An Effect of Parasite Attack on Host Mortality, as Exemplified by Encarsia formosa and Trialeurodes vaporariorum

1962 ◽  
Vol 94 (7) ◽  
pp. 673-679 ◽  
Author(s):  
T. Burnett
Keyword(s):  
Field Tests ◽  
Trialeurodes Vaporariorum ◽  
Host Feeding ◽  
Encarsia Formosa ◽  
Mature Adult ◽  
Bracon Hebetor ◽  
Black Scale ◽  
Host Mortality ◽  
Host Parasite ◽  
Juvenilizing Effect

It is not unusual for parasite attack on insect hosts to have different consequences for individuals of the same species. An indication of the variation in types of alternative effects is given by a consideration of three host-parasite relationships. First, although most hosts in a population are susceptible to parasitization, some are immune to attack: about one in 3,000 larvae of the Mediterranean flour moth, Anagasta kühniella (Zeller), was found by Payne (1934) to be immune to attack by Bracon hebetor Say. Second, tile morphology of hosts may be modified differentially by parasitism: unhatched eggs of Aphdius platensis Brethes exert a juvenilizing effect on nymphs of Aphis craccivora Koch whereas parasite larvae sometimes cause the appearance of adult characters (Johnson, 1959). Third, some hosts are successfully parasitized whereas others are killed long before parasite progeny can mature: adult females of Metaphycus helvolus (Com.) kill the black scale, Saissetin oleae (Bern.), by parasitization, by mutilation with the ovipositor, and by host-feeding at wounds made by the ovipositor. Field tests showed that up to 97 per cent of a black-scale infestation may be killed by the parasite over a period of several months.

HOST LARVAL MORTALITY IN AN EXPERIMENTAL HOST–PARASITE POPULATION

1964 ◽  
Vol 42 (5) ◽  
pp. 745-765 ◽  
Author(s):  
T. Burnett
Keyword(s):  
Larval Mortality ◽  
Trialeurodes Vaporariorum ◽  
Parasite Population ◽  
Rapid Decline ◽  
Encarsia Formosa ◽  
Host Protection ◽  
Host Mortality ◽  
Host Parasite ◽  
Parasite Populations ◽  
Two Populations

Two populations of Trialeurodes vaporariorum (Westw.) and its chalcid parasite Encarsia formosa Gahan were reared on tomato plants in the greenhouse at 72–76 °F for 26 weeks. Although the abundance of both species fluctuated with peaks of increasing amplitude, the population that was initially larger remained so throughout the period of sampling because the parasite inflicted similar rates of mortality in both cases. The fluctuations of the two separate populations were synchronized throughout the period of propagation. Host mortality, which resulted either from almost immediate killing of host scales following attack by adult parasites or from death of host larvae following parasitization and development of parasite progeny, was determined by parasite density, host size, and possibly by a number of other factors such as the age structure of host larval populations, age of adult parasites, and succulence of leaves on which the host larvae developed. The interaction of host and parasite produced cycles in the age structures of host and parasite populations that, in turn, influenced the interaction of the two species. The death of host larvae following attack by adult parasites was a form of host protection, as it ensured the rapid decline in the abundance of the parasite population and was, therefore, the primary factor in the maintenance of the host–parasite system.

ASPECTS OF THE INTERACTION BETWEEN A CHALCID PARASITE AND ITS ALEURODID HOST

1967 ◽  
Vol 45 (4) ◽  
pp. 539-578 ◽  
Author(s):  
T. Burnett
Keyword(s):  
Larval Mortality ◽  
Trialeurodes Vaporariorum ◽  
Host Population ◽  
Population Variation ◽  
Encarsia Formosa ◽  
Greenhouse Whitefly ◽  
Parasite Abundance ◽  
Tomato Plants ◽  
Host Mortality ◽  
Dominant Process

Three populations of the greenhouse whitefly, Trialeurodes vaporariorum, and its chalcid parasite Encarsia formosa were propagated each year for three consecutive years on tomato plants in the greenhouse. The abundance of the host and parasite species fluctuated either with peaks of increasing amplitude, with peaks of decreasing amplitude, or with irregular peaks. The dominant process in the interaction was the occurrence of two qualitatively different types of host larval mortality: (a) parasitization, and (b) almost immediate killing after attack by adult parasites. Fluctuations in host and parasite abundance resulted from the almost immediate killing of small host larvae and the death of the short-lived adult parasites. The parasite population tended to destroy similar percentages of host populations of different densities but host mortality was also related to the age structure of the host population. Variation in host reproduction, caused by differences in rearing temperature and by seasonal variation in the physical environment, influenced host and parasite densities.

scholarly journals The suitability of biotypes Q and B ofBemisia tabaci(Gennadius) (Hemiptera: Aleyrodidae) at different nymphal instars as hosts forEncarsia formosaGahan (Hymenoptera: Aphelinidae)

