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1.
The relationship between signaling and aggression is still unclear despite several decades of research. However, there is a growing interest in studying signals that predict aggressive behavior or fighting ability. The goals of our study were threefold: we investigated the relationship between signaling effort and aggression, the relationship between body condition and aggression, and the effect of fighting experience on subsequent signaling behavior in wild-caught and laboratory-reared male spring field crickets (Gryllus veletis). We found that aggressive behavior was not related to signaling effort, body size, or body condition. For contest winners, wild-captured males were more aggressive than laboratory-reared males. Signaling effort was highly repeatable within individuals, but aggressive behavior had low repeatability. We found no evidence for a winner or loser effect on signaling; there was no change in signaling effort when we compared contest winners and losers before and after they participated in aggressive contests. Long-distance acoustic signaling and aggressive behavior appear to be independent of one another in spring field crickets, perhaps serving different functions in female attraction and male–male competition, respectively. 相似文献
2.
Maria I. Sandell 《Behavioral ecology and sociobiology》2007,62(2):255-262
In the European starling, Sturnus vulgaris, optimal mating systems differ between males and females. Males gain from polygyny, whereas monogamy increases female fitness.
The cost of polygyny to females lead to intense female–female competition, and it has previously been shown that the intensity
of female aggression during the pre-breeding period can predict the realised mating system. The physiological regulation of
such female aggression in starlings is not yet known. This study examines the role of testosterone in mediating aggressive
behaviours involved in intra-specific reproductive competition in female starlings. Testosterone levels were experimentally
elevated with testosterone implants in females during the pre-laying period. To simulate a situation in which an additional
female tried to mate with the focal female’s mate, a caged female was presented close to a nest-site to which the male could
attract a secondary female. Testosterone was significantly related to several behaviours involved in female–female interactions.
Females with testosterone implants spent significantly more time close to the caged female and produced more song bouts than
control females. In contrast, male behaviour was unrelated to the experimental status of the mate. Females mated to males
that attracted a secondary female were less aggressive towards the caged female than those that remained monogamously mated.
The effect of exogenous testosterone in this study indicates that androgens may mediate social behaviours in female starlings
during the breeding season. 相似文献
3.
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
4.
Erica M. Tennenhouse Robert B. Weladji Øystein Holand Knut H. Røed Mauri Nieminen 《Behavioral ecology and sociobiology》2011,65(2):287-295
In polygynous species, males devote considerable effort to reproduction during the rut. Both the number of females in the
mating group and the ratio of sexually mature males to sexually mature females [adult sex ratio (ASR)] are expected to affect
the amount of effort a male devotes to reproductive activities. We predicted the reproductive effort of dominant male reindeer,
measured as relative mass loss, proportions of active reproductive behaviors, and frequencies of agonistic behaviors would
(1) increase with an increasing number of females in the mating group and eventually level off, and (2) exhibit a dome shape
with respect to ASR in the mating group. We tested these predictions using 12 years of data collected from semi-domesticated
reindeer in northern Finland. We found a positive relationship between relative mass loss and the mean number of females in
the mating group for mature, but not young males. The relationship between the proportion of active reproductive behaviors
performed by mature males and the mean number of females in the group was quadratic while agonistic behaviors of mature males
increased with the increasing female group size. We also found that active reproductive behaviors decreased with a rising
mating group ASR for mature males; whereas, young males performed more agonistic behaviors as group ASR increased. Our results
point to age-specific patterns of mass loss and activity during the mating season. They also indicate that both the number
of females and ASR in the mating group are important factors in determining the level of reproductive effort of dominant male
reindeer. 相似文献
5.
