Changes in the spermatophoric plasma during spermatophore development and during the spermatophoric reaction in the giant octopus of the north pacific,Octopus dofleini martini

Concentrations of Na, K, Cl, Ca and Mg were measured in the spermatophoric plasma and certain other body fluids of Octopus dofleini martini. The most striking change associated with maturation and passage of the spermatophore in the male reproductive tract, was a decline in the concentration of NaCl in the spermatophoric plasma. This was completely reversed during the spermatophoric reaction owing to influx of salt from the seawater. The outer tunic of a spermatophore undergoing spermatophoric reaction is also permeable to other substances. It allows an influx of inorganic phosphate and glucose, and an efflux of organically bound nitrogen, carbohydrate and aminosugar.     

Increased sperm numbers in the vas deferens of meadow voles, <Emphasis Type="Italic">Microtus pennsylvanicus,</Emphasis> in response to odors of conspecific males

Sperm competition occurs when the sperm of two or more males compete to fertilize the egg/s of a particular female. Males of some species respond to a high risk of sperm competition by increasing the number of sperm in their ejaculates. Males may accomplish such a response by increasing the intensity or duration of contraction of the cauda epididymidis and vas deferens. During emission (first phase of the ejaculatory process), the vas deferens receives sperm from the cauda epididymidis and propels the sperm to the urethra. In this paper, we tested the hypothesis that males exposed to a high risk of sperm competition mobilize larger numbers of sperm from the cauda epididymidis to the vas deferens before initiation of copulatory behavior. This accumulation of sperm in the vas deferens would result in a larger number of sperm in the ejaculate. To test this hypothesis, we exposed male meadow voles, Microtus pennsylvanicus, to either low or high risks of sperm competition using soiled bedding of conspecific individuals. At three different times after this exposure (15, 30, or 60 min), we removed both vasa deferentia and counted the sperm within them. We found a significant increase in sperm numbers in the vas deferens of males after 30 min of being exposed to a high risk of sperm competition. The lower sperm numbers after 15 and 60 min of exposure suggest that the observed response is relatively slow and that sperm mobilized to the vasa deferentia may return to the cauda epididymides if ejaculation does not occur some time after the observed response. Our results indicate that the physiological response that may result in high sperm numbers in the ejaculate in relation to high risk of sperm competition can occur before initiation of copulatory behavior.     

Spermatophore characteristics in bushcrickets vary with parasitism and remating interval

Male bushcrickets provide females with a nuptial gift, a spermatophore, which is transferred to females at mating. The spermatophore consists of a gelatinous mass, the spermatophylax, and the sperm-containing ampulla. Male spermatophore size is positively correlated with insemination rate and female refractory period and therefore with male reproductive success. In this study, we examined spermatophylax weight, ampulla weight and sperm number in males of Poecilimon mariannae parasitized by the acoustically orienting fly Therobia leonidei. We show that in parasitized males, spermatophylax weight decreases with the level of parasitism. In line with the hypothesis that parasitism is a cost to reproduction, we found that spermatophylax weight was reduced at remating. In contrast, the replenishment of the spermatophylax in unparasitized males was complete after 2 days and was increased no further after 3 days. Both sperm number and ampulla weight showed an increase over time since last mating and sperm production was estimated at a constant rate of 500,000 per day in all individuals, regardless of parasitism. The allocation of investment in components of the spermatophore varies greatly with parasitism and remating. Both factors had rather independent effects on spermatophore constitution, revealing functional constraints acting on spermatophore characteristics in bushcrickets, which are important for understanding the selection pressures working on its components. Received: 13 September 1999 / Received in revised form: 4 February 2000 / Accepted: 13 March 2000     

Male reproductive biology of the red frog crab,Ranina ranina,off Hachijojima,Izu Islands,Japan

