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1.
J. Wodinsky 《Marine Biology》1973,20(2):154-164
Typically three events occur when Octopus vulgaris Cuvier mates. The male inserts its hectocotylus into the mantle cavity of the female; the hectocotylus and the bodies of the male and female become quiescent; and the female increases its ventilation rate about 2.5 times, on the average, above its precopulatory base rate. It is hypothesized that the increased ventilation rate of the female provides the stimulus to the male to transfer its spermatophore to the oviduct. Since the insertion of the hectocotylus and the female's increased ventilation rate may be dissociated, it is suggested that copulation be defined as the attachment of the hectocotylus to the oviduct. A conditioned ventilation-rate increase in the female was observed with repeated testing. Observation of arching and pumping movements of the male as well as measurements of its ventilation rate before and during copulation indicate that only a few spermatophores are transferred per copulation. 相似文献
2.
Kathryn B. McNamara Therésa M. Jones Mark A. Elgar 《Behavioral ecology and sociobiology》2007,61(8):1177-1184
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. 相似文献
3.
Sperm economy and limitation in spiny lobsters 总被引:5,自引:0,他引:5
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 相似文献
4.
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. 相似文献
5.
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. 相似文献
6.
In many animal species, male and female interests often differ when it comes to decisions over mating and fertilization. However, it is intrinsically difficult to determine the degree to which males and females exert control over the various processes that determine the outcome of reproductive interactions, and thus to predict how such conflicts will be resolved. For example, in species where sperm are transferred to females via a spermatophore or other external sperm packaging device, it is unclear which sex determines subsequent sperm transfer dynamics to the female reproductive tract. To address this question, we used a reciprocal cross experimental design in a bushcricket species (Poecilimon veluchianus) comprising two subspecies differing in the dynamics of sperm transfer. The reciprocal crosses show that in these bushcrickets the timing of sperm transfer in inter-subspecies crosses closely resemble those typical of the subspecies of the male partner, indicating that it is the properties of the spermatophore rather than its handling by the female that determine sperm transfer dynamics. There was neither a significant female influence nor any indication of an interaction between males and females with regard to the number of sperm transferred after a set interval. Our study suggests that males rather than females appear to control the timing of the insemination process in this species. 相似文献
7.
Lesley Vande Velde Pauline Silvestre David Damiens Hans Van Dyck 《Behavioral ecology and sociobiology》2012,66(3):347-359
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. 相似文献
8.
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 相似文献
9.
Spermatophore characteristics in bushcrickets vary with parasitism and remating interval 总被引:4,自引:0,他引:4
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 相似文献
10.
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 相似文献
11.
12.
Katharina Maria Jörger Martin Heß Timea Pamela Neusser Michael Schrödl 《Marine Biology》2009,156(6):1159-1170
Sperm transfer via spermatophores is common among organisms living in mesopsammic environments, and is generally considered
to be an evolutionary adaptation to reproductive constraints in this habitat. However, conclusions about adaptations and trends
in insemination across all interstitial taxa cannot be certain as differences in mode of insemination via spermatophores do
exist, details of insemination are lacking for many species, and evolutionary relationships in many cases are poorly known.
Opisthobranch gastropods typically transfer sperm via reciprocal copulation, but many mesopsammic Acochlidia are aphallic
and transfer sperm via spermatophores, supposedly combined with dermal fertilisation. The present study investigates structural
and functional aspects of sperm transfer in the Mediterranean microhedylacean acochlid Pontohedyle milaschewitchii. We show that spermatophore attachment is imprecise. We describe the histology and ultrastructure of the two-layered spermatophore
and discuss possible functions. Using DAPI staining of the (sperm-) nuclei, we document true dermal insemination in situ under
the fluorescence microscope. Ultrastructural investigation and computer-based 3D reconstruction from TEM sections visualise
the entire spermatozoon including the exceptionally elongate, screw-like keeled sperm nucleus. An acrosomal complex was not
detected. From their special structure and behaviour we conclude that sperm penetrate epithelia, tissues and cells mechanically
by drilling rather than lysis. Among opisthobranchs, dermal insemination is limited to mesopsammic acochlidian species. In
this spatially limited environment, a rapid though imprecise and potentially harmful dermal insemination is discussed as a
key evolutionary innovation that could have enabled the species diversification of microhedylacean acochlidians. 相似文献
13.
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 相似文献
14.
Klaus Reinhold 《Behavioral ecology and sociobiology》1999,45(3-4):293-299
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 相似文献
15.
A comprehensive understanding of sexual selection requires knowledge of the traits and mechanisms responsible for increasing a male’s paternity share (proportion of progeny sired) relative to that of other males mating with the same female. In this study we manipulated by starvation the expression of traits that might influence male paternity share in Tribolium castaneum. We then conducted experiments to examine how male starvation affects male performance during sequential episodes of sexual selection from mating to progeny production, and investigated female control over specific stages by using live vs dead females. Comparison of starved vs fed males revealed that T. castaneum females have control over spermatophore transfer during mating, as live females rejected inseminations by starved (“low quality”) males. None of the measured male copulatory behaviors (leg-rubbing frequency, asymmetry, and percent of time spent rubbing) affected the probability of successful insemination, but the last two were positively associated with male paternity share. Spermatophore positioning within the female reproductive tract was not affected by male treatment (starved/fed), by female treatment (live/dead), or by male copulatory behaviors. Starvation, however, had a dramatic effect on male reproductive physiology, decreasing both accessory gland size and total number of sperms transferred (but not sperm viability in seminal vesicles). In addition, females who mated to starved males stored fewer sperms in their spermathecae, which, together with decreased ejaculate size, may explain the reduced paternity share of starved males compared to fed males. This study elucidates some cryptic mechanisms influencing male reproductive success and aids our understanding of trait evolution through sexual selection. 相似文献
16.