Julia Ostner Peter M. Kappeler Michael Heistermann 《Behavioral ecology and sociobiology》2002,52(6):485-495
The aim of this study was to examine effects of seasonal and social factors on male androgen excretion in a seasonally breeding primate living in multimale-multifemale groups. By combining detailed behavioural observations (>2,500 h) on 3 groups of redfronted lemurs living in Kirindy Forest/Madagascar with non-invasive hormone analysis of >800 faecal samples collected concomitantly from the same animals, we tested predictions on: (1) the effect of social status on immunoreactive testosterone (iT) excretion; (2) seasonal variation of iT across reproductive periods; and (3) the relationship between aggression and iT excretion. The study lasted 14 months, covering two mating and one birth season. The results revealed that males fall into two distinct social classes, with one dominant male and several subordinate males in each group. In contrast to our prediction, the behavioural differences between these two classes were not reflected by differences in androgen levels, making physiological suppression of testicular function an unlikely mechanism of male reproductive competition. As expected for a seasonally breeding animal, iT values were elevated during the mating season. Androgen levels tracked the increase in the rate of reproductive aggression during the mating season as predicted by the challenge hypothesis. An increase in aggression due to spontaneous social instability outside the mating season, however, was not linked to a parallel rise of iT. Furthermore, the highest iT levels were obtained during the birth season, which may be part of a male strategy to remain aggressive during this period of high infanticide risk. These findings suggest that redfronted lemurs do not respond with increases in androgens to short-term challenges and that high androgen levels instead correlate with longer-lasting and predictable situations, such as the mating and birth seasons. 相似文献
6.
Female choice and male–male aggression are two modes of sexual selection that can lead to elaboration of male morphological
and behavioral traits. In lek-mating species, male mating success is often strongly skewed, and it is puzzling why variation
in male traits is still observed given directional female choice. If male traits correlated with reproductive success are
honest signals of male quality, there may be survival costs associated with the expression of those traits. In this study,
we examined whether morphological, behavioral, and territorial traits are correlated with male mating success and survival
in the lek-mating greater prairie-chicken (Tympanuchus cupido). We introduce a novel application of multinomial discrete choice models for analysis of female mate choice behavior. We
found that behavioral and territorial attributes showed 6.5 times more variability among males than morphological traits.
Both display and aggressive behaviors were strong predictors of male mating success, suggesting that both female choice and
male–male aggression were important in determining mating success among male greater prairie-chickens. Moreover, annual survival
of male prairie-chickens was independent of mating success and male traits. Females appear to be choosing males based on behavioral
traits where large variation exists between males (coefficient of variation >30%). Behavioral traits were the most important
factor in determining mating success of male prairie-chickens, but the mechanism underlying this relationship is unknown.
In the future, experimental manipulations of male hormones or parasite loads could bridge the proximate mechanisms and ultimate
consequences of factors mediating male mating success in lek-mating grouse. 相似文献
7.
Sjouke A. Kingma István Szentirmai Tamás Székely Veronika Bókony Maarten Bleeker András Liker Jan Komdeur 《Behavioral ecology and sociobiology》2008,62(8):1277-1288
Melanin-based ornaments are often involved in signaling aggression and dominance, and their role in sexual selection is increasingly
recognized. We investigated the functions of a melanin-based plumage ornament (facial ‘mask’) in male Eurasian penduline tits
Remiz pendulinus in the contexts of male–male aggression, mating success, and parental care. The penduline tit is a passerine bird with a
unique mating system in which both sexes may mate with several mates in a breeding season, and one (or both) parent deserts
the clutch. Our study revealed that mask size of males is more likely an honest signal used by females in their mate choice
decisions than a trait involved in male–male competition. First, mask size increased with both age and body condition, indicating
that the mask may signal male quality. Second, males with larger masks paired more quickly and had more mates over the breeding
season than males with smaller masks. Third, we found no evidence that male mask size signals male–male aggression or dominance
during competitive encounters. The increased mating success of large-masked males, however, did not translate into higher
reproductive success, as nestling survival decreased with mask size. Therefore, we conclude that there is either no directional
selection on male mask size or males with larger masks receive indirect, long-term benefits. 相似文献
8.
Frank Marlowe 《Behavioral ecology and sociobiology》1999,46(1):57-64
Paternal care figures prominently in many scenarios of human evolution. Recently, however, such scenarios have been challenged
on two scores. First, the level of male contribution may be insignificant. Second, male care may be provided as a form of
mating effort, rather than parenting effort. In theory, since men can enhance their Darwinian fitness both by providing care
to their own offspring if this raises offspring fitness and by pursuing additional mates if this leads to additional offspring,
men should respond to payoffs from both mating and parenting effort. If men respond to payoffs from parenting effort, paternity
ought to make a difference. And if men respond to payoffs from mating effort, mating opportunities ought to make a difference.
