Matthias Burger

Complex female genitalia indicate sperm dumping in armored goblin spiders (Arachnida, Araneae, Oonopidae)

In promiscuous females, sperm ejection from the sperm storage site can be a strong mechanism to influence sperm priority patterns. Sperm dumping is reported from different animals including birds, insects, and humans. In spiders, it has been documented for four species including the oonopid Silhouettella loricatula. Oonopidae are a diverse spider family comprising many species with peculiar female genitalia. Especially in species where studies of mating behavior are difficult, morphological investigations of the genitalia help to understand their function and evolution. In the present study, the genitalia of the oonopids Myrmopopaea sp., Grymeus sp., and Lionneta sp. are investigated by means of histological serial sections and scanning electron microscopy (SEM). The results are compared with previous findings on S. loricatula. In Myrmopopaea sp. and Grymeus sp., the same morphological components are present that are involved in sperm dumping in S. loricatula. Inside the receptaculum, sperm are enclosed in a secretory sac which can be moved to the genital opening and dumped during copulation by muscle contractions. The female genitalia of Lionneta sp. are asymmetric. They show the same characteristics as S. loricatula but all the investigated females were unmated. The results strongly suggest that sperm dumping occurs in Myrmopopaea sp., Grymeus sp., and Lionneta sp. and happens by the same mechanism as in S. loricatula. Sperm dumping might even be common within a clade of oonopids. As in S. loricatula, the sperm transfer forms in the investigated species consist of several spermatozoa. Papillae with unknown function occur on the receptacula of all females.

The Male Genital System of Goblin Spiders: Evidence for the Monophyly of Oonopidae (Arachnida: Araneae)

Abstract The male reproductive system of spiders consists of paired, tubular testes and often long and convoluted deferent ducts, which are fused near the genital opening to form an ejaculatory duct. In rare cases and as revealed in previous studies the testes can be partly fused (anteriorly or posteriorly), as reported, for example, for Dysderidae (Dysderoidea). In order to determine whether this pattern is also present in other dysderoids, we studied the genital system of Oonopidae for the first time by means of light microscopy. The following species were included, covering both conventionally recognized subfamilies (Gamasomorphinae and Oonopinae): Neoxyphinus ogloblini Birabén, 1953; Silhouettella loricatula (Roewer, 1942); Opopaea recondita Chickering, 1951; Myrmopopaea sp.; Scaphiella hespera Chamberlin, 1924; Lionneta sp.; Orchestina moaba Chamberlin and Ivie, 1935; Oonops balanus Chickering, 1971, and Stenoonops reductus (Bryant, 1942). In contrast to other spider taxa observed to date, all studied goblin spiders possess an unpaired (completely fused) testis, which seems to be a synapomorphic trait for Oonopidae supporting the monophyly of the family. The deferent ducts of goblin spiders are mostly convoluted and of varying diameter whereas the ejaculatory duct is very small. Moreover, we found a remarkable diversity in the organization of the testis and spermatozoa, which underlines the high potential of the reproductive system for systematic studies on Oonopidae as well as other dysderoids. The putative sister group of Oonopidae is Orsolobidae; since the organization of the male genital system of orsolobids is unknown as well, we included one species (Ascuta media Forster, 1956) in the present study. It possesses the typical genital organization for male spiders represented by paired and unfused tubular testes.

Female genital morphology and mating behavior of Orchestina (Arachnida: Araneae: Oonopidae).

