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1.
The function of prostaglandin-F2 alpha (PGF2 alpha) in reproductive behavior of adult female paradise fish (Macropodus opercularis) was evaluated. In experiment 1, females were allowed to spawn normally with a male and were left with that male until the following day when testing occurred. Subjects were then randomly assigned to one of three groups: PGF2 alpha (N = 8), vehicle control (N = 3), or a handling control (N = 3); for testing, females were removed, injected, then returned to the same tank. Seven of the eight subjects injected with 500 ng PGF2 alpha initiated complete reproductive behavior following injection. Vehicle and handling control subjects did not show any female reproductive behaviors. Prostaglandin-induced increases in sexual behaviors were seen from 15 to 75 min after the injection and were maximal approximately 45 min postinjection. In experiment 2, mature but unspawned (and presumably sexually naive) females were placed for 1 hr with males which were actively nestbuilding and parenting, following which subjects were either injected with PGF2 alpha (N = 6) or given a vehicle injection (N = 6). Experimental females did not behave differently from control females. Neither groups was observed to approach the male or initiate spawning behaviors following treatment; all subjects in both groups spawned on the following day. In experiment 3, sexually mature females were given extended familiarity with the male and the test tank. Pairs which had not spawned after 6 days (unspawned) were randomly assigned to experimental (N = 6) or control (N = 5) groups. Pairs which had spawned 1 day previously (N = 6) formed a "prespawned" comparison group. Females from the experimental and prespawned groups were injected with PGF2 alpha (500 ng), while the control females received a vehicle injection. Half of the "prespawned" females performed spawning acts while none of the unspawned or control females did so. Detailed behavioral analyses showed little or no effect of PG treatment, despite greater familiarity with the male. In experiment 4, females were placed with males and observed until the early signs of spawning, at which time they were injected with indomethacin (a PG synthesis inhibitor) or vehicle. The behavior of females treated with 35 micrograms (N = 3) or 70 micrograms (N = 6) of indomethacin was unaffected by indomethacin and largely indistinguishable from controls (N = 6). In summary, exogenous prostaglandins reinstate sexual behavior in female paradise fish. However, responsiveness to prostaglandins is influenced by prior sexual experience.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

2.
Synopsis We studied the reproductive behavior of wild caught and captive-born, first generation offspring of the Lake Malawi fish, Tramitichromis intermedius(Teleostei, Cichlidae), held in aquaria. Spawning behavior includes an exchange of actions with dominant males performing bower construction and courtship behaviors while females focus on oviposition and mouthbrooding. Egg counts per oviposition and brooding and interbrooding periods of wild caught T. intermedius follow records of other mouthbrooding cichlid fishes. Observation of circling behavior suggests this behavioral trait may be used in mate choice as longer circling, indicating a secure territory and thus male dominance, leads to more oviposition events and hence the potential for larger broods. Comparisons of clutch size and total length of young at release from full-sized females vs. first spawners reveal smaller clutches and young from the younger females, most likely stemming from differences in body size. Investigation of spawning photoperiodicity also noted distinctions between the two groups with wild caught T. intermedius spawning activity peaking in the middle of the light cycle and captive-born, first spawners exhibiting no significant peak in activity. The trend to spawn midday is most likely influenced by predation factors, while the lack of a spawning periodicity in the offspring may be explained by developmental processes, the absence of environmental cues or the tendency for smaller males to be opportunistic in spawning events. The details of spawning behavior recorded in this study provide a database to investigate species differences and to indicate changes due to chemical and physical disturbances.  相似文献   

