Untersuchungen �ber den Nahrungserwerb der Waldameisen (Formica polyctena Foerster) im Eichenwald

Abstract

The number of ants running out of or into the nest depends mainly on temperature (with a maximum near 23° C), and to a small degree on day-time. Disturbing factors are darkness and rainfall.The pieces of prey brought into the nest measure on average 7 mm, consisting mainly of Lepidoptera (predominantly Tortrix viridana L., which at the time of this investigation was at the culminating point of a gradation), Rhynchota and Diptera. About 8% of the pieces of prey were dried out. The number of pieces brought into the nest depends mainly on temperature. In the course of a day a minimum of prey objects is carried at night and a maximum at day-time, depending on the group of insects to which the prey belongs. Between 19 and 7 o'clock 14% of the daily supply of prey is brought in.The crop volume of the ants running into the nest varies between means of 0.5 and 4.5 mm, reaching a maximum in the morning. The crop volume of the ants running out of the nest at the same time amounts to approximately 8% of those quantities. The crop liquid contains about 22% sugar which concentration is constant in the course of a day, but lower in humid than in dry weather. The protein concentration amounts to an average of 0.5%. The quantities of liquid, sugar and protein brought into the nest per unit time attain a minimum at night and a maximum at about noon. Between 19 and 7 o'clock 29% of the daily supply are brought in.

Wood ants as biological control of the forest pest beetles Ips spp.

“…The complex polydomous system of F. polyctena requires a large amount of food that is provided by foraging in mass 29,32 , covering an extensive area of the forest. Moreover, the nuptial flight of bark beetles occurs in spring 67 , coinciding with the presence of the sexual larvae that determines the peak of predation in red wood ants, and the presence of small populations of lachnids, the main food source of red wood ants later on the season 68 . In this scenario, bark beetles can easily become the target prey species of red wood ants, mostly in the spring period.…”