Age-Specific Interaction Between the Greenhouse Whitefly 1 and Encarsia formosa:2 Influence of the Parasite on Host Development

1977 ◽  
Vol 6 (2) ◽  
pp. 207-210 ◽  
Author(s):  
James R. Nechols ◽  
Maurice J. Tauber
Keyword(s):  
Specific Interaction ◽  
Encarsia Formosa ◽  
Greenhouse Whitefly ◽  
Host Development

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.

The Effect of Aggregation on Egg and Larval Survival in Neodiprion swainei Midd. (Hymenoptera: Diprionidae)

1962 ◽  
Vol 94 (1) ◽  
pp. 49-58 ◽  
Author(s):  
L. A. Lyons
Keyword(s):  
Spatial Distribution ◽  
Larval Survival ◽  
Predatory Mite ◽  
Prey Population ◽  
Laboratory Studies ◽  
Encarsia Formosa ◽  
Natural Control ◽  
Greenhouse Whitefly ◽  
Rate Of Development ◽  
Recent Laboratory

Recent laboratory studies have shown that the type of spatial distribution of a host or prey population may affect the degree of natural control exerted by parasites and predators. For example, Burnett (1958) showed that the rate of paratisitism of the greenhouse whitefly, Trialeurodes vaporarium (Westw.), by Encarsia formosa Gahan, was considerably greater when the hosts were aggregated than when regularly distributed. In this case, searching parasites were better able to find groups of hosts than isolated ones. Similar results have been obtained by Huffaker (1958) in experiments with a predatory mite, Typhlodroms occidentalis Nesbitt, and a phytophagous mite, Eotetranychus sexmaculatus (Riley). Other important effects of aggregation are evident in the growing literature on this subject, as exemplified by the work of Long (1955), Mizuta (1960), and Morimoto (1960), who showed that the rate of development of some lepidopterous larvae in groups is greater than that of isolated larvae.

Sign in / Sign up

Export Citation Format

Share Document