Effect of Temperature and Host Life Stage on Efficacy of Soil Entomopathogens Against the Swede Midge (Diptera: Cecidomyiidae)

2015 ◽  
Vol 108 (2) ◽  
pp. 473-483 ◽  
Author(s):  
B. G. Evans ◽  
K. S. Jordan ◽  
M. Brownbridge ◽  
R. H. Hallett
Keyword(s):  
Life Stage ◽  
Effect Of Temperature ◽  
Swede Midge ◽  
Host Life

scholarly journals Life-stage and sex influence Philornis ectoparasitism in a Neotropical woodpecker (Melanerpes striatus) with essential male parental care

2021 ◽  
Author(s):  
Joshua Burke LaPergola
Keyword(s):  
Parental Care ◽  
Recent Work ◽  
Life Stage ◽  
Bird Species ◽  
Adult Males ◽  
Sex Influence ◽  
Adult Females ◽  
Overnight Incubation ◽  
Per Se ◽  
Host Life

The nestlings of many Neotropical bird species suffer from Philornis (Diptera: Muscidae) ectoparasitism. While nestlings are typically considered the intended targets, recent work indicates that Philornis infest adult birds more frequently than previously appreciated, yet few studies have concurrently surveyed nestlings and adults for Philornis in the same population. Over six field seasons (2012 to 2017), I documented the presence of current or recent subcutaneous Philornis infestations on adult and nestling Hispaniolan Woodpeckers (Melanerpes striatus) from the same population. I tested the following three non-mutually exclusive hypotheses regarding occurrence of Philornis on adult birds: (1) nestlings are more vulnerable to Philornis parasitism than adults, (2) nesting is associated with Philornis parasitism in adults, and (3) Philornis parasitism is associated with incubation and brooding investment. While nestling and adult woodpeckers exhibited similar prevalence of parasitism, parasitized nestlings hosted on average 3.5 times more Philornis wounds (larvae plus scars) than parasitized adults. Nesting per se was not significantly associated with parasitism among adults, as breeding and non-breeding adults showed similar prevalence and intensity. However, adult males, which perform overnight incubation and brooding, were significantly more likely to be parasitized than adult females. This last result supports the hypothesis that incubation and brooding investment increase the risk of Philornis parasitism for adults, but this conclusion is complicated by the lack of an association between parasitism and nesting status. Together, these results raise questions about the degree of host life-stage specialization and whether adult parasitism is incidental or part of an alternative parasitic strategy for Philornis.

scholarly journals The expression of virulence for a mixed-mode transmitted parasite in a diapausing host

Parasitology ◽  
2014 ◽  
Vol 141 (8) ◽  
pp. 1097-1107 ◽  
Author(s):  
ELHAM SHEIKH-JABBARI ◽  
MATTHEW D. HALL ◽  
FRIDA BEN-AMI ◽  
DIETER EBERT
Keyword(s):  
Hatching Success ◽  
Life Stage ◽  
Horizontal Transmission ◽  
Resting Eggs ◽  
Life Stages ◽  
Infected Female ◽  
Population Prevalence ◽  
High Virulence ◽  
Host Life ◽  
Adaptive Nature

SUMMARYMany parasites survive harsh periods together with their hosts. Without the possibility of horizontal transmission during host diapause, parasite persistence depends entirely on host survival. We therefore hypothesize that a parasite should be avirulent during its host's diapausing stage. In contrast, the parasite may express higher virulence, i.e. parasite-induced fitness reduction of the host, during host life stages with good opportunities for horizontal transmission. Here we study the effects of a vertically and horizontally transmitted microsporidium parasite, Hamiltosporidium tvaerminnensis, on the quantity and survival of resting eggs of its host Daphnia magna. We find that the parasite did not affect egg volume, hatching success and time to hatching of the Daphnia's resting eggs, although it did strongly reduce the number of resting eggs produced by infected females, revealing high virulence during the non-diapause phase of the host's life cycle. These results also explain another aspect of this system – namely the strong decline in natural population prevalence across diapause. This decline is not caused by mortality in infected resting stages, as was previously hypothesized, but because infected female hosts produce lower rates of resting eggs. Together, these results help explain the epidemiological dynamics of a microsporidian disease and highlight the adaptive nature of life stage-dependent parasite virulence.

scholarly journals A link between mitochondrial gene expression and life stage morphologies in Trypanosoma cruzi

