Are males with more attractive resources more selective in their mate preferences? A test in a polygynous species

In many polygynous species, males typically direct more intensecourtship toward more fecund females. Here we examined thisbehavior in relation to the attractiveness of a male's resource.We used the territorial polygynous beaugregory damselfish (Stegastesleucostictus) and manipulated the quality of male breeding territorieswith two types of artificial sites. We also investigated variablenatural breeding territories. Previous studies have shown thatthese different breeding sites were of different qualities,as judged by the number of eggs accrued by the defending male.Males on all three types of breeding sites did court females,and males using the highest quality sites exhibited significantlyhigher courtship intensity. However, only the group of maleson the highest quality site-type modulated their courtship intensityto female quality (i.e., female size). This indicates that males requiredsome minimal level of resource attractiveness (i.e., a threshold) beforethey exhibited mate preferences based on female quality. Further differencesin the resource attractiveness for males defending the high-qualityartificial sites were not related to differences in courtship behavior.     

Mate inspection patterns in the female beaugregory damselfish (<Emphasis Type="Italic">Stegastes leucostictus</Emphasis>)

We observed female beaugregory damselfish (Stegastes leucostictus) as they interacted with males to see whether their movements fit the predictions of different mate-search models. We established high-quality and low-quality groups with low variance in breeding site quality and a medium-quality, high-variance breeding site group and compared focal observations of female nonforaging forays in each group. Only 8% of 137 forays monitored resulted in spawning events. Eighty-nine percent of the forays were less than 240 s and were within 7 m of the focal female’s territory. Average foray times and straight-line foray distances did not differ for females traveling between males in each group. Females entered high-quality breeding sites at a higher rate than low-quality sites and round-trip distances were also greatest in high-quality groups, indicating that females were following a more convoluted path. We interpret these results to mean that (a) female beaugregories separate the tasks of mate assessment and mate choice by conducting information-gathering forays between mating events, (b) forays are energetically costly and therefore usually short in duration and overall distance traveled, (c) information collection takes approximately the same time for high-quality and low-quality mates, but (d) females will alter their foray patterns in high-quality areas to collect additional information. These data are also consistent with the hypothesis that females optimize their search by employing a tiered process of assessment during information-gathering forays, first using an adjustable threshold to accept or reject each male based on his courtship and subsequently a fixed threshold to assess the quality of each breeding site.     

Movement patterns and gallery use by the sexually dimorphic Wellington tree weta

The Wellington tree weta, Hemideina crassidens, is a harem-polygynous nocturnal insect whose males defend and mate groups of females residing in cavities in trees. In this study I examined sexual differences in gallery use (number of galleries occupied per unit time), distance travelled per night and activity patterns after sunset. In addition, I investigated how gallery size affected each of these variables. On average, males and females did not differ in the number of galleries visited per night, or in the distance they travelled per night; however, adult males were more likely to be seen earlier in the night than later. Although males and females did not differ in their gallery use or distance travelled, adult males occupied a significantly greater number of galleries and travelled greater distances per night at sites with small galleries than did males at sites with large galleries. These results suggest that habitat structure of a forest patch influences intrasexual tree weta behaviour.     

Female-female aggression and female mate choice on black grouse leks

We studied female-female aggression in relation to female mate choice in black grouse, Tetrao tetrix, in central Finland, in 1994-1998. Aggression occurred on average every other minute when there was more than one female on a territory, and aggressive behaviour was most prominent when several females attended the lek. Interactions tended to be proportionally most frequent on the territories of the highest-ranking males, although not significantly so. Females that were chased by other females did not mate with lower-ranking males than their aggressors did. Furthermore, chased females were only rarely (6% of cases) forced to move off the territory by agonistic interactions and copulations were disrupted by other females even less often (3% of cases). The choice of a mating territory did not depend on the outcome of aggression even though the aggressors were more likely to mate on the territory where aggression occurred than elsewhere. There was a marginally significant tendency for aggressors to mate earlier in the season. Females placed themselves further away from other females on the territory when soliciting a copulation than just before aggression. Our results suggest that aggression between females does not effectively constrain female choice in black grouse. Its function may be to aid females to secure undisturbed mating opportunities for themselves rather than to prevent others from mating with a particular male. Copyright 2000 The Association for the Study of Animal Behaviour.     

