ON SPERMATIC TRANSMISSION IN SPIDERS 
By J. W. Abalos ' 1 and E. C. Baez 2 
Lister observed in 1678 that in copulation the male spider applies 
its palpi to the genital opening of the female, and since then the 
mechanics of sperm transmission has provided a fascinating problem 
for research. Formerly it was thought that there existed an internal 
communication between the organs of spermatogenesis and the palpi; 
careful studies have shown a total lack of such a connection. 
In 1843, Menge described the construction by the mature male of 
a nuptial web into which (or directly into the web of the female) 
he deposits a drop of semen. The semen is produced in his abdominal 
reproductive organs, a pair of gonads with their respective deferent 
ducts meeting to form a terminal duct, opening at the midline of the 
body into a seminal vesicle in the epigastric furrow. This drop of 
semen is then taken up by the copulatory apparatus situated in the 
male palpi, which are transformed for this purpose into more or less 
complex organs, according to the spider family. Once the palpi are 
filled with sperm, the male is ready for mating. 
Copulation is preceded by a courtship typical for each species and 
described by various authors. The male introduces the embolus of one 
palpus into the female epigynum, transferring the sperm into the 
seminal receptacle; immediately afterwards he repeats the operation 
with the other palpus. The deposition of the sperm in the nuptial 
web as described by Menge was later observed by various authors, 
among whom Montgomery (1903) suggested the term “sperm in- 
duction”. 
Various authors have tried to explain the origin of this double 
process (sperm induction and copulation). Alexander and Ewer 
( J 957) summarize the literature and try to explain sperm induction, 
postulating a protoarachnid that, originally aquatic and later becoming 
terrestrial, was unable to return to the water and thus transformed 
fertilization to an internal process in agreement with its new habitat. 
Considering the reproductive process in those arachnid groups in 
which there is no direct contact of the respective genital openings 
(scorpions, pseudoscorpions, solpugids and some mites), the authors 
consider the different possibilities available to the protoarachnid, and 
arrive at the following conclusion: “From a comparative survey of 
the mating habits of those arachnids for which the facts are known, 
^Institute) Nacional de Microbiologia, Santiago del Estero, Argentina. 
2 Instituto de Animales Venenosus, Santiago del Estero, Argentina. 
Manuscript received by the editor April 10, 1963. 
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