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1863 ◽  
Author(s):  
Xin Liu ◽  
Youjun Zhang ◽  
Wen Xie ◽  
Qingjun Wu ◽  
Shaoli Wang
Keyword(s):  
Biological Control ◽  
Feeding Rate ◽  
Trialeurodes Vaporariorum ◽  
Host Feeding ◽  
Encarsia Formosa ◽  
Greenhouse Crops ◽  
Commercial Strain ◽  
Promising Tool ◽  
Adult Parasitoid ◽  
Biotype B

Encarsia formosaGahan (Hymenoptera: Aphelinidae) is a solitary endoparasitoid that is commercially reared and released for augmentative biological control of whiteflies infesting greenhouse crops. In most areas in China, the invasive and destructive whiteflyBemisia tabaci(Gennadius) (Hemiptera: Aleyrodidae) biotype Q has replacedB. tabacibiotype B and has become dominant between the two. A better understanding of the suitability of different nymphal instars ofB. tabacibiotypes Q and B as hosts forE. formosais needed to improve the use of this parasitoid for biological control. Parasitism of the four nymphal instars ofB. tabacibiotypes Q and B by the commercial strain ofE. formosamass reared onTrialeurodes vaporariorum(Westwood) (Hemiptera: Aleyrodidae) was assessed in the laboratory. The results indicated thatE. formosaparasitized and successfully developed on all instars of both biotypes but performed best on the 3rd instar ofB. tabacibiotype B and on the 2nd, 3rd, and 4th instars ofB. tabacibiotype Q. The host-feeding rate of the adult parasitoid was generally higher on nymphal instars ofB. tabacibiotype Q than on the corresponding nymphal instars of biotype B and was significantly higher on the 2nd and 3rd instars. For both whitefly biotypes, the parasitoid’s immature developmental period was the longest on the 1st instar, intermediate on the 2nd and 3rd instars, and the shortest on the 4th instar. The parasitoid emergence rate was significantly lower on the 1st instar than on the other three instars and did not significantly differ betweenB. tabacibiotype B and biotype Q. Offspring longevity was greater on the 3rd and 4th instars than on the 1st instar and did not significantly differ between the twoB. tabacibiotypes. The results indicate that commercially-producedE. formosacan parasitize all instars ofB. tabacibiotypes B and Q, making this parasitoid a promising tool for the management of the two biotypes ofB. tabacipresent in China.

AN INSECT HOST–PARASITE POPULATION

1960 ◽  
Vol 38 (1) ◽  
pp. 57-75 ◽  
Author(s):  
Thomas Burnett
Keyword(s):  
General Trend ◽  
Trialeurodes Vaporariorum ◽  
Parasite Population ◽  
Insect Host ◽  
Growth Forms ◽  
Encarsia Formosa ◽  
Tomato Plants ◽  
Sources Of Variation ◽  
Host Parasite

Eight populations of Trialeurodes vaporariorum and Encarsia formosa were propagated on tomato plants in the greenhouse for about eight months. Although there was some variation in the growth-forms of host and parasite among the experiments, the general trend in each experiment was one of fluctuations of slightly, but distinctly, increasing amplitude. As extraneous sources of variation had only a slight influence on the growth-forms, the fluctuations resulted from host–parasite interaction. The T. vaporariorum – E. formosa system, is well suited for an investigation of the principles of host–parasite interaction.

NOTES ON MATING BEHAVIOR AND OVIPOSITION OF CHRYSOCHARIS LARICINELLAE (HYMENOPTERA: EULOPHIDAE), A PARASITE OF THE LARCH CASEBEARER (COLEOPHORA LARICELLA)

1967 ◽  
Vol 99 (3) ◽  
pp. 326-331 ◽  
Author(s):  
F. W. Quednau
Keyword(s):  
Mating Behavior ◽  
Fourth Instar ◽  
Egg Laying ◽  
Feeding Pattern ◽  
Host Feeding ◽  
Chemical Surface ◽  
Coleophora Laricella ◽  
Host Mortality

AbstractChrysocharis laricinellae (Ratz.) mated readily in the laboratory when several individuals of both sexes were held together in a vial. The courtship dance performed by the male is described. Parasite females develop mature eggs 3 days after emergence and are apparently capable of resorbing the eggs if hosts are not available, and to produce new ones after host-feeding. Storage of eggs in the ovary for 5 months at 55°F and sterility (phasic castration) of certain individuals is reported. Longevity of egg-laying females at 75°F was about 1 month less than that of parasites that had been denied contact with hosts. Odor apparently plays little or no role in the location of the larch casebearer larvae by C. laricinellae, but chemical surface stimuli seem to exist on the surface of a mine or case of Coleophora laricella (Hbn.). The parasite is also stimulated by vibrations of the host in its case. The oviposition and host-feeding pattern of C. laricinellae is described. Host-feeding on fourth-instar larvae of the larch casebearer contributed little to host mortality.

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