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1.
The relationship between intermoult duration (coloration), sex, size and seasonal variations in fatty acid (FA) profiles
was studied in a population of shore crabs, Carcinus maenas, inhabiting the Isefjord, Denmark. For male shore crabs, the total hepatopancreas FA content was high in July and December
(12.7 to 16.0 mg g−1 dry weight, dw) but lower in May and September (7.3 to 10.0 mg g−1). This indicates that male shore crabs are in relatively good condition before winter, when the crabs migrate off shore,
but in relatively poor condition when they return to shallow waters during spring. The hepatopancreas FA content also decreased
over the mating season. After the mating season the hepatopancreas FA content of males had decreased to approximately 60%
of that prior to the mating season. Female shore crabs had significantly higher hepatopancreas FA levels than males in May
(11.7 mg g−1 dw), September (12.6 mg g−1 dw) and December (17.9 mg g−1 dw) but lower levels in July (9.5 mg g−1 dw). This indicates that the spawning season is the most energy-demanding part of the female reproductive cycle. For all
seasons, the hepatopancreas FA content of green shore crabs was significantly higher than that of red shore crabs. For both
colour forms, the amount of polyunsaturated fatty acids (PUFAs) was significantly higher than that of saturated fatty acids
(SAFAs) and monounsaturated fatty acids (MUFAs), with the relative proportion of PUFAs increasing when the total hepatopancreas
FA content decreased. For both genders and colour forms, the most dominating SAFA was palmitic acid (16:0). Palmitoleic acid
(16:1ω7), vaccenic acid (18:1ω7) and oleic acid (18:1ω9) were the three MUFAs found in highest concentrations. The most dominating
PUFA was eicosapentaenoic acid (EPA, 20:5ω3). Docosahexaenoic acid (DHA, 22:6ω3) and arachidonic acid (AA, 20:4ω6) were also
abundant in all samples. The results demonstrated that season, sex, size and intermoult duration all influence the amount
of FAs present in the hepatopancreas of shore crabs.
Received: 23 September 1999 / Accepted: 29 April 2000 相似文献
2.
N. Aizawa 《Marine Biology》1998,131(3):523-532
In several species of ocypodid crabs, including Ilyoplax pusilla (De Haan), waving displays tend to be synchronized among neighboring individuals. However, no quantitative study has yet
been conducted. In this study, responses of I. pusilla males to waving of video and real crabs were examined. Spontaneous, periodic waving was observed even when no stimulus waves
were present. When single isolated waves of the video crab were randomly delivered (single pulse perturbation), crabs waved
either immediately after the stimuli or after some time had elapsed. Assuming that waves immediately after the stimuli were
triggered prior to those stimuli, crabs typically responded after a roughly constant delay from the onset of each stimulus.
The delay (response time) was close to, but slightly shorter than, the spontaneous wave period. Dependency of response time
upon timing of the stimulus (stimulus time) was at most weak. Responses of crabs to periodic waves of the video crabs and
waves of␣the real crabs were basically consistent with the results of single pulse perturbation, although there was a consistent
tendency for stimulus time and response time to be negatively correlated near stimulus time = 0 s. Overall, these results
demonstrate that males of I. pusilla adjust signal timing relative to a neighbor in a manner of phase delay synchrony. The similar response pattern has also been
noted in synchronous flashing of fireflies and the calling of katydids. Moreover, these experiments with I.␣pusilla demonstrate the value of video playback as a research tool in this species.
Received: 4 April 1997 / Accepted: 17 December 1997 相似文献
3.