Male red frog crabs, Ranina ranina, were collected year round in 1990 and 1991 off Hachijojima for histological study of the reproductive system and cycle. The testis containing the lobules and seminiferous ducts is surrounded by connective tissue. The seminiferous duct connects to the anterior end of the vas deferens, which can be histologically divided into three portions similar to one another in appearance. It was surrounded by fibrous connective tissue, muscle fibrils and columnar epithelium. Muscle fibrils were absent in the anterior portion. Multiple sperm masses were not formed in the vas deferens and ejaculatory duct, but the sperm mass was covered with a capsule composed of two layers. The outer layer of the capsule was periodic acid Schiff (PAS)-positive, but the inner layer was negative. Both layers were Alcian Blue negative, except the vacuoles in the outer layer that were stained blue. The small round androgenic gland was attached to the posterior end of the vas deferens of the coxa of the eighth thoracic appendage. The ejaculatory duct was distinguishable from the vas deferens by the absence of columnar epithelium and the presence of thick longitudinal muscle fibers. Spermatogenesis was histochemically examined. The acrosomal vesicle appeared to be derived from PAS-positive vesicles in the cytoplasm of the spermatid at the early stage of spermiogenesis. The arms were positive to the Feulgen reaction and the subacrosomal region was negative to PAS. Seasonal changes in reproductive cycle were inconspicuous histologically and microscopically. Sperm were always present in the testis and vas deferens throughout the year and occupied 5.1 to 19.6% of testis observed in cross sections. The minimum size of maturity is less than 39 mm carapace length, but the minimum size capable of successful mating was estimated to be ca. 55 mm.     

Sperm precedence, mating interval, and a novel mechanism of paternity bias in a beetle (Tenebrio molitor L.)

When females mate with more than one male, the ensuing sperm competition leads to the evolution of male mechanisms that skew paternity. Males of the yellow mealworm beetle (Tenebrio molitor) transfer a spermatophore to females during copulation, but sperm release and storage occur later. We investigated how the interval between two matings with different males affects sperm precedence by varying the interval between the copulations so that the second mating was either: (1) before sperm release from the first spermatophore (<5 min); (2) after sperm release but before spermatophore ejection (15–20 min); (3) after spermatophore ejection but before sperm storage (4 h), or (4) after complete sperm storage (24 h). We collected offspring over a period of 2 weeks and determined paternity by protein electrophoresis. There was second-male sperm precedence in all treatments, but when the interval was <5 min, the second male usually (86% of cases) had complete sperm precedence (i.e., P ₂=1). Investigations into the mechanism of second-male sperm precedence during <5-min mating intervals indicate that sperm release from the first spermatophore is inhibited, a phenomenon which has not been previously documented. Received: 31 January 2000 / Revised: 9 June 2000 / Accepted: 26 August 2000     

Gonopod tegumental glands: a new accessory sex gland in the Brachyura

It is not yet known whether gonopod tegumental glands (GTG) previously described in one species of brachyuran crab (Chionoecetes opilio) are a general feature in this large taxon. In order to determine the prevalence and role of GTG in the Brachyura, the first gonopods of six species of boreo-temperate and tropical brachyurans belonging to four families were examined morphologically and histologically, using the PAS–Alcian-blue staining protocol: Carcinus maenas, Portunus sebae, and Ovalipes ocellatus (Portunidae), Cancer irroratus (Cancridae), Grapsus grapsus (Grapsidae), and Petrolisthes armatus (Porcellanidae). Discrete rosette-type GTG were found in all species examined, although the longitudinal extent and location differed somewhat between taxa. The GTG were invariably grouped about the ejaculatory canal, and communicated with the lumen of the ejaculatory canal via ducts which traversed pores in the cuticle; staining properties of secretions at the duct openings to the ejaculatory canal matched those of the GTG. Neither GTG, ducts, nor pores were observed in regions distal to the ejaculatory canal. These data indicate that the prime, if not exclusive, role of the GTG is in reproduction, and that GTG may therefore be considered accessory sex glands. Together with previous and current investigations such GTG have been observed in all eight brachyuran species examined from five families, and are thus probably ubiquitous within the Brachyura. The organization and nature of the gland secretions differed between taxa: alternating acid (AMPS) and neutral mucopolysaccharide (NMPS) layers in the three Portunidae, AMPS only in Cancer irroratus, and NMPS only in Grapsus grapsus and Petrolisthes armatus. When combined with data on gonopod morphology and occurrence of spermatophore-less sealant in the ejaculate of various brachyurans, two plausible functions of the AMPS GTG secretions emerge: protection of the male's genetic investment (stored spermatophores) from opportunistic microbes following copulation, and the reciprocal processes of sperm competition and paternity assurance. The NMPS secretions may function as a lubricant to reduce mechanical wear of the ejaculatory canal by the second gonopod during copulation, and to reduce the viscosity of the ejaculate from the vas deferens as it enters the narrow ejaculatory canal. Received: 26 January 1998 / Accepted: 11 June 1998     

