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Description of a novel mating plug mechanism in spiders and the description of the new species Maeotasetastrobilaris (Araneae, Salticidae).

Garcilazo-Cruz U, Alvarez-Padilla F - Zookeys (2015)

Bottom Line: In spiders several types of mating plugs have been documented, the most common ones include solidified secretions, parts of the bulb or in some extraordinary cases the mutilation of the entire palpal bulb.Here, we describe the first case of modified setae, which are located on the cymbial dorsal base, used directly as a mating plug for the Order Araneae in the species Maeotasetastrobilaris sp. n.In addition the taxonomic description of Maeotasetastrobilaris sp. n. is provided and based on our findings the geographic distribution of this genus is extended to the Northern hemisphere.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratorio de Aracnología. Facultad de Ciencias, Universidad Nacional Autonoma de Mexico s/n Ciudad Universitaria, México D. F. Del. Coyoacán, Código postal 04510, México.

ABSTRACT
Reproduction in arthropods is an interesting area of research where intrasexual and intersexual mechanisms have evolved structures with several functions. The mating plugs usually produced by males are good examples of these structures where the main function is to obstruct the female genitalia against new sperm depositions. In spiders several types of mating plugs have been documented, the most common ones include solidified secretions, parts of the bulb or in some extraordinary cases the mutilation of the entire palpal bulb. Here, we describe the first case of modified setae, which are located on the cymbial dorsal base, used directly as a mating plug for the Order Araneae in the species Maeotasetastrobilaris sp. n. In addition the taxonomic description of Maeotasetastrobilaris sp. n. is provided and based on our findings the geographic distribution of this genus is extended to the Northern hemisphere.

No MeSH data available.


Related in: MedlinePlus

Maeotasetastrobilaris mating plug SEM images. 24 cymbium at retrolateral view showing the seta 25 same view without seta 26 epigynal genital openings plugged by seta 27 close up of mating plug 28 strobilate seta brakeage disk 29 strobilate setae attached to cymbial membrane 30 detached strobilate seta. Scale bars 10 microns in all Figures. (B) basis of seta, (BD) breakage disc, (M) thin cuticular layer between articles, (As) adjacent minor setae, (stS) Strobilar seta, (CO) copulatory opening.
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Figure 4: Maeotasetastrobilaris mating plug SEM images. 24 cymbium at retrolateral view showing the seta 25 same view without seta 26 epigynal genital openings plugged by seta 27 close up of mating plug 28 strobilate seta brakeage disk 29 strobilate setae attached to cymbial membrane 30 detached strobilate seta. Scale bars 10 microns in all Figures. (B) basis of seta, (BD) breakage disc, (M) thin cuticular layer between articles, (As) adjacent minor setae, (stS) Strobilar seta, (CO) copulatory opening.

Mentions: The dorsal base of cymbium presents a cluster of modified setae on its edge used during copulation as a mating plug. They are located over a pit between the membrane joining tibia-tarsus articles (Fig. 25: M). Inside the pit are three to four strobilate setae, the largest used as a mating plug while the others remain attached to the tibia-tarsus joint (Fig. 25). The largest of these strobilate setae is detached in several specimens and was found blocking the copulatory ducts entrance (Figs 24, 29: stS; 27, 28: CO). Evidence supporting the use of this strobilate seta as a mating plug lies in their rupture from a basal breakage disc (Fig. 28: BD) attached to weak setal basis (Figs 27, 30: B) and the texture that makes it difficult to mechanically extract the setae from the genital openings. The function of the smaller setae is unknown, but they could work either as pressure indicators controlling the detachment of the larger seta, or guiding it throughout the mating plug function. Total sample consisted of 127 specimens (Table 1) where 62% were females. Almost 50% of these females had the seta at least in one of their genital openings, while 60% of the males lost at least one seta from both pedipalps. Absence of both setae in males was higher than the presence of two setae in females with a ratio of 10:1. Accidental loss of setae from specimens after preservation is unlikely: exemplars collected 30 years ago that were examined in MCZ presented the structures in the same proportions as exemplars captured in 2011, suggesting that handling does not lead to accidental loss of these setae. The low proportion of females with both copulatory ducts plugged suggests a negative response to the insertion of a second seta.