3.
The effectiveness of testosterone (T) and 11-ketotestosterone (K) in inducing male-typical sex behaviors in goldfish was examined by implanting intact adult females with one empty (blank) Silastic implant (B females), one implant containing T or K, or one T and one K implant (T + K females). Behavior of the four female groups was compared to that of untreated males and males containing a blank implant. Male-typical behaviors (coutship, spawning) and associated behavioral changes (increased activity, reduced spontaneous feeding) were assessed 3.5 and 4.5 months after implant in 30-min tests in which the test female or male was allowed to interact with a stimulus female in which sexual receptivity and attractivity had been induced by acute prostaglandin Finjection. Prostaglandin-induced female-typical spawning behavior in the test females and males was also assessed 4.5 months after implant in a 60-min test for female-typical behavior in which the test fish was injected with prostaglandin and placed immediately with a sexually active male. Blood samples 5 months postimplant showed that implants generated physiological levels of T and K. In both tests for male-typical behaviors, K and T + K females exhibited the full suite of behaviors shown by spawning males, e.g., male-typical courtship and spawning, increased swimming activity, and reduced spontaneous feeding. Although behaviors of K and T + K females did not differ, those of T + K females were more often equivalent to those of males and significantly different from those of B females. T females exhibited marginal male-typical behaviors which never differed significantly from those of B females. Androgen-treated females exhibited female-typical; spawning behaviors equivalent to that of males and B females. The results show that adult female goldfish can be behaviorally masculinzed without behavioral defeminization, and suggest that male-typical sex behaviors in goldfish are dependent on K, although other steroids also may be required. The inducible behavioral bisexuality of goldfish, a gonochoristic species, is discussed in terms of the prevalence of hermaphroditism in teleosts.  相似文献   

4.
In resource-based promiscuous mating systems, synchronous spawning of females affects competition among males and variation in the reproductive success of males. We documented the mating behavior of Japanese charr (Salvelinus leucomaenis japonicus) through an annual breeding season to examine the relationship between female spawning synchrony and male mating behavior. Females spawned highly synchronously in the population studied, i.e., approximately half the spawning was finished within the first three days of the entire spawning season (11 days). The daily operational sex ratio (OSR) was nearly 1:1 through the spawning period. The number of males around a spawning female was very small (1.21+/-0.49 males per female) over the spawning ground and period, suggesting that a competitive male could effectively chase subordinate males away from a spawning female. A few males attempted to sneak near the oviposition site of females (16%; 9 of 57 breeding groups), while some males adopted sneaking tactics in the initial phase of females' spawning (24%). We did not observe any males to succeed in sneak fertilizations. We conclude that in this Japanese charr population, the synchronous spawning of females was related to the unbiased daily OSR, male aggregation around females, and consequently whether and how efficiently males engaged in sneak mating behavior.  相似文献   

5.
Females can adjust their reproductive effort in relation to their partner’s perceived fitness value. In zebrafish (Danio rerio), large males are typically preferred mating partners. However, females have been observed to reduce their reproductive output with exceptionally large males but it remains unknown whether it is due to sexual harassment or aggressive behavior to establish and maintain dominance. Here, we study the association between relative male size, sexual harassment and dominance behavior, female stress status (stress behaviors and whole-body cortisol concentration), and reproductive success during a 4 day spawning trial. We found female cortisol to correlate negatively with female body size and positively with female dominance behavior. However, male and female behavior as well as female cortisol level were not related to relative male size. Females mating with relatively large males produced more and most of their eggs during the first spawning day, while females with smaller males produced few eggs during the first day but then increased egg production. Despite females produced more eggs when mating with relatively larger males, their eggs had substantially lower fertilization rates compared to females mating with relatively smaller males. Hence, overall, the reproductive fitness was lowest when females mated with a relatively large male. These findings could help to explain the maintenance of male size variation under natural conditions.  相似文献   

6.
研究通过人工产卵环境模拟, 成功诱导青海湖裸鲤(Gymnocypris przewalskii)自然产卵受精, 通过标志跟踪和视频监控等方法对青海湖裸鲤的繁殖行为进行了研究。结果表明, 青海湖裸鲤的繁殖过程包含了追逐、伴游、潜尾、溅戏和交尾等典型行为。其中溅戏行为(单尾雌鱼或雄鱼背鳍露出水面并用尾部拍击水面)首次被观察确认, 常被误认为是交配行为。追逐、伴游、潜尾和溅戏等繁殖行为平均频次分别为: 5.7、14.7、9.3和3.5 次/d。通过采用不同性比重复配对实验发现, 在观测到的34次交配行为中, 32次(94.1%)均为1雌和1雄配对交配。研究还发现性成熟的雌性青海湖裸鲤为一次产卵类型, 短时间内多次交尾排卵, 雌雄交配(排卵授精)行为约每天3—9次, 每次排卵耗时约4—9s, 每次平均排卵量131粒(范围15—376), 每尾雌鱼可连续交配产卵3—7d。观测到34次的交配行为中, 31次(91.1%)均发生在夜间(23: 00—次日2: 00), 3次(8.9%)发生在白天(早晨6:00—7:00)。研究首次基于人工模拟产卵环境观察描述了青海湖裸鲤的繁殖行为特征, 可为青海湖裸鲤人工产卵场构建、自然繁殖监测和产卵场保护提供科学依据。  相似文献   

