Ranging behaviour of little bustard males, Tetrax tetrax, in the lekking grounds

We investigated the ranging behaviour during the breeding season of 18 radiotracked little bustard (Tetrax tetrax) males, a disperse-lekking species inhabiting the cereal pseudo-steppes. The average kernel 95% home range was 60±50 ha and the average cluster 85% area was 17±17 ha. Range structure was as relevant as home range size for explaining the variation in the ranging behaviour of males, which could be partially explained by age, habitat quality and site. Ranging behaviour varied from males defending small and concentrated home ranges with high habitat quality, to males holding larger home ranges composed by several arenas. Our results suggest that social dominance and resource availability may affect ranging behaviour of males during the breeding season. Also, mating systems constraints may play a role on the use of space of males within the lekking ground. The ranging behaviour of a given male may be determined by a tendency to reduce and concentrate the home range as age and social status increase, and several fine-tuning mechanisms adjusting the ranging behaviour to the prevailing environmental or social factors on a given site and year.     

Limited indirect fitness benefits of male group membership in a lekking species

In group living species, individuals may gain the indirect fitness benefits characterizing kin selection when groups contain close relatives. However, tests of kin selection have primarily focused on cooperatively breeding and eusocial species, whereas its importance in other forms of group living remains to be fully understood. Lekking is a form of grouping where males display on small aggregated territories, which females then visit to mate. As females prefer larger aggregations, territorial males might gain indirect fitness benefits if their presence increases the fitness of close relatives. Previous studies have tested specific predictions of kin selection models using measures such as group‐level relatedness. However, a full understanding of the contribution of kin selection in the evolution of group living requires estimating individuals' indirect fitness benefits across multiple sites and years. Using behavioural and genetic data from the black grouse (Tetrao tetrix), we show that the indirect fitness benefits of group membership were very small because newcomers joined leks containing few close relatives who had limited mating success. Males' indirect fitness benefits were higher in yearlings during increasing population density but marginally changed the variation in male mating success. Kin selection acting through increasing group size is therefore unlikely to contribute substantially to the evolution and maintenance of lekking in this black grouse population.     

Choosy males in a haplochromine cichlid: first experimental evidence for male mate choice in a lekking species

Current theories of mate choice predict that the level of choosiness of males and females will depend on their relative investment in parental care. Males often invest less than females and are expected to be less choosy, especially in lekking species where males contribute only sperm. Our study of the haplochromine cichlid fish Astatotilapia flaviijosephi, a maternal mouthbrooder, provides the first experimental evidence for male mate choice in a lekking species. In this species the number of eggs spawned is positively correlated with female weight, thus making larger females potentially better mates. In the laboratory, we conducted a simultaneous choice experiment where males had the opportunity to associate with, and court, each of two females that differed in size. Males preferred to court the larger female and spent more time courting during experimental trials involving larger females. This selective allocation of courtship effort to more attractive (i.e. heavier) females suggests that there may be constraints on males in fertilizing multiple females, thus compelling them to be choosy.Copyright 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.      

Seasonal variation in lek attendance and lekking behaviour by male Black Grouse Tetrao tetrix

Eleven Black Grouse Tetrao tetrix leks in the Scottish Highlands were visited at dawn once every week for a year. Apart from July and three leks which were unoccupied in winter, males visited leks throughout the year. Total numbers of males attending leks peaked in March in one study area (six leks) and in April in the second (five leks). The number of males present and the proportion of leks occupied varied seasonally. The proportion of males at leks was at a maximum in April (80% of males) when all leks were attended, with a secondary peak in September when 60% of leks had males present. Males spent the most time displaying in April. The optimal conditions for attendance were calm, dry mornings just after dawn. Most reliable counts of numbers of males were those made between the last week of March and the end of the first week of May.     