Male variation in mating success after female numbers are reduced

A significant decline was found in the quantity of eggs that polygynous male beaugregory damselfish Stegastes leucosticus received after reducing the number of available females, which indicated that a significant number of females was removed from the experimental community. The operational sex ratio (OSR) hypothesis, which presumes that a sex becomes increasingly more selective as the number of alternative mates increases, was not supported as the variance in male mating success was unchanged after the females were removed. The relative mating success among males was also unchanged. That is, male ranks remained relatively the same (pre-test and post-test) after the removal of females. The large variance in male mating success within this species may be a function of polymorphic mate preferences exhibited by females that may be based on male location.     

Competitor intrusions and mate-search tactics in a territorial marine fish

Recent theoretical studies have drawn attention to the importanceof understanding the costs females experience during mate choiceand mating and how females resolve the trade-offs presentedby such costs. In garibaldi damselfish (Hypsypops rubicundus)females defend permanent feeding and shelter territories andmust leave their territories to search for and spawn with nestingmales. Both mate searching and spawning occur in bouts, separatedby returns to the territory. I used focal female observationsto test predictions of the hypothesis that such behavior isa means of minimizing the amount of food lost to competitorsthat enter the female's territory while she is searching foror spawning with males. Consistent with this hypothesis, therewas a strong likelihood that the number of intruders enteringthe territory would increase linearly, and hence their totalimpact exponentially, with time away. In addition, the averageduration of searching bouts and the duration of a spawning boutwere significantly inversely related to a measure of territorialintruder pressure. Most intruders were heterospecific food competitors;incidence of intrusion by conspecifics was rare, and intrudingconspeciflcs did not contest the owner upon her return. In addition,the time females spent in their territories before beginninganother bout of searching was not positively related to theduration of the previous bout. Thus, there, is no support forthe alternative hypotheses that returning to the territory isa means of preventing takeover of the territory by conspedflcsor is the result of fatigue.     

Direct selection on mate choice: female redlip blennies pay more for better mates

Sexual selection may be reduced by costs of mate choice suchas predation risk and energetic expense. Despite their theoreticalimportance, such costs have rarely been quantified or relatedto the quality of mate obtained. We performed such a study witha wild population of redlip blennies in Barbados. In this coralreef fish, females traveled 0.2–12 m from their feedingterritories to the territories of nesting males, where theyspawned and left their eggs in the males' care. Previous studieshave shown that larger and older males are better parents andare preferred by females. Here, we found that long-distancetrips by females were made primarily toward larger males, andthe extra distance traveled beyond the nearest male was correlatedwith the improvement in size of male obtained. Comparisons withfeeding budgets while the females remained on their home territoriessuggested that costs from lost time and energy were minor, andno predation attempts on females were observed. However, onlonger trips the females faced more aggressive attacks fromdamselfishes, whose territories they crossed. In contrast, noattacks were observed from damselfish when the blennies remainedon their own territories. These attacks appeared to be responsiblefor a greater incidence of scars on females than on males. Thisdifference between the sexes became more pronounced as spawningprogressed, and then decreased as females healed during thenonspawning interval. Thus, female blennies endure a cost ofinterspecific harassment which is correlated with the qualityof mate obtained. This cost may restrain sexual selection inthis species.     

