Host Selection of the Spherical Mealybug (Homoptera: Pseudococcidae) by Anagyrus indicus (Hymenoptera: Encyrtidae): Influence of Host Stage on Parasitoid Oviposition, Development, Sex Ratio, and Survival

1985 ◽  
Vol 14 (1) ◽  
pp. 32-37 ◽  
Author(s):  
James R. Nechols ◽  
Rosalie S. Kikuchi
Keyword(s):  
Sex Ratio ◽  
Host Selection ◽  
Host Stage ◽  
Anagyrus Indicus ◽  
Selection Of

Computer model of the maintenance and selection of genetic heterogeneity in polygamous helminths

Parasitology ◽  
1995 ◽  
Vol 111 (4) ◽  
pp. 531-536 ◽  
Author(s):  
A. Saul
Keyword(s):  
Genetic Drift ◽  
Computer Model ◽  
Genetic Heterogeneity ◽  
Host Selection ◽  
Selection Pressure ◽  
Intestinal Helminths ◽  
Infection Rates ◽  
Stochastic Fluctuations ◽  
Stochastic Simulation Model ◽  
Selection Of

SUMMARYA stochastic simulation model of the transmission and maintenance of genetic heterogeneity in the absence and presence of external selection pressures is presented for polygamous intestinal helminths such as Ascaris. The model assumes that the density distribution of the adult parasites is highly aggregated and that density-dependent effects on fecundity are important. The model gives rise to stable infection rates in the host. Where the parasite population contains genetic heterogeneity, with the exception of stochastic fluctuations which models genetic drift, the ratio of the different alleles remained constant over extended periods of time. This result contrasts with that of an earlier analytical model (Anderson, R. M., May, M. R. & Gutpa S. (1989) Parasitology 99, S59–S79), in which uneven mating probabilities for the different combinations of worm possible in a host was postulated to inevitably lead to fixation of the most abundant allele. New results suggest that in spite of the restricted choice of mating available to a worm in the confines of a host, selection pressure always leads to enrichment of the parasites carrying resistant alleles.

Notes on parasites of Pentatomidae and Scutelleridae (Hemiptera-Heteroptera) in Middle East countries, with observations on biological control

1962 ◽  
Vol 53 (2) ◽  
pp. 241-256 ◽  
Author(s):  
E. S. Brown
Keyword(s):  
Biological Control ◽  
Middle East ◽  
Host Selection ◽  
Biological Control Agent ◽  
Control Agent ◽  
Sunn Pest ◽  
Eurygaster Integriceps ◽  
Middle East Countries ◽  
Central Turkey ◽  
Selection Of

A number of observations were made on parasites of certain Pentatomoids (sunn pest) attacking wheat in Middle East countries, during the course of other work on these pests. The principal host species studied were Eurygaster integriceps Put., E. maura (L.) and Aelia rostrata Boh. The data concern both Dipterous (Tachinid) endoparasites of the adult bugs, and also Hymenopterous (Scelionid) egg-parasites; the observations were made principally in central Turkey, and in the Varamine district of Iran. A few observations on predators were made also.The data concerning Tachinids consist of host records for six species of parasites. In no case observed by the author did these parasites appear to be of great importance in reducing the numbers of sunn pest; the same is true of the few instances of predators recorded.Observations were made on six species of Scelionid egg-parasites (five species of Asolcus and one of Hadronotus), five of which were bred from eggs of four species of Pentatomoid hosts collected in the field. The species concerning which the most comprehensive data were obtained were Asolcus rufiventris (Mayr), A. semistriatus (Nees) and A. vassilievi (Mayr). Egg-parasites are well known to be more efficacious in reducing sunn-pest populations, and A. semistriatus has been extensively used in Iran as a biological control agent. The data obtained enabled some ideas which are of importance for the use of egg-parasites in biological control to be formed and discussed. These concern principally (a) the susceptibilities of different hosts to parasitisation; (b) host selection by parasites; (c) the selection of a species of parasite most suitable for biological control in a particular area.

