Flexible timing of reproductive effort as an alternative mating tactic in black grouse (Lyrurus tetrix) males

Alternative reproductive tactics often take the form of dichotomous behavioural phenotypes. Focusing attention on such obvious dichotomy means that flexible patterns of behaviour within tactics is largely ignored. Using a long-term dataset of black grouse Lyrurus tetrix lek behaviours, we tested whether there were fine-scale differences in reproductive effort (lek attendance, fighting rates) and whether these were related to age and phenotype. Yearling males increased their lek attendance and fighting rate to a peak when adult male effort was declining. Adults and yearlings allocated reproductive effort according to their body mass but this was unrelated to differences in timing of effort. In adult males, different patterns of lek attendance were associated with different costs of reproduction, measured by mass loss or gain. Overall, our work demonstrates that individuals can use flexible patterns of reproductive effort both in terms of their own condition, their age and the likely costs of behaviours

Curse of the black spot: spotting negatively correlate with fitness in black grouse Lyrurus tetrix

There is growing evidence that achromatic plumage can act as honest indicators of male quality. In some species with areas of white plumage, black melanin spots can be found on parts of the feathers. The functional significance of these spots and the relationship with male quality is yet poorly understood. We investigated the relationship between black melanin spots in an otherwise totally white ornament, the undertail covert, in relation to age, fitness and covariance with past and present expression of sexual traits, in the lekking black grouse Lyrurus tetrix. We found that spots at tips of feathers (tip spots) were negatively related to survival and reproductive success, and covaried negatively with current fighting rate. They also covaried positively with past fighting rate, suggesting high investment in fighting leads to carryover effects on male condition. In contrast, spots found further down the feather (vane spots) were unrelated to fitness and morphological and behavioural trait expression. Our results show that melanin spots can indicate some relationship with male quality and that the location of the spots has some importance in this relationship. However, the exact drivers of melanin spot expression and how these link to male quality, are currently unknown

No behavioural response to kin competition in a lekking species

The processes of kin selection and competition may occur simultaneously if limited individual dispersal i.e. population viscosity, is the only cause of the interactions between kin. Therefore, the net indirect benefits of a specific behaviour may largely depend on the existence of mechanisms dampening the fitness costs of competing with kin. In lekking species, males may increase the mating success of their close relatives (and hence gain indirect fitness benefits) because female prefer large leks. At the same time, kin selection may also lead to the evolution of mechanisms that dampen the costs of kin competition. As this mechanism has largely been ignored to date, we used detailed behavioural and genetic data collected in the black grouse Lyrurus tetrix to test whether males mitigate the costs of kin competition through the modulation of their fighting behaviours according to kinship and the avoidance of close relatives when establishing a lek territory. We found that neighbouring males’ fighting behaviour was unrelated to kinship and males did not avoid settling down with close relatives on leks. As males’ current and future mating success are strongly related to their behaviour on the lek (including fighting behaviour and territory position), the costs of kin competition may be negligible relative to the direct benefits of successful male-male contests. As we previously showed that the indirect fitness benefits of group membership were very limited in this black grouse population, these behavioural data support the idea that direct fitness benefits gained by successful male-male encounters likely outbalance any indirect fitness benefits

Analyse écorégionale marine de Nouvelle-Calédonie : atelier d'identification des aires de conservation prioritaires

Dans le cadre de l'initiative pour les récifs coralliens du Pacifique sud (CRISP), le WWF-France a souhaité développer un projet pour la protection des récifs et des lagons néo-calédoniens. L'atelier, qui s'est déroulé les 10 et 11 août à Nouméa, avait pour objectif de rassembler les scientifiques et les experts du lagon néocalédonien pour identifier, sur la base de leur connaissance experte, les zones les plus remarquables du lagon (richesse, endémisme, originalité des faunes et flores, espèces emblématiques, zones d'intérêt fonctionnel) sur lesquelles doivent porter en priorité les efforts de conservation. Il a permis d'identifier 20 aires prioritaires pour la conservation, parmi lesquelles 6 ont un intérêt mondial, 4 ont un intérêt sur le plan régional, les autres ayant un intérêt local