Ranging behaviour of male capercaillie Tetrao urogallus outside the lekking ground in spring

During the breeding season, adult male capercaillies Tetrao urogallus display on leks in the early morning. During the day, they occupy more or less exclusive home ranges within 1 km of the lekking ground, but little is known about their movements and range use patterns during this period. In three spring seasons we monitored the daily movement of 15 radio-tagged adult males, associated with six different leks, in a coniferous forest of southeast Norway. The objective was to relate dynamics of male movement and spatial distribution to changes in food resource availability and mating-related activities. In late winter, males exhibited a pattern of short daily relocations (distance between bird locations in successive days) within small ranges. Relocation distances and home ranges then increased markedly during two weeks preceeding the main mating period. During the mating and post-mating periods, movements again decreased, followed by another short peak at the time when females with depredated nests return to the lek for remating. These temporal changes in range use were not related to changes in food resources and probably not to shifts in anti-predator behaviour, and they differed between age groups: The increase in relocation distance during the pre-mating period was most pronounced among young resident males (3 and 4 year-olds), and range area of older males were smaller and did not increase as much during this period. The observed age-related changes in space use may reflect an alternative mating strategy by young and subdominant males; they seek out females outside the lekking ground where competition from more dominant males is less intense.     

Virgin females compete for mates in the male lekking species Ceratitis capitata

Abstract. Aggressive behaviour occurring in intrasexual competition is an important trait for animal fitness. Although female intrasexual aggression is reported in several insect species, little is known about female competition and aggressive interactions in polygynous male lekking species. The interactions of female Mediterranean fruit flies, Ceratitis capitata (a male lekking species), with other females and mating pairs under laboratory conditions are investigated. Mature, unmated (virgin) females are aggressive against each other and against mating pairs, whereas immature females are not. Female aggression against other females decreases dramatically after mating; however, mated females maintain aggression against mating pairs. In addition, higher intrasexual aggression rates are observed for mature, virgin females than for virgin males of the same age. The results show that female aggressiveness is virginity related, suggesting female competition for mates. These findings have important implications for understanding the physiological aspects of a complex social behaviour such as aggression and should stimulate further research on female agonistic behaviour in male lekking mating systems.     

Density and habitat preferences of male little bustard across contrasting agro-pastoral landscapes in Sardinia (Italy)

The little bustard Tetrax tetrax has undergone severe range contraction within Europe due to abandonment of traditional agro-pastoral activities. Previous studies of habitat selection have mainly focused on extensive cereal and cropland mosaics, while the species’ ecology in pastoral landscapes is understood less well, and data are completely lacking from the Sardinian population. We conducted distance sampling surveys of displaying males across three contrasting landscapes in Sardinia and modelled habitat preference at both the landscape and local (within pastures and recent fallows) scale. Abbasanta, with a balance of pasture and cropland, the greatest isolation from roads and shortest vegetation, supported the highest little bustard densities (95%CI 2.7–3.4 males/100 ha). Significantly lower densities were found in two landscapes with lower isolation from roads and taller vegetation within grasslands: Campeda (0.1–0.2 males/100 ha), comprising cropland and pasture in similar proportions to those found at Abbasanta, and Campidano (0.3–0.4 males/100 ha) that was dominated by cereal agriculture. At the landscape level, males preferred pastures and recent fallows over arable lands. At the local scale, within grasslands, probability of occurrence was greater with shorter vegetation, more legume and green herb cover and at points remote from roads. Shorter vegetation in grasslands resulted from high grazing pressure, and habitat suitability for breeding males depends strongly on extensively grazed grasslands. Conservation efforts for this species should focus on maintaining traditional agro-pastoral practices which maintain large areas of extensively grazed pastures and recent fallows located far from roads.     

Determinants and costs of natal dispersal in a lekking species

Avoidance of competition and inbreeding have been invoked as the major ultimate causes of natal dispersal, but proximate factors such as sex, body condition or birth date can also be important. Natal dispersal is expected to be of particular importance to understanding the ecological and evolutionary implications of dispersal strategies, since 1) numerous evidences suggest that individual differences in dispersal strategies are expressed early in life (i.e. at the onset of dispersal movement), 2) ultimate and proximate factors are more likely to act during this stage and 3) this stage is associated with the highest mortality rates in most vertebrates. We analysed the natal dispersal (hereafter, dispersal) behaviour in 100 marked individuals of a lekking species, the North African houbara bustards Chlamydotis undulata undulata, during four years. We investigated the effects of proximate factors on dispersal pattern and distance, as well as the mortality cost associated with movement using multievent models, allowing uncertainty in sex assignment and mixture of live recaptures and dead recoveries. Overall, males exhibited longer dispersal distances than females, contrary to the common pattern in birds. Moreover, males in poorer body condition moved further than those in better condition, whereas distance was independent of body condition in females. Finally, survival rates during dispersal were lower for females than for males and were negatively correlated with the distances covered with a similar distance‐survival slope in the two sexes. Collectively, our results suggest that 1) there is substantial dispersal cost in both sexes, 2) dispersal is strongly male‐biased, 3) this bias is unlikely to be explained by differential movement costs of each sex, and 4) dispersal differences found across different categories of individuals are in broad agreement with both the inbreeding avoidance and intraspecific competition mechanisms for dispersal.     

