HARVEST-SPIDERS 143 



Mating habits 



Mating in harvest-spiders is as casual as eating or drinking. 

 Mature males and females that encounter one another in the field 

 ordinarily mate briefly, separate and continue their wanderings. A 

 short time later they may mate again with one another or with 

 different individuals. The necessity for frequent matings may per- 

 haps be correlated with the fact that the eggs mature a few at a 

 time and are deposited at intervals throughout, and in most 

 British species, towards the end of summer. Secondary sexual 

 differences are very slight. No true courtship has been observed in 

 Opiliones, but some curious behaviour sometimes occurs in Mito- 

 pus morio, one of the dominant Arachnids in Iceland (Cloudsley- 

 Thompson, 1948a, b). This species is particularly evident on sunny 

 days. The male, recognisable by his smaller body, longer legs and 

 paler colour, runs towards a moving female and takes up a position 

 with his body just above and legs straddling hers. The two run in 

 this position for several inches before stopping. The male then 

 moves forward slightly so that his body is now in front of that of 

 the female and turns about to face her. His long external genitalia 

 are now thrust forward and mating takes place. In the majority of 

 species, however, it is probable that copulation takes place at night. 



Forster (1954) has observed mating in the New Zealand Lania- 

 tores of both Nuncia and Algidia spp. Copulation is direct with 

 little prenuptial behaviour. The male approaches the female 

 rapidly, touching her with the tarsi of the second pair of legs. 

 When face to face he clasps her pedipalps with his own. Both 

 bodies are then raised, bringing the genital openings in line. The 

 long penis of the male is then exserted and placed directly into the 

 genital opening of the female: in no case observed has the female 

 exserted her ovipositor to receive the penis. 



In Leiobununi calcar, a common, widely distributed species of 

 Palpatores in North America, the males are easily recognised by 

 the presence on the femur of the pedipalp of a large, ventro-lateral 

 spur. The patella is short, strongly arched above and curved ven- 

 trally and its swollen base is armed with short dark denticles. 

 Because of the shortness of the patella the spur on the femur may 

 be apposed to the swollen base of the tibia to form an efficient 

 grasping organ. When a male encounters a female he rushes at her 



