EVOLUTION IN A LABORATORY HOST–PARASITOID SYSTEM AND ITS EFFECT ON POPULATION KINETICS

1980 ◽  
Vol 112 (10) ◽  
pp. 1049-1060 ◽  
Author(s):  
Nasser Zareh ◽  
Mark Westoby ◽  
David Pimentel
Keyword(s):  
Selection Pressure ◽  
Experimental Treatment ◽  
House Fly ◽  
Control Treatment ◽  
Pupal Weight ◽  
Laboratory System ◽  
Nasonia Vitripennis ◽  
Population Kinetics ◽  
Upper Limit ◽  
Pupal Mortality

AbstractA laboratory system was developed that allowed populations of the house fly, Musca domestica, and its hymenopterous, wasp parasitoid, Nasonia vitripennis, to interact and fluctuate in numbers, subject only to an upper limit on Musca density. In one (experimental) treatment, the selection pressure from Nasonia was allowed to operate, while in the control all Musca adults were replaced in each generation by individuals from a Musca population not exposed to Nasonia. Evolution for resistance of Musca to Nasonia became noticeable within four generations in the experimental treatment. Measured changes finally included increased fly pupal weight (although larval development period was not allowed to increase), less time spent as pupa, increased pupal mortality, and reduced fecundity of adults. Total per-generation increase of both control and experimental Nasonia was much reduced on experimental compared with control Musca. This was caused by reductions both in the longevity of female Nasonia and in the number of progeny they produced each day. From early in the experiment the increased resistance of Musca produced lower Nasonia densities in the experimental treatment. During the first 20 or so generations no difference could be detected in mean Musca density between the two treatments. After that time the density of adult Musca became greater, and fluctuated less, in the experimental than in the control treatment. This situation continued until the experiment ended at 50 generations.

Effects of rhizobacteria on the biology and behavior of Plutella xylostella (Lepidoptera: Plutellidae)

2017 ◽  
Vol 43 (2) ◽  
pp. 195
Author(s):  
Robson Thomaz Thuler ◽  
Fernando Henrique Iost Filho ◽  
Hamilton César De Oliveira Charlo ◽  
Sergio Antônio De Bortoli
Keyword(s):  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Insect Behavior ◽  
Control Treatment ◽  
Pupal Weight ◽  
Larval Feeding ◽  
Direct Effects ◽  
Plant Feeding ◽  
Kluyvera Ascorbata ◽  
And Behavior

Plant induced resistance is a tool for integrated pest management, aimed at increasing plant defense against stress, which is compatible with other techniques. Rhizobacteria act in the plant through metabolic changes and may have direct effects on plant-feeding insects. The objective of this study was to determine the effects of cabbage plants inoculated with rhizobacteria on the biology and behavior of diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae). Cabbage seeds inoculated with 12 rhizobacteria strains were sowed in polystyrene trays and later transplanted into the greenhouse. The cabbage plants with sufficient size to support stress were then infested with diamondback moth caterpillars. Later, healthy leaves suffering injuries were collected and taken to the laboratory to feed P. xylostella second instar caterpillars that were evaluated for larval and pupal viability and duration, pupal weight, and sex ratio. The reduction of leaf area was then calculated as a measure of the amount of larval feeding. Non-preference for feeding and oviposition assays were also performed, by comparing the control treatment and plants inoculated with different rhizobacterial strains. Plants inoculated with the strains EN4 of Kluyvera ascorbata and HPF14 of Bacillus thuringiensis negatively affected the biological characteristics of P. xylostella when such traits were evaluated together, without directly affecting the insect behavior.

Effects of Superparasitism on Nasonia vitripennis (Walk.) (Hymenoptera: Pteromalidae)

1965 ◽  
Vol 97 (3) ◽  
pp. 326-331 ◽  
Author(s):  
H. G. Wylie
Keyword(s):  
Musca Domestica ◽  
House Fly ◽  
Food Shortage ◽  
Nasonia Vitripennis ◽  
Rate Of Development

AbstractSuperparasitism created a food shortage and thereby reduced survival and size of adult Nasonia vitripennis (Walk.) (Hymenoptera: Pteromalidae) reared on pupae of the house fly, Musca domestica L. Superparasitism also reduced the percentage of females in the adult progeny but had no effect on rate of development, ability to emerge, or incidence of diapause in N. vitripennis.