Absence of male reproductive skew,along with high frequency of polyandry and conspecific brood parasitism in the lekking Houbara bustard Chlamydotis undulata undulata

Behavioural studies have led to the perception that lekking species experience a high male reproductive skew as a consequence of females’ selective mate choice. In addition, observations suggest that females copulate only once and therefore polyandry seems unlikely as females are supposed to choose the best male available. In order to analyse the mating strategy of the Houbara bustard, an endangered lekking species under reinforcement in eastern Morocco, we used microsatellite data to perform paternity analyses. None of our observations followed common expectations under a lek mating system: we found no male reproductive skew suggesting no apparent selective female mate choice and no apparent male benefit from lekking. In contrast, a high level of polyandry (60 % of the nests) was recorded suggesting that sperm competition may operate. In addition, we present another case of conspecific brood parasitism in a lekking species and this was an unexpected alternative strategy for a species presenting high parental cost and low fecundity. The increasing number of studies contradicting common assumptions on lekking species suggests that alternative breeding strategies such as males pursuing an off‐lek mating strategy, female polyandry and even conspecific brood parasitism might be more widespread in lekking species than previously thought.     

Effects of avian malaria on male behaviour and female visitation in lekking blue‐crowned manakins

Avian malaria, the infection by blood parasites of the genus Plasmodium, can reduce host fitness not only through mortality, but also by impairing the expression of sexual selection traits. Although different studies highlight the association of parasitism with a decrease in host reproductive success, few studies have addressed the role of parasites in honest signalling by lekking species. Hence, it is still uncertain which fitness components are affected by parasites in these species. We investigated whether avian malaria is associated with a decrease in mating behaviour of male blue‐crowned manakins Lepidothrix coronata and whether it affects female visitation in leks of a population in the central Amazon. Through behavioural observations, we estimated the rates of total male activity and social interaction, as well as the frequency of female visits at individual perches. We then examined if individuals were infected with Plasmodium spp. using molecular techniques. Avian malaria was associated with a decrease in male mating behaviour in each lek, and mating behaviour correlated with female visitation. Although rates of social interaction were not correlated with avian malaria among males, we observed that interacting with several individuals within a lek may be advantageous for males, as they also vocalized and displayed more, thus increasing their chances of being visited by females. Although female visitation was not associated with avian malaria in individuals or leks, it is still possible that female visitation is indirectly affected by avian malaria through the latter's effects on male activity. We suggest a role for male activity as an honest sexual signal for females. Thus, male display rate could be used by females as cue for the probability of a male being infected.     

Intersexual spatial relationships in a lekking species: blue-crowned manakins and female hot spots

Leks offer an intriguing evolutionary problem: why do malesaggregate when this apparently leads to fitness costs? Aggregationcosts can be balanced if males settle on patches where theyare more likely to encounter females (hot-spot hypothesis).We evaluated whether female hot spots can account for patternsof lek structure in the blue-crowned manakin (Lepidothrix coronata)by modeling female distribution patterns relative to lek locationsin two 100-ha plots. Individual females were mapped based onnest locations and capture points and had their home ranges(HRs) modeled based on radiotelemetry data. The number of femalesthat lekking males can be expected to encounter was estimatedas the number of individual female HRs overlapping each maleterritory; hot spots were defined as patches where more femalesare found than average. We investigated how changes in femaleHR size and devaluation effects (decrease in female availabilitydue to the presence of neighboring males) influence male accessto females. Both factors strongly influenced the expected ratesof female encounter, but the hot-spot hypothesis was not supported:most male territories consistently overlapped fewer or justas many female HRs as expected by chance. Leks were not closerto hot spots than similar-sized nonlek sites. A proportion ofmales were, indeed, settled at hot spots, but, contrary to predictionsof the hot-spot hypothesis, they belonged to smaller leks thanmales located outside hot spots. Our results indicate that thislack of spatial correlation between males and females resultspartly from differences in sex-specific habitat preferences.     