Information parasitism in foraging Bar-tailed Godwits Limosa lapponica

Foraging behaviour of sympatric Bar-tailed Godwits Limosa lapponica and Whimbrels Numenius phaeopus was studied in the period prior to egg-laying. Godwit females preferred wet bogs, while godwit males and Whimbrels foraged on dry palsas in the bogs. Habitat overlap between godwit males and Whimbrels was larger than intersexual overlap in the godwits. Observations of scanning behaviour of foraging godwits showed that the vigilance level of males was not affected by the presence or absence of their mates. Female vigilance levels, however, dropped significantly when females fed near their mate, and—in the absence of the mate—near Whimbrels. While female godwits benefited from associating with Whimbrels, males seemed to avoid close proximity to this species. Whimbrels chased godwit males more often than females, presumably because they used the same foraging habitats.     

The impact of limb autotomy on mate competition in blue crabs Callinectes sapidus Rathbun

Summary This study is the first to demonstrate experimentally that autotomy (self-amputation of a body part) adversely affects competition for mates. Experiments were conducted using blue crabs Callinectes sapidus Rathbun to examine the consequences of limb loss and pairing precedence on mate acquisition by males. Two adult males of equivalent size were introduced sequentially into pools containing a sexually-receptive female and observed after 24 h and 48 h. One male in each pair was left intact, while the other experienced: (1) no autotomy, (2) autotomy of one cheliped, or (3) autotomy of both chelipeds, one walking leg, and one swimming leg. In the absence of a competitor (first 24 h), both intact and injured males established precopulatory embraces with females. Intact males were highly successful (84–95%) in defending females from intact or injured intruders in the second 24 h period. Both autotomy treatments, however, significantly reduced the ability of males to defend females from intact intruders. Females in experiments suffered greater frequency of limb loss than did males. In the field, paired blue crabs showed significantly higher incidence of limb loss than unpaired crabs. Limb loss frequency increases with body size, and field observations indicated that larger males may be more successful than smaller males in obtaining females. Both experimental manipulations and field studies provide strong evidence for mate competition in this ecologically and commercially important portunid species.     

Female aggregation and male competition reduce costs of sexual harassment in the mosquitofish Gambusia holbrooki

Male mosquitofish allocate a large proportion of their time budget to attempting to inseminate unreceptive females. Because females invest considerable time and energy in avoiding unwanted copulations, sexual harassment is expected to conflict with other activities such as foraging. We found that sexual harassment more than halved the foraging efficiency of the female in a task requiring the retrieval of food items scattered on the water surface. The presence of shoalmates relieved the female from harassment and foraging efficiency increased with the number of females in the group. Small males attempted to mate significantly more than large males, causing a greater reduction in the female's foraging efficiency. When several males competed for the same female, the larger, dominant male prevented all the other males from attempting to mate and so had fewer opportunities to attempt copulation. Harassment from solitary males appeared to be more costly, as females foraged more efficiently when chased by a group of males. Because male sexual activity has a large impact on a female's feeding efficiency and possibly on her survival and reproduction, sexual conflict is expected to be important in shaping association patterns of female mosquitofish with conspecifics of both sexes. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour      

Mating system of the Amazonian cichlid angel fish, Pterophyllum scalare.

The species, Pterophyllum scalare distinguishes itself by its breeding behavior, involving competition for territory, sexual partners, courtship and parental care. The purpose of this study was to identify the mating system adopted by this species of fish. Twenty males and twenty females were observed under semi-natural and experimental conditions to test the hypothesis of serial monogamy. Under semi-natural conditions, after the third breeding cycle, the couples changed mates. Under experimental conditions, the couples changed partners after the first breeding cycle. Under experimental conditions, mate recognition was investigated through the preference of the females, indicated by the time they spent with the males. The females were available or not for courtship from new males, depending on their aggressiveness or submission. The larger and more aggressive males obtained new mating opportunities while the submissive males were rejected by the females. The mated fish were aggressive towards intruders in the presence of the mate, protecting their pair bond. In the interval between breeding cycles, the couples did not display aggression towards intruders, confirming the hypothesis of serial monogamy. Best mate selection by the females and the opportunity of new matings for both sexes influenced the reproductive success of this species.     