I analyzed the impact of these two factors on variation in male care among the Hadza, a foraging society in Tanzania. Two
predictions were tested: (1) biological children will receive more care than stepchildren, and (2) men will provide less care
to their biological children as their mating opportunities increase. Both predictions were supported. These results suggest
men provide care, in part, as parenting effort, and that they trade off parenting effort for mating effort when they have
greater mating opportunities.
Received: 21 January 1998 / Received in revised form: 24 January 1999 / Accepted: 1 February 1999 相似文献
9.
David Bierbach Vanessa Sassmannshausen Bruno Streit Lenin Arias-Rodriguez Martin Plath 《Behavioral ecology and sociobiology》2013,67(4):675-683
Selection imposed by male competition (intrasexual selection) and female choice (intersexual selection) can be con- or discordant. Specifically, females may or may not prefer mating with dominant males, and direct costs of interacting with dominant (and possibly more harassing) males have been suggested to explain avoidance of dominant males. Here, we exemplify that inter- and intrasexual selection may normally act in the same direction, but can be temporarily conflicting when social information becomes available. Using video playback techniques, we presented females of the Mexican livebearing fish Poecilia mexicana with two size-matched males and established association preferences. Half of the females could then observe the same two males fight and establish dominance, while control females saw both males side by side, but physically separated, and female preferences were subsequently re-evaluated. Females in the control group showed a significant preference for future winners in the subsequent testing, confirming an innate or acquired preference for male traits that are indicative of physical superiority, even when body size as a choice criterion is excluded. When allowed to eavesdrop on male fights, however, females did not show a preference for observed winners and even decreased time spent with them relative to the control treatment in which no fight was shown. A subsequent experiment found contest winners to show elevated levels of sexual behavior, so we argue that the temporary offset of the intrinsic female preference for dominant males after having observed a fight is indeed driven by direct costs females expect from more harassing contest winners. 相似文献
10.
In mammalian polygynous mating systems, male reproductive effort consists mainly of male–male competition and courting of
females, which entail substantial somatic costs. Males are thus expected to adjust their reproductive effort according to
their age and condition. In this study, we examined how activity budgets of male mountain goats (Oreamnos americanus), a polygynous ungulate, varied with age in a marked population over two periods: (1) summers 1995–2006 and (2) ruts 2004–2006.
We then assessed if the proportions of time spent in male–male competition and courtship behaviors were influenced by age-specific
body mass and social rank during the rut. Males spent most of their time foraging and resting during summer, and rested more
and foraged less with increasing age. During the rut, pronounced shifts in activity budgets occurred as juveniles (1–2 years)
increased time spent foraging, whereas adults (≥3 years) increased standing and time spent in social interactions at the expense
of foraging. At old age, reproductive effort either stabilized or decreased slightly, providing weak support for the ‘mating
strategy–effort’ hypothesis, predicting that courtship behaviors should peak in prime-aged males. Age-specific body mass did
not affect time spent in male–male competition, but was positively related with time spent in courtship behaviors, providing
support for the ‘individual quality’ hypothesis, predicting that males with more resources at the start of the rut should
spend more time in mating-related activities. Age-specific social rank did not affect reproductive effort. Surviving to prime
age while increasing mass each year should thus allow male ungulates to gain greater ability to court estrus females. 相似文献
11.
Testosterone and the allocation of reproductive effort in male house finches (Carpodacus mexicanus) 总被引:9,自引:1,他引:8
Testosterone has been proposed to serve as the mediator that controls the relative effort that an individual male bird will
devote to mating effort versus parental effort. Here, we demonstrate a testosterone-influenced trade-off between parental
and mating efforts in male house finches. Male house finches with experimentally elevated testosterone fed nestlings at a
significantly lower rate, but sang at a higher rate than males without manipulated testosterone levels. Females mated to testosterone-implanted
males fed nestlings at a significantly higher rate than females mated to males without testosterone implants, resulting in
similar feeding rates for both treated and untreated pairs. The effects of testosterone on male house finches, however, were
not as dramatic as the effects of testosterone observed in some other socially monogamous species of birds. Because extra-pair
copulations are uncommon in house finches and males provide substantial amounts of parental care, these more modest effects
may be due to differences in how the allocation of reproductive effort affects the costs and benefits of different reproductive
behaviors.