2019 ◽  
Author(s):  
Roger Ramirez-Barrios ◽  
Emily K. Susa ◽  
Sean P. Faacks ◽  
Charles K. Liggett ◽  
Sara L. Zimmer
Keyword(s):  
Gene Expression ◽  
Trypanosoma Cruzi ◽  
Mitochondrial Gene ◽  
Life Stage ◽  
Mitochondrial Rna ◽  
Mitochondrial Gene Expression ◽  
Signaling Mechanism ◽  
Transport Chain ◽  
Host Life ◽  
Induced Changes

SummaryThe protozoan Trypanosoma cruzi has a complicated dual-host life cycle, and starvation can trigger transition from the replicating insect stage to the mammalian-infectious nonreplicating insect stage (epimastigote to trypomastigote differentiation). Abundance of some mature RNAs derived from its mitochondrial genome increase during culture starvation of T. cruzi for unknown reasons. Here we examine T. cruzi mitochondrial gene expression in the mammalian intracellular replicating life stage (amastigote), and uncover implications of starvation-induced changes in gene expression in insect-stage cells. Mitochondrial RNA levels in general were found to be lowest in actively replicating amastigotes. We discovered that mitochondrial respiration decreases during starvation, despite the previously-observed increases in mitochondrial mRNAs encoding electron transport chain components. Surprisingly, T. cruzi epimastigotes in replete medium grow at normal rates when we genetically compromised their ability to perform insertion/deletion editing and thereby generate mature forms of some mitochondrial mRNAs. However, these cells, when starved, were impeded in the epimastigote to trypomastigote transition. Further, they experience a short-flagella phenotype that may also be linked to differentiation. We hypothesize a scenario where levels of mature RNA species or editing in the single T. cruzi mitochondrion are linked to differentiation by a yet-unknown signaling mechanism.

scholarly journals Effect of Temperature, Vector Life Stage, and Plant Access Period on Transmission of Banana bunchy top virus to Banana

2008 ◽  
Vol 98 (6) ◽  
pp. 743-748 ◽  
Author(s):  
M. D. Anhalt ◽  
R. P. P. Almeida
Keyword(s):  
Life Stage ◽  
Plant Viruses ◽  
Transmission Efficiency ◽  
Effect Of Temperature ◽  
Access Time ◽  
Banana Bunchy Top Virus ◽  
Access Period ◽  
Pentalonia Nigronervosa ◽  
The Relationship ◽  
Transmission Biology

The study of the transmission biology of insect-borne plant viruses is important to develop disease control practices. We characterized the transmission of a nanovirus, Banana bunchy top virus (BBTV), by its aphid vector Pentalonia nigronervosa Coquerel (Hemiptera, Aphididae) with respect to temperature, vector life stage, and plant access time. Adult aphids transmitted BBTV more efficiently than third instar nymphs at all temperatures tested. Adult aphids transmitted the virus more efficiently at 25 and 30°C than at 20°C, but temperature had no impact on transmission efficiency by nymphs. By decoupling the relationship between temperature and aphid BBTV acquisition or inoculation, we determined that temperature affected inoculation events more strongly than acquisition. Longer plant access periods increased viral acquisition and inoculation efficiencies in a range of 60 min to 24 h. Both BBTV acquisition and inoculation efficiencies peaked after 18 h of plant access period. We also show that BBTV transmission by P. nigronervosa requires a latent period. Our results demonstrate that vector transmission of BBTV is affected by temperature, vector life stage, and plant access period.

scholarly journals TEMPERATURE-DEPENDENT DEVELOPMENT OF THE MOUNTAIN PINE BEETLE (COLEOPTERA: SCOLYTIDAE) AND SIMULATION OF ITS PHENOLOGY

1991 ◽  
Vol 123 (5) ◽  
pp. 1083-1094 ◽  
Author(s):  
Barbara J. Bentz ◽  
Jesse A. Logan ◽  
Gene D. Amman
Keyword(s):  
Mountain Pine Beetle ◽  
Lodgepole Pine ◽  
Life Stage ◽  
Temporal Distribution ◽  
Effect Of Temperature ◽  
Life Stages ◽  
Temperature Dependent ◽  
Dependent Development ◽  
Mountain Pine ◽  
Pine Beetle

AbstractTemperature-dependent development of the egg, larval, and pupal life-stages of the mountain pine beetle (Dendroctonus ponderosae Hopkins) was described using data from constant-temperature laboratory experiments. A phenology model describing the effect of temperature on the temporal distribution of the life-stages was developed using these data. Phloem temperatures recorded in a beetle-infested lodgepole pine (Pinus contorta Douglas) were used as input to run the model. Results from model simulations suggest that inherent temperature thresholds in each life-stage help to synchronize population dynamics with seasonal climatic changes. This basic phenological information and the developed model will facilitate both research and management endeavors aimed at reducing losses in lodgepole pine stands caused by mountain pine beetle infestations.

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