Peter Weygoldt

Complex brood care and reproductive behaviour in captive poison-arrow frogs, Dendrobates pumilio O. Schmidt

SummaryBrood care in Dendrobates pumilio not only involves egg attendance and tadpole transport, but also tadpole attendance and feeding. Each tadpole is carried by the attending female to a water-filled bromelial leaf axil and regularly fed on unfertilized eggs. The tadpole responds to an approaching adult with a specialized, conspicuous behavior signalling its presence. Male-male competition includes fighting, egg eating, and male tadpole transport. D. pumilio is the first frog known to feed its free-living larvae.

Ontogeny of the Arachnid Central Nervous System

Our knowledge of the development of nervous systems has greatly increased during the last few years. Specific cell markers like horseradish peroxidase and monoclonal antibodies have made possible studies of the cell lineages leading to the formation of neuromeres in insects and leeches. In both cases, the number of neuroblasts that form a particular ganglion is known; in leeches it was even possible to trace the history of these neuroblasts back to individual blastomeres. Similar studies are under way for vertebrates (Barald 1982; Goodman 1982; Jacobsen 1982; Stent et al. 1982). In the grasshopper, Goodman and coworkers have shown the events by which—by a fixed pattern of cell divisions and differentiation—neurons are formed by particular neuroblasts. These authors have been able to demonstrate that the neurons derived from a particular neuroblast share certain features, such as transmitters, and vary with respect to others, such as electrical properties, which, however, are shared by the progeny of a given birth position (Goodman et al. 1980; Goodman and Spitzer 1981a, b). In addition, the problem of pathfinding by growing axons and of the formation of synaptic connections has been studied with success. In insects, pioneer neurons and muscle pioneers have been identified that are formed early in development and later guide axons to their targets (Edwards 1982; Flaster et al. 1982; Goodman et al. 1981, 1982; Ho et al. 1983).

Spermatophorenbau und samenübertragung bei uropygen (Mastigoproctus brasilianus C. L. Koch) und amblypygen (Charinus brasilianus Weygoldt und Admetus pumilio C. L. Koch) (Chelicerata, Arachnida)

The spermatophores of Amblypygi and Uropygi are complicated structurs and vary in different species. In Mastigoproctus, the size and shape of the spermatophores prevent bastardation between M. giganteus and M. brasilianus. Taxonomic and phylogenetical implications are discussed.

Beobachtungen zur fortpflanzungsbiologie und zum verhalten der geißelspinne tarantula marginemaculata C. L. Koch (Chelicerata, Amblypygi)

The „social” behaviour of T. m. includes ritualized fights. Sperm transfer is achieved by means of a spermatophore deposited on the ground and by the male pulling the female over it. The behaviour and the spermatophore are described and compared to those of other arachnids and the phylogenetical implications are discussed.

Untersuchungen zur Embryologie und Morphologie der GeißelspinneTarantula marginemaculata C. L. Koch (Arachnida, Amblypygi, Tarantulidae)