Activity pattern and spatial strategy in Pachygrapsus marmoratus (Decapoda: Grapsidae) from Mediterranean and Atlantic shores 总被引:2,自引:0,他引:2
The spatial strategies and activity patterns of two populations of Pachygrapsus marmoratus (Fabricius), from Italy and Portugal, were studied in the field. The Mediterranean site was a non-tidal splash zone about
30 cm wide, while the Atlantic site was a 30 m wide intertidal belt. Almost all P. marmoratus of both populations were active on the emerged rocks, rarely entering the sea. The Mediterranean crabs actively fed on the
algal turf throughout the 24 h, while in Portugal active crabs were more numerous at night. In the Italian population, all
crabs were packed together, although large males had larger activity areas than females and smaller males. In Portugal, the
large males were more concentrated in the sublittoral fringe, while both small males and females were confined to the eulittoral
and littoral fringe. The Italian P. marmoratus performed feeding loops within areas smaller than 9 m2. Although most Portuguese crabs showed the same spatial strategy, some of them performed feeding migrations to the sublittoral
fringe, covering distances of up to 20 m. Environmental factors (e.g. temperature), physical factors (e.g. refuge availability)
and biotic factors (e.g. competitors and predators) of the different shores probably determine the behavioural plasticity
of␣P.␣marmoratus.
Received: 1 February 1998 / Accepted: 13 November 1998 相似文献
4.
The genetic mating system of a sex-role-reversed pipefish (Syngnathus typhle): a molecular inquiry 总被引:4,自引:0,他引:4
Adam G. Jones Gunilla Rosenqvist Anders Berglund John C. Avise 《Behavioral ecology and sociobiology》1999,46(5):357-365
In the pipefish Syngnathus typhle as in other species of Syngnathidae, developing embryos are reared on the male's ventral surface. Although much laboratory
research has been directed toward understanding sexual selection in this sex-role-reversed species, few studies have addressed
the mating behavior of S. typhle in the wild, and none has capitalized upon the power of molecular genetic assays. Here we present the first direct assessment
of the genetic mating system of S. typhle in nature. Novel microsatellite loci were cloned and characterized from this species, and employed to assay entire broods
from 30 pregnant, field-captured males. Genetic analysis of 1340 embryos revealed that 1–6 females (mean = 3.1) contributed
to each brooded clutch, the highest rate of multiple maternity yet documented in any pipefish. Evidence of multiple mating
by females was also detected. Thus, this population of S. typhle displays a polygynandrous mating system, a finding consistent with previous field and laboratory observations. Our results,
considered together with similar studies of other syngnathid species, provide preliminary support for the hypothesis that
the genetic mating system is related to the evolution of sexual dimorphism in the fish family Syngnathidae.
Received: 19 January 1999 / Received in revised form: 15 April 1999 / Accepted: 9 May 1999 相似文献
5.
Pablo D. Ribeiro John H. Christy Rebecca J. Rissanen Tae Won Kim 《Behavioral ecology and sociobiology》2006,61(1):81-89
Courting male fiddler crabs Uca terpsichores (1 cm carapace width) sometimes build mounds of sand called hoods at the entrances to their burrows. Males wave their single
enlarged claws to attract females to their burrows for mating. It was shown previously that burrows with hoods are more attractive
to females and that females visually orient to these structures. In this study, we test whether males also use their hoods
to find their burrows. We first determined the maximum distance that males can see and find a burrow opening without a hood.
Males were removed from their burrows and placed on the sand at a range of distances from a burrow opening. If they were more
than about 8 cm (seven units of eye-height) away, they were unable find the burrow. In contrast, males that were burrow residents
used a non-visual path map to return to their burrows from much greater distances. To determine if hoods help males find their
burrows when there are errors in their path maps, we moved residents 1–49 cm on sliding platforms producing errors equal to
the distances they were moved. Males with self-made hoods or hood models at their burrows relocated their burrows at significantly
greater distances than did males with unadorned burrows. Hood builders also relocated their burrows faster. Hence, hoods have
two functions: they attract females and they provide a visual cue that males use to find their burrows quickly and reliably
when their path maps fail.
An erratum to this article can be found at 相似文献
6.