Description of a novel mating plug mechanism in spiders and the description of the new species Maeotasetastrobilaris (Araneae, Salticidae).

Garcilazo-Cruz U, Alvarez-Padilla F - Zookeys (2015)

Maeotasetastrobilaris mating plug SEM images. 24 cymbium at retrolateral view showing the seta 25 same view without seta 26 epigynal genital openings plugged by seta 27 close up of mating plug 28 strobilate seta brakeage disk 29 strobilate setae attached to cymbial membrane 30 detached strobilate seta. Scale bars 10 microns in all Figures. (B) basis of seta, (BD) breakage disc, (M) thin cuticular layer between articles, (As) adjacent minor setae, (stS) Strobilar seta, (CO) copulatory opening.
© Copyright Policy - creative-commons-attribution
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493341&req=5

Figure 4: Maeotasetastrobilaris mating plug SEM images. 24 cymbium at retrolateral view showing the seta 25 same view without seta 26 epigynal genital openings plugged by seta 27 close up of mating plug 28 strobilate seta brakeage disk 29 strobilate setae attached to cymbial membrane 30 detached strobilate seta. Scale bars 10 microns in all Figures. (B) basis of seta, (BD) breakage disc, (M) thin cuticular layer between articles, (As) adjacent minor setae, (stS) Strobilar seta, (CO) copulatory opening.
Mentions: The dorsal base of cymbium presents a cluster of modified setae on its edge used during copulation as a mating plug. They are located over a pit between the membrane joining tibia-tarsus articles (Fig. 25: M). Inside the pit are three to four strobilate setae, the largest used as a mating plug while the others remain attached to the tibia-tarsus joint (Fig. 25). The largest of these strobilate setae is detached in several specimens and was found blocking the copulatory ducts entrance (Figs 24, 29: stS; 27, 28: CO). Evidence supporting the use of this strobilate seta as a mating plug lies in their rupture from a basal breakage disc (Fig. 28: BD) attached to weak setal basis (Figs 27, 30: B) and the texture that makes it difficult to mechanically extract the setae from the genital openings. The function of the smaller setae is unknown, but they could work either as pressure indicators controlling the detachment of the larger seta, or guiding it throughout the mating plug function. Total sample consisted of 127 specimens (Table 1) where 62% were females. Almost 50% of these females had the seta at least in one of their genital openings, while 60% of the males lost at least one seta from both pedipalps. Absence of both setae in males was higher than the presence of two setae in females with a ratio of 10:1. Accidental loss of setae from specimens after preservation is unlikely: exemplars collected 30 years ago that were examined in MCZ presented the structures in the same proportions as exemplars captured in 2011, suggesting that handling does not lead to accidental loss of these setae. The low proportion of females with both copulatory ducts plugged suggests a negative response to the insertion of a second seta.

Bottom Line: In spiders several types of mating plugs have been documented, the most common ones include solidified secretions, parts of the bulb or in some extraordinary cases the mutilation of the entire palpal bulb.Here, we describe the first case of modified setae, which are located on the cymbial dorsal base, used directly as a mating plug for the Order Araneae in the species Maeotasetastrobilaris sp. n.In addition the taxonomic description of Maeotasetastrobilaris sp. n. is provided and based on our findings the geographic distribution of this genus is extended to the Northern hemisphere.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratorio de Aracnología. Facultad de Ciencias, Universidad Nacional Autonoma de Mexico s/n Ciudad Universitaria, México D. F. Del. Coyoacán, Código postal 04510, México.

ABSTRACT
Reproduction in arthropods is an interesting area of research where intrasexual and intersexual mechanisms have evolved structures with several functions. The mating plugs usually produced by males are good examples of these structures where the main function is to obstruct the female genitalia against new sperm depositions. In spiders several types of mating plugs have been documented, the most common ones include solidified secretions, parts of the bulb or in some extraordinary cases the mutilation of the entire palpal bulb. Here, we describe the first case of modified setae, which are located on the cymbial dorsal base, used directly as a mating plug for the Order Araneae in the species Maeotasetastrobilaris sp. n. In addition the taxonomic description of Maeotasetastrobilaris sp. n. is provided and based on our findings the geographic distribution of this genus is extended to the Northern hemisphere.

No MeSH data available.


Related in: MedlinePlus