CONTROL OF EGG FERTILIZATION BY NASONIA VITRIPENNIS (HYMENOPTERA: PTEROMALIDAE) WHEN LAYING ON PARASITIZED HOUSE FLY PUPAE

1973 ◽  
Vol 105 (5) ◽  
pp. 709-718 ◽  
Author(s):  
H. G. Wylie
Keyword(s):  
Musca Domestica ◽  
House Fly ◽  
Nasonia Vitripennis ◽  
House Flies

AbstractFemales of Nasonia vitripennis (Walk.) lay a smaller percentage of fertilized (i.e. female) eggs on house fly, Musca domestica L., pupae previously parasitized by their own species, by Muscidifurax zaraptor K. & L., or by Spalangia cameroni Perk. (Hymenoptera: Pteromalidae) than on unparasitized hosts. They respond to changes in the fly pupae associated with death, and in the case of house flies attacked by N. vitripennis, to "venoms" injected at that time or to changes unrelated to death. By not fertilizing eggs that they lay on attacked hosts, the females also conserve sperm, for immature N. vitripennis on previously-attacked fly pupae are usually killed by parasite larvae already present.

Some Effects of Host Age on Parasitism by Nasonia vitripennis (Walk.) (Hymenoptera: Pteromalidae)

1963 ◽  
Vol 95 (8) ◽  
pp. 881-886 ◽  
Author(s):  
H. G. Wylie
Keyword(s):  
House Fly ◽  
Host Age ◽  
Adult Males ◽  
Nasonia Vitripennis ◽  
Female Adult ◽  
Different Ages

AbstractMortality of immature Nasonia vitripennis (Walk.) was least on young house fly pupae (less than 48 hours old, at 24.5 ± 0.5 °C.) and increased with increasing host age. Increased mortality on old hosts was manifested principally as a decrease in female adult progeny, numbers of adult males and of mature diapause larvae remaining approximately constant. Reduction in the percentage of females in the adult progeny reared on old hosts probably resulted from superparasitism. This kills more female than male larvae and occurred more commonly on old hosts, each of which provides a smaller quantity of suitable food for the immature parasites. Adults reared on old hosts were smaller and relatively fewer of them were able to emerge. The proportion of the total mature parasite progeny that remained in diapause was greater on old hosts, probably because of qualitative differences in the food provided by hosts of different ages.

scholarly journals Combined effects of elevated epilimnetic temperature and metalimnetic hypoxia on the predation rate of planktivorous fish

2019 ◽  
Vol 41 (5) ◽  
pp. 709-722 ◽  
Author(s):  
Piotr Maszczyk ◽  
Ewa Babkiewicz ◽  
Krzysztof Ciszewski ◽  
Kamil Dabrowski ◽  
Przemysław Dynak ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Experimental Treatment ◽  
Fish Predation ◽  
Predation Rate ◽  
Control Treatment ◽  
Combined Effects ◽  
Daphnia Longispina ◽  
Scardinius Erythrophthalmus ◽  
Tank System ◽  
Experimental Treatments

Abstract Increased temperature in the epilimnion and hypoxia in the metalimnion of a lake would result in an increase of positive-size-selective fish predation on zooplankton and in turn in a decrease of mean body size in zooplankton populations and communities. We tested this hypothesis in four types of experiments with juvenile rudd (Scardinius erythrophthalmus) foraging on Daphnia longispina in an indoor twin column tank system. In each experiment of the first three types, one column contained one of three types of experimental treatments differing from the control treatment (in the other column) by the following: (i) elevated temperature in the epilimnion, (ii) hypoxia in the metalimnion and (iii) simultaneous elevated temperature in the epilimnion and hypoxia in the metalimnion. In the fourth type of experiment, the gradients of temperature and oxygen concentration in both columns were the same, but prior to the experiments, Daphnia and fish in the control treatment were acclimated to normoxia and, in the experimental treatment, to hypoxia. The results confirmed our hypothesis, since the predation rate of fish was greater in each of the first three experimental treatments than in the control. We did not detect an effect of the acclimation to hypoxia on the predation rate of the fish.