SummaryThe embryonic development ofTarantula marginemaculata can be devided into two phases. Cleavage, germ layer formation, and formation of the body form take place during the protembryonic phase which takes about 20 days and ends with an embryonic moult and rupture of the egg shell. During the following 70 to 80 days (the deutembryonic phase) organogenesis and histogenesis take place, and finally a prenymph emerges from the brood pouch.Cleavage is superficial and ends with yolk contraction. A small germ band is formed by aggregations of cells and a blastopore area appears in its centre.Germ layer formation is achieved by immigration of cells from the blastopore area. The germ band enlarges, and in front of the blastopore area a number of concentric quarter-circular thickenings appear, representing the rudiments of the prosomal segments. At the same time, the cumulus separates from the germ band and migrates towards the future dorsal side. The opisthosomal segments are later formed by proliferation from the caudal lobe.The rudiments of the prosomal segments soon become more distinct and narrower. Later, each is devided into two halves which, during reversion, separate and migrate to lateral positions. Reversion is similar to that of mygalomorph and haplogyn spiders.The cumulus migrates along the dorsal midline nearly towards the front end of the embryo and finally desintegrates by forming yolk cells which participate in the formation of the anterior mid gut rudiment.Seven pairs of coelomic cavities are formed within the prosoma and 12 within the opisthosoma. The formation of dorsal and ventral diaphragma, heart, endosternite, musculatur etc. is described and the significance of the ventral diaphragma and endosternite is discussed.The first pair of coelomic cavities, the precheliceral coelom, underlies the head lobes and later supplies the labrum (rostrum) and stomodaeum and forms the aorta anterior and the arteriae crassae. This coelom is most likely homologous to the preantennulary coelom of many mandibulates. It is the only indication of a precheliceral segment which has been lost or fused with the acron.The most conspicuous characters of the amblypygid brain are huge globuli-cell masses covering the entire brain, and glomeruli in the first leg ganglia. A well developed stomodeal bridge is present, giving rise to an unpaired rostral nerve and perhaps paired lateral nerves also. Development of the central nervous system involves many small invaginations. The brain is formed from the large precheliceral lead lobes which are later devided into the median part and lateral vesicles. Most of the brain, including central body, corpora pedunculata, and median optic masses, are formed by the median part of the head lobes. The lateral vesicles give rise to the optic masses of the lateral eyes and part of the optic centre. These and other structures can hardly be regarded as precheliceral segmental neuromeres. The lateral vesicles may be homologous to the optic lobes of the Mandibulata. The neuromeres of hypothetical precheliceral segments (prosocephalon, deutocephalon) have either been completely lost or completely fused to the archicerebrum, or the prosocerebrum is represented by the rostral ganglia.ZusammenfassungDie Embryonalentwicklung vonTarantula marginemaculata vollzieht sich in zwei Phasen. In der 20 Tage dauernden protembryonalen Phase finden Furchung, Keimblätterbildung und Entwicklung der Körpergestalt statt. Sie endet mit dem Sprengen der Eihülle und mit einer embryonalen Häutung. Organogenese und Histogenese folgen in der 70 bis 80 Tage dauernden deutembyonalen Phase, die mit der Häutung zur Praenymphe und dem Verlassen des Brutsackes endet.Die Furchung ist superfiziell und endet mit der Dotterkontraktion. Durch Zusammenscharen von Zellen entsteht ein kleiner Keimstreif mit der Blastoporusregion im Zentrum. Vor der Blastoporusregion entstehen die Segmentanlagen des Prosomas als konzentrisch angeordnete viertelkreisförmige Verdickungen. Gleichzeitig trennt sich der Cumulus vom Keimstreif und wandert nach hinten und an die Dorsalseite. Die Segmente des Hinterkörpers entstehen in der caudalen Sprossungszone.Der Cumulus wandert über die Dorsalseite des Embryos bis fast ans Vorderende, wo er sich bei der Bildung von vitellophagenähnlichen Zellen auflöst, die später die vordere Mitteldarmanlage bilden.Im Prosoma entstehen 7 Paare von Coelomhöhlen, im Opisthosoma 12. Ihre Entwicklung und die Bildung von Blutgefäßsystem, dorsalem und ventralem Diaphragma, Endosternit usw. werden beschrieben und die Bedeutung des ventralen Diaphragmas und des Endosternites diskutiert.Das vorderste Coelomsackpaar, das Praechelicerencoelom, unterlagert das Gehirn, versorgt Oberlippe (Rostrum) und Stomodaeum und bildet die Aorta anterior und Arteriae crassae. Es entspricht nach Lage und Entwicklung dem Praeantennencoelom vieler Mandibulaten und ist das einzige Indiz für ein verlorenes oder mit dem Acron verschmolzenes Segment.Das zentrale und stomatogastrische Nervensystem werden beschrieben. Eine deutliche Stomodaealbrücke mit unpaarem Rostralnerv, vielleicht auch paarigen schwächeren Rostrainerven, sind vorhanden. Bei der Entstehung der Ganglien treten vorübergehend zahlreiche kleine und größere Einstülpungen auf. Vor den Neuromeren der Cheliceren liegen zunächst große, paarige Kopflappen, von denen an den Seiten die Lateralvesikel abgetrennt werden. Die medianen Teile der Kopflappen bilden Zentralkörper, Corpora pedunculata, die Sehmassen der Mittelaugen und die zentralen Hirnteile. Segmentale Ganglienanlagen sind in ihnen nicht nachzuweisen. Die Lateralvesikel bilden die Sehmassen der Seitenaugen und die optischen Zentren. Sie können darum kaum mit dem Deutocerebrum der Mandibulaten homologisiert werden, sondern eher mit den optischen Loben. Prosocerebum und Deutocerebrum sind entweder verlorengegangen oder vollständig mit dem Archicerebrum verschmolzen, oder das Prosocerebrum wird durch die Rostralganglien repräsentiert.