The ultrastructure and activity of sperm in Acanthodoris pilosa,a nudibranchiate mollusk

The sperm of Acanthodoris pilosa were examined in fresh preparations, histochemically stained samples, electronmicroscope sections, and in paraffin sections of the whole reproductive mass. Sperm are morphologically the same in the ampulla (vas deferens) and the spermatotheca and spermatocyst (bursae for sperm received during copulation). The electron micrographs show sperm with a long spiralled, fibrous, nuclear head with non-fibrous tongue-like acrosome. The tail, attached directly to the posterior of the head, has a 9+2 filamentous arrangement surrounded by a spiralled sheath which contains mitochondria and granular thread running the length of the tail. The thin-walled ampulla contains non-motile sperm and no energy sources such as polysaccharides and lipids. The bursae hold motile sperm and, with histochemical stains, were shown to contain polysaccharide droplets in walls and lumen. The lack of self-fertilization in nudibranchs appears to be associated with a physiological immaturity of the sperm in the hermaphroditic duct, where egg and sperm meet as they leave the ovotestis.     

Male reproductive investment relative to age and flight behaviour in the monandrous butterfly Pararge aegeria

Male reproductive investment may signify a considerable cost to male insects that produce sperm packages or spermatophores. Male butterflies allocate much of their active time budget to mate location, and they may adopt different behavioural strategies to do so. In the speckled wood butterfly (Pararge aegeria L.), males adopt either a territorial wait-and-fight strategy (territorial perching) or a fly-and-search strategy in wider areas (patrolling). In this study, we analysed the impact of male age, male size and male behaviour (i.e. behavioural strategies and levels of activity) on spermatophore investment (i.e. spermatophore mass, number of eupyrene sperm bundles). As predicted, reproductive investment increased with male age and size. Nevertheless, the increase of spermatophore mass with age and the number of eupyrene sperm bundles (i.e. fertile sperm) was stronger in low-activity males compared to active flying males. This suggests that flight activity has a negative impact on male reproductive investment. However, males that were forced to fly in the laboratory produced more eupyrene sperm bundles than resting males. We discuss the potential effects of male–male competition and predation risk on current versus future male reproduction. Males adopting different mate-locating strategies (perching and patrolling) in outdoor cages did not differ in spermatophore traits as was predicted from their very different flight performances. Copulations of territorial perching males took somewhat longer than copulations with non-perching males. There was a significant family effect of spermatophore size and of the expression of male mate-locating strategies suggesting heritable variation. Female traits (i.e. age and size) did not strongly affect spermatophore production. We discuss the results relative to both ultimate and proximate explanations of the complex relationships between butterfly activity, behavioural strategies, age and spermatophore production.     

The ultimate function of nuptial feeding in the bushcricket Poecilimon veluchianus (Orthoptera : Tettigoniidae : Phaneropterinae)

Summary During mating the males of the bushcricket Poecilimon veluchianus transfer a large spermatophore of about a quarter of their body weight to the female. Such nuptial feeding is often thought to function as paternal investment by increasing the fitness of the male's offspring. According to an alternative, though not mutually exclusive, hypothesis, the size of the spermatophore is maintained because of its function as a sperm protection device. In this case the cost to the male should be classified as mating effort. To discriminate between these two hypotheses we measured the duration of sperm transfer into the female spermatheca and the time taken for spermatophore consumption. A comparison of durations revealed that spermatophore consumption interferes with the process of sperm transfer (Fig. 4). There was no significant effect of spermatophore consumption on number of eggs laid, weight of eggs or absolute weight of hatched larvae. The relative dry weight of hatched larvae, however, was increased as a result of spermatophore consumption (Table 1). Thus spermatophylax size is adjusted in accordance with a sperm protection function and the spermatophylax therefore represents mating effort. The increase in relative dry weight indicates that there may also be a paternal investment effect of the spermatophylax, if the offspring that benefit from spermatophylax materials are fathered by the donating male. Correspondence to: K. Reinhold     