Non-random mating in classical lekking grouse species: seasonal and diurnal trends

This paper is the first to integrate both field and theoretical approaches to demonstrate that fertility benefits can be a direct benefit to females mating on the classical lek. Field data collected for male sharp-tailed grouse (Tympanuchus phasianellus), a classical lekking species, revealed potential fertility benefits for selective females. Adult males and individuals occupying centrally located territories on the lek were found to have significantly larger testes than juveniles and peripheral individuals. Further, using empirical data from previously published studies of classical lekking grouse species, time-series analysis was employed to illustrate that female mating patterns, seasonal and daily, were non-random. We are the first to show that these patterns coincide with times when male fertility is at its peak. Received: 26 February 1999 / Revised: 13 December 1999 / Accepted: 15 March 2000     

Dominant females have brighter ornamentation in a sexually dimorphic lekking species

Males often exhibit elaborate ornamentation that contributes to their fitness. Similarly, females can also exhibit elaborate ornamentation, but we have a relatively limited understanding of its function. Recent studies have demonstrated that female ornamentation can function in both intrasexual competition and male mate choice, but few studies have been conducted on lekking species. We therefore investigated the possibility that female ornamentation provides information about the dominance status of the bearer, which could mediate intrasexual competition. We examined this possibility using Indian peafowl (Pavo cristatus), a sexually dimorphic lekking species in which females exhibit elaborate ornamentation in the form of iridescent green neck plumage. We tested whether female ornamentation predicts dominance status using an information theoretic model averaging approach. We found that females with brighter ornamentation are more socially dominant than females with darker ornamentation. These results suggest that female ornamentation in this species provides social information about the dominance status of the bearer. This study provides insight into the evolution of conspicuous female traits by suggesting a potential role for female ornamentation in intrasexual competition in a lekking species.     

Steroid hormones in bluegill, a species with male alternative reproductive tactics including female mimicry

The proximate mechanisms underlying the evolution and maintenance of within-sex variation in mating behaviour are still poorly understood. Species characterized by alternative reproductive tactics provide ideal opportunities to investigate such mechanisms. Bluegill (Lepomis macrochirus) are noteworthy in this regard because they exhibit two distinct cuckolder (parasitic) morphs (called sneaker and satellite) in addition to the parental males that court females. Here we confirm previous findings that spawning cuckolder and parental males have significantly different levels of testosterone and 11-ketotestosterone. We also report, for the first time, that oestradiol and cortisol levels are higher in cuckolders than in parental males. The two cuckolder morphs did not differ in average levels of any of the four hormones. However, among satellite males which mimic females in appearance and behaviour, there was a strong negative relationship between oestradiol levels and body length, a surrogate for age. This finding suggests that for satellite males, oestradiol dependency of mating behaviour decreases with increasing mating experience. Although such decreased hormone dependence of mating behaviour has been reported in other taxa, our data represent the first suggestion of the relationship in fishes.     

Correlates of male mating success in a lekking bird with male-male cooperation

Correlates of male mating success were examined in a population of long-tailed manakins, Chiroxiphia linearis, that included 270 colour-banded individuals. Long-tailed manakins have a lek mating system and male-male cooperation in courtship display. Multivariate analysis of behavioural variables indicated that female visitation correlated with the number of unison ‘toledo’ calls given by male partners. Given a female vist, copulatory success was correlated with the ‘butterfly’ display component of the dual-male dance. Both ‘toledo’ output and dance display differed significantly between perch-zones. Only six to eight partnerships in a local population of as many as 55 males per season performed call displays at a level (75–335 toledos per h) that was correlated with any female visitation. Data on crown plumage of female visitors suggested that younger females may have been less discriminating than were older females. The relationship between variance in mating success and the evolution of cooperative male display is discussed.