Kampf, Paarungsverhalten, Spermatophorenmorphologie und weibliche Genitalien bei neotropischen Geißelspinnen (Amblypygi, Arachnida)

SummaryAgonistic and mating beaviour and Spermatophore morphology ofTarantula (Phrynus) palmata (Herbst) andHeterophrynus alces Pocock are similar to those of other species of the Tarantulidae (Phrynidae). Males ofTrichodamon froesi Mello Leitao perform a different agonistic behaviour. Their pedipalps bear small apical chelae and are extremely elongate. During fighting, each male grasps the tibiae of the opponents third legs and pushes them upward and backward. During mating, the male performs vibrating and tapping movements with its antenniform legs and occasionally grasps the female. The female responds by performing characteristic movements of her antenniform legs. The spermatophore is a complicated structure. It is emptied by the females pressing down two levers which causes two sperm packages to become elevated. These are then grasped by the females seminal receptacles and by two hook-like structures of her gonopods and finally pulled off the spermatophore. Comparison of the species so far studied shows that the mating behaviour, although it varies in different species, does not exhibit differences useful for taxonomic research. But the different spermatophores show family characteristic structural properties.ZusammenfassungAgonistisches Verhalten, Samenübertragung und Spermatophorenmorphologie vonTarantula (Phrynus) palmata (Herbst) undHeterophrynus alces Pocock sind ähnlich wie bei anderen Arten der Familie Tarantulidae (Phrynidae). Anders ist das agonistische Verhalten vonTrichodamon froesi Mello Leitao. Die Palpen tragen an ihren Spitzen kleine Scheren und sind beim Männchen stark verlängert. Beim Kampf versucht jeder, die Tibien des 3. Beinpaares des Gegners zu ergreifen und dann nach hinten und hochzustemmen. Die Balz besteht aus Serien von vibrierenden und trillernden Bewegungen der Fühlerbeine und gelegent lichen Eingreifen des Weibchens; das Weibchen antwortet darauf mit charakteristischen Fühlerbeinbewegungen. Die komplizierte Spermatophore wird dadurch entleert, daß das Weibchen auf zwei Hebel drückt und dadurch die Samenpakete hochschnellen läßt. Diese werden dann in die Receptacula eingeführt und mit den hakenartigen Strukturen an den Gonopoden ergriffen und abgerissen. Ein Vergleich der bisher untersuchten Arten zeigt, daß das Paarungsverhalten keine charakteristischen Unterschiede bei verschiedenen Familien oder Gattungen zeigt. Aber die Spermatophoren zeigen familientypische Baueigenschaften.