Stabilising selection on immune response in male black grouse Lyrurus tetrix

Illnesses caused by a variety of micro- and macro- organisms can negatively affect individuals’ fitness, leading to the expectation that immunity is under positive selection. However, immune responses are costly and individuals must trade-off their immune response with other fitness components (e.g. survival or reproductive success) meaning that individuals with intermediate response may have the greatest overall fitness. Such a process might be particularly acute in species with strong sexual selection because the condition-dependence of male secondary sexual-traits might lead to striking phenotypic differences amongst males of different immune response levels. We tested whether there is selection on immune response by survival and reproduction in yearling and adult male black grouse (Lyrurus tetrix) following an immune challenge with a novel antigen and tested the hypothesis that sexual signals and body mass are honest signals of the immune response. We show that yearling males with highest immune response to these challenges had higher survival, but the reverse was true for adults. Adults with higher responses had highest mass loss and adult males with intermediate immune response had highest mating success. Tail length was related to baseline response in adults and more weakly in yearlings. Our findings reveal the complex fitness consequences of mounting an immune response across age classes. Such major differences in the direction and magnitude of selection in multiple fitness components is an alternative route underpinning the stabilizing selection of immune responses with an intermediate immune response being optimal

Mating behaviour of the black grouse : genetic characteristics and physiological consequences