Adaptive timing of detachment in a tick parasitizing hole-nesting birds

Parasitology ◽  
2011 ◽  
Vol 139 (2) ◽  
pp. 264-270 ◽  
Author(s):  
J. WHITE ◽  
D. J. A. HEYLEN ◽  
E. MATTHYSEN
Keyword(s):  
Experimental Treatment ◽  
Control Treatment ◽  
Control Group ◽  
Suitable Habitat ◽  
Nest Boxes ◽  
Tree Holes ◽  
Ixodes Arboricola ◽  
Experimental Treatments ◽  
Experimental Group ◽  
Engorgement Weight

SUMMARYIn non-permanent parasites with low intrinsic mobility such as ticks, dispersal is highly dependent on host movements as well as the timing of separation from the hosts. Optimal detachment behaviour is all the more crucial in nidicolous ticks as the risk of detaching in non-suitable habitat is high. In this study, we experimentally investigated the detachment behaviour of Ixodes arboricola, a nidicolous tick that primarily infests birds roosting in tree-holes. We infested great tits with I. arboricola larvae or nymphs, and submitted the birds to 2 experimental treatments, a control treatment in which birds had normal access to nest boxes and an experimental treatment, in which the birds were prevented access to their nest boxes for varying lengths of time. In the control group, most ticks detached within 5 days, whereas in the experimental group, ticks remained on the bird for as long as the bird was prevented access (up to 14 days). This prolonged attachment caused a decrease in survival and engorgement weight in nymphs, but not in larvae. The capacity of I. arboricola larvae to extend the duration of attachment in non-suitable environments with no apparent costs, may be an adaptation to unpredictable use of cavities by roosting hosts during winter, and at the same time may facilitate dispersal of the larval instars.

SURVEY AND RELEASE OF PARASITOIDS (HYMENOPTERA) ATTACKING HOUSE AND STABLE FLIES (DIPTERA: MUSCIDAE) IN DAIRY OPERATIONS

1999 ◽  
Vol 131 (6) ◽  
pp. 743-756 ◽  
Author(s):  
Tanja McKay ◽  
Terry D. Galloway
Keyword(s):  
House Fly ◽  
Stomoxys Calcitrans ◽  
Stable Fly ◽  
Nasonia Vitripennis ◽  
Pupal Parasitoid ◽  
House Flies ◽  
Stable Flies ◽  
Naturally Occurring ◽  
The Status ◽  
No Releases

AbstractIn 1995, Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae), a commercially available pupal parasitoid of the house fly, Musca domestica L., and stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), was purchased to examine the status of wasps being sold to Manitoba producers. Percentage of pupae parasitized, numbers of parasitoids per pupa, total parasitoids, and parasitoid sex ratio were determined for each shipment of parasitoids received. To determine the extent to which these wasps could successfully parasitize house flies and stable flies, parasitoids were released weekly in four Manitoba dairy barns and levels of parasitism estimated. In 10 622 freeze-killed sentinel house fly pupae, 2.2% were parasitized throughout the season by N. vitripennis, and 5.8% were parasitized by eight other species of parasitoids. Of 11 897 naturally occurring house fly and stable fly pupae, 0.6% were parasitized by N. vitripennis, and 3.4% by eight other species of parasitoids. In four barns where there were no releases of N. vitripennis, 1.1% of 11 779 sentinel pupae were parasitized by four species of parasitoids and 3.8% of 8384 naturally occurring house fly and stable fly pupae were parasitized by nine species. The release of an estimated 3 648 093 N. vitripennis did not result in substantial parasitism in either sentinel pupae or naturally occurring pupae. In 1996, live sentinel house fly pupae (n = 50 842) and house fly and stable fly pupae occurring naturally (n = 4691) were collected in two of the nonrelease barns from the 1995 study to examine the activity of endemic parasitoids. Of the sentinel and naturally occurring pupae sampled, 4.0% and 9.4% were parasitized, respectively. Phygadeuon fumator Gravenhörst (Hymenoptera: Ichneumonidae) was the most abundant parasitoid, accounting for 97.4% and 79.9% of parasitoids collected from sentinel pupae and naturally occurring pupae, respectively. Other parasitoids included Urolepis rufipes (Ashmead), Muscidifurax raptor Girault and Sanders, Muscidifurax zaraptor Kogan and Legner, Spalangia subpunctata Först, Spalangia cameroni Perkins, Spalangia nigra Latreille, and a species of Trichomalopsis Crawford (Hymenoptera: Pteromalidae).

scholarly journals Selective tooth clipping in the management of low-birth-weight piglets

1995 ◽  
Vol 75 (3) ◽  
pp. 285-289 ◽  
Author(s):  
S. Robert ◽  
B.K. Thompson ◽  
D. Fraser
Keyword(s):  
Weight Gain ◽  
Birth Weight ◽  
Low Birth Weight ◽  
Experimental Treatment ◽  
Control Treatment ◽  
Small Litter ◽  
Growth And Survival ◽  
Lower Birth Weight ◽  
Potential Benefits ◽  
Piglet Mortality