7.
为了解中华峭(Octopus sinensis)繁殖行为特征,通过肉眼观察及水下摄像对其行为进行研究.结果 表明,中华蛸在繁殖期有运动、捕食、求偶、交配、产卵和护卵行为.中华蛸运动依靠漏斗喷水的反作用力进行游泳和爬行;以突然袭击的方式捕食日本蟳(Charybdis japonica),繁殖后期不再进食;中华蛸具明显的求...  相似文献   

8.
The sexual behavior of Drosophila melanogaster gynandromorphs was studied to analyze the relationship between different steps in the female reproductive pathway. It was assumed that, in some gynandromorphs, certain female functions are missing because the corresponding control sites (foci) are either composed of male tissue or did not develop. A given gynandromorph can show elements of both male and female reproductive pathways. None of the steps of the female reproductive pathway appeared to be dependent on any other, in contrast to male behavior where, for example, following of females is a prerequisite for attempted copulation. By correlating each of the behaviors with the genotype of the cuticle, we confirmed previous findings that the focus for the female sex appeal is located in the abdomen, but receptivity to copulation is controlled by a site in the head. Many of the gynandromorphs did not lay eggs, presumably because either the focus controlling egg transfer from the ovaries to the uterus or the one controlling egg deposition was composed of male tissue. Many of the nonovipositing gynandromorphs laid eggs while dying or could be induced to deposit eggs after implantation of hormone-producing glands or topical application of a juvenile hormone analog. Some of the noninseminated gynandromorphs laid eggs at the rate characteristic for inseminated females, suggesting that an oviposition focus (mapping in the head region) suppresses oviposition in virgin females, but not in gynandromorphs whose focus is composed of male tissue. Some of the inseminated gynandromorphs oviposited eggs at a low rate, possibly because the focus responsible for detection of insemination could not function properly. Some of the inseminated gynandromorphs laid unfertilized eggs, revealing the importance of the focus controlling sperm release from the seminal receptacle. Foci controlling egg transfer, egg deposition and sperm release are located in the thorax, according to mosaic fate mapping results and studies on the reproductive behavior of decapitated females. The location of egg deposition in the culture vial seems to be controlled by a brain site. Sexual behavior in Drosophila does not depend on the presence (or absence) of the ovary or germ line.  相似文献   

9.
Size of habitat, availability of oviposition substrate, and population density were manipulated to determine their effects on the structure and dynamics of the pupfish breeding system. The fish established a territorial breeding system in large tanks, irrespective of population density or oviposition substrate. A dominance hierarchy, in which one male controlled most of the oviposition substrate and spawned with most females, was established in small tanks at low densities. Both population density and oviposition substrate affected the number of males defending territories. Male spawning success was inversely related to availability of oviposition substrate, but was not affected either by density or tank size. Location of a territory and its size also influenced spawning success. Males with bigger territories had higher spawning success. A “carryover” effect of neighbors was observed; males with reproductively active neighbors spawned more often than those with less successful neighbors. Interference with spawning was affected both by tank size and density. Agonistic behavior of breeding males was not affected by any manipulation, but it was positively associated with male spawning success at high but not at low densities. In all treatments the mortality of breeding males was approximately 8 times as high as that of females, suggesting that, under these experimental conditions, the cost of reproducing is substantially higher for males. Comparisons between breeding pupfish in these experiments and in natural environments provide a basis for understanding the selective pressures that have favored the maintenance of these extremely plastic breeding systems.  相似文献   