Received: 6 June 2000 / Accepted: 17 July 2000 相似文献
12.
Katrin Brauch Keith Hodges Antje Engelhardt Kerstin Fuhrmann Eric Shaw Michael Heistermann 《Behavioral ecology and sociobiology》2008,62(9):1453-1466
In a wide variety of species, male reproductive success is determined by contest for access to females. Among multi-male primate
groups, however, factors in addition to male competitive ability may also influence paternity outcome, although their exact
nature and force is still largely unclear. Here, we have investigated in a group of free-ranging Barbary macaques whether
paternity is determined on the pre- or postcopulatory level and how male competitive ability and female direct mate choice
during the female fertile phase are related to male reproductive success. Behavioural observations were combined with faecal
hormone analysis for timing of the fertile phase (13 cycles, 8 females) and genetic paternity analysis (n = 12). During the fertile phase, complete monopolisation of females did not occur. Females were consorted for only 49% of
observation time, and all females had ejaculatory copulations with several males. Thus, in all cases, paternity was determined
on the postcopulatory level. More than 80% of infants were sired by high-ranking males, and this reproductive skew was related
to both, male competitive ability and female direct mate choice as high-ranking males spent more time in consort with females
than low-ranking males, and females solicited copulations mainly from dominant males. As most ejaculatory copulations were
female-initiated, female direct mate choice appeared to have the highest impact on male reproductive success. However, female
preference was not directly translated into paternity, as fathers were not preferred over non-fathers in terms of solicitation,
consortship and mating behaviour. Collectively, our data show that in the Barbary macaque, both sexes significantly influence
male mating success, but that sperm of several males generally compete within the female reproductive tract and that therefore
paternity is determined by mechanisms operating at the postcopulatory level. 相似文献
13.
Leeann T. Reaney Jean M. Drayton Michael D. Jennions 《Behavioral ecology and sociobiology》2011,65(2):217-225
Body size strongly predicts fighting behaviour and outcome in many species, with the larger opponent usually winning contests. However, recent fighting experience can have a strong influence on the establishment of dominance hierarchies, with recent winners being more likely to win subsequent contests, while recent losers are more likely to lose. Recent fighting experience therefore has the potential to modify the effect of body size in determining contest behaviour and outcome. Here, we investigate whether recent fighting experience weakens the role of body size in predicting contest behaviour in the black field cricket, Teleogryllus commodus. We compared the role of body size in determining contest outcome during initial non-physical encounters and escalated aggressive physical encounters (grapples), as well as the probability of escalation occurring, in contests involving either a naïve or experienced smaller male against a naïve larger male. We found that recent fighting experience only affected contest outcome during non-physical encounters. Once a contest had escalated into grappling, the effect of previous wins and losses was no longer apparent and body size strongly predicted contest outcome. Thus, once males can directly assess their opponent's fighting ability, recent fighting experience did not alter the effect of body size on contest behaviour and outcome. 相似文献
14.
The diversity of mammalian mating systems is primarily shaped by sex-specific reproductive strategies. In the present study, we explored determinants and consequences of a unique mating system exhibited by fossas (Cryptoprocta ferox), the largest Malagasy carnivore, where females mate polyandrously on traditional mating trees, and males exhibit intrasexual size dimorphism. Males face both contest and scramble competition, and inter-sexual size dimorphism can be pronounced, but its magnitude depends on the male morph. Using a continuous behavioral observation of six estrous females over 4 years, we investigated correlates of male contest competition and female choice based on 316 copulations. Furthermore, we assessed correlates of male scramble competition based on testes size and movement data obtained from GPS tracking. We found that females dominated males regardless of their smaller size and that females actively solicited copulations. Heavy males had highest mating success during the female’s peak mating activity, but were discriminated against afterwards. Female choice and male–male competition thus converged to generate a mating advantage for heavier males. Our results suggest that females actively seek polyandrous matings, presumably for indirect genetic benefits. Since body mass is the major determinant of male mating success and is at the same time dependent on the degree of sociality and associated hunting mode of the respective male morph, a male’s feeding ecology is likely to influence its reproductive tactic. A combination of benefits from female polyandry and the consequences of different subsistence strategies may thus ultimately explain this unusual mating system. 相似文献
15.