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. 相似文献
17.
Age-specific information on individual octopus reproductive development and investment from wild populations has until recently
been unobtainable. Using daily-formed increments within stylets (internal shells) the individual ages of 503 wild Octopus pallidus were determined. In addition, detailed reproductive information was collected for each of the aged octopus, along with reproductive
data for an additional 925 octopus. All of the octopus were collected from Bass Strait waters in south-eastern Australia from
November 2004 to November 2006. This information was used to investigate seasonal trends in reproductive scheduling and investment,
fecundity and egg size. Maturation in O. pallidus primarily depends on size with little relationship to age and is highly variable between genders, with females >350 days
still maturing in comparison to all males >142 days being mature. Size at 50% maturity for females was approximately 473 g,
which is considerably larger than male 100% maturity at <250 g. This indicates that for females at least, maturity does not
necessarily come with age. Seasonal scheduling in reproductive investment between genders revealed an optimal spawning period
between late summer and early autumn. These results reinforce the view that individual growth and maturity is highly variable
in cephalopods. 相似文献
18.
Andreas Vermeulen Sierk Engels Klaus Peter Sauer 《Behavioral ecology and sociobiology》2008,63(1):77-83
Variation in traits closely related to fitness is expected to be low. This is because these traits are under directional selection
and the best genotype should prevail. However, there have been a number of studies demonstrating the existence of considerable
variance in sexually selected traits, which is generally known as the lek paradox. Accordingly, earlier studies found substantial
variation in sperm transfer rates in Panorpa vulgaris. Aiming at finding the mechanism that maintains this variation, we analyzed the condition dependence and the narrow sense
heritability of sperm transfer rates. Food deprivation in the larval/adult phase caused a decrease in the males’ capability
of saliva secretion resulting in shorter copulations and a reduced number of transferred sperm. There was a positive correlation
between mean sperm transfer rates and mean body mass. Additionally, intermale variation in sperm transfer rates decreased
with increasing food availability. Hence, we suggest that sperm transfer rates in P. vulgaris are influenced by adult feeding history. Heritability analyses of sperm transfer rates did not provide significant results,
which is consistent with the general hypothesis that additive genetic variance in traits closely related to fitness is small.
Since a trait’s potential to respond to selection is proportional to the amount of contained additive genetic variance, the
ascertained small heritability provides a satisfying explanation for the maintenance of substantial variation in sperm transfer
rates. 相似文献
19.
Sperm motility and longevity in the giant cuttlefish, Sepia apama (Mollusca: Cephalopoda) 总被引:1,自引:1,他引:1
The sperm kinetics and fertilisation literature in marine invertebrates is heavily biased toward free-spawning species. Nonetheless,
many species (e.g. cephalopods) transfer and/or fertilise gametes in confined external spaces or internally, creating very
different selective pressures on sperm storage, sperm longevity and hence sperm competition. Here we report the results of
an investigation into the effects of sperm age, water temperature and sperm concentration on sperm motility in the giant cuttlefish
(Sepia apama). Significant positive correlations were found between percent motility and sperm concentration, and between sperm motile
speed and sperm concentration. Mean percent motility of cuttlefish sperm suspension was still 9% eight hours after being released
from the spermatophore and diluted into filtered seawater at 12°C (ambient field temperature during the spawning season).
Sperm resuspended from spermatangia taken from (mated) females in the field were motile for up to 100 hours. When spermatophores
were stored at 4°C motility was still observed in resuspended sperm after two months. Our results show that spermatangia and
spermatophores can retain and release live sperm for long periods. The observed longevity of sperm in S. apama greatly increases the potential for sperm competition in this species. 相似文献
20.
L. W. Simmons R. J. Teale M. Maier R. J. Standish W. J. Bailey P. C. Withers 《Behavioral ecology and sociobiology》1992,31(1):57-62
Summary The cost of reproductive effort is known to result in a trade-off between current and future reproduction. Similarly, trade-offs in energy allocation may occur between components of reproductive effort, mating and parental effort, within a single reproductive episode. We investigated the energy allocated to mating effort (calling to attract females) and parental effort (donation of spermatophore nutrients at mating) by male bushcrickets, Requena verticalis, under two dietary regimes. Males provided with a low quality diet reduced the daily energy allocated to calling activity while maintaining their investment in spermatophores. Males provided with a high quality diet did not allocate more resources per day to their spermatophores but stored excess energy for future reproduction. Thus, on a per day basis, males appear to hold constant their investment in the spermatophore at the cost of reduced mating effort when resources are limited. Males on both diets, however, increased the size of their spermatophore donations when the interval between female encounters was increased. One explanation for this pattern could be a frequency-dependent optimization of spermatophore size.
Correspondence to: L.W. Simmons 相似文献