1971] 
Talbot — Formica dakotensis 
179 
morning because temperatures at which they occurred were rather 
high. No alates were seen below 74 0 and flying started at about 
75°. The most favorable flying temperatures were between 78° 
and 88° F. (in sun, 10 inches above the ground.) 
When wind swayed the vegetation alates held still or turned and 
went down. Flying ceased during a gust and was resumed when 
the wind subsided. 
Ants flew under a wide range of light conditions, from rather 
dim to quite bright light (2400 to 8600 ft. c.), but fluctuating 
light, due to moving clouds, tended to disrupt flight. Lessening 
light and the accompanying lowering of temperature (even in a 
favorable range) could stop flying. 
Swarms. Ground swarms formed towards the ends of flights, with 
males flying over the whole nest area and females standing on grasses 
or berries. Females seemed to attract males at a short distance and 
sometimes two or three males converged on a female at once. These 
swarms were quite similar to those of F. obscuripes except that they 
involved only one colony and took place at the nest, while those of 
F. obscuripes were made up of alates from many colonies that met 
at a swarming ground unassociated with any. 
Comparison with two other rufa ants. The late development of 
alates and late flights of F. dakotensis are in marked contrast to 
the habits of two other members of the rufa group on the George 
Reserve. F. obscuripes Forel has not only worker and alate pupae 
but also adult males and females when observations begin in the 
first week of June. Flights can begin as early as June 3 or before 
and are over by the last of June. F. obscuriventris Mayr has alate 
pupae by the middle of June and adult alates by the middle of July. 
Flights take place between the third week of July and the middle 
of August. The late flights of F. dakotensis may be linked with 
the fact that their females are thought to be temporary social para- 
sites of such ants as F. fusca and by September there may be numerous 
new colonies which can be invaded. 
Table II gives a summary of flights of the three species. 
Literature Cited 
Talbot, Mary 
1959. Flight activities of two species of ants of the genus Formica. 
The American Midland Naturalist. 61: 124-132. 
1964. Nest structure and flights of the ant Formica obscuriventris Mayr. 
Animal Behavior. 12: 154-158. 
