scholarly journals Brood size and sex ratio in response to host quality and wasp traits in the gregarious parasitoidOomyzus sokolowskii(Hymenoptera: Eulophidae)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2919 ◽  
Author(s):  
Xianwei Li ◽  
Liangting Zhu ◽  
Ling Meng ◽  
Baoping Li
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Clutch Size ◽  
Brood Size ◽  
Linear Trend ◽  
Offspring Sex Ratio ◽  
Host Body ◽  
Larval Host ◽  
Host Instar ◽  
Host Body Size

This laboratory study investigated whether the larval-pupal parasitoidOomyzus sokolowskiifemales adjust their brood size and sex ratio in response to body size and stage ofPlutella xylostellalarval hosts, as well as to their own body size and the order of oviposition. These factors were analyzed using multiple regression with simultaneous entry of them and their two-way interactions. Parasitoids brood size tended to increase with host body size at parasitism when the 4th instar larval host was attacked, but did not change when the 2nd and 3rd instar larvae were attacked. Parasitoids did not vary in brood size according to their body size, but decreased with their bouts of oviposition on a linear trend from 10 offspring adults emerged per host in the first bout of oviposition down to eight in the third. Parasitoid offspring sex ratio did not change with host instar, host body weight, wasp body size, and oviposition bout. Proportions of male offspring per brood were from 11% to 13% from attacking the 2nd to 4th instar larvae and from 13% to 16% across three successive bouts of oviposition, with a large variation for smaller host larvae and wasps. When fewer than 12 offspring were emerged from a host, one male was most frequently produced; when more than 12 offspring were emerged, two or more males were produced. Our study suggests thatO. sokolowskiifemales may optimize their clutch size in response to body size of matureP. xylostellalarvae, and their sex allocation in response to clutch size.

Explaining variability in parasite aggregation levels among host samples

Parasitology ◽  
2013 ◽  
Vol 140 (4) ◽  
pp. 541-546 ◽  
Author(s):  
ROBERT POULIN
Keyword(s):  
Body Size ◽  
Strong Relationship ◽  
Host Susceptibility ◽  
Helminth Parasites ◽  
Susceptibility To Infection ◽  
Host Body ◽  
Parasite Aggregation ◽  
Using Data ◽  
Species Specific ◽  
Host Body Size

SUMMARYAggregated distributions among individual hosts are a defining feature of metazoan parasite populations. Heterogeneity among host individuals in exposure to parasites or in susceptibility to infection is thought to be the main factor generating aggregation, with properties of parasites themselves explaining some of the variability in aggregation levels observed among species. Here, using data from 410 samples of helminth parasites on fish hosts, I tested the contribution of (i) within-sample variation in host body size, taken as a proxy for variability in host susceptibility, and (ii) parasite taxon and developmental stage, to the aggregated distribution of parasites. Log-transformed variance in numbers of parasites per host was regressed against log mean number across all samples; the strong relationship (r2 = 0·88) indicated that aggregation levels are tightly constrained by mean infection levels, and that only a small proportion of the observed variability in parasite aggregation levels remains to be accounted for by other factors. Using the residuals of this regression as measures of ‘unexplained’ aggregation, a mixed effects model revealed no significant effect of within-sample variation in host body size or of parasite taxon or stage (i.e. juvenile versus adult) on parasite aggregation level within a sample. However, much of the remaining variability in parasite aggregation levels among samples was accounted for by the number of individual hosts examined per sample, and species-specific and study-specific effects reflecting idiosyncrasies of particular systems. This suggests that with most differences in aggregation among samples already explained, there may be little point in seeking universal causes for the remaining variation.

scholarly journals Costs of immune responses are related to host body size and lifespan

2017 ◽  
Vol 327 (5) ◽  
pp. 254-261 ◽  
Author(s):  
Amber J. Brace ◽  
Marc J. Lajeunesse ◽  
Daniel R. Ardia ◽  
Dana M. Hawley ◽  
James S. Adelman ◽  
...  
Keyword(s):  
Body Size ◽  
Immune Responses ◽  
Host Body ◽  
Host Body Size

scholarly journals Absence of complementary sex determination in Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae)

2019 ◽  
Author(s):  
Quan-quan Liu ◽  
Jin-cheng Zhou ◽  
Chen Zhang ◽  
Qian-jin Dong ◽  
Su-fang Ning ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
Brood Size ◽  
Indirect Evidence ◽  
Parasitoid Wasp ◽  
Mass Rearing ◽  
Diploid Male ◽  
Diploid Males ◽  
Offspring Sex Ratio ◽  
Complementary Sex Determination

