Courtship and Sperm Transfer in the Whip Spider Phrynus Gervaisii (Amblypygi, Phrynidae): a Complement to Weygoldt's 1977 Paper
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2002. The Journal of Arachnology 30:588±600 COURTSHIP AND SPERM TRANSFER IN THE WHIP SPIDER PHRYNUS GERVAISII (AMBLYPYGI, PHRYNIDAE): A COMPLEMENT TO WEYGOLDT'S 1977 PAPER Alfredo V. Peretti: CONICET- CaÂtedra de Diversidad Animal I, Facultad de Ciencias Exactas, FõÂsicas y Naturales, Universidad Nacional de CoÂrdoba. Avda. VeÂlez Sars®eld 299 (5000), CoÂrdoba, Argentina. E-mail: [email protected] ABSTRACT. The aim of this study was to provide descriptive and quantitative data regarding behaviors involved in courtship and in sperm transfer of the whip spider Phrynus gervaisii (Pocock 1894) in order to complete the previous description for this same species given by P. Weygoldt. The specimens were captured in anthills of Paraponera clavata, on Barro Colorado Island, Panama. Ten courtship and ®ve sperm transfer sequences were recorded. Four out of ®ve mating sequences with sperm transfer ocurred between adults with similar body size and in the other case the female was smaller than the male. Sexual interactions did not occur between very small adults. Two male behavior patterns that have not been reported were observed during the initial stage of courtship: ``pedipalp rubbing'' and ``female operculum rubbing''. Contrary to Weygoldt's description, in this study the female never performed ``shaking'' move- ments with her antenniform legs. It was observed that the two distal horn-like extensions of the sper- matophore facilitate the females movements during the sperm transfer. The distal part of the spermatophore stalk provides a suspension area when the female rests on those horns. It was veri®ed that the female can move the claw-like sclerites of the gonopods in all directions. The male executed copulatory courtship and successfully transferred sperm in ®ve analyzed sequences. The female did not pick up the sperm packages when copulatory courtship was not performed. Males that lacked one antenniform leg were able to mate, however they had to perform vibrations more intensely with their non-injured leg for a longer duration. The data are compared with those previously obtained in other whip spiders. Some functional characteristics of the spermatophore and female genitalia of P. gervaisii are also discussed. RESUMEN. El objetivo de este trabajo es aportar datos descriptivos y cuantitativos sobre patrones de comportamiento que ocurren durante el cortejo y transferencia espermaÂtica del amblipõÂgido Phrynus ger- vaisii (Pocock 1894) con la ®nalidad de completar la descripcioÂn previa de P. Weygoldt para esta misma especie. Los especõÂmenes fueron capturados en hormigeros de Paraponera clavata, en la Isla de Barro Colorado, PanamaÂ. Se registraron 10 secuencias de cortejo y cinco de transferencia espermaÂtica. Cuatro de las cinco secuencias de apareamiento con transferencia espermaÂtica completa ocurrieron entre adultos de tamanÄo corporal similar mientras que en el otro caso la hembra fue maÂs pequenÄa que el macho. No se produjeron interacciones sexuales entre adultos muy pequenÄos. Durante la etapa inicial del cortejo fueron observados dos patrones de comportamiento masculinos que no habõÂan sido citados con anterioridad: ``roces de pedipalpos'' y ``roces al opeÂrculo genital femenino''. Al contrario de la descripcioÂn de Weygoldt, en el presente estudio la hembra nunca realizo movimientos de ``latigueo'' con sus patas anteniformes. Se observo que las dos expansiones distales con forma de cuerno del espermatoÂforo facilitan los movi- mientos de la hembra durante la transferencia espermaÂtica. La parte distal del tallo del espermatoÂforo ofrece un aÂrea de suspensioÂn cuando la hembra se apoya sobre estos cuernos. Se veri®co que la hembra puede mover los escleritos en form de unÄa de sus gonoÂpodos hacia todas las direcciones. El macho efectuo cortejo copulatorio en cinco secuencias analizadas, en ellas la transferencia espermaÂtica fue existosa. Por el contrario, la hembra no recogio los paquetes espermaÂticos cuando no existio cortejo copulatorio. Los machos que carecõÂan de una pata anteniforme tambieÂn fueron capaces de aparear. Sin embargo, ellos tuvieron que realizar maÂs intensamente las vibraciones con sus patas no danÄadas, y sobre todo durante un tiempo maÂs prolongado para evitar que la hembra se alejara. Se comparan los datos aquõ registrados con aquellos previamente obtenidos en otros amblipõÂgidos. Se discuten algunas caracterõÂsticas funcionales del espermatoÂforo y genitalia femenina de P. gervaisii. Keywords: Phrynus gervaisii, Amplypygi, courtship, sperm transfer, spermatophore Whip spiders (Amblypygi) represent an in- natural history of which are still poorly teresting group of arachnids, the biology and known. Whip spiders have strong, raptorial 588 PERETTIÐMATING BEHAVIOR IN PHRYNUS GERVAISII 589 pedipalps armed with sharp spines. Since goldt (1990, etc.) has mentioned the presence whip spiders continue to molt and grow after of antenniform tapping along with other male- reaching sexual maturity, adults of the same female contact during the sperm