Article contents
STUDIES ON THE ARTHROPOD FAUNA OF ALFALFA: IV. SPECIES ASSOCIATED WITH THE CROWN1
Published online by Cambridge University Press: 31 May 2012
Abstract
The arthropod fauna associated with deteriorating crowns of alfalfa, Medicago sativa L., was studied at Ithaca, N.Y., during 1968–1969. Four decompositional stages of crowns were delimited, ranging from those of healthy, 1-year-old plants to those of dead plants. A total of 77 arthropod species, including 44 species of Diptera, were reared from the four stages of crowns. Information given for each species includes relative abundance, and associated stage of crown and number of crowns. Adults of several reared species had been collected from alfalfa foliage samples in previous years of study and were species for which the relationship to alfalfa had been obscure and which might in most insect–plant studies have been dismissed as being of chance occurrence or accidental on the plants. However, species breeding within the crowns contributed to the richness of the alfalfa fauna. Because species breeding within the microhabitat of decaying crowns were only rarely found to be associated with other morphological parts of the alfalfa plant, the crown community can be considered as a “centre of action” within the total alfalfa–arthropod community. The possible importance of considering species comprising the crown community in studies on communal stability is discussed.
None of the species of the crown community were shown to be definite primary invaders in crowns of healthy plants, although several reared species have been reported to damage living plant tissue. Many of the species probably were feeding on microorganisms and partitioning the available food resources by feeding preferentially on different classes of microorganisms. The majority of species should be classed as secondary invaders. While mechanical and winter injury probably were the main causes of initial damage to the crowns, feeding activities of the secondary-invading arthropods may have accelerated the process of crown deterioration and further opened tissues of the crown to penetration by pathogens.
- Type
- Articles
- Information
- Copyright
- Copyright © Entomological Society of Canada 1973
References
- 2
- Cited by