10.
Prostaglandin (PG) synthetase was present in the testes, seminal vesicles, and spermatophores of the male house cricket, Acheta domesticus. The enzyme was not detected in bursa copulatrix, spermatheca, spermathecal canal, and oviducts from virgin females, while substantial activity was measured in the same tissue from mated females. The female appears to receive the enzyme from the spermatophore. A PGE2-like material was detected by radioimmunoassay in A. domesticus testes and to a lesser extent in the remainder of the male reproductive tract. PG went undetected in virgin female reproductive tissues, while the same tissues from mated females contained an average of 589 pg of PGE2-like material per female. In in vivo studies, injected PGE1, PGE2, and to a smaller degree PGF stimulated oviposition by virgin females. Moreover, N-acetyl-p-aminophenol, a PG synthetase inhibitor, suppressed oviposition in mated females. Post-copulatory PG biosynthesis in the female reproductive tract might be partially responsible for triggering oviposition in A. domesticus. Since PG synthetase appears to be acquired from the male, it could be considered a primer pheromone.  相似文献   

11.
In goldfish, injection of ovulated eggs (from donor females) through the ovipore and into the ovarian lumen of females with vitellogenic oocytes induces spawning behaviour within several hours. Intraperitoneal (i.p.) injection of indomethacin (IM), 10 μg/g, either 10 h prior to, or coincident with, injection of ovulated eggs, completely inhibits the onset of spawning behaviour. IM injection similarly terminates ongoing spawning behaviour induced by egg injection. PGF (5 μg/g; i.p. injection) restores spawning behaviour of egg-injected, IM-blocked fish; at the same dosage, PGE2 is marginally effective and PGE1 is without effect. As PGF and PGE2 also induce spawning behaviour in females which have not been injected with ovulated eggs, it is suggested that distension of the oviduct following ovulation or egg injection results in the release of PG which then acts in some way to induce spawning behaviour. The ability of PG to induce spawning behaviour is eliminated by hypophysectomy and restored by treatment with salmon gonadotropin: no steroid treatment was effective in restoring PG-induced spawning in fish which had been hypophysectomized for 3–4 months. The possible mode of action of PG in inducing spawning behaviour in female goldfish is discussed.  相似文献   

12.
Tank spawning of first generation domestic green sturgeon   总被引:1,自引:0,他引:1  
Green sturgeon Acipenser medirostris from hatchery spawned wild‐caught broodfish matured under aquaculture conditions. The first females (three out of four) matured at age 8 years, were successfully induced to ovulate by hormonal injections, and their eggs collected by caesarean surgery for fertilization. While the incision healed completely, unknown complications resulted in mortalities 5–12 months later. To minimize handling stress and to eliminate mortalities associated with surgery, a semi‐natural tank spawning technique was used in subsequent years. A female was placed into a 3.7 m diameter flat‐bottom circular fiberglass tank, depth 0.7 m, with two or three males, and the fish were injected with gonadotropin‐releasing hormone analog (GnRHa) and white sturgeon pituitary extracts to induce spawning. Fuller’s Earth was continually added to the spawning tank using a belt feeder to minimize egg adhesion to other eggs and to the tank surfaces. The tank was checked hourly for oviposition, and the eggs collected using a fine mesh dip net, every 1–3 h. Spawning lasted 15–21 h, and 53–80 000 eggs were collected from individual spawning females. Direct observation of spawning activity was not possible because of the high turbidity caused by Fuller’s Earth. However, the female and males occasionally breached at the water surface and appeared to be interacting. After oviposition was completed, viable milt was collected from all males, and fertilization success ranged from 7% to 83% in five spawning events. Over three consecutive years (2009–2011) all five females and 11 males used in semi‐natural tank spawning ovulated or spermiated, and were not subject to post‐spawning mortality. The relatively slow deposition of eggs and the continuous addition of Fuller’s Earth minimized the adhesion of eggs into large clumps. While the egg fertility and hatchability varied greatly among individual females, the tank spawning technique presented a feasible alternative to other more invasive methods for obtaining fertilized eggs of green sturgeon, and may be applicable for other sturgeons, particularly endangered species.  相似文献   