Morphologisch-histologische untersuchungen an den geschlechtsorganen der amblypygi unter besonderer Berücksichtigung von Tarantula marginemaculata C. L. Koch (Arachnida)

SummaryThe male genital system of Tarantula consists of paired testes, ventral glands, lateral glands, and the genital chamber with the cone like spermatophore organ.Spermatogenesis occurs in spermatocysts. Mature spermatozoa first are corkscrew like in shape but later become rolled up and encysted. They are stored in a pair of vesicula seminalis.In the ventral glands, secretion is holocrinous and a granular substance is formed. The lateral glands produce a transparent, homogenous material. Both substances do not mix; they are stored in large reservoirs.The cone like spermatophore organ is a complex structure formed by a pair of gonopods which first splits into two paires and later unites to form a hollow organ with a complicated system of cavities.No precursor of a spermatophore exists when a male starts depositing the spermatophore. The secreted material first runs along latero-ventral tubes to two ventral openings. There, it is fixed to the substrate and formed to the spermatophore stalk by the males rising its body. Thereafter, the central cavity of the spermatophore organ is filled with secreted material and acts as a matrix which presses the upper parts of the spermatophore. This is finally pulled out through a mid-dorsal opening.The female organs consist of paired ovaries and oviducts, an unpaired uterus, and the genital chamber with the gonopods. The oocytes develop outside the ovary but remain fixed to it by a solid funiculus. There are two phases of vitellogenesis, the second one is started after mating. But there are allways a number of resting oocytes which do not enter the second phase of vitellogenesis. Since whip spiders may live for many years and may lay egss one to three times a year these are stored for later breeding periods. Before oviposition, the egg stalks widen, and the eggs finally pass through the funiculi into the ovary.Mating not only induces the second phase of vitellogenesis but also causes the ovary and oviducts to secret a filamentous material which is invaded by many haemocytes. Immediately before oviposition, this material is extruded. It surrounds the eggs and later hardens and forms the egg sac.The female genital atrium is a broad and wide cavity. The gonopods are two protrudible organs which, like the male organs, originate from the inner wall of the genital operculum. In Tarantula, each gonopod bears a claw like sclerite pointed backwards and inwards. By means of these sclerites the sperm packages are pulled out of the spermatophore. Simultaneously, the sperm is pressed out of the sperm packages, which may remain underneath the sclerites for many days, and sucked into two seminal receptacles laying just beneath the bases of the claw like sclerites. In Charinus brasilianus, the gonopods are cone like and lack sclerites and seminal receptacles. The sperm, in this species, is stored within a posterior pocket of the genital atrium.At oviposition, all stored sperm is used up, and at each molt all sperm is lost. Females therefore have to be reinseminated after breeding and molting.ZusammenfassungDas männliche Genitalsystem von Tarantula besteht aus paarigen Hoden, Lateraldrüsen, Ventraldrüsen und dem Genitalatrium mit dem Genitalanhang.Die Spermatozoen entwickeln sich in Spermatocysten. Sie sind zunachst langgestreckt und korkenzieherförmig. Später rollen sie sich ein and encystieren sich. In diesem Zustand werden sie in paarigen Vesicula seminalis gespeichert.Die Ventraldriisen produzieren durch holokrine Sekretion ein granuläres Sekret. Das Produkt der Lateraldrüsen ist homogen und hyalin. Beide Sekrete mischen sich nicht; sie werden in großen Sekretreservoiren gespeichert.Die Genitalanhang entsteht aus paarigen Gonopoden, die sich zunächst teilen und darn zusammenlegen und so ein hohles, kompliziertes Organ bilden.Die Spermatophore ist nicht vorgebildet, wenn das Männchen sich anschickt, sie abzusetzen. Die beiden Sekrete laufen zunächst entlang zweitr Ventralrinnen zu zwei ventralen Öffnungen. Dort werden sie am Untergrund befestigt und dann durch Anheben des Körpers zum Stiel ausgezogen. Danach werden die Ventralrinnen geschlossen, und das Sekret fließt in den zentralen Hauptraum des Genitalanhangs, der als Negativ-Form für den oberen Teil der Spermatophore dient. Dieser wird anschließend durch eine dorsale Öffnung herausgezogen.Die weiblichen Organe bestehen aus paarigen Ovarien, Ovidukten und Oviduktanhängen, einem unpaaren Uterus und dem. Genitalatrium mit den Gonopoden.Die Oocyten treten fresh aus dem Ovar aus, mit dem sic durch einen Funiculus verbunden bleiben. In der Leibeshöhle vollzieht sich der Dottereinbau in zwei Phasen; die zweite beginnt normalerweise nach der Paarung. Doch bleiben immer einige ruhende Oocyten, die nicht die zweite Vitellogenese-Phase beginnen. Kurz vor der Eiablage dehnen sich die Funiculi stark und lassen die Eier wahrscheinlich zurück ins Ovar schlüpfen.Nach der Paarung werden außerdem die Ovarien, Ovidukte und Oviduktanhänge sekretorisch tätig. Sie liefern ein aus fädigen Elementen bestehendes Sekret, in das viele Hämocyten einwandern. Vor der Eiablage tritt dieses Material aus der Geschlechtsöffnung und bildet den Brutsack.Das weibliche Genitalatrium ist ein weiter Baum. Die Gonopoden sind Schwellkörper, die dem Genitaloperculum innen aufsitzen. Bei Tarantula tragen sie je ein klauenartiges Sklerit, mit dem die Samenpakete aus den Spermatophoren gerissen werden. Das Sperma wird in zwei Receptacula seminis gespeichert, deren Öffnungen direkt unter den Basen der Sklerite liegen. Charinus brasilianus besitzt keine solchen Sklerite und keine Receptacula; die Spermien werden in einer hinteren Ausbuchtung des Genitalatriums gespeichert.Bei jeder Eiablage werden alle Spermien aufgebraucht. Bei Häutungen bleibt das Sperma in der Exuvie und geht verloren. Die Weibchen miissen sich darum vor jeder Fortpflanzungsperiode erneut paaren.

