Futterverteilung durch Männchen im Ameisenstaat

1. Young males of two species of carpenter ants (Camponotus herculeanus and C. ligniperda) offer food in a characteristic behavior pattern to emerging or newly emerged nest mates. 2. Older nest mates elicit only begging behavior in males. When crop-contents are exchanged between two males, food is flowing from the fuller crop to the emptier one. 3. When females or workers are begging food from a male, the latter give off crop-contents only when their crop is full. 4. The males tendency to distribute food was studied using radioactive tracer substances (P³², J¹³¹). Four phases can be defined: I. A social phase lasting from imaginal ecdysis to beginning of the winterrest: males receive plenty of food from workers and they regurgitate to males, other workers and females. They rarely take up food by themselves. II. A resting phase (hibernation): food exchange is reduced. III. A sexual phase from the end of the winterrest till swarming: males receive only little food from workers; their tendency to distribute food is weak; food uptake by themselves is increasing. IV. In the finalphase from swarming till death males are nearly inactive. 5. Formica polyctena males, which are in contrast to Camponotus males short-lived, show a weak tendency to distribute food in the very first days after emerging; this is soon succeeded by strong sexual activity. 6. These differences in social behavior are closely related to gonadal maturation: in Camponotus males other than in Formica males spermatogenesis ist not yet completed at the time of imaginal ecdysis. Maturation of the gonads continues up to the 25 day of imaginal live. For the proper development of the gonads and the normal time-course of the individual's aging social contact between males and workers is essential. 7. Camponotus males isolated from workers in the social phase survive longer when living in groups then whenkept solitary. During the sexual phase this group effect is lacking. To ensure the normal life span and the normal sequence of the behavioral phases a ratio of males to workers of 1:4 is required. 8. The fatbody which has been built up during the social phase is reduced at the beginning of the sexual phase, when the social bonds of the males are loosening. The fatbody is almost completely used up when swarming begins. 9. The fatbody is reduced more quickly at higher temperatures (26-28° C); accordingly the males tend to swarming already soon after hibernation. If the experimental colonies are kept at 18° C, the males remain in the social community and hibernate a second time in the old nest. 10. Movement of the spermatozoa to the seminal vesicles, as well as the filling of the reservoirs of the accessory glands and the control of swarming tendency is almost independent of social contacts in adult Formica males.