Paternal investment in Poecilimon veluchianus bushcrickets: beneficial effects of nuptial feeding on offspring viability

In most bushcrickets, males transfer a large spermatophore during copulation that is afterwards consumed by the female. In some species this nuptial gift enhances offspring fitness and is therefore believed to function as paternal investment. To determine whether this is the case, I examined whether a male's own offspring benefit from spermatophore consumption in the bushcricket Poecilimon veluchianus. Females that consumed a spermatophore produced offspring with increased residuals of dry weight compared to females that were prevented from feeding on the spermatophore. This beneficial effect of spermatophore consumption occurred within the first 4 days after copulation. An increased dry weight indicates higher energy reserves because offspring dry weight correlates significantly with the lifespan of starved larvae and because spermatophore consumption increased the lifespan of starved offspring. During egg-laying, females apply a liquid substance to the soil that hardens and probably serves as protection for the egg clutch. The amount of this substance correlated with the number of eggs laid but did not differ between spermatophore treatments. In P. veluchianus, females mate frequently and there is last-male sperm precedence. The spermatophore thus only constitutes paternal investment when offspring produced before female remating benefit from spermatophore consumption. The dry weight of offspring increased during the first 4 days after spermatophore consumption and thus within the natural remating interval. This shows that the spermatophore has a paternal investment function in addition to its already known sperm protection function. Received: 15 May 1998 / Accepted after revision: 11 October 1998     

No cost of male mating experience on female reproductive success in the almond moth, <Emphasis Type="BoldItalic">Cadra cautella</Emphasis> (Lepidoptera; Pyralidae)

Male copulation experience may have a profound impact on female reproductive success if male reproductive investment declines over consecutive copulations and if females are unlikely to re-mate. Male reproductive investment is particularly interesting in lepidopterans because males produce dimorphic sperm: a fertilizing (eupyrene) and a non-fertilising (apyrene) sperm. In two experiments, we explored the lifetime reproductive investment of male almond moths, Cadra cautella (also known as Ephestia cautella) and examined its influence on female reproductive success. In the almond moth, females re-mate infrequently and males transfer sperm in a spermatophore. Attached to the spermatophore is a large chitinous process, the function of which is unknown. One group of males were permitted consecutive copulations with virgin females and the amount of sperm and size of the spermatophore transferred were compared for all females. We found that the number of both eupyrene and apyrene sperm per ejaculate decreased with his increased mating frequency, while the size of the spermatophore process decreased dramatically after the male’s first copulation. In a second experiment, we allowed males to mate with females throughout their lives and then compared female fecundity and fertilisation success. We found no obvious decrease in female fecundity and fertilisation success with increased male copulation experience, despite the likely reduction in male gametic investment. We discuss potential explanations for the development of this enlarged and elaborate first spermatophore of male almond moths given that it confers no clear fitness advantage to females.     

The cost of mating with a non-virgin male in a monandrous butterfly: experimental evidence from the speckled wood, Pararge aegeria

Contrary to vertebrates, sperm production in insects may bear considerable costs for males. This is especially true in species that donate spermatophores containing sperm and nutrient-rich accessory gland products like in butterflies. Hence, spermatophores at first and subsequent copulations can differ in a quantitative and qualitative way. Such effects have particularly been shown in polyandrous species providing large spermatophores. Here we experimentally tested the effect of male mating status (virgin male vs recently mated male) on copulation duration, spermatophore size and females’ fitness components in a monandrous butterfly Pararge aegeria that typically donates small spermatophores. Copulations with non-virgin males lasted on average five times longer than that with virgin males and resulted in a spermatophore which was on average three times smaller. Number of eggs laid and female life span were not affected by the mating status treatment, but there was a significant effect on the number of living caterpillars a female produced, as copulations with virgin males resulted in higher numbers of larval offspring. Interestingly, the difference in spermatophore mass at the first and the second copulation increased with male body size. This suggests differential spermatophore allocation decisions among males of different size. Consequences for females and potential mechanisms influencing female fitness components are discussed. Given the small absolute size of spermatophores in P. aegeria, components other than consumable nutrients (perhaps hormones) should cause the observed effects.     