Joanna P. Y. Chan Pei Rong Lau Ai Jie Tham Daiqin Li 《Behavioral ecology and sociobiology》2008,62(5):639-646
In experiments that comprised of three phases (fight, choice, and mating) under “seen” and “unseen” conditions, we examined
the effects of the outcomes of male–male contests and female eavesdropping on female mate choice and male mating success in
the fighting spider, Thiania bhamoensis (Salticidae). The results revealed female eavesdropping on agonistic interactions. Females that had watched an aggressive
interaction showed no distinctive preference for the winner over the loser, but they preferred the loser when they had not
observed a fight. Winners, however, achieved a greater mating success than did losers during the mating phase. Gaining access
to females was based on the insistence of the winners in courtship in terms of the number of quivers, rather than on the fighting
behavior of the males. Hence, the outcome of male–male contests may not be an important determinant of a male’s mating success
in T. bhamoensis. Instead, courtship display plays an important role in determining the success of male mating in this species. This study
also suggests that female mate preference may not be a good indicator of eventual female mate choice and male mating success.
Thus, a causal relationship between female mate preference and male mating success cannot be inferred.
Joanna P. Y. Chan, Pei Rong Lau, and Ai Jie Tham contributed equally. 相似文献
16.
Summary Male wasps of three sympatric species of Nearctic Megarhyssa (Hymenoptera: Ichneumonidae) typically form mixed-species (61.7%) aggregations composed of up to 28 males over sites of female emergence. Observations of 107 aggregations over two seasons in New York state revealed two male mating strategies: postemergence copulation on the tree surface and preemergence insemination accomplished by male abdominal insertion into the female emergence hole. Insertions by one or more males (as many as ten consecutively but not more than two simultaneously) occurred at 88% of the aggregations, with each inserting for an average of 24.8 min. Insemination as a result of preemergence insertion had a success rate of 83% while postemergence copulation attempts were successful 30% of the time (average duration 61.9 s). Individual male reproductive success was very low and not correlated with size, arrival order at emergence sites, or tenacity at the site. Males frequently aggregated at sites of male emergences as well as those of nonconspecifics, though conspecifics to the emerger ultimately played the major role at aggregations. Male-male aggression in aggregations was not apparent, though jostling occurred during the insertion period and during postemergence copulation attempts. 相似文献
17.
Coalitionary mate guarding by male chimpanzees at Ngogo, Kibale National Park, Uganda 总被引:13,自引:0,他引:13
David P. Watts 《Behavioral ecology and sociobiology》1998,44(1):43-55
Cooperative mate guarding by males is unusual in mammals and birds, largely because fertilizations are non-shareable. Chimpanzees
live in fission-fusion communities that have cores of philopatric males who cooperate in inter-group aggression and in defending
access to the females in their community. Male contest mating competition is restrained within communities, but single high-ranking
males sometimes try to mate guard estrous females. Data from an unusually large chimpanzee commmunity at Ngogo, Kibale National
Park, Uganda, that contains more males than any previously studied community show new variation in chimpanzee mate-guarding
behavior. Contrary to expectation given the large number of males, mate guarding was as common as, or more common than, at
other sites, and males other than the alpha male guarded more often. More strikingly, pairs or trios of top-ranking males
sometimes engaged in cooperative aggression to prevent estrous females from mating with other males, but tolerated each other's
mating activities. Both single males and coalitions mostly guarded periovulatory females. Mate-guarding coalitions were previously
unknown in chimpanzees. Coalitions occurred in large mating parties, seemingly because these often contained too many males
for single males to maintain exclusive access to estrous females. Coalition members gained higher shares of copulations than
they could have expected from solo mate guarding, and suffered lower per capita costs of guarding (as inferred from aggression
rates). Two males who most often participated in coalitions formed two-male coalitions at about the point where the number
of males present made it unlikely that either could get 50% or more of total copulations on his own, and formed trios when
this value dropped below 33%. Kin selection could be a factor in cooperation among male chimpanzees, but coalition members
were not necessarily close relatives and the apparent structure of payoffs fit that of mutualism. Furthermore, reliance of
male chimpanzees on support from allies to maintain high rank could have led to trading of mating exclusivity for support
against mating competitors.