The unusual reproductive biology of many spider species makes them compelling targets for evolutionary investigations. Mating behavior studies combined with genital morphological investigations help to understand complex spider reproductive systems and explain their function in the context of sexual selection. Oonopidae are a diverse spider family comprising a variety of species with complex internal female genitalia. Data on oonopid phylogeny are preliminary and especially studies on their mating behavior are very rare. The present investigation reports on the copulatory behavior of an Orchestina species for the first time. The female genitalia are described by means of serial semi-thin sections and scanning electron microscopy. Females of Orchestina sp. mate with multiple males. On average, copulations last between 15.4 and 23.54min. During copulation, the spiders are in a position taken by most theraphosids and certain members of the subfamily Oonopinae: the male pushes the female back and is situated under her facing the females sternum. Males of Orchestina sp. possibly display post-copulatory mate-guarding behavior. The female genitalia are complex. The genital opening leads into the uterus externus from which a single receptaculum emerges. The dorsal wall of the receptaculum forms a sclerite serving as muscle attachment. A sclerotized plate with attached muscles lies in the posterior wall of the uterus externus. The plate might be used to lock the uterus during copulation. The present study gives no direct evidence for cryptic female choice in Orchestina sp. but suggests that sexual selection occurs in the form of sperm competition through sperm mixing.

Genital morphology of the haplogyne spider Harpactea lepida (Arachnida, Araneae, Dysderidae)

Female Harpactea lepida possess a single genital opening leading into a diverticulum. This diverticulum shows no secretory layer. It continues posteriorly into a receptaculum which is associated with gland cells. In the two already described dysderids, Dysdera crocata and D. erythrina, the bilobed spermatheca lies anteriorly to the diverticulum. Gland cells are associated with the spermatheca and the diverticulum. In H. lepida, the sclerotized genital structures lie dorsally to the diverticulum and consist of a posterior and an anterior part. The posterior part shows a lamella extending laterally to sclerites functioning as muscle attachments. The anterior part has two roundish structures. A hollow stalk-like sclerite functioning as muscle attachment extends towards anterior. The posterior and the anterior part of the sclerotized genital structures fit together. A narrow uterine valve connecting the uterus externus with the diverticulum forms between them. It may be opened by muscles as also suggested for D. erythrina. In H. lepida, spermatozoa embedded in secretion are found in the diverticulum and the receptaculum. There is no evidence that they are stored under different conditions like in D. erythrina. Additional spermatozoa are found in the uterus externus of H. lepida which could be an indication for internal fertilization. Spermatogenesis occurs in cysts in the testes of male H. lepida. In the vasa deferentia, the ductus ejaculatorius and the palpal bulb, the spermatozoa are embedded in homogenous secretion. The palpal bulb has a distal extension bearing a crown-like structure. The embolus is situated at the base of the extension.

The New Australasian Goblin Spider Genus Prethopalpus (Araneae, Oonopidae)

Abstract The new goblin spider genus Prethopalpus is restricted to the Australasian tropics, from the lower Himalayan Mountains in Nepal and India to the Malaysian Peninsula, Indonesia, Papua New Guinea, and Australia. Prethopalpus contains those species with a swollen palpal patella, which is one to two times the size of the femur, together with a cymbium and bulb that is usually separated, although it is largely fused in four species. The type species Opopaea fosuma Burger et al. from Sumatra, and Camptoscaphiella infernalis Harvey and Edward from Western Australia are newly transferred to Prethopalpus. The genus consists of 41 species of which 39 are newly described: P. ilam Baehr (♂, ♀) from Nepal; P. khasi Baehr (♂), P. madurai Baehr (♂), P. mahanadi Baehr (♂, ♀), and P. meghalaya Baehr (♂, ♀) from India; P. bali Baehr (♂), P. bellicosus Baehr and Thoma (♂, ♀), P. brunei Baehr (♂, ♀), P. deelemanae Baehr and Thoma (♂), P. java Baehr (♂, ♀), P. kranzae Baehr (♂), P. kropfi Baehr (♂, ♀), P. leuser Baehr (♂, ♀), P. magnocularis Baehr and Thoma (♂), P. pahang Baehr (♂), P. perak Baehr (♂, ♀), P. sabah Baehr (♂, ♀), P. sarawak Baehr (♂), P. schwendingeri Baehr (♂, ♀), and P. utara Baehr (♂, ♀) from Indonesia and Malaysia; and P. alexanderi Baehr and Harvey (♂), P. attenboroughi Baehr and Harvey (♂), P. blosfeldsorum Baehr and Harvey (♂), P. boltoni Baehr and Harvey (♂, ♀), P. callani Baehr and Harvey (♂, ♀), P. cooperi Baehr and Harvey (♂), P. eberhardi Baehr and Harvey (♂, ♀), P. framenaui Baehr and Harvey (♂, ♀), P. humphreysi Baehr and Harvey (♂, ♀), P. kintyre Baehr and Harvey (♂), P. scanloni Baehr and Harvey (♂), P. pearsoni Baehr and Harvey (♂), P. julianneae Baehr and Harvey (♂), P. maini Baehr and Harvey (♂, ♀), P. marionae Baehr and Harvey (♂, ♀), P. platnicki Baehr and Harvey (♂, ♀), P. oneillae Baehr and Harvey (♂), P. rawlinsoni Baehr and Harvey (♂), and P. tropicus Baehr and Harvey (♂, ♀) from Australia and Papua New Guinea. Three separate keys to species from different geographical regions are provided. Most species are recorded from single locations and only three species are more widely distributed. A significant radiation of blind troglobites comprising 14 species living in subterranean ecosystems in Western Australia is discussed. These include several species that lack abdominal scuta, a feature previously used to define subfamilies of Oonopidae.