How does a parent respond when its mate emphasizes the wrong role? A test using a monogamous fish

The convict cichlid fish, Archocentrus nigrofasciatus, is biparental: the male spends the majority of his time defending the territory and the female spends much of her time close to the offspring. Under natural conditions, this separation into sex-typical roles is somewhat blurred as males do spend some time with the offspring and females do attack intruders. Here we tested whether an individual selects a parental role based on the location (i.e. parental role) of its mate. For example, do females emphasize offspring care because the male is away from the offspring? Will males be more likely to care for the offspring when the female is away from the offspring? We manipulated the location of one parent by placing it in a transparent plastic box, either near the offspring or at the far end of the tank near a clear plastic compartment that held a conspecific male intruder. We tested both male and female parent under the following four conditions: boxed mate near offspring with no intruder present, boxed mate near offspring with intruder present, boxed mate near intruder compartment with no intruder present, and boxed mate near intruder compartment with intruder present. We found that both parents spent more time with the offspring and less time attacking the intruder when the mate was positioned near the offspring and more time away from the offspring and more time attacking the intruder when the mate was near the intruder. Males were more affected by the location of their mates than were females and we concluded that males were attracted both to their mates' location and their offspring while females were mostly attracted to their offspring. Overall, the location of the mate had little effect on the types of aggressive activities used against the intruder. We did find that males increased their aggression towards boxed females when they were positioned far from the offspring, whereas the aggressive behaviour of females towards boxed males when they were positioned near the offspring was ambiguous. We suggest that males in particular enforce the separation of sex-specific parental roles via this aggression.     

Resource attractiveness of the male beaugregory damselfish and his decision to court or defend

We examined the decisions territorial male beaugregory damselfish (Stegastes leucostictus) make when presented with mating and aggressive situations simultaneously. Specifically, we testedhow males responded to simultaneous and consecutive presentationsof conspecific males and females in bottles. We hypothesizedthat (1) territorial males would show lower levels of courtshiptoward females when a competing male is also present comparedto when only the female is present and (2) territorial maleswould show higher levels of aggression toward intruding maleswhen a female is also present on their territories than whenonly the intruder is present. We predicted that males withhigh-quality breeding sites would court females and attackcompetitors more vigorously than males with low-quality breedingsites. Males on low-quality breeding sites exhibited fewerconspicuous courtship displays toward bottled females and alower bite rate toward bottled males than did the males onhigh-quality breeding sites. We concluded that poor breeding-sitequality was responsible for the decline in the most conspicuous aspects of both courtship and aggression. When presented simultaneouslywith a bottled male and a bottled female, defenders of bothbreeding-site types drastically reduced the number of courtshipdisplays and the amount of time they spent near the female.Thus, all aspects of courtship were reduced in the presenceof a male intruder. Time spent near the bottled male also decreased in these simultaneous presentations; however, this decreasewas less dramatic than the reduction in time spent near bottledfemales. Habitat quality did not affect these trade-off decisions,but the bite rate exhibited toward the bottled male increasedin the simultaneous presentations compared to the single presentations.Due to this increase in a territorial male's defensive behaviorwhen a female is present, we conclude that the presence of afemale temporarily increased the value of a territory. We suggestthat the possible loss of a territory to an intruding maletakes priority over the potential benefits of successfullycourting a single female and that it is a male's future reproduction,as well as his current reproduction, by which he assesses hisbenefits.     