Received: 28 May 1997 / Accepted after revision: 16 May 1998 相似文献
18.
Fleur E. Champion de Crespigny Nina Wedell 《Behavioral ecology and sociobiology》2007,61(8):1229-1235
The maternally inherited bacterium Wolbachia pipientis generates strong reproductive incompatibilities between uninfected females and infected males (cytoplasmic incompatibility),
significantly reducing both female and male reproductive success. Such fitness costs are thought to place selective pressure
on hosts to evolve pre-copulatory preferences for mating with compatible mates, thereby enabling them to avoid the reproductive
incompatibilities associated with Wolbachia. Therefore, uninfected females are predicted to prefer mating with uninfected males, whereas infected males are predicted
to prefer mating with infected females. Despite these predictions, previous investigations of pre-copulatory mate preferences
in Wolbachia-manipulated Drosophila have not found evidence of female preference for uninfected or compatible males. However, none of these studies utilised
a design where focal individuals are provided with a simple choice in a relatively non-competitive situation. We examined
both female and male pre-copulatory mate preference based on mate infection status in Drosophila simulans and D. melanogaster using simple choice assays involving between 30–50 replicates per treatment. Although we found no evidence of female pre-copulatory
mate preferences in either species, male D. simulans exhibited some preference for mating with females of the same infection status. However, this preference was not evident
when we repeated the experiment to confirm this finding. Consequently, we conclude that neither male nor female D. melanogaster and D. simulans exhibit significant Wolbachia-associated pre-copulatory mate preferences. 相似文献
19.
Palestina Guevara-Fiore Jessica Stapley Penelope J. Watt 《Behavioral ecology and sociobiology》2010,64(10):1665-1672
Males vary in the degree to which they invest in mating. Several factors can explain this variation, including differences
in males’ individual condition and the fact that males allocate their energy depending on the context they face in each mating
attempt. Particularly, female quality affects male reproductive success. Here, we studied whether male guppies (Poecilia reticulata) strategically allocated more mating effort, in terms of mating behaviour and male–male competition, when they were matched
with a receptive (R) female than a non-receptive one. In accordance with our prediction, we found that males increased their
mating behaviour when they were with a receptive female. Even though male guppies can inseminate non-receptive females, we
only found high levels of courtship between males that were with a receptive female rather than a non-receptive one. Although
there was little affect of female receptivity on male–male competition, we found that males chased and interrupted courtships
more with receptive females than with non-receptive females regardless of odour. Finally, we also studied whether the sexual
pheromone produced by receptive female guppies is a cue that males use in order to increase their mating effort. We found
that males were more attracted to a female when they perceived the sexual pheromone, but only increased their mating and aggressive
behaviours when females showed receptive behaviour. This strategic increase in mating effort could result in higher male reproductive
success because mating attempts towards receptive females are likely to be less costly and males could have a greater probability
of fertilisation. 相似文献
20.
This laboratory study examined the combined effects of male and female behaviors on the outcome of mating encounters in Octopus bimaculoides. We found that male–male competition for mating opportunities depends on female maturity; the presence of immature females elicited significantly higher levels of aggression between competing males. We conclude that males are able to assess the reproductive status of females. The study also found that immature and mature females resisted male mating attempts to a similar extent but that males that showed more aggression toward male competitors were able to spend more time in contact with females. We suggest that the lack of prominent visual displays in these mating trials indicates the importance of chemical cues in Octopus mating systems, as has been demonstrated for other cephalopods. This study contributes to the growing research on cephalopod mating systems and in particular shows that Octopus mating dynamics may be more behaviorally complex than initially assumed. 相似文献