Goblin spiders without distinct receptacula seminis (Arachnida: Araneae: Oonopidae)

The mechanism of sperm transfer in spiders is unique among arthropods. Males use their modified pedipalps to transmit sperm which is received by females of most spider groups in specialized organs, the receptacula seminis. Oonopidae are a diverse spider family belonging to the Haplogynae. Female haplogynes have supposedly simple genitalia where the receptacula derive from the uterus externus, which is the duct passed by the eggs. The purpose of the present study is to describe the unusual female genitalia of the oonopids Xyphinus sp. and Ischnothyreus sp. by combining three methods of investigation: histological serial sections, scanning electron microscopy, and X‐ray ultra microscopy, and to compare the results with previous findings on haplogynes. Furthermore, the male palps are briefly described. The female genitalia of both investigated species do not correspond to the general description of haplogyne genitalia given in the literature. Distinct receptacula are lacking in both species. In Xyphinus sp., sperm are deposited into the uterus internus. A sclerite with attached muscles in the uterus wall might serve females to lock the uterus during copulation in order to prevent sperm from getting into it. The male palp of Xyphinus sp. bears complicated structures indicating that males could use the palps as copulatory courtship devices. The ventral scutum of female Ischnothyreus sp. forms a large depression which was always empty in the examined specimens. Sperm could be stored in a large fold of the uterus externus. As in Xyphinus sp., spermatozoa inside the uterus internus of Ischnothyreus sp. indicate that fertilization takes place in the uterus or the ovary. The function of a sclerotized squiggled tube in females of Ischnothyreus sp. remains unknown. Surrounding glandular tissue suggests the involvement of the tube in glandular activity. The male palp shows a simple embolus accompanied by a small conductor. J. Morphol. 271:1110–1118, 2010.

Functional genital morphology of armored spiders (Arachnida: Araneae: Tetrablemmidae).