13.
Oviposition is a female-specific behavior that directly affects fecundity, and therefore fitness. If a fertilized female encounters another male that she has evaluated to be of better quality than her previous mate, it would be beneficial for her to remate with this male rather than depositing her eggs. Females who decided not to remate exhibited rejection behavior toward a courting male and engaged in oviposition. Although recent studies of Drosophila melanogaster identified sensory neurons and putative second-order ascending interneurons that mediate uterine afferents affecting female reproductive behavior, little is known about the brain circuitry that selectively activates rejection versus oviposition behaviors. We identified the sexually dimorphic pC2l and female-specific pMN2 neurons, two distinct classes of doublesex (dsx)-expressing neurons that can initiate ovipositor extension associated with rejection and oviposition behavior, respectively. pC2l interneurons, which induce ovipositor extrusion for rejection in females, have homologues that control courtship behavior in males. Activation of these two classes of neurons appears to be mutually exclusive and each governs hierarchical control of the motor program in the VNC either for rejection or oviposition, contributing centrally to the switching on or off of the alternative motor programs.  相似文献   

14.
The study of male insects’ accessory gland (MAG) secretions will promote our understanding of reproductive strategies and their evolution, and will facilitate the development of new approaches for pest control. Here, we carried out a series of experiments to determine the functions of MAG secretions on modulating female post-mating behavior in the moth Spodoptera litura. Results showed that females injected with MAG secretions called and mated significantly less than controls in the night after treatment, which were independent of mechanical stimulation during mating and the presence of sperm. However, a successful mating resulted in a longer loss in sexual receptivity (lasting to the second night after mating). This study also demonstrated that MAG secretions not only triggered oviposition but also promoted egg development, which also were not dependent on mechanical stimulation during mating and the presence of sperm. MAG secretions also showed negative effect on female longevity, which may be because MAG secretions stimulate females to allocate more resources to egg development and oviposition, leaving fewer resources for survival. Results of this study also suggest that oviposition behaviors incur energy costs. The hypothesis that virgin females may conduct oosorption to prolong longevity is not supported.  相似文献   

15.
Synopsis This study investigates the role of male mating status in female choice patterns in the carmine triplefin, Axoclinus carminalis, a tripterygiid fish that exhibits paternal care. The distribution of daily reproductive activity is clumped, with many males receiving no mates and some receiving three or more. Females in this species do not prefer larger males, and characteristics of the oviposition site appear to have minimal effects on male mating success. When a female is removed from a male early in the daily spawning period, that male attracts fewer additional females for the remainder of the spawning period than does a control male. These changes in mating success are temporary, and do not affect mating success on subsequent days. A preference for mating males or males that are guarding eggs could provide asymmetric benefits for males to defend oviposition sites. This preference for males with eggs could be acting alone or with other factors such as high variance in oviposition site quality to favor the evolution of paternal care in fishes.  相似文献   

16.
Movement behaviors are central to ecology and conservation. Movement sensing technologies can monitor behaviors that are otherwise difficult to observe under field conditions and may enhance the ability to quantify behaviors at the population scale. We monitored steelhead trout (Oncorhynchus mykiss) spawning behaviors in a seminatural enclosure using accelerometer telemetry tags while simultaneously observing behaviors with underwater cameras. Behavioral assignments from visual observations were compared to acceleration histories to develop assignment criteria for acceleration data, including for a key behavior (oviposition). Behavioral events independently classified using acceleration data prior to reviewing video were compared to video scoring and 97% of holding behaviors, 93% of digging behaviors, and 86% of oviposition/covering behaviors were correctly assigned using acceleration data alone. We applied the method to at‐liberty steelhead in spawning tributaries. Acceleration records revealed putative spawning and oviposition in at‐liberty female steelhead, and time budgets for at‐liberty steelhead were similar to those monitored within enclosures. The use of similar movement sensing tags and classification approaches offers a method for monitoring movement behavior, activity budgets, and habitat use in a broad array of aquatic and terrestrial taxa, and may be especially useful when behaviors are cryptic.  相似文献   