Males of the sac-winged bat, Saccopteryx bilineata, actively fill their propatagial sacs with secretions from the genital region, the gular gland, urine and saliva. From our
observations and those of Starck we deduce that propatagial sacs in S. bilineata do not have a glandular function, but are instead organs for the storage and display of odours. In addition to the already
known “salting” and hovering behaviour of male S. bilineata, we describe in detail how odour is fanned to roosting individuals during the complex, stereotypic hovering displays. S. bilineata males also coat the fur of their backs with saliva using the wing tip and might scent-mark territory boundaries. “Yawning”
may represent a visual as well as an olfactory cue. Odour seems to play an important role in the social communication of S. bilineata and in other emballonurids, as revealed by the broad distribution of wing sacs in this family. S. bilineata males display odour during energetically costly hovering flights in front of females. We demonstrate that the number of hovering
displays increases with harem size. The mating effort of S. bilineata males comprises a multimodal signalling behaviour. Although males defend harem territories in which females gather, females
seem to be able to choose the father of their progeny freely among the males of a colony. This may have led to the evolution
of the complex mating displays by male S. bilineata.
Received: 9 December 1998 / Received in revised form: 6 May 1999 / Accepted: 13 June 1999 相似文献
7.
The Norway lobster Nephrops norvegicus (L.) inhabits burrows in muddy clay sediments (e.g. on the Swedish west coast), where an autumnal oxygen deficiency in the
bottom water can occur. Our experiments investigated whether the irrigation of the burrows would reflect a behavioural adaptation
to hypoxia, and whether any gender differences of such behaviour exist. Irrigation is performed by the pleopods which may
compensate for a decreasing oxygen tension. Pleopod activity (total number of strokes per sampling time), associated with
oxygen concentration and gender, was studied in N. norvegicus kept in artificial burrows resembling their natural habitat. Male and female lobsters were separately exposed to either normoxia
(70% oxygen saturation) or hypoxia (30% oxygen saturation). A sexual difference in behaviour was found, where females irrigated
the burrow less than males during normoxia. Females showed a significant increase of pleopod activity in hypoxia compared
with normoxic conditions, which was not displayed by the males probably due to the degree of individual variation found. However,
when only males were studied during progressive hypoxia (from 60 to 5% oxygen saturation), following any changes of irrigational
behaviour, a significant increase of accumulated pleopod activity occurred. A major increase of pleopod activity appeared
between 60 and 50% oxygen saturation, below which the activity remained high until a critical point (<10% saturation, 11 °C,
33 psu) where irrigation dropped to a level close to that of normoxic values. Activity sessions during hypoxia were longer
and had a higher stroke rate than during normoxia.
Received: 22 October 1997 / Accepted: 26 February 1998 相似文献
8.
M. Thiel 《Marine Biology》1998,132(1):107-116
The reproductive traits of a deposit-feeding amphipod that engages in extended parental care were examined. At the study
site in Lowes Cove, Maine, USA, Casco bigelowi (Blake, 1929) occurred in highest densities in soft sediments just below mean low water (MLW). During most months, the sex
ratio was ≃1. Many females hosted males in their burrows throughout the summer, but after fertilization of females in September,
all adult males disappeared from the study area. In October almost 80% of the females were ovigerous, and in November about
the same percentage was parental, i.e. caring for juveniles in their burrows. The females produced only one brood each in
late fall which they accommodated in their burrows for 2 mo or longer. The average number of juveniles per female was ∼20
in November, and continuously decreased until January. Juveniles reached sizes >10 mm length in the maternal burrows. In early
December the first juveniles were found in their own burrows, but major recruitment took place in late December and January.
It is concluded that for C. bigelowi, the delay of recruitment into the winter months with low predation pressure and the large offspring size at this time are
major advantages gained by extended parental care. C. bigelowi is host to the peritrich ciliate Cothurnia sp. on its gills, and during the summer months >70% of all amphipods had ciliates on their gills. Juveniles still living
in their mother's burrows showed infestation rates similar to that of the parent; those of highly infested mothers were more
heavily infested than those of “clean” mothers. Facilitated epibiont transmission during intimate and long-lasting (2␣mo)
parent–offspring associations may be a consequence of extended parental care.
Received: 25 November 1997 / Accepted: 14 April 1998 相似文献
9.
