FURTHER EXPERIMENTS ON THE GENUS LASIUS. 135 



Further experiments on the temporary social parasitism in ants 



of the genus Lasius, Fab., with a note on Antennophorus 



uhlmanni. 



By W. C. CRAWLEY. B.A., F.E.S. 



While staying at Seaton, Devon, last summer, I was able to 

 procure a number of naturally-deillated or freshly-fertilised $ $ of 

 Lasius niiier and L. umbratiis, after a marriage-flight of these two 

 species on September 15th. 



In dealing with ants of this genus, I prefer to use fertile 2 ? , as 

 though I have made experiments with artificially-dealated 2 ? of 

 iinihratiis, two of which were permanently adopted by queenlesa 

 colonies of L. niger (Extr. 2nd, Inti'vii. Comj. Ent., Oxford, 1912), the 

 $ 2 never behaved like fertile 2 2 , were always restless, and attempted 

 to escape from the nest. The number of experiments to be described 

 was necessarily limited, since I had only three colonies of L. ni(/er in 

 my possession at the time, and I was afraid that the 2 2 of L. 

 vuibiatus, which, unlike those of ;;i///6'>-, alienus, and fiavits, are very hard 

 to keep alive in captivity without ^ ^ , would not survive the delay 

 necessary to establish fresh colonies of the host species in artificial 

 nests. The experiments, nevertheless, give additional proof of the 

 parasitic habits of L. iiinhratiis, eliminate the possibility of 2 2 of the 

 two species combining to found colonies, and suggest a method by 

 which the host queen, if present, may be destroyed by the parasitic 

 queen. The J J and 2 2 , some winged and others already deiilated, 

 began to appear on the roads about 2.0 p.m. on September 15th. One 

 deiilated niiibratiis 2 was seen to enter a hole under a wall, which 

 proved to be one of the entrances to a nest of L. nu/er, the host species. 



Three iiiiibyatiis 2 2 , still winged, and a J , were confined together 

 overnight ; in the morning the ^ and one 2 were dead, the latter cut 

 up into three pieces, head, thorax, and abdomen. One colony of L. 

 nif/er that swarmed on September 15th, had already been observed to 

 swarm earlier in the summer, July 14th. 



A. Experiments with a colony of L. nir/er, dating from 1911' 

 containing over 1,000 ^ ^ , queen, and brood (nest number, 40). 



Exp. 1. September 15th, 1912. — An artificially deiilated L. 

 initbratns 2 was placed in the fourth or outer chamber of nest 40. She 

 at once entered the next chamber, which was dark, was surrounded by 

 ants, and taken into chamber two. Many ants attacked her, though a 

 few saluted. She made no attempt at resistance, and before long was 

 dead. 



Exp. 2. — Soon after Exp. 1 an artificially deiilated 7>. jiii/er 2 

 was placed in the outer chamber of nest 40. She was at once 

 attacked and eventually killed. There were no signs of friendliness. 

 This only confirms numerous experiments, which seem to show that 

 this species will never accept strange 2 2 of its own kind. 



Exp. 3. September 17th, 1912. — A naturally deiilated {i.e., 

 fertilized) L. xuihratus 2 was placed in the outer chamber of nest 40, 

 the entrance to the other chambers having been closed. There were 

 nine ^ ^ with the 2 , all of which were friendly to her. Two days 

 later, all still being on good terms, the barrier to the other chambers 

 was removed. A few fresh ants attacked, but others saluted the 2 • 

 Later she was held by both antennae and two legs, and as it was 

 evident she would be killed, I removed her. 



