Leistungsfähigkeit der aphidophagen GallmückeAphidoletes aphidimyza(Rond.) (Diptera, Cecidomyiidae) in Abhängigkeit von verschiedenen Einflußfaktoren

Autor: H.-L. Kuo-Sell, P. Sell
Rok vydání: 1987
Předmět:
Zdroj: Journal of Applied Entomology. 103:434-447
ISSN: 1439-0418
0931-2048
DOI: 10.1111/j.1439-0418.1987.tb01005.x
Popis: Factors influencing the efficiency of the aphidophagous gall midge, Aphidoletes aphidimyza (Rond.) (Diptera, Cecidomyiidae) Experiments on the efficiency of Aphidoletes aphidimyza (Rond.) were carried out in the laboratory at 21 °C and 75 % rel. humidity with its natural prey, the green peach aphid, Myzus persicae (Sulz.) reared either on brussel sprouts (Brassica oleracea var. gemmifera) or on artificial diet. When preying on 1–2 day-old green peach aphids the total food consumption of the female larvae of A. aphidimyza was higher than that of the males. Larvae of both sexes, however, consumed about 50 % of their total food requirements in the last day—fourth day—of their development. Three-day-old larvae were inclined to pupate prematurely, if they were exposed to a period of starvation as short as only a few hours. The percentage of premature larvae inclined to pupate increased with extended period of starvation. Newly emerged females transfered reserve substances accumulated during larval development into egg production within the first two days of the adult life. The number of eggs thus produced was independent on the presence or absence of honeydew and males. The number of eggs produced did not change with increasing aging of the females, if they were supplied with only water. Adult midges of A. aphidimyza take in honeydew of the aphids, which is essential for the maintainance of their life. The life span of the males was, however, always shorter than that of the females. Also the total egg production of the females was significantly increased when honeydew was supplied. Under optimal nutritive conditions in both larvae and adult stage the honeydew intake of the famales made out 50–60 % of the total egg production, if the single females were kept together with only one male. Another 40–50 % could be realized through larval food without honeydew intake of the adults. These percentages varied, however, with the quality of the larval food and the proportion of ovipositing females. Insufficient feeding in the larvae stage due to starvation or less nutritiv quality of the supplied prey aphids (for instance, dead aphids killed with insecticides or through deep-freezing) led to a reduction in egg production initially effected by larval reserve substances. Such a reduction could not be compensated through later intake of honeydew by adults. Mating is an absolute prerequisite for oviposition. This did not affect the number of eggs produced from the larval reserve substances in the first two days of adult life, if no honeydew was supplied. In the presence of honeydew, however, the weight of the females was significantly increased with a slight rise in egg production. During the whole adult life oviposition stimulated significantly the maturing of the eggs, and the total egg production was correspondingly increased significantly. The nutritive quality as well as the stimulating effect of honeydew on egg production, adult life span and oviposition was not significantly changed when fresh and 15 days'-old honeydew was supplied. Similarly, there were no differences when honeydew produced by young aphids was compared with that by old ones. Tendentially, better performance was observed in substrates containing fresh honeydew or honeydew excreted by old aphids. Zusammenfassung Larven von Aphidoletes aphidimyza (Rond.), aus denen sich Weibchen entwickelten, vertilgten signifikant mehr 1–2 Tage alte Pfirsichblattlause (Myzus persicae [Sulz.]) als solche, die sich zu Mannchen entwickelten. Bei 21 °C und 75 % rel. Luftfeuchte erbrachten die Larven beider Geschlechter an ihrem letzten, dem vierten Entwicklungstag, ca. 50 % ihrer gesamten Frasleistung. Larvale Reservestoffe setzten die Weibchen innerhalb des ersten Tages nach dem Schlupf in reife Eier um, deren Zahl sich mit zunehmendem Alter der Weibchen nicht anderte, sofern ihnen nur Wasser zur Verfugung stand. Nach drei Entwicklungstagen stimmte Hunger von wenigen Stunden die Larven vorzeitig in die Bereitschaft zur Verpuppung um, obwohl sie bis dahin erst annahernd die Halfte ihrer potentiellen Frasleistung erbracht hatten. Der Anteil der vorzeitig zur Verpuppung umgestimmten Larven, die ohne weitere Nahrungsaufnahme in den Boden einwanderten, nahm mit zunehmender Lange der Hungerphase zu. Honigtau von Blattlausen wird von den Mucken als Nahrung aufgenommen und verwertet. Die Imaginalernahrung verlangerte die Lebensdauer der Mucken (Mannchen lebten kurzer als Weibchen) und steigerte die Eiproduktion je Weibchen. Bei gunstigen Ernahrungsbedingungen fur Larven und Imagines hatte die Imaginalernahrung einen leicht hoheren Anteil an der gesamten Eiproduktion als die larvalen Reservestoffe. Ablage von Eiern stimulierte die Eireifung, setzt aber die Begattung voraus. Weibchen mit Eiablage produzierten insgesamt mehr Eier als diejenigen ohne Eiablage. Entsprechend erhohte sich der Anteil der Eiproduktion aus der Imaginalernahrung. Fehlende larvale Reservestoffe, infolge Mangelernahrung der Larven mit toten Blattlausen (getotet durch Kalte oder Insektizid), konnten die Adulten zwar bei der Lebensdauer durch die Imaginalernahrung ausgleichen, nicht aber bei der Eiproduktion. Der Honigtau von Pfirsichlausen besas fur die Imagines von A. aphidimyza, unabhangig von seiner Lagerungsdauer und dem Alter der ihn ausscheidenden Blattlause, annahernd gleichen Nahr- und Reizwert.
Databáze: OpenAIRE
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