Pushy males and choosy females: courtship disruption and mate choice in the lekking great snipe

We studied the effects of male disruptive behaviour on female mate choice and male mating success in the great snipe, Gallinago media, a lekking bird. Harassment from neighbouring males, a widespread behaviour in lekking animals, was the most prevalent cause of females leaving a male territory. Several lines of evidence show that females did not prefer to mate with males able to protect them from harassment. Males that obtained mating success were no less likely to suffer disruptions and females were no less likely to be disrupted when with their preferred male. Females returned to the male they later mated with, despite being repeatedly chased away by neighbours. The probability that an individual female returned and solicited mating from a male was 15 times higher for the male she was chased away from compared to the neighbour that chased her away. Females returned as often or more to the territory owner after being disrupted, compared to after leaving the territory without being harassed. Our results suggest that female great snipes are extremely choosy, but also that females do not gain direct benefits (harassment avoidance) by mating with certain males. Females appear to have neither direct nor indirect preferences for dominance that could give them such benefits: females appeared choosy despite, not because of, harassment. If females gain indirect benefits (genetically superior offspring) by being choosy, this is also likely to be unrelated to any dominance among males.     

Cross-fostering Does Not Influence the Mate Preferences and Territorial Behaviour of Males in Lake Victoria Cichlids

The ability to recognise conspecifics in contexts of mate choice and territorial defence may have large effects on an individual's fitness. Understanding the development of assortative behaviour may shed light on how species assortative behaviour evolves and how it may influence reproductive isolation. This is the case not only for female mate preferences, but also for male mate preferences and male territorial behaviour. Here we test with a cross-fostering experiment whether early learning influences male mate preferences and male–male aggression biases in two closely related, sympatrically occurring cichlid species Pundamilia pundamilia and Pundamilia nyererei from Lake Victoria. Males that had been fostered, either by a conspecific female or by a heterospecific female, were tested for their aggression bias, as well as for their mate preferences, in two-way choice tests. Males cross-fostered with conspecific and heterospecific foster mothers selectively directed their aggression towards conspecific intruders. The cross-fostering treatment also did not affect male mate preferences. These results are in striking contrast with the finding that females of these species show a sexual preference for males of the foster species.     

Intruders in Nests of the Spotless Starling: Prospecting for Public Information or for Immediate Nesting Resources?

The prospective behaviour for nests by conspecific intruders may be a strategy to gather public information for future reproduction or to secure resources for immediate reproduction. Although the relationship between the sex, age and breeding experience of intruders and the sex and age of residents may be crucial for understanding the significance of nest‐prospecting behaviour, a precise determination of these traits has rarely been addressed in field studies. In a free‐ranging population of spotless starlings ( Sturnus unicolor), inexperienced birds were the predominant intruders. The ratio of male‐to‐female intruders was higher among birds without previous breeding experience, although our results did not allow us to determine whether more inexperienced males or females intruded nests. The average annual rate of intrusion of either sex was strongly correlated with the number of fledglings produced in the study colony the previous year, which seems to indicate that the inexperienced intruders were, in general, yearlings. The proportion of the sexes among the intruders in each study year was correlated with the average age of male owners but not with the age of female owners. This result suggests that the presence of intruding males in the nests was affected by an increased opportunity to find vacancies in nesting territories as resident males became older. This finding supports the hypothesis that, in most cases, birds visited nests to obtain personal information about nesting resources. However, the intrusion rates were higher when there were nestlings than during the incubation period, which suggests that collecting public information was also involved in the intruding behaviour. Both sexes regularly attacked intruders, which implies that the intruders inflicted some kind of cost on the owners. Female floaters were more frequently chased, probably because they regularly lay parasitically in conspecific nests.     

The effects of exposure to seaweed on willingness to mate, oviposition, and longevity in seaweed flies

