Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-13T04:31:37.808Z Has data issue: false hasContentIssue false

THE RELATIONSHIP BETWEEN A PARASITE, TETRASTICHUS INCERTUS (HYMENOPTERA: EULOPHIDAE), AND ITS HOST, THE ALFALFA WEEVIL, HYPERA POSTICA (COLEOPTERA: CURCULIONIDAE), IN NEW YORK1

Published online by Cambridge University Press:  31 May 2012

David J. Horn
Affiliation:
Department of Entomology, Cornell University, Ithaca, New York

Abstract

Tetrastichus incertus, a parasite of the alfalfa weevil (Hypera postica) larva, occurs throughout the northeastern United States, including almost all of New York. Field studies in 1967 and 1968 indicated that the parasite and its host were not closely synchronized in New York; the parasite was uncommon in June when hosts were abundant while the opposite was true in July. In 1966 and 1967, the proportion of parasites entering diapause increased throughout the summer, from 1–31% in June to 67–100% in September. Therefore, most parasites produced in June, when hosts were abundant, emerged in July when hosts were scarce. Winter mortality among parasites in diapause was high (51–64%) in field cages. The survivors of the overwintering generation of T. incertus constituted a small fraction of the annual production of parasites.

In the laboratory the offspring of older T. incertus tended more to enter diapause than did the offspring of younger parasites. This indicated the incidence of diapause may be correlated with host availability; when hosts are uncommon, diapausing parasites are produced.

Field and laboratory data indicated a ratio of one T. incertus to eight alfalfa weevil larvae would be necessary to achieve 50% parasitism of the host population. Such a host:parasite ratio never occurs when the hosts are common.

Type
Articles
Copyright
Copyright © Entomological Society of Canada 1971

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Chamberlin, T. R. 1925. A new parasite of the alfalfa weevil. J. econ. Ent. 18: 597602.CrossRefGoogle Scholar
Clancy, D. W. 1969. Biological control of the Egyptian Alfalfa Weevil in California and Arizona. J. econ. Ent. 62: 209214.CrossRefGoogle Scholar
Coles, L. W., and Puttler, B.. 1963. Status of the alfalfa weevil biological control program in the eastern United States. J. econ. Ent. 56: 609611.CrossRefGoogle Scholar
Cothran, W. R. 1966. A bibliography of the alfalfa weevil, Hypera postica (Gyllenhal). Bull. ent. Soc. Am. 12: 151160.Google Scholar
Cothran, W. R. 1968. A bibliography of the alfalfa weevil, Hypera postica (Gyllenhal). Supplement I. Bull. ent. Soc. Am. 14: 285288.Google Scholar
Cothran, W. R., and Gyrisco, G. G.. 1966. A container for rearing phytophagous insects with potential application to controlled humidity experiments. J. econ. Ent. 59: 481482.CrossRefGoogle Scholar
DeBach, P. (Ed.). 1964. Biological control of insect pests and weeds. Reinhold, New York.Google Scholar
DeLong, D. M. 1932. Some problems encountered in the estimation of insect populations by the sweeping method. Ann. ent. Soc. Am. 25: 1317.CrossRefGoogle Scholar
Flanders, S. E. 1944. Diapause in the parasitic Hymenoptera. J. econ. Ent. 37: 408411.CrossRefGoogle Scholar
Gray, H. E., and Treolar, A. E.. 1933. On the enumeration of insect populations by the method of net collection. Ecology 14: 356367.CrossRefGoogle Scholar
Griffiths, K. J. 1969. The importance of coincidence in the functional and numerical responses of two parasites of the European Pine Sawfly, Neodiprion sertifer. Can. Ent. 101: 673713.CrossRefGoogle Scholar
Horn, D. J. 1967. Biological control of the alfalfa weevil, Hypera postica (Gyllenhal) in New York. M.S. Thesis, Cornell U., Ithaca, N.Y.Google Scholar
Horn, D. J. 1969. The biological relationship between a parasite, Tetrastichus incertus (Ratzeburg) (Hymenoptera: Eulophidae) and its host, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae). Ph.D. Thesis, Cornell U., Ithaca, N.Y.Google Scholar
Hsiao, T. H., and Holdaway, F. G.. 1966. Seasonal history and host synchronization of Lydella grisescens (Diptera: Tachinidae) in Minnesota. Ann. ent. Soc. Am. 59: 125133.CrossRefGoogle Scholar
Kelleher, J. S. 1966. The parasite Doryphorophaga doryphorae in relation to populations of the Colorado potato beetle in Manitoba. Ann. ent. Soc. Am. 59: 10591061.CrossRefGoogle Scholar
Legner, E. F. 1969. Distribution pattern of hosts and parasitization by Spalangia drosophilae (Hymenoptera: Pteromalidae). Can. Ent. 101: 551557.CrossRefGoogle Scholar
Mathys, G., and Guignard, E.. 1967. Enseignements recueillis au cours de neuf ans travaux avec Prospaltella perniciosi Tow., parasite du pou de San José (Quadraspidiotus perniciosus Comst.). Entomophaga 12: 212222.CrossRefGoogle Scholar
Michelbacher, A. E. 1940. Effect of Bathyplectes curculionis on the alfalfa-weevil population in lowland middle California. Hilgardia 13: 8199.CrossRefGoogle Scholar
Miller, M. C. 1966. Emergence and mating of Tetrastichus incertus, a parasite of the alfalfa weevil. J. econ. Ent. 59: 15321533.CrossRefGoogle Scholar
Puttler, B. 1967. Interrelationship of Hypera postica (Coleoptera: Curculionidae) and Bathyplectes curculionis (Hymenoptera: Ichneumonidae) in the eastern United States with particular reference to encapsulation of parasite eggs by the weevil larvae. Ann. ent. Soc. Am. 60: 10311038.CrossRefGoogle Scholar
Quednau, F. W. 1967. Notes on mating behavior and oviposition of Chrysocharis laricinellae (Hymenoptera: Eulophidae), a parasite of the larch casebearer. Can. Ent. 99: 326331.CrossRefGoogle Scholar
Schoonhoven, L. M. 1962. Synchronization of a parasite/host system, with special reference to diapause. Ann. appl. Biol. 50: 617621.CrossRefGoogle Scholar
Schroder, R. F. W., Huggans, J. L., Horn, D. J., and York, G. T.. 1969. Distribution and establishment of Tetrastichus incertus in the eastern United States. Ann. ent. Soc. Am. 62: 812815.CrossRefGoogle Scholar
Simmonds, F. J. 1948. Some difficulties in determining by means of field samples the true value of parasitic control. Bull. ent. Res. 39: 435440.CrossRefGoogle ScholarPubMed
Southwood, T. R. E. 1966. Ecological methods. Methuen, London.Google Scholar
Steel, R. G. D., and Torrie, J. H.. 1960. Principles and procedures of statistics. McGraw-Hill, New York.Google Scholar
Streams, F. A., and Fuester, R. W.. 1967. Biology and distribution of Tetrastichus incertus, a parasite of the alfalfa weevil. J. econ. Ent. 60: 15741579.CrossRefGoogle Scholar
van den Bosch, R., Schlinger, E. I., Lagace, C. F., and Hall, J. C.. 1966. Parasitization of Acyrthrosiphon pisum by Aphidius smithi, a density-dependent process in nature. Ecology 47: 10491055.CrossRefGoogle Scholar