On the Use of Ampullate Gland Silks by Wolf Spiders (Araneae, Lycosidae) for Attaching the Egg Sac to the Spinnerets and a Proposal for Defining Nubbins and Tartipores

Abstract

The means by which female wolf spiders attach an egg sac to their spinnerets was investigated using scanning electron microscopy. In four Pardosa species, we observed that silk fibers emerging from ampullate gland spigots had been affixed to the surface of the egg sac. More specifically, primary (1°) and secondary (2°) major ampullate (MaA) glands and 1° and 2° minor ampullate (Mi A) glands all contributed fibers for this purpose. The diameters of the 2° MaA and 2° MiA fibers were greater than those of the 1° MaA and 1° MiA fibers and, correspondingly, the widths of the 2° ampullate spigots were clearly greater than those of the 1° ampullate spigots. Larger 2° ampullate spigots were also observed in adult females of species from three other lycosid genera. Thus, 2° ampullate glands, which in araneoids function only in juveniles during proecdysis, are not only functional in adult female lycosids (and adult females of several other families), but they appear to play a greater role than the 1° ampullate glands in egg sac attachment. Observations made on the 1° and 2° ampullate spigots of adult females from species belonging to several other families are also presented. Cuticular structures referred to as nubbins and tartipores are present in some spinning fields on spinnerets. A proposal is made for defining these terms by a criterion, namely their different origins, which differs from that applied previously.

Comparative study of spinning field development in two species of araneophagic spiders (Araneae, Mimetidae, Australomimetus)

“…It would be disingenuous, however, not to acknowledge that the term 'tartipore' was initially applied, not to proecdysial tartipores functioning as pores, but to post-ecdysial, post-functional tartipores (Shear et al 1989, Yu and). Townley and Tillinghast (2003) continued this restricted, post-ecdysial use of the term and thus defined tartipores as cuticular scars, very much in accord with Murphy and Roberts' (2015) use of 'cicatrices'. The proecdysial, functional form of tartipores were referred to as 'tartipore progenitors'.…”

“…In the literature up through about 1994 (and sometimes beyond), the structures now identified as 2° MaA/MiA tartipores were generally referred to as nubbins [non-vestigial-type nubbins in Townley et al (1993)] because the terms 'nubbin' and 'tartipore' were originally applied to non-spigot protuberances in spinning fields on the basis of whether or not they can be individually specified (Coddington 1989, Yu and. Later, once the very different developmental origins of nubbins and tartipores were better understood, 'nubbin' was restricted to its current meaning of vestigial spigot (Townley 1993, Townley andTillinghast 2003). The above terms are summarized in Table 1.…”

The Morphology And Phylogeny Of Dionychan Spiders (Araneae: Araneomorphae)

“…253 below). The ontogeny of these two spigots is well known for Araneus (Tillinghast and Townley, 1994;Townley and Tillinghast, 2003). See also Griswold et al (2005: char.…”

“…* Nubbins from aciniform spigots were sporadically reported for males of Argiope bruennichi (Araneidae; Mü ller and Westheide, 1993), some Uloboridae (Kovoor and Peters, 1988), and females of Hogna species (Lycosidae; Townley and Tillinghast, 2003). At least in Hogna the nubbins are in a very stereotyped, symmetrical location.…”

Spinnerets and silk-producing system of Segestria senoculata (Araneae, Araneomorphae, Segestriidae)

“…Tartipores are found on the spinning fields of many entelegyne specialists with a much larger spinning glands diversity than the one found in Segestriidae, starting with the second instar. The function of these structures was described in depth by Townley & Tillinghast (2003, 2009) and Dolejš et al (2014). Segestriidae do not possess developed secondary (those that are tartipore-accommodated) ampullate glands (and their spigots) and none of the identified silk glands categories are tartiporeaccommodated (Garrison et al, 2016).…”