Over 60 species in Hymenoptera have been reported to possess a complementary sex determination (CSD) system. Under CSD, sex is determined by allelic complementation at one or several sex loci. But this mechanism is still uninvestigated in parasitoid wasp Trichogramma dendrolimi, one of the most important biocontrol agents widely used against Lepidopteran pests. We tested CSD in this species by conducting ten consecutive generations of inbreeding, to monitor both direct evidence (diploid male production) and indirect evidence (brood size, sex ratio, mortality). In total 475 males detected from this inbreeding regime, only one was determined as diploidy. The observed proportions of diploid male offspring significantly differed from expected values under CSD model involving up to ten independent loci, allowing us to safely reject CSD in T. dendrolimi. Meanwhile, the possibility of unviable diploid males was excluded by the absence of significant differences in brood size, offspring sex ratio and offspring mortality among different generations. Our study of sex determination in T. dendrolimi provides useful information for the mass rearing conditions in a biofactory and the quality improvement of this biocontrol agent. It also brings necessary background to further study of the sex determination in Trichogramma.

Host instar influence on offspring sex ratio and female preference of Neodryinus typhlocybae (Ashmead) (Hymenoptera, Dryinidae) parasitoid of Metcalfa pruinosa (Say) (Homoptera, Flatidae)

2018 ◽  
Vol 125 ◽  
pp. 113-120
Author(s):  
Riccardo Favaro ◽  
Jacob Roved ◽  
Vincenzo Girolami ◽  
Isabel Martinez-Sañudo ◽  
Luca Mazzon
Keyword(s):  
Sex Ratio ◽  
Female Preference ◽  
Offspring Sex Ratio ◽  
Host Instar ◽  
Offspring Sex

scholarly journals Host body size and the diversity of tick assemblages on Neotropical vertebrates

2016 ◽  
Vol 5 (3) ◽  
pp. 295-304 ◽  
Author(s):  
Helen J. Esser ◽  
Janet E. Foley ◽  
Frans Bongers ◽  
Edward Allen Herre ◽  
Matthew J. Miller ◽  
...  
Keyword(s):  
Body Size ◽  
Host Body ◽  
Host Body Size

scholarly journals Consumer and host body size effects on the removal of trematode cercariae by ambient communities

Parasitology ◽  
2018 ◽  
Vol 146 (3) ◽  
pp. 342-347
Author(s):  
Jennifer E. Welsh ◽  
Anke Hempel ◽  
Mirjana Markovic ◽  
Jaap van der Meer ◽  
David W. Thieltges
Keyword(s):  
Body Size ◽  
Size Effects ◽  
Laboratory Experiments ◽  
Feeding Activity ◽  
Removal Rates ◽  
Host Interactions ◽  
Host Body ◽  
Species Specific ◽  
Host Body Size ◽  
Significant Mortality

AbstractParasite transmission can be altered via the removal of parasites by the ambient communities in which parasite–host interactions take place. However, the mechanisms driving parasite removal remain poorly understood. Using marine trematode cercariae as a model system, we investigated the effects of consumer and host body size on parasite removal rates. Laboratory experiments revealed that consumer or host body size significantly affected cercarial removal rates in crabs, oysters and cockles but not in shrimps. In general, cercarial removal rates increased with consumer (crabs and oysters) and host (cockles) body size. For the filter feeding oysters and cockles, the effects probably relate to their feeding activity which is known to correlate with bivalve size. Low infection levels found in cockle hosts suggest that parasite removal by hosts also leads to significant mortality of infective stages. The size effects of crab and shrimp predators on cercarial removal rates were more complex and did not show an expected size match-mismatch between predators and their cercarial prey, suggesting that parasite removal rates in predators are species-specific. We conclude that to have a comprehensive understanding of parasite removal by ambient communities, more research into the various mechanisms of cercarial removal is required.

scholarly journals Analysis of the Influence of the Host Body Size on Morphometrical Characteristics ofAncylodiscoides SiluriandAncylodiscoides Vistulensis

2009 ◽  
Vol 23 (sup1) ◽  
pp. 735-741 ◽  
Author(s):  
K. Mancheva ◽  
E. Karaivanova ◽  
G. Atanasov ◽  
S. Stojanovski ◽  
I. Nedeva
Keyword(s):  
Body Size ◽  
Host Body ◽  
Host Body Size
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