Fluctuating asymmetry and sperm transfer in male decorated field crickets (Gryllodes sigillatus)

Fluctuating asymmetry (FA) in limb size in female decorated field crickets (Gryllodes sigillatus) was associated with a reduction in the size of the spermatophore and the amount of sperm transferred by males and an increase in the time taken to transfer a spermatophore following introduction of a female. There was a weaker negative relationship between limb asymmetry in males and sperm number but no significant relationship between asymmetry in either sex and spermatophylax size. In line with a previous study, female size did not appear to influence spermatophore production or mating decisions by males. The results imply that developmental instability affects both gamete production and mating decisions among males, although the relationships between spermatophore size, sperm number and asymmetry in females are unlikely to be the result of males perceiving differences in female FA. Received: 24 July 1999 / Received in revised form: 22 November 1999 / Accepted: 31 December 1999     

Reversal and transfer of spermatophores by Octopus vulgaris and O. hummelincki

Copulatory behavior in the octopus consists of a patterned series of movements whose individual functions are not well understood. Observations and experiments on mating in Octopus vulgaris and O. hummelincki from Bimini, Bahamas and Haiti were made over a number of years in the laboratory. The study reveals how the male octopus reverses its spermatophore prior to transferring it to the female. The male’s terminal organ (penis) extrudes the sperm end of the spermatophore as it exits from Needham’s sac up to the cap or filament thread and then, holding onto the cap thread, inserts the ejaculatory end of the spermatophore into the groove of the hectocotylus, thus reversing it. It is hypothesized that the primary function of the cap or filament thread, one part of the spermatophore, is to be a handle by which the reversal and transfer is accomplished. The siphon is merely a conduit through which the terminal organ functions and plays no role whatsoever in either the reversal of the spermatophore or in its insertion into the groove. The stimulus to which the male orients to find the groove of the hectocotylus is the apex of the retracted interbrachial membrane between the third and fourth right arms, which bears a fixed spatial relationship to the origin of the groove. A number of deviations from the successful transfer process, which represent loss of sperm from the reproductive process, are illustrated. Despite these deviations, the delicately balanced integration of the various movements serves to transfer the spermatophore to the female to ensure reproductive success.     

Ecological and evolutionary significance of pelagic spermatophores of vermetid gastropods

Sperm are disseminated in vermetid gastropods by spermatophores released freely into the ocean. Spermatophores from 7 species of vermetids, including 3 genera, were obtained from reproductively active males or offshore plankton tows or both. Each vermetid spermatophore consists of a sperm mass containing highly ordered eupyrene and apyrene sperm enveloped concentrically by 3 transparent capsules. Generic and specific differences occur in the size, shape and composition of the sperm mass and capsule. The complexly layered spermatophore is assembled in the male reproductive tract, which includes and elaborate set of pallial reproductive glands for capsule production. Spermatophores are liberated by males into the seawater, and there dispersed by water movements. Some of these drifting spermatophores become entangled in the mucous feeding nets of female vermetids and are then activated by feeding movements. Activation of the complex ejaculatory apparatus appears to result from an interplay of osmotic and mechanical mechanisms. Spermatophores remain viable in the laboratory for 12 to 20 h after release from the male; after 20 h, the sperm mass breaks down and the sperm become immotile. Plankton tows capture some spermatophores with motile sperm and others in which sperm are no longer active. Evolutionary implications of the relationship between production of pelagic spermatophores, sessile mode of life and other aspects of vermetid biology are discussed.     

Imposex in Hexaplex trunculus (Gastropoda: Muricidae): first results from biomonitoring of tributyltin contamination in the Mediterranean

Imposex (the occurrence of penis and vas deferens in females) in Hexaplex trunculus collected from Malta (Central Mediterranean) in 1992 is reported. This phenomenon is related to the levels of tributyltin (TBT) in the organisms as well as in sediments. Imposex indices (relative penis size and vas deferens sequence) are used to biomonitor coastal contamination by TBT for the first time in the Mediterranean. In its response to TBT, H. trunculus is ranked as one of the most sensitive neogastropod species studied so far. Accumulation of TBT and its metabolites in the digestive glands, gonads and the rest of the body are described, and sex-related differences are shown. No preferential female mortalities are recorded in populations exposed to high levels of TBT. However, a reported shift in the size frequency distribution of H. trunculus in contaminated sites, towards bigger snails, may suggest reduced reproductive potential.     