The sex ratio of a gilt’s birth litter can affect her fitness as a breeding female

2018 ◽  
Vol 58 (9) ◽  
pp. 1567 ◽  
Author(s):  
J. Seyfang ◽  
R. N. Kirkwood ◽  
A. J. Tilbrook ◽  
C. R. Ralph
Keyword(s):  
Sex Ratio ◽  
Reproductive Performance ◽  
Reproductive Potential ◽  
Group Housing ◽  
Pork Industry ◽  
Welfare Issue ◽  
Breeding Herd ◽  
Uterine Environment ◽  
Animal Welfare Issue ◽  
Selection Of

Lifetime reproductive performance and behaviour are established in utero driven by genetics and the steroidal milieu of the uterine environment. Developing males synthesise androgens that can be absorbed by females in the litter. Consequently, the proportion of males in a litter has the potential to affect both lifetime reproductive performance and behaviour of female littermates. Although reproductive potential is understandably important for gilt selection, behaviour is becoming progressively more important as group housing of sows increases. Aggression can be a cause for removal from the breeding herd, and can also negatively affect reproductive performance and herd longevity. This review covers existing evidence of masculinisation in rodents and sheep, the mechanism causing masculinisation, and the knowledge gaps surrounding masculinisation in pigs. Premature culling of gilts is an economic and animal welfare issue in the pork industry resulting in low retention of gilts and reduced productivity. The selection of gilts needs to be improved to incorporate both lifetime reproductive potential and behaviour. We determined that there is cause to investigate the effect of the birth litter sex ratio of a gilt on her suitability for selection into the breeding herd.

FECUNDITY, LONGEVITY, AND SEX RATIO OF APHIDIUS NIGRIPES (HYMENOPTERA: APHIDIIDAE) PARASITIZING DIFFERENT STAGES OF ITS HOST, MACROSIPHUM EUPHORBIAE (HOMOPTERA: APHIDIDAE)

1981 ◽  
Vol 113 (3) ◽  
pp. 193-198 ◽  
Author(s):  
Conrad Cloutier ◽  
Jeremy N. McNeil ◽  
Jacques Regnière
Keyword(s):  
Sex Ratio ◽  
Direct Relationship ◽  
Developmental Stages ◽  
Macrosiphum Euphorbiae ◽  
Separate Experiment ◽  
Female Parasite ◽  
Potato Aphid ◽  
Aphidius Nigripes ◽  
Host Stage ◽  
Female Longevity

AbstractThe longevity and age specific fecundity, as well as the sex ratio of the progeny, were obtained for Aphidius nigripes Ashmead females given access to the five developmental stages of the potato aphid, Macrosiphum euphorbiae (Thomas). Neither female longevity nor fecundity, as measured by the total number of aphids parasitized, were significantly different for the various host stages. The percentage of females in the progeny decreased as the female parasite aged, and the overall sex ratio of progeny was significantly affected by the host stage attacked although no direct relationship with host size was evident. However in a separate experiment where parasitism was controlled (females not permitted to attack more than 10 hosts per day), the host stage (size) significantly affected the sex ratio of progeny, with more females emerging from larger than smaller hosts.These data indicate that all developmental stages of M. euphorbiae, when presented separately, are suitable to A. nigripes.

On the Flight and Host Selection of the Douglas-fir Beetle, Dendroctonus pseudotsugae Hopk. (Coleoptera: Scolytidae)

1962 ◽  
Vol 94 (12) ◽  
pp. 1309-1325 ◽  
Author(s):  
L. H. McMullen ◽  
M. D. Atkins
Keyword(s):  
Experimental Data ◽  
Life Cycle ◽  
Host Selection ◽  
Bark Beetles ◽  
Time Of Flight ◽  
Field Studies ◽  
Douglas Fir ◽  
Major Portion ◽  
Dendroctonus Pseudotsugae ◽  
Selection Of

