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| ŠUMARSKI LIST 1-2/2013 str. 53 <-- 53 --> PDF |
THE DEVELOPMENT OF CATERPILLARS OF GYPSY MOTH (Lymantria dispar L.) FEEDING ON FOOD AFFECTED BY NITROGEN Razvoj gusenica gubara (Lymantria dispar L.) na hranljivom substratu obogačenom dušikom Emanuel Kula, Alena Pešlová, Petr Martinek, Pavel Mazal Summary In laboratory rearing, affects were monitored of the differentiated content of nitrogen (17.17–38.89 mg.g–1) in birch (Betula pendula Roth) leaves on the development, mortality and consumption of food of caterpillars of Lymantria dispar L. The low content of nitrogen in food was the cause of the higher mortality of caterpillars, smaller weight of pupae and the prolongation of development. Caterpillars of future males fed on food with the insufficient content of nitrogen needed the higher amount of food to complete their development. This experiment supported a hypothesis that spring phytophages preferred tissues with the higher content of nitrogen. Caterpillars can respond to the above-standard content of nitrogen similarly as to the lack of nitrogen. Key words: nitrogen, stress, Betula pendula, Lymantria dispar, caterpillars, laboratory rearing, development Introduction Uvod Nitrogen shows an irreplaceable role in the metabolism of many biopolymers: – proteins, amines, amides, pigments, growth substances etc. It affects the creation and quality of biomass. Nitrogen is the basic component of protoplasm and enzymes (Larcher 1988). Stress in a plant caused e.g. by air pollutants or changes of weather produces the growth of the content of nitrogen in some tissues and the increased mobility of available nitrogen. Thus, the plant can become the source of food of higher quality for herbivores (White 1984). The growth and production of phytophagous insect is affected by the quantity and quality of proteins and amino acids in food (McNeil, Southwood 1978). During the growing season, the assimilatory apparatus of trees is exposed to the attack of the broad spectrum of insects (Feeny 1970, Lindquist, Miller 1976). Herbivores are adapted to obtain necessary energy and food, to overcome defensive responses of plants and other factors of the environment (Mattson 1980). The level of nitrogen in the assimilatory organs of broadleaved species (10–40 mg.g–1) (Larcher |