A study was designed to test the potential benefits of selective tooth clipping (the practice of leaving the eye teeth intact in the smallest piglets of a litter to make them more competitive) under commercial conditions. A total of 346 litters were assigned to either the control treatment where all piglets had their teeth clipped, or the experimental treatment where one or more piglets of low birth weight had their teeth left intact. Piglets were weighed within 24 h of birth and at 7, 21 and 56 d. In litters of 12–14 animals, but not in smaller litters, the lower-birth-weight piglets had lower mortality in experimental than in control litters (32.0 vs. 39.8%), whereas higher-birth-weight piglets showed a trend in the opposite direction, with 14.4% mortality in experimental vs. 13.2% in control litters (P = 0.05). The weight gain of lower-birth-weight piglets was greater (166 vs. 143 g d−1) in experimental than in control litters of 9–11 piglets, but the heavier piglets competing against the small litter-mates with intact teeth had lower weight gains than the controls (177 vs. 187 g d−1) (P < 0.02). Within-litter variance of 21-d weights was about 15% smaller (P < 0.005) in experimental than in control litters. Thus, selective tooth-clipping does not improve overall growth and survival, but it contributes to more uniform weaning weights and may help the most vulnerable piglets to remain alive until fostering or other intervention can be accomplished. Key words: Tooth clipping, piglet, mortality, weight gain

scholarly journals A field-wide assessment of differential high throughput sequencing reveals widespread bias

2021 ◽  
Author(s):  
Taavi Päll ◽  
Hannes Luidalepp ◽  
Tanel Tenson ◽  
Ülo Maiväli
Keyword(s):  
High Throughput ◽  
Marked Improvement ◽  
High Throughput Sequencing ◽  
Experimental Treatment ◽  
Data Repository ◽  
P Value ◽  
P Values ◽  
Upper Limit ◽  
File Structures ◽  
Over Time

AbstractHere we assess reproducibility and inferential quality in the field of differential HT-seq, based on analysis of datasets submitted 2008-2019 to the NCBI GEO data repository. Analysis of GEO submission file structures places an overall 59% upper limit to reproducibility. We further show that only 23% of experiments resulted in theoretically expected p value histogram shapes, although both reproducibility and p value distributions show marked improvement over time. Uniform p value histogram shapes, indicative of <100 true effects, were extremely few. Our calculations of π0, the fraction of true nulls, showed that 36% of experiments have π0 <0.5, meaning that in over a third of experiments most RNA-s were estimated to change their expression level upon experimental treatment. Both the fraction of different p value histogram types and π0 values are strongly associated with the software used for calculating these p values by the original authors, indicating widespread bias.

scholarly journals Available soil water upper limit by modeling and direct determination in a greenhouse

2019 ◽  
pp. 357
Author(s):  
Matheus Pena Campos ◽  
José Carlos Moraes Rufini ◽  
Bruno Montoani Silva ◽  
Saulo Saturnino de Sousa ◽  
Deniete Soares Magalhães ◽  
...  
Keyword(s):  
Direct Method ◽  
Direct Determination ◽  
Field Capacity ◽  
Relative Accuracy ◽  
Control Treatment ◽  
Laboratory Methods ◽  
Mean Values ◽  
Upper Limit ◽  
A Direct Method

Pot capacity (PC) is a direct method of determining field capacity (FC) for experiments with plantings in pots. The objective of this study was to evaluate different laboratory methods to determine field capacity and compare them with the pot capacity method. The experimental design was completely randomized (CRD), with nine treatments (methods of obtaining FC) and four replications, totaling 36 experimental plots. The mean values of moisture contents in the FC of the nine methods were compared, being eight empirically obtained and one directly in the greenhouse, defined as a control treatment (PC). The relative accuracy (RA) for all treatments was determined in relation to the control treatment. The estimation of the upper limit of available water in the soil varies depending on the method, and a decreasing order of moisture levels can be observed at FC: FC-Lab4pts > FC-Labip > FC-Lab8pts > PC > FC-Lab6pts > FC-6KPa > FC-LabSWRC > FC-10KPa > FC-33KPa. The treatment FC-Lab6pts has the relative accuracy closest to 100% and can be a practical alternative to PC. The use of 4, 6, 8 or 10 points for modeling the SWRC does not interfere with the quality of the FC estimated by the Dexter inflection point method, which is much more efficient for experiments of this nature. The use of potentials -10 kPa and -33 kPa is not adequate to estimate FC in tests with pots in a greenhouse.

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