Abstract  1. Large male seaweed flies (Diptera: Coelopidae) are more likely to mate than smaller males. This is due to sexual conflict over mating, by which females physically resist male attempts to copulate. In some species, large males are simply more efficient at overpowering female resistance.
2. Female reluctance to mate is likely to have evolved due to the costs of mating to females. In many dipterans, males manipulate female behaviour through seminal proteins that have evolved through sperm competition. This behavioural manipulation can be costly to females, for example forcing females to oviposit in sub-optimal conditions and increasing their mortality.
3. Previous work has failed to identify any ubiquitous costs of mating to female coelopids. The work reported here was designed to investigate the effects of exposure to oviposition sites ( Fucus algae) on the reproductive behaviour of four species of coelopid. Algae deposition in nature is stochastic and females mate with multiple males in and around oviposition sites. Spermatogenesis is restricted to the pupal stage and there is last-male sperm precedence. It was predicted that males would avoid wasting sperm and would be more willing to mate, and to remain paired with females for longer, when exposed to oviposition material compared with control males. Females were predicted to incur longevity costs of mating if mating increased their rate of oviposition, especially in the presence of algae.
4. The behaviour of males of all four species concurred with the predictions; however mating did not affect female receptivity, oviposition behaviour, or longevity. Exposure to algae induced oviposition and increased female mortality in all species independently of mating and egg production. The evolutionary ecology of potential costs of mating to female coelopids are discussed in the light of these findings.     

Spawning behaviour and acoustic communication in Atlantic cod

Cannibalism of small numbers of offspring by a parent has been proposed as an adaptive parental strategy, by providing energy to support parental care. There are few empirical studies, however, to support this hypothesis. The beaugregory damselfish, Stegastes leucostictus , is a marine teleost that does not actively ventilate its eggs by fanning them. Partial cannibalism is common in this species, but in field studies was found to be unrelated to ration level. Filial cannibalism differed from predation in the pattern of egg eating; filial cannibalism was characterised by a random pattern of egg loss from a clutch rather than an aggregated distribution. Embryos developed quicker and had higher survival rates when they were at low densities and in nest sites where oxygen levels were high, and experimental reduction of oxygen levels increased rates of filial cannibalism. Here I present a hypothesis for filial cannibalism in the beaugregory damselfish; males cannibalise egg clutches in order to reduce clutch density and improve oxygen supply to the remaining embryos. I use a model of filial cannibalism to demonstrate how oxygen mediated cannibalism may be adaptive, and discuss the evolution of filial cannibalism in the beaugregory damselfish and other teleosts.     

Risk-sensitive resource defense in a territorial reef fish

As coral reefs are home to dense aggregations of a variety of species, aggressive territoriality is often a critical component of individual behavior. Identification and assessment of the risk posed by intruders is crucial to defending a territory, and fishes on coral reefs have been found to attend to body shape, body size, and coloration when responding to intruders. We examined the extent to which dusky damselfish (Stegastes adustus) discriminate among distinct categories of intruders by measuring the distance at which a fish attacks an intruder and the relative intensity and frequency of those attacks. We found that S. adustus discriminated among perceived threats, attacking conspecifics more intensely and more often than egg-predators and herbivores, and showing a trend of attacking those groups more often than invertebrate-feeders, which do not compete with damselfish for resources. Furthermore, territory holders attacked initial-phase wrasses from a farther distance than terminal-phase wrasses, suggesting that they can discriminate among classes of individuals within a species other than their own. Dusky damselfish thus exhibit the ability to make fine distinctions among intruders in a diverse ecosystem.     

Regulation of sexual receptivity of female Mediterranean fruit flies: old hypotheses revisited and a new synthesis proposed

The objective of this study was to examine the relative contributions of copula duration and sperm transfer to the inhibition of sexual receptivity of female Mediterranean fruit flies (Ceratitis capitata, Diptera: Tephritidae). Females choosing to remate had significantly fewer sperm in their spermathecae than females who chose not to remate. Duration of a female's first copulation did not affect her subsequent receptivity. Furthermore, on the first day following copulation significantly more females whose first mate was sterile and from a laboratory strain (sterile males transfer fewer sperm than wild males) chose to copulate than did females whose mate was fertile and recently derived from wild stock. Finally, we offer a synthesis of the available information on remating in this species, and suggest that while females are facultatively polyandrous, copula duration, sperm transfer and male accessory gland secretions act in succession to inhibit female receptivity.