This study describes the female genitalia of the tetrablemmid spiders Brignoliella acuminata, Monoblemma muchmorei, Caraimatta sbordonii, Tetrablemma magister, and Ablemma unicornis by means of serial semi‐thin sections and scanning electron microscopy and compares the results with previous findings on Indicoblemma lannaianum. Furthermore, the male palps and chelicerae are briefly described. The general vulval organization of females is complex and shows similarities in all of the investigated species. The copulatory orifice is situated near the posterior margin of the pulmonary plate. The opening of the uterus externus lies between the pulmonary and the postgenital plate. Paired copulatory ducts lead to sac‐like receptacula. Except for A. unicornis, the male emboli of all investigated species are elongated and thread‐like. However, they are too short to reach the receptacula. Hence, the spermatozoa have to be deposited inside the copulatory ducts. The same situation was also found in I. lannaianum. Females of this species store sperm encapsulated in secretory balls in their receptacula. The secretion is produced by glands adjoining the receptacula. The presence of paired fertilization ducts and spermatozoa in the uterus internus suggested that fertilization takes place internally in I. lannaianum. Secretory balls in the receptacula are found in all of the investigated species in this study, showing that sperm are stored in the same way. The place of fertilization may also be identical since dark particles, presumably spermatozoa, are located in the uterus internus of all investigated species except for T. magister. However, fertilization ducts are only found in B. acuminata and M. muchmorei. A sclerotized central process with attached muscles is present in A. unicornis, M. muchmorei, C. sbordonii and T. magister. Only in A. unicornis does the central process show an internal lumen and hold spermatozoa. In the other species, it could be used to lock the uterus during copulation in order to prevent sperm from getting into it as suggested for certain oonopid species. The uterus externus of all investigated species shows a sclerotized dorsal fold with attached muscles, previously described as “inner vulval plate.” Contractions of the muscles lead to a widening of the dorsal fold, thus creating enough space for the large oocytes to pass the narrow uterus externus. The males of all investigated species have apophyses on their chelicerae. At least in B. acuminata and A. unicornis, where females have paired grooves on the preanal plate, these apophyses allow males to grasp the female during copulation as described for I. lannaianum.

COPULATORY BEHAVIOR AND WEB OF INDICOBLEMMA LANNAIANUM FROM THAILAND (ARACHNIDA, ARANEAE, TETRABLEMMIDAE)

Abstract The present study reports for the first time on the behavior prior to, during and after the copulation of a member of the haplogyne spider family, Tetrablemmidae and describes the web of this species. Prior to copulation, male and female of Indicoblemma lannaianum from Thailand sometimes avoided each other or the female scared the male away, apparently by vigorous vibrations of her body. When first copulations were initiated, they lasted from 1.21 to 3.8 h with an average of 2.25 ± 0.71 h (n = 17). Some females accepted a second male for mating 3–9 days after first mating. There was no significant difference between the duration of first and second copulations but significantly more trials were needed to induce the second copulations. In the copulatory position, the male was inverted and faced in the same direction as the female. He seized the females opisthosoma with apophyses on his chelicerae which fit into grooves on a females ventral plate in this way building a locking mechanism during copulation. The pedipalps were inserted alternately. The web of I. lannaianum consisted of a longish narrow sheet, which was made of many short threads forming a zigzag pattern and additional long oblique threads overdrawing the sheet and functioning as signal threads.

Copulatory behaviour of the goblin spider Silhouettella loricatula (Arachnida: Araneae: Oonopidae)

Summary Knowledge of the reproductive biology of spiders belonging to the group Haplogynae is very limited. Oonopidae are a diverse haplogyne family systematically placed within the Dysderoidea. The life history of most oonopids is unknown. The present study describes the copulatory behaviour of Silhouettella loricatula (Roewer, 1942), a member of the subfamily Gamasomorphinae, including pre- and postcopulatory behaviour, avoidance behaviour, and female aggressive behaviour. Eleven out of 29 females mated in the laboratory and the first-copulations lasted 0.6–1.33 h. Five out of eleven females that had copulated once in the laboratory accepted a second male for copulation. The second-copulations lasted 0.66–1.26 h. Previous studies on S. loricatula revealed that females dump sperm of previous males during subsequent matings. The prolonged copulation duration in S. loricatula can be best explained by processes involving sperm dumping. In addition, males may perform mate guarding during the long matings. It is suggested that the male palp movements during copulation function as copulatory courtship in order to stimulate the female. Females showed seemingly more aggression during the trials for the second-copulations, indicating that they become less receptive with increasing copulation numbers.

A new species of blind subterranean Tetrablemma (Araneae: Tetrablemmidae) from Australia

Abstract The first blind Australian species of Tetrablemmidae and only the fourth in the world, Tetrablemma alaus, new species, is described from subterranean habitats in northwestern Australia. The total loss of eyes is correlated with its subterranean existence and is complemented by other troglomorphies including slightly elongated appendages and pale coloration.