Reproductive biology of a wood-boring isopod, Sphaeroma terebrans, with extended parental care 总被引:1,自引:0,他引:1
M. Thiel 《Marine Biology》1999,135(2):321-333
The isopod Sphaeroma terebrans Bate, 1866 burrows in aerial roots of the red mangrove Rhizophora mangle L. The burrows serve as shelter and as a reproductive habitat, and females are known to host their offspring in their burrows.
I examined the reproductive biology of S. terebrans in the Indian River Lagoon, a shallow lagoon stretching for ∼200 km along the Atlantic coast of Florida, USA. Reproductive
isopods were found throughout the year, but reproductive activity was highest in the fall and during late spring/early summer.
During the latter periods, large numbers of subadults established their own burrows in aerial roots. The average numbers of
S. terebrans per root were high during the fall, but decreased during the winter and reached lowest levels at the end of the summer. Females
reached maturity at a larger size than males, but also grew to larger sizes than the males. The average size of females varied
between 8 and 10 mm, the average size of males between 6.5 and 8.5 mm. The number of embryos female−1 was strongly correlated with female body length. No indication for embryo mortality during development was found. Parental
females (i.e. with juveniles in their burrows) hosted on average between 5 and 20 juveniles in their burrows (range 1 to 59).
Most juveniles found in female burrows were in the manca stage and 2 to 3 mm in body length. Juveniles did not increase in
size while in the maternal burrow, and juveniles of similar sizes could also be found in their own burrows. Males did not
participate in extended parental care, since most of them left the females after copulation. Many females that were born in
the summer produced one brood in the fall and a second during winter/early spring. Females that were born in the fall produced
one brood during spring/early summer, but then probably died. Extended parental care in S. terebrans is short compared to other peracarid crustaceans. It is concluded that this reproductive strategy in S. terebrans serves primarily to shelter small juveniles immediately after they emerge from the female body, when their exoskeleton is
still hardening and their physiological capabilities are still developing. Thus, in S. terebrans, extended parental care probably aids to protect small juveniles from adverse physical conditions in their subtropical intertidal
habitat.
Received: 9 December 1998 / Accepted: 24 June 1999 相似文献
10.
We provide evidence that male lizards can use chemosensory cues to identify individual females and probably therefore maintain
long-term associations with these females in the wild. In the laboratory, males preferentially followed the scent trail of
their vitellogenic female “partner” rather than that of another vitellogenic female. Our 5-year field study of the small viviparous
scincid lizard (Niveoscincus microlepidotus) in alpine Tasmania showed that sexually mature males and females commonly formed “pairs” for long periods (on average 29 days).
These pairs occurred primarily during the mating season, always involved one adult male and one adult female, and usually
involved vitellogenic rather than gravid females. Our laboratory experiments suggest that a significant factor in maintaining
those prolonged partnerships is male scent trailing of partners.
Received: 28 October 1997 / Accepted after revision: 28 May 1998 相似文献
11.
Cadmium accumulation in the female shore crab Carcinus maenas during the moult cycle and ovarian maturation 总被引:2,自引:0,他引:2
The influence of moulting and ovarian maturation on cadmium accumulation in the tissues of female shore crabs Carcinus maenas exposed to 1 mg Cd l−1 in the water was investigated. Cadmium accumulation in all tissues examined was markedly increased in crabs in the postmoult
stages (A and B) compared to crabs in all other moult stages. During the moult cycle, average cadmium accumulation in the
midgut gland ranged from 29 μg Cd g−1 dw at premoult stage (D2) to 589 μg Cd g−1 dw at postmoult stage (A). Average cadmium concentrations in the haemolymph ranged from 0.56 μg Cd ml−1 at intermoult stage (C4) to 4.6 μg Cd ml−1 at postmoult stage (A), while the gills accumulated from 103 μg Cd g−1 dw in intermoult stage (C3) to 352 μg Cd g−1 dw in postmoult stage (A). Cadmium concentration in gills and haemolymph was also significantly higher in crabs in late premoult
stage (D3) compared to C4-crabs, while midgut gland cadmium concentration remained elevated in C1- and C3- intermoult stages relative to C4. During ovarian maturation the cadmium accumulation in midgut gland, gills, ovaries and haemolymph decreased. Average cadmium
concentration in the midgut gland decreased from 63 μg g−1 dw in ovarian Stage I to 19 μg g−1 dw in ovarian Stage VI. The same pattern was observed for gills, haemolymph and ovaries. The present study demonstrates that
cadmium accumulation in the female shore crab strongly depends on the physiological status of the animal. A possible association
between physiological calcium requirements and cadmium accumulation during moulting is discussed.