Potential histopathological and molecular changes in rat vas deferens inhaled by Boswellia papyrifera and Boswellia carterii

Boswellia papyrifera and Boswellia carterii released from smoke contaminate indoor environment and consequently adversely affect humans as evidenced by respiratory disturbances. The aim of this study was to determine the effects of these plants on pathological and biochemical changes in vas deferens of albino rats. Animals were administered 4 g/kg body weight B. papyrifera and B. carterii daily for 120 days along with controls. Significant changes were observed in epithelial cell types and some cells showed signs of degeneration. The ultrastructural studies revealed marked changes in cytoplasmic organelles. Microvilli were missing and lysosomes were found in the cytoplasm. In addition, all treated groups plasma fructose and other biochemical parameters were decreased indicating reduced energy necessary for motility and contractility of spermatozoa. Many spermatozoa were disorganized and agglomerated. Data suggest that smoke from these plants adversely affects vas deferens.     

Pre-mating sperm removal in the bushcricket Metaplastes ornatus Ramme 1931 (Orthoptera, Tettigonoidea, Phaneropteridae)

Summary Mating in the bushcricket Metaplastes ornatus Ramme 1931 entails a number of peculiar genital couplings that precede the transfer of the large spermatophore. During these phase-I couplings, the male introduces his specially structured subgenital plate into the female's genital chamber, performs back-and-forth movements, and turns her genital chamber inside out when he withdraws, whereupon the female carefully cleans her everted genital chamber with her mouthparts. During the last coupling (phase II) the male's subgenital plate is not introduced but the large spermatophore, which averages 22% of a male's body weight, is transferred. Counts of sperm in the spermathecae of females suggested that the phase-I couplings, which occur prior to spermatophore transfer, function to remove, or at least to reduce, the sperm of a female's previous mates. The form of the keel of the male's subgenital plate, its position within the female's genital tract during phase-I couplings, and the back-and-forth movements suggest that the male may stimulate release of sperm from the female's spermatheca by a mechanism similar to fertilization as eggs pass through the genital chamber during oviposition.     

Sperm economy and limitation in spiny lobsters

Sperm limitation, when female fertilisation success is constrained by the supply of sperm, is generally perceived to be an uncommon feature of reproduction in species which directly transfer gametes during copulation. Male size, previous copulations, and the balance of expected reproductive return and future mating opportunity may, however, limit the amount of sperm males transfer to females. We used laboratory experiments where mate size could be manipulated and its consequences on spermatophore size and clutch size determined, to show that in two genera of spiny lobsters (Crustacea: Palinuridae) male reproductive output limits the size of clutches brooded by females. In Panulirus argus from the Florida Keys, we show that while male size affects spermatophore area, males also vary the amount of ejaculate positively with female size. Furthermore, the area of the spermatophore has a greater influence than female size on subsequent clutch weight. In Jasus edwardsii from New Zealand, female size, male size and mate order all affect clutch weight. In both species, clutches fertilised by small males in the laboratory are significantly smaller than clutches fertilised by large males. These results suggest that to ensure they receive sufficient sperm, females should either mate several times prior to oviposition, mate as early as possible in the reproductive season, or choose large, preferably unmated males as partners and thus compete with other females for preferred males. Sperm-limited female fecundity has the potential to limit the egg production of fished populations where large males are typically rare. Received: 18 May 1998 / Received in revised form: 20 November 1998 / Accepted: 30 November 1998     

The androgenic gland of the shrimp Palaemon dayanus

The androgenic gland of Palaemon dayanus Henderson differs in morphology and anatomy from that of all other known natantian decapods. The gland is attached to the distal extremity of the was deferens as a thin, plate-like structure made up of numerous parallel strands in close juxtaposition. The gland is clearly separated by intervening thick muscle bands from the epithelium of the vas deferens. The structure of the gland shows distinct zones of activity such as growth and degenerating zones. The presence of degenerating zones together with zones of activity in the same gland at the same time is attributed to a holocrine mode of secretion in the androgenic gland.