population dynamics of the nematodes and their bacteria within the host cadaver, the availability and utilization of resources, and other conditions and cues that trigger the formation and release of IJs; and much of this could be associated with intense intraspecific competition.…”

Section: Intraspecific Competition and Cooperation Among Entomopathogmentioning

confidence: 99%

“…When a host is colonized by EPNs, a certain number of IJs are necessary to overcome host defenses Wang, Gaugler, & Cui, 1994) and to guarantee mating for steinernematids but too many IJs might impede development, survival, and reproduction (Selvan, Campbell, & Gaugler, 1993;Zervos, Johnson, & Webster, 1991; but see Therese & Bashey, 2012). Given the large number of IJs that emerge from a single cadaver, various strategies could have evolved to regulate dispersal and infectivity.…”

Section: Intraspecific Competition and Cooperation Among Entomopathogmentioning

confidence: 99%

See 1 more Smart Citation

Entomopathogenic Nematodes in the Soil Environment: Distributions, Interactions and the Influence of Biotic and Abiotic Factors

Stuart¹,

Barbercheck

Grewal³

2015

Nematode Pathogenesis of Insects and Other Pests

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Section: Intraspecific Competition and Cooperation Among Entomopathogmentioning

confidence: 99%

Section: Intraspecific Competition and Cooperation Among Entomopathogmentioning

confidence: 99%

Entomopathogenic Nematodes in the Soil Environment: Distributions, Interactions and the Influence of Biotic and Abiotic Factors

Stuart¹,

Barbercheck

Grewal³

2015

Nematode Pathogenesis of Insects and Other Pests

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“…If we consider that "reproductive success can be defined as the passing of genes on to the next generation in a way that they too can pass those genes on" (Pagel, 2009) -that is, we must not only consider the reproductive success of an individual or population but also the probability passing on that capacity to the progeny -then "the genetic contribution of a subpopulation to the next generation depends not only on the number of propagules produced but also critically on the fitness of these propagules" (Therese & Bashey, 2012). In this regard, only certain fraction of a female's eggs hatch into larvae, and only a portion of those larvae will have an adequate infective capacity, in order to pass on those genes to the next generation.…”

Section: Discussionmentioning

confidence: 99%

“…Such multiple fecundations could result in a major degree of genetic variability in the progeny and as a consequence affect the reproductive success. Furthermore, in the example of the gordiids, what must also be kept in mind is "the importance of the host environment to the fitness of parasites and the potential for trans-hosts [sic] effects to alter the ecological and evolutionary dynamics of parasite populations" (Therese & Bashey, 2012).…”

Section: Discussionmentioning

confidence: 99%

Analysis of the Infectivity of Chordodes Nobilii Larvae (Gordiida, Nematomorpha)

Achiorno

Villalobos

Ferrari

2016

RBT

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Abstract:The gordiids are freshwater representatives of the parasite phylum Nematomorpha that function as a link between aquatic and terrestrial ecosystems. In recent years, different ecotoxicologic studies have been made with the South-American gordiid species, Chordodes nobilii, that have demonstrated the capacity of this group to act as a bioindicator of contamination. Despite the Gordiida's ecologic relevance, further studies are still needed to elucidate different aspects of the biology of the class, and among those, the infective capacity, a parameter that can be evaluated by the infection index mean abundance (IIMA). A knowledge of the intrinsic variability in the infective capacity of C. nobilii would warrant priority in order to establish, the range of acceptable responses for normal or standard conditions in the laboratory, and, to compare the criteria among different assays. The objective of this study was to establish a baseline value for the infective capacity for C. nobilii larvae, under controlled laboratory conditions, by employing the IIMA as the evaluation parameter. To that end, we analyzed the infective capacity of C. nobilii larvae that had hatched from different strings of eggs laid in the laboratory by a total of 12 females. The C. nobilii adults were collected from streams within the Argentina Sauce Grande basin, between 2006 and 2009. Once in the laboratory, after mating, the females were placed in individual containers for oviposition. The egg strings obtained from each female were cut in 3 mm long segments; and when free larvae were observed, the segments (N= 90) were placed together with 30 Aedes aegypti larvae for evaluation of the gordiids' infective capacity. After 72 h, the mosquito larvae were observed by microscopy in order to quantify the C. nobilii larvae in body cavities. The IIMAs were calculated as the total number of C. nobilii larvae present divided by total number of A. aegypti larvae examined. For analysis of the IIMAs obtained, the data were grouped according to the female who made the original ovoposition. Our results enabled the corroboration of an ample range of responses in the infective capacity of this species, a characteristic that would normally be linked to the progenitors originating the hatch. Because this relationship prevents the establishment of a baseline for making comparisons among assays with gordiids, through the IIMA as a response parameter, we recommend expressing the IIMA values in each assay relative to their respective controls. These findings also provide evidence for the greater success in infections by certain members of the progeny over others. Finally, on the basis of the results obtained from this study, we stress the relevance of the use of the IIMA as a decisive aspect to be considered in different studies on the biology of Gordiida. Rev. Biol. Trop. 65 (1): 1-8. Epub 2017 March 01.Key words: parasite, Nematomorpha, infective capacity, infection index mean abundance, female.Within aquatic environments, the gordiids -freshwater representa...

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“…2007). Thus, species differences in initial energy reserves (Therese and Bashey 2012), host foraging behavior (Lewis et al. 1995), or reliance on their bacterial symbiont (Sicard et al.…”

Section: Methodsmentioning

confidence: 99%

Aging alters interspecific competition between two sympatric insect–parasitic nematode species

Bashey

Sarin

Lively

2016

Ecology and Evolution

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Interspecific competition can vary depending on the stage, age, or physiological state of the competitors. Competitive ability often increases with age or size; alternatively, senescence can lead to a loss of viability and reduced competitive success. Differences between species in their age‐specific competitive abilities can promote coexistence in the face of substantial niche overlap.We examined two sympatric species of nematodes (genus Steinernema) to determine whether their competitive relationship changes as a function of age. These obligately killing insect parasites are known for their broad host ranges and are transmitted from insect to insect via a juvenile stage propagule that is free‐living in the soil. Here, we tested whether the two species differed in the effects of age by examining the mortality of insect hosts infected with young or old transmission stage nematodes of each species. We also performed mixed infections, where an equal ratio of both species was simultaneously exposed to a host, to determine the effect of age on competitiveness.One species showed reduced performance with age, as older propagules were slower at inducing host mortality. In contrast, the other species increased in killing speed with age. In competition, insect mortality rate was predictive of competitive outcome, such that if one species induced considerably faster host death in a single‐species infection, it was competitively dominant in the coinfection. Accordingly, we found a shift in the competitive relationship between the two species with age.Our work demonstrates that species differences in the effects of aging can lead to dramatic shifts in reproductive success. As these effects are realized solely in a competitive environment, both spatial patchiness and temporal niche partitioning may be important for promoting coexistence.

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Natal-Host Environmental Effects on Juvenile Size, Transmission Success, and Operational Sex Ratio in the Entomopathogenic NematodeSteinernema carpocapsae

Cited by 11 publications

References 57 publications

Entomopathogenic Nematodes in the Soil Environment: Distributions, Interactions and the Influence of Biotic and Abiotic Factors

Entomopathogenic Nematodes in the Soil Environment: Distributions, Interactions and the Influence of Biotic and Abiotic Factors

Analysis of the Infectivity of Chordodes Nobilii Larvae (Gordiida, Nematomorpha)

Aging alters interspecific competition between two sympatric insect–parasitic nematode species

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