Entelegynae

Entelegynae
	Clubiona corticalis
Systematics
Trunk :	Arthropod (arthropoda)
Sub-stem :	Jawbearers (Chelicerata)
Class :	Arachnids (arachnida)
Order :	Spiders (Araneae)
Subordination :	Real spiders (Araneomorphae)
Partial order :	Entelegynae
Scientific name
	Entelegynae

Entelegynae is a suborder of the real spiders . They are mainly characterized by the complexly built genital organs ( epigyne and globe ). With approx. 78 families, which comprise over 34,000 species in over 3,000 genera , they represent the largest suborder among the real spiders .

anatomy

Epigyne of Pardosa pullata (micrograph)

While haplogyne spiders only have simply built sexual organs, the structure of the sexual organs of entelegynous spiders is much more complex. Since the epigyne and the globe are built in a species-specific manner and also show clear differences in otherwise very similar species, they are also used to identify the species. By microscopic examination of the epigyne or the globe, the species can usually be reliably determined without the aid of other, possibly variable, characteristics. For example, only a few groups of species require a preparation of the vulva in order to identify the species.

Both in the female and in the male, the complex structures of the epigyne or the bulb at the tip of the pedipalps are not yet developed in the subadult animal. The genital orifices are closed and the secondary structures are covered by the cuticle . Only after the moult are both exposed and functional.

In the female there is a hardened (sclerotized) plate of the cuticle, the epigyne , above the internal genital organs . This is usually intricately folded and has one or two openings that are connected to the spermatheks by spiral tubes . This is where the male's sperm reaches during mating and is stored there. The female is thus able to temporally separate the mating and fertilization of the eggs. The female herself transports the sperm from the sperm library via tubes to the external uterus located further inside . Only there does fertilization take place during oviposition. Even after only one mating, the female can produce and fertilize several clutches at intervals.

Pedipalpus of Xysticus kochi (micrograph)

In males, the primary sexual organs for producing sperm are internal. The sperm is released to the outside through a small opening in the epigastric groove. However, copulation does not take place with the primary sexual organs. Instead, the males' pedipalps are transformed into complex secondary sex organs. The male first releases the sperm onto a small sperm network. From there it is taken up into the sperm store of the pedipalp, the globe , and stored there. During copulation, only the tip of the bulb, the embolus, is inserted into the epigyne openings of the female and the sperm is released via muscle contractions.

Significance of the epigyne for speciation

Due to the complex anatomy, only the globe and epigyne of animals of the same species usually fit together ( key-lock principle ). It has been assumed that this prevents two different species from crossing ( hybridization ). However, this assumption could not be confirmed in the experiment. Another argument against this theory is that even in haplogynous spiders or tarantula-like hybridizations between closely related species were not observed. Instead, mating behavior is apparently a stronger factor. If the male is courting a female of the wrong species, he will either be ignored or attacked. Mating is ruled out in advance and the anatomical differences do not even come into play. Conversely, in the experiment, females were briefly anesthetized during the courtship of a male of a closely related species, thus enabling mating. The copulations were successful and hybrid offspring developed from the eggs.

In more recent studies, therefore, not only morphological, but also behavioral aspects are used more than before to delimit some species (see also Pardosa lugubris ).