Received: 20 January 2000 / Accepted: 20 July 2000 相似文献
12.
Ivo H. Machatschke Barbara E. Bauer Cornelia Schrauf John Dittami Bernard Wallner 《Behavioral ecology and sociobiology》2008,62(8):1341-1350
Polygynous mating systems can inflict considerable costs on males, often causing the emergence of alternative mating strategies
to ensure reproductive success. These strategies can lead to different morphs of color, size, or behavior. The present work
was done on guinea pigs, a polygynous rodent species. Some males can show a reduced readiness for conflict, perhaps employing
an alternative mating strategy. To test this hypothesis, a two-stage experiment was set up, with males (N = 16) and females (N = 16) initially living in isosexual groups. Visual and olfactory contact was possible through a wire mesh. Male agonistic
behavior was observed for 15 days, confirming the existence of less-conflict-involved (LCI, N = 7) and more-conflict-involved males (MCI, N = 9). Significant differences were found for a conditional parameter, body mass, and a morphometric one, testis width: LCI
consistently surpassed MCI. Hormonally, cortisol was comparable, while testosterone was distinctly higher in MCI. Next, males
and females were joined and observed for further 24 days. Males initially lost weight but reached original mass towards the
end of the experiment. Testis width patterns were similar. Again, LCI had higher body mass. Cortisol was comparable, but testosterone
release 3 days after merging was significantly higher in LCI. Behaviorally, LCI exhibited significantly less male–male aggression
and more socio-sexual behavior than MCI. The former were more successful, with 57% capable of accessing females, in contrast
to 11% of MCI. The existence of two distinct behavioral phenotypes in guinea pig males suggests that different reproductive
strategies may exist in this species. 相似文献
13.
Polyandry and enhanced reproductive success in the harlequin-beetle-riding pseudoscorpion 总被引:1,自引:0,他引:1
J. A. Zeh 《Behavioral ecology and sociobiology》1997,40(2):111-118
The growing molecular evidence that females of many species mate with several males calls for a critical reassessment of
the selective forces which act to shape female mating tactics. In natural populations of the harlequin-beetle-riding pseudoscorpion,
Cordylochernes scorpioides, females are polyandrous and typically produce mixed-paternity broods. Laboratory behavioral analyses and breeding experiments
indicate that polyandry in this pseudoscorpion is an active strategy which increases female reproductive success. Females
restricted to mating with a single male experienced a higher rate of embryo failure and produced significantly fewer offspring
than either females mated to more than one male in the laboratory or females naturally inseminated in the field. Forced copulation,
insufficient sperm from a single mating, male nutrient donations and variation in inherent male genetic quality cannot explain
the greater number of nymphs hatched by polyandrous females in this study. Evidence suggests that, by mating with several
males, C. scorpioides females may exploit postcopulatory mechanisms for reducing the risk and/or cost of embryo failure resulting from fertilization
by genetically incompatible sperm.
Received: 5 May 1996 / Accepted after revision: 16 October 1996 相似文献
14.
Effect of female molt stage and sex ratio on courtship behavior of the blue crab Callinectes sapidus
In many species, males and females actively participate in courtship, and the outcome of pre-mating interactions influences
the mating success of both sexes. Female blue crabs, Callinectes sapidus, mate soon after their final molt to maturity; thus female molt stage dictates the timing of mating. In a field experiment,
we manipulated female molt stage and sex ratio to test their effects on the courtship behavior of both sexes, if female behavior
influences the behavior and pairing success of males, and if male courtship influences male pairing-success. Early-molt-stage
females avoided males during courtship, whereas late-molt-stage females sought out males. As a result, males had to pursue
and capture early-molt-stage females whereas males displayed to late-molt-stage females and more easily physically controlled
them. Males sometimes abandoned late-molt-stage females, but this occurred more often when females were abundant. The rate
at which females avoided males was positively correlated with that of males abandoning females, and males that were unsuccessful
at pairing met with higher rates of female resistance than successful males, suggesting that female behavior influences male
pairing-success. Unlike unsuccessful males, successful males more often made the transition between display and maintaining
physical control of the female. At high male sex ratios, males initiated courtship more readily; thus both sexual competition
and female behavior influence male courtship in this species.
