Spermathecal morphology and sperm dynamics in the female Schizocosa malitiosa (Araneae: Lycosidae)

Abstract

Abstract. The linkage between spermathecal morphology and sperm dynamics was experimentally analysed in Schizocosa malitiosa (Tullgren, 1905) using histological serial sections and SEM. We recognised three connected sections for each spermatheca: basal atrium, stalk and head. The head ends blindly, is sclerotized, provided with few large pores, and surrounded by thick, presumably glandular epithelium. The atrium is also sclerotized, and connects with both copulatory and fertilization ducts, lying close to each other. A porous plate is located in the stalk-atrium connection. Nine adult females were fixed in eight reproductive conditions for reconstructing sperm dynamics: virgin, immediately after mating, one day after mating, three days after mating, one day after remating without oviposition (first male with a single useful palp, second male normal), immediately before oviposition, three days after oviposition, and one day after remating with oviposition (female had eaten first egg-sac and had remated). Our results suggest female control of sperm transport because the penetration of encapsulated sperm into the spermathecal head continues after mating. Stored sperm is maintained in an encapsulated condition until oviposition, when sperm is totally activated. Sperm cells may remain viable for a long time in the decapsulated state. There was evidence for sperm mixing in the female that remated after ovipositi on.

Changes in male sexual responses from silk cues of females at different reproductive states in the wolf spider Schizocosa malitiosa

“…Moreover, Useta et al (2007) found that S. malitiosa females decapsulate all sperm cells during the first oviposition. Thus, remating from females could be expected, allowing sperm supply as well as improving sperm viability, assuming that new, encapsulated sperm cells persist more than decapsulated sperm from the first mating.…”

“…However, genital morphology is not the only predictor of sperm use patterns (Huber 2005). Recent studies on S. malitiosa (Useta et al 2007) suggest that, in spite of having a conduit spermathecae, it functions like a cul-de-sac rather than a conduit system, because the copulatory and fertilisation ducts connect to the spermathecal atrium very close to each other. Moreover, the apparent absence of sperm stratification gives no support to the predicted sperm precedence pattern.…”

“…Finally, chemical attractiveness could re-appear after oviposition, as was reported for Latrodectus hasselti (Stoltz et al 2007;Perampaladas et al 2008). S. malitiosa females activate (decapsulate) all their sperm cells when they oviposit (Useta et al 2007) and they could then readvertise to attract another male, obtain new sperm for encapsulation, thereby increasing the genetic diversity of their offspring (Austad 1984).…”

Potential for CFC in Black Widows (Genus Latrodectus): Mechanisms and Social Context

“…For example, since the spermathecae often contain proteins and fluids even before mating ( 8 Greven 2002 8 2005;Useta et al 2007;Michalik and Ramírez 2014), females that opened this valve during copulation (rather than during fertilization) might draw fluids out of the spermatheca, thus affecting pressure in the spermathecae and copulatory ducts. Such a change could alter the likelihood of effective insemination or even plug placement by the female's current mate.…”

“…First, the additional time may allow males to transfer more ejaculatory fluids or proteins (e.g., Vocking et al 2013), and these may mediate fertilization success (e.g., via SC or SAC: Simmons and Siva-Jothy 1998). Second, females may preferentially store more sperm (Useta et al 2007) or preferentially use sperm from males that copulate for longer (CFC, e.g., Argiopidae: Welke and Schneider 2009) and perhaps are better at stimulating the female through copulatory courtship (Eberhard 1994). Third, males that copulate for longer may be higher 'quality' spiders with a range of traits that reflect superior resource acquisition and allocation, including more sperm ( 10 Snow and Andrade 2005).…”