pick-up, it is species may be different sizes (Weygoldt neccesary to add more details to increase our 1995). The courtship behavior and spermato- knowledge of this behavior (e.g., do all the phore morphology are two of the most fasci- males of a same species always perform cop- nating subjects to be analyzed in these ani- ulatory courtship?, can any male traits, such mals. Whip spiders use vibration of the as body size, affect copulatory courtship be- ``anteniform'' ®rst pair of legs during court- havior?). ship (Thomas & Zeh 1984; Weygoldt 1990). The aim of this study was to provide de- After a prolonged dance, the male turns until scriptive and quantitative data regarding be- facing away from the female and deposits a haviors involved in courtship and in sperm stalked spermatophore. Then he turns towards transfer of the whip spider Phrynus gervaisii the female again and lures her to approach the (Pocock 1894) in order to complement the spermatophore and pick up the spermatozoa previous general description given by Wey- (Weygoldt 1990, 1998). Few amblypygid spe- goldt (1977) for this species. Weygoldt stud- cies have been observed (i.e., Weygoldt and ied the mating behavior and spermatophore of others have studied the courtship of 19 out of Tarantula palmata Kraepelin 1899, using approximately 125 described species). Al- adults specimens captured in Santa Martha, though the literature contains general descrip- Colombia. Quintero (1981), in the important tions of the mating, we lack many descriptive revision of the amblypygid genus Phrynus in and quantitative details of behaviors involved the Americas, synonymized this species with in each stage of the courtship and sperm trans- Phrynus gervaisii. Thus, in this study Wey- fer. In fact, the elaborate displays involved in goldt's observations are adopted as the most the courtship and spermatophore deposition of important and direct antecedents, comparing whip spiders show the importance of more de- the data with those published by this author tailed observations not only to increase our and, mainly, adding new details to that general general knowledge but also to lend insight description, in particular with respect to be- into the sexual selection that shaped the dis- havioral variation. plays. Spermatophore morphology and sperm METHODS transfer mechanisms vary among genera and Capture site and laboratory condi- families and provide useful characters for sys- tions.ÐTwenty females and 13 males of P. tematics (Weygoldt, 1998). One of these fam- gervaisii were collected in October, 1996 in ilies, the Phrynidae, contains medium to lar- Barro Colorado Island (Smithsonian Tropical ged-sized whip spiders and occurs in tropical Research Institute -STRI), Panama, where the and semitropical areas of the Americas (Quin- observations were carried out under labora- tero, 1981). The spermatophores of phrynids tory conditions (see details below). The spec- are large and have triangular, heavily sculp- imens were captured in the morning and in the tured heads (Weygoldt 1969, 1974, 1977, early afternoon in anthills of Paraponera cla- 1990, 1999). The female genitalia are char- vata (Hymenoptera, Formicidae) inside the acterized by the existence of two gonopods, parcel of 50 hectares that STRI has on the each equipped with a claw-like sclerite that is island. Externally, these anthills consist of ex- used to pick up the small sperm packages cavations at the base of a tree. Phrynus ger- from the spermatophore (Weygoldt 1990, vaisii lives inside galleries of the anthills, go- 1999). It is currently unclear how these claw- ing out at night to feed (PeÂrez Mendieta 1996; like sclerites come into contact with the sperm Peretti, pers. obs.). In order to capture packages. Similarly, it would be of interest to specimens I hit the base of a tree containing understand the behaviors, such as copulatory anthills several times with a metal rod. This courtship, that occur during and after the made many ants to run out very quickly and sperm transfer. In arachnids copulatory court- made some whips spiders leave the anthills ship has been observed in spiders (Eberhard and climb the tree; immediately afterward the 1994), scorpions and solpugids (Peretti 1997, specimens were captured (by covering them pers. obs.). Although in whip spiders Wey- with plastic containers 9.6 cm in diameter). 590 THE JOURNAL OF ARACHNOLOGY The animals were housed individually in cag- stained with methylene blue and examined es of different sizes, all furnished with a piece with a light microscope. Genitalia of live and of tree bark set vertically so that they could ®xed (in alcohol) females were compared and climb. They were fed crickets and locusts ®t with unused spermatophores in order to de- once a week. Moist cotton balls were used to termine the correspondence among the struc- maintain high humidity and the temperature tures that are closely in contact during the varied from 24±32 8C. Following Weygoldt & sperm transfer. Finally, each individuals will- Hoffmann (1995), all animals were kept under ingness to perform a new mating was ob- a light/dark cycle of 12:12 hours. In the pre- served daily. sent work the dark phase started at 1100 h.