Received: 7 July 1996 / Accepted: 10 January 1998 相似文献
15.
Historically, most mammals have been classified as polygynous; although recent molecular evidence suggests that many mammals
may be polygynandrous, particularly the ground-dwelling sciurids. We genotyped 351 round-tailed ground squirrels (Xerospermophilus tereticaudus) using seven microsatellite loci to determine paternity in 31 litters from 2004 to 2007. Polygyny was evident in all years
except in 2007, when the population size was reduced. Multiple paternity occurred in the majority of litters (55%) with 2.5 ± 0.26
sires/litter (n = 31). Forty-nine percent of resident males (n = 114) sired offspring, and of males that sired offspring (n = 56) 27% sired young in multiple litters in a single breeding season. Litter size was positively correlated with the number
of sires. Through an indirect analysis of paternity, we found 21 litters (68%) with an average relatedness of 0.5 or less.
Males had a greater opportunity for sexual selection (I
s = 1.60) than females (I
s = 0.40); Bateman’s gradient was also greater in males (1.07 ± 0.04, n = 56) than females (0.82 ± 0.08, n = 31). The mating system in round-tailed ground squirrels defined through genetic analyses and Bateman’s gradients is polygynandrous
compared to the previously suggested polygynous mating system as established by behavioral observations and fits within the
predictions of the ground squirrel sociality models. Upon evaluating the predictions of the sociality models among sciurid
species, we found a negative relationship between the level of sociality with litter size and the average percentage of multiple
paternity within a litter. Thus, recent genetic information and reclassification of mating systems support the predictions
of the ground-dwelling squirrel sociality models. 相似文献
16.
We studied sampling behaviour and mate choice in the fiddler crab Uca mjoebergi. Once a female selects a mate, she copulates in his burrow and remains there until releasing her aquatic larvae. U. mjoebergi occurs in habitats that are inundated only by the highest amplitude spring tides. Females can only release their larvae during
these tides, and release before or after will result in complete failure of reproductive effort. Matings occur over a 5-day
period near the end of neap tides. Our results suggest that within the mating period, females adjust their larval developmental
rates by selecting specific burrows in which to incubate their clutches. We found that at the start of the mating period,
females chose larger males as mates. Since male size was positively correlated to burrow width, females were selecting wide
burrows and effectively incubating at lower temperatures. This would slow down the developmental rates of larvae. In contrast,
females that mated late in the mating period selectively chose small males. By incubating in narrower, warmer burrows, these
females may increase the developmental rates of larvae. We propose that females are selecting burrows to influence incubation
rate and ensure timely release of their larvae. Female U. mjoebergi appear to adjust their preference for the direct benefits of mate choice to increase their reproductive success. 相似文献
17.
We estimated the cost to females of the lekking butterfly Coenonympha pamphilus of visiting males on leks instead of taking off and soliciting courtship from males passing them outside leks, as occurs
in the non-lekking congener C. tullia. We followed released virgin females of C. pamphilus in the field until they mated. We estimated the time they lost by remaining perched and not approaching males that passed
them, and observed how often and at what distance virgin females were passed by males in the field. We then calculated how
much faster these females would have been detected if they had taken off and approached these males, using probabilities of
detection as a function of passing distance derived from field observations on C. tullia females. C. pamphilus females on average lost 201 min by not approaching males on their way to leks. To estimate what this time loss meant in terms
of fitness, we measured how the age at mating affected fecundity. Using field measures of fecundity and mortality, the time
loss translated into an average 2.8% reduction in fecundity as a best estimate, and an average 1.3% reduction in fecundity
as a lower estimate. This fitness cost is larger than has been reported earlier for a lekking bird, but is probably too small
to eliminate the possibility of indirect benefits of mating with males on leks.