Coexistence of two species of whip spiders (Genus Heterophrynus) in the neotropical rain forest (Arachnida, Amblypygi)

SummaryHeterophrynus longicornis Butler and H. alces Pocock are sympatric and syntopic in Serra do Navio in the central part of Amapá, N.-E. Brazil. Both species are of similar sizes during part of their life cycles. Competition is probably reduced by utilization of different hiding places and strata. In H. longicornis, adults are tolerant towards conspecifics. Male and female are usually found close to each other and, under laboratory conditions, courtship behaviour can be observed even when the female is not receptive. H. alces, on the other hand, is very intolerant, and usually only single specimens are found. Under laboratory conditions, cannibalism is frequent. The ecological implications of these differences are discussed.

Courtship Behaviour and Sperm Transfer in the Giant Whip Scorpion, Mastigoproctus Giganteus (Lucas) (Uropygi, Thelyphonidae)

1. Courtship dance, sperm transfer, and spermatophore morphology of Mastigoproctus giganteus are described. 2. During spermatophore formation, the male stands in front of the female, both animals face the same direction and the female embraces the males opisthosoma with her pedipalps. 3. After spermatophore formation, the female picks up two long sperm carriers which the male then pushes into her genopore, embracing her from above and using his palpal fingers. 4. The reproductive biology is compared to that of other arachnids, the similarities between Uropygi and Amblypygi are demonstrated and the phylogenctical implications are discussed.

Fighting, Courtship, and Spermatophore Morphology of the Whip Spider Musicodamon atlanteus Fage, 1939 (Phrynichidae) (Chelicerata, Amblypygi)

Abstract The behaviour of Musicodamon atlanteus differs markedly from that of most other amblypygid species. First, this species has modified fighting behaviour. The fighting prelude with the “fencing posture” of other species has become the final fight during which opponents tap and beat at each other with their third legs. Further, Musicodamon has greatly reduced its mating behaviour. The spermatophore clearly shows similarities to those of Phrynichus and Trichodamon . Finally, its female genitalia resemble those of Trichodamon and, in particular, Damon uncinatus . This raises the possibility that complex spermatophores with bars and levers like those of the Phrynichinae are plesiomorphic within the Phrynichinae; they are apomorphic for the genera Damon , Musicodamon , Trichodamon , Phrynichus , and Euphrynichus . The spermatophores of most Damon species with their large sperm masses and simple mechanism are probably simplified and apomorphic.