The flight of bark beetles covers a short but important period of their life cycle, during which they are exposed to conditions not encountered during the major portion of their life under the bark. The time of flight and the factors which affect it are important, not only to the dispersal and survival of the insect, but also in the interpretation of experimental data dependent upon the beetle's flight activity.Chapman (1954), Rudinsky and Vité (1956), and Atkins (1959, 1960, 1961) studied the flight of the Douglas-fir beetle under laboratory conditions, but there is scant reference to field studies on the flight of this insect. Chapman and Kinghorn (1958) recorded the number caught in window flight traps near Cowichan Lake, B.C., and unpublished reports describe emergence records obtained from cage studies conducted near Lumby, B.C.

HOST-SPECIFICITY AND HOST-SELECTION OF FLEAS IN FOCI OF HUMAN PLAGUE IN YUNNAN CHINA

1999 ◽  
Vol 6 (4) ◽  
pp. 370-377 ◽  
Author(s):  
Xianguo Guo ◽  
Zhengda Gong ◽  
Tijun Qian ◽  
Xiguang Feng ◽  
Xingde Duan ◽  
...  
Keyword(s):  
Host Specificity ◽  
Host Selection ◽  
Selection Of

scholarly journals Investigation into Host Selection of the Cecal Acetogen Population in Rabbits after Weaning

PLoS ONE ◽  
2016 ◽  
Vol 11 (7) ◽  
pp. e0158768 ◽  
Author(s):  
Chunlei Yang ◽  
Lan Mi ◽  
Xialu Hu ◽  
Jianxin Liu ◽  
Jiakun Wang
Keyword(s):  
Host Selection ◽  
Selection Of

Host Age Effects on Ovipositional and Developmental Biology of Baryscapus chrysopae (Hymenoptera: Eulophidae), a Parasitoid of Chrysopid Larvae

1995 ◽  
Vol 30 (2) ◽  
pp. 287-293
Author(s):  
John R. Ruberson ◽  
Timothy J. Kring
Keyword(s):  
Developmental Biology ◽  
Sex Ratio ◽  
Developmental Time ◽  
Age Effects ◽  
Host Age ◽  
Larval Stages ◽  
Chrysoperla Rufilabris ◽  
Host Stage ◽  
Gregarious Parasitoid

The parasitoid, Baryscapus (=Tetrastichus) chrysopae (Crawford), is a widely-distributed gregarious parasitoid of chrysopid larvae. The ovipositional and developmental biology of this parasitoid in relation to the stage of its host, Chrysoperla rufilabris (Burmeister), was examined. Female B. chrysopae attacked all larval stages of the host tested (instars 1 to 3), and paralyzed all hosts soon after mounting and stinging. During the host's paralysis, females oviposited in and fed on hosts. The time females spent on hosts was directly related to host stage. All hosts recovered from paralysis. Parasitoid developmental time was inversely related to host stage and ranged from 27.5 d in 1-d-old hosts to 20.5 d in 10-d-old hosts. Most development of parasitoid larvae appears to occur after the host has spun its pupal cocoon. The number of parasitoids produced per host was unrelated to host stage, ranging from 10.5 (in 1-d-old hosts) to 14.2 (in 7-d-old hosts) parasitoids per host. The sex ratio was skewed toward females (81.6% pooled across host stages) and was unrelated to host stage. The developmental biology of B. chrysopae appears to be well synchronized with that of its host.

DIFFERENCES IN HOST SELECTION OF ACTINOSPORES OF TWO MYXOSPOREANS, MYXOBOLUS ARCTICUS AND THELOHANELLUS HOVORKAI

2006 ◽  
Vol 92 (4) ◽  
pp. 725-729 ◽  
Author(s):  
Hiroshi Yokoyama ◽  
Jeong-Ho Kim ◽  
Shigehiko Urawa
Keyword(s):  
Host Selection ◽  
Selection Of
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