Received: 15 August 1996 / Accepted after revision: 24 January 1997 相似文献
18.
Sexual cohabitation as mate-guarding in the leaf-curling spider Phonognatha graeffei Keyserling (Araneoidea, Araneae) 总被引:1,自引:1,他引:1
The leaf-curling spider Phonognatha graeffei incorporates a twisted leaf into the central hub of its orb-web that is used as a retreat. This species is unusual among orb-weaving
spiders because males cohabit in the leaf retreat with both immature and mature females, mating with the former shortly after
the female molts. Cohabitation appears to be a form of mate-guarding because cohabiting males respond agonistically to rival
males that venture onto the web, and their behaviour depends upon the reproductive status of the female; males defending immature
females are more aggressive than those defending virgin, adult females. Males copulate with previously mated females for significantly
longer than with virgin females. Females may cannibalise cohabiting males, which occurs independently of whether the female
has been deprived of food. Females that cannibalise a single male do not have a higher fecundity than non-cannibalistic females.
Received: 2 February 1996 / Accepted after revision: 27 October 1996 相似文献
19.
Parental investment, potential reproductive rates, and mating system in the strawberry dart-poison frog, Dendrobates pumilio 总被引:1,自引:0,他引:1
We studied the effect of relative parental investment on potential reproductive rates (PRRs) to explain sex differences in
selectivity and competition in the dart-poison frog Dendrobates pumilio. We recorded the reproductive behavior of this species in a Costa Rican lowland rainforest for almost 6 months. Females spent
more time on parental care than males, and `time out' estimates suggest that PRRs of males are much higher than than those
of females, rendering females the limiting sex in the mating process. Males defended territories that provide suitable calling
sites, space for courtship and oviposition, and prevent interference by competitors. Male mating success was highly variable,
from 0 to 12 matings, and was significantly correlated with calling activity and average perch height, but was independent
of body size and weight. Estimates of opportunity for sexual selection and variation in male mating success are given. The
mating system is polygamous: males and females mated several times with different mates. Females were more selective than
males and may sample males between matings. The discrepancy in PRRs between the sexes due to differences in parental investment
and the prolonged breeding season is sufficient to explain the observed mating pattern i.e., selective females, high variance
in male mating success, and the considerable opportunity for sexual selection.
Received: 9 June 1998 / Received in revised form: 27 March 1999 / Accepted: 3 April 1999 相似文献
20.
Akiko Matsumoto-Oda 《Behavioral ecology and sociobiology》1999,46(4):258-266
For female chimpanzees (Pan troglodytes schweinfurthii) in the Mahale Mountains National Park, Tanzania, the most common mating pattern is opportunistic. In such opportunistic
matings, females copulated promiscuously but not randomly. This study describes female mate choice during 1-year observation
of six females who exhibited regular genital-swelling cycles. During the study period, 169 opportunistic matings and four
restrictive matings were recorded over the course of 51 days. As female estrus progressed, mating frequency and the number
of adult male mating partners increased, although the number of potential mating partners did not change. Criteria of female
choice examined were the direction and consent/rejection of courtship, proximity maintenance, and female grooming. Adult-male
courtships were successful more often than those of adolescent males. During the earlier phase of estrus, females copulated
rather promiscuously with many males. But during the later phase of estrus when the likelihood of conception is expected to
be highest, they copulated repeatedly with high-ranking adult males. There was a positive correlation between female grooming
frequency and mating frequency when the likelihood of conception was greatest. Female chimpanzees are thought to choose high-ranking
males as fathers of their offspring. Moreover, female chimpanzees may adopt one or both of two mating strategies, i.e., a
many-male strategy and a best-male strategy.
Received: 23 November 1998 / Received in revised form: 12 April 1999 / Accepted: 26 April 1999 相似文献