17.
Males of the hermit crab, Pagurusfilholi, often grasp the edges of shells occupied by females and drag them during the mating season. This behavior was experimentally confirmed to be a precopulatory guarding behavior displayed by males for ripe females, and males were found to recognize females which were within about 5 days of spawning. Most theoretical models for mating preference assume the choosing sex (the male in the present case) has complete reproductive information about potential mates, and predict that males will preferably choose more fecund females and/or females that will require less guarding time (i.e. that will spawn sooner) as partners. Several male-choice experiments between two ripe females, both previously guarded by other males, were carried out to examine the above predictions. Males did not prefer females of larger size, higher fecundity or with less time remaining until spawning. These results suggest that males may not have complete information about potential partners, rather that male hermit crabs may adopt a mating strategy of pairing with the first ripe female they encounter. Even with such incomplete mate assessment, males may enhance their reproductive success by recognizing ripe females that will spawn within a given time (about 5 days in the present case).  相似文献   

18.
Golden egg bug (Phyllomorpha laciniata) females lay eggs on the bodies of conspecifics of both sexes. We investigated to what extent reproduction depended on the availability of conspecifics as oviposition substrate and the acceptability of the host plant as an alternative oviposition substrate in the absence of conspecifics. Mated females were placed in experimental enclosures each containing a sprig of fresh host plant. Each experimental female was subjected to one of three treatments: isolated from conspecifics (solitary), paired with another female, or paired with a male. Solitary females laid a few eggs on the host plant but then stopped laying eggs, and solitary females laid significantly fewer eggs than those enclosed with another female or a male. Females enclosed with a male laid no more eggs than those enclosed with a female. When two previously isolated females were later enclosed together, they soon renewed oviposition. Females in nature contained significantly more oviducal eggs than did females that were enclosed with other females for a short period. Thus the availability of suitable conspecifics as oviposition substrate stimulates the deposition of mature eggs, and reproduction depends on the presence of conspecifics of either sex as oviposition substrate.  相似文献   

19.
Both sexes of Atlantic salmon Salmo salar were very sensitive to the absence of their mate on the spawning ground, particularly females during the last hour before oviposition. The improvement of behavioural chaining just before viposition might elicit the accurate timing of synchronized gamete release for successful fertilization. While the reproductive behaviour of the opposite sex could largely affect breeding activity, relative mate size appeared to be the prevailing sexual motivation factor in this species. Even in the absence of courtship, large mate size may constitute a supra-stimulus inducing an increase in spawning behaviour of the other sex. Females with smaller males delayed their first spawning activity, took longer to spawn and made more nests than those with large males. However, female egg retention was not influenced by relative male size.  相似文献   

20.
Male reproductive gland proteins (mRGPs) impact the physiology and/or behavior of mated females in a broad range of organisms. We sought to identify mRGPs of the yellow fever mosquito, Aedes aegypti, the primary vector of dengue and yellow fever viruses. Earlier studies with Ae. aegypti demonstrated that "matrone" (a partially purified male reproductive accessory gland substance) or male accessory gland fluid injected into virgin female Ae. aegypti affect female sexual refractoriness, blood feeding and digestion, flight, ovarian development, and oviposition. Using bioinformatic comparisons to Drosophila melanogaster accessory gland proteins and mass spectrometry of proteins from Ae. aegypti male accessory glands and ejaculatory ducts (AG/ED) and female reproductive tracts, we identified 63 new putative Ae. aegypti mRGPs. Twenty-one of these proteins were found in the reproductive tract of mated females but not of virgin females suggesting that they are transferred from males to females during mating. Most of the putative mRGPs fall into the same protein classes as mRGPs in other organisms, although some appear to be evolving rapidly and lack identifiable homologs in Culex pipiens, Anopheles gambiae, and D. melanogaster. Our results identify candidate male-derived molecules that may have an important influence on behavior, survival, and reproduction of female mosquitoes.  相似文献   

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