Christophe Lebigre tutki väitöskirjassaan teeren soidinkäyttäytymistä sekä koiraiden pariutumismenestystä, ja näiden seurauksia teeripopulaatioiden geneettiseen rakenteeseen ja koirasyksilöiden kuntoon. Soidin on pariutumissysteemi, jossa koiraat kerääntyvät avoimille alueille eli soitimille päämääränään pariutua naaraiden kanssa. Koska koiraat eivät osallistu jälkeläishuoltoon, naaraat voivat hyötyä koiraasta ainoastaan sen geenien avulla. Aikaisemmat tutkimukset ovat osoittaneet huimia eroja koiraiden parittelumenestyksessä ja naaraiden valinnan voimakkuutta. Jos naaraat valikoivat jatkuvasti tietyntyyppisiä koiraita, saattaa perimä yksipuolistua.Lebigre havaitsi tutkimuksessaan, että teerinaaraiden parinvalinnalla on erittäin merkittävä rooli. Tästä seuraa, että soitimen rakenteen häiriöillä voi olla kauaskantoisia evolutiivisia seuraamuksia.- Esimerkiksi syyssoitimella tapahtuva tahaton valikoiva metsästys voi poistaa soitimen kannalta tärkeitä yksilöitä, elinvoimaisia huippukukkoja, jolloin naaraat joutuvat valitsemaan kumppaninsa heikompilaatuisista yksilöistä. Toiseksi, jos huippukukot on poistettu soitimilta, voivat naaraiden jälkeläiset päästä huippukukon asemaan liian aikaisin, ja näin ollen lisätä sisäsiitoksen riskiä, jos naaraat pariutuvat omien poikiensa kanssa, Lebigre havainnollistaa. Teeren soitimilla tehdyt aikaisemmat havainnot olettavat, että naaraan toistuvat parittelut saman koiraan kanssa tai parittelut enemmän kuin yhden koiraan kanssa olisivat harvinaisia. Silti on havaittu, että myös soidinlajeilla esiintyy monien muiden lintulajien tapaan poikueita, joiden poikasilla on eri isiä.- Tutkimukseni geneettiset isyysanalyysit paljastavat, että lähes kaikki poikueet olivat yksi-isäisiä. Soidin todellakin on koiraiden pariutumisareena, ja vain yksi parittelukerta riittää hedelmöittämään koko suuren (8-11 poikasta) teeripoikueen. Tämä viittaa teeren hyvin korkeaan huippukukkojen hedelmällisyyteen, selventää Lebigre.Huippukukot menettivät suhteellisesti enemmän massaa kevään kuluessa verrattaessa vähemmän menestyneisiin koiraisiin. Kuitenkin huippukukot ovat pääasiassa yksilöitä, jotka ovat selvinneet hengissä kolmesta viiteen vuotta, kun aikuisten kukkojen vuotuinen kuolleisuus on 60 % luokkaa. Lebigre seurasi, eroavatko koiraiden stressi-indikaattorit ja loistaakka huippukukkojen ja heikompimenestyksellisten kukkojen välillä. Hän tarkkaili kukkojen hengissä säilymistä kesän yli, soidinkäyttäytymistä ja parittelumenestystä. Koirasryhmät eivät eronneet näiden mittareiden suhteen. Koska huippukukkojen paino kuitenkin tippui muita enemmän, voi olla, että kukkojen täytyy tasapainoilla hengissä säilymisen ja soidinkäyttäytymiseen panostuksen välilläheikompikuntoiset yksilöt eivät pysty panostamaan soidinkäyttäytymiseen tarpeeksi.Eläinten geenivirta johtuu paljolti levittäytymisestä, jolla tarkoitetaan nuorien yksilöiden siirtymistä synnyinseuduiltaan toisille alueille. Linnuilla naaraat ovat tyypillisiä levittäytyjiä, kun taas koiraat jäävät yleensä lähelle synnyinseutuaan. Tästä seuraa, että osa alueen linnuista on toisiaan enemmän sukua keskenään. Levittäytymisen ajatellaankin olevan kehittynyt osaksi sisäsiitoksen välttämiseksi.Lebigren geneettisten analyysien mukaan pariutumiskumppanien väliset sukulaisuussuhteet olivat kaukaisia. Naaraat eivät kuitenkaan tietoisesti näyttäneet välttävän pariutumista sukulaiskoiraan kanssa. Tutkimuksessa Lebigre simuloi sisäsiitoksen riskiä muuttamalla naaraiden levittäytymisetäisyyttä.- Simulaatiossa vanhempiensa parveen jääneillä naarailla oli paljon suurempi todennäköisyys pariutua sukulaiskoiraan kanssa kuin kauemmaksi levittäytyneillä naarailla. Naaraiden levittäytyminen voisi siis yksinään selittää sisäsiittoisuuden harvinaisuuden teerellä, valottaa Lebigre.Koska teerellä parittelut keskittyvät yhdelle tai vain muutamalle soitimen huippukukolle, jää suurin osa koiraista ilman paritteluja. Miksi sitten koiraskertymät eli soitimet silti ovat olemassa?- Aikaisempien tutkimusten mukaan naaraat suosivat alueensa suurimpia soitimia. Oma tutkimukseni osoittaa, että soitimen koiraat ovat vain harvoin sukulaisia keskenään. Tämä voi johtua siitä, että huippukukot vaihtuvat lähes vuosittain soitimen sisällä, ja osa koiraista kuitenkin levittäytyy, mutta lyhyempiä matkoja kuin naaraat, Lebigre toteaa. Leks are clusters of males visited by females for the sole purpose of mating. As males do not provide any parental care, females mostly gain indirect fitness benefits from their mate choice. In the lekking black grouse (Tetrao tetrix), previous studies have reported extreme mating biases and a strong female choice which might exert a directional selection on the traits underlying male performance. To understand the maintenance of this mating system, we studied the mating behaviour of black grouse using molecular markers and tested whether male performance was related to several physiological factors.Most females mated with lekking males. There was a strong consistency between observed copulations and true paternity. Most females were seen mating only once with a single male and multiply-sired broods were rare. Hence, lek observations are reliable estimates of male reproductive success and female choice. Black grouse females did not discriminate against relatives during mate choice, but female-biased dispersal might efficiently decrease the likelihood of mating with close relatives. Because females prefer large aggregations, males may gain indirect benefits by settling on leks where relatives are displaying.However, most lekking males were unrelated and did not choose to display with or close to relatives. Therefore, the indirect fitness benefits associated with the lekking behaviour are probably limited. Stress may affect male fitness through the re-allocation of the energy necessary for the stress response from other functions. However, a stress indicator was not related to male activity, mating success or survival. Thus, the measured stress levels did not have strong deleterious effects on male fitness. Lek activity was not related to changes in parasite load or other health measurements. However, the most successful males lost more weight than subordinate males suggesting energetic costs of the lek display

Black grouse males do not modulate their lekking behaviour according to their neighbour’s kinship

The processes of kin selection and competition may occur simultaneously if limited individual dispersal i.e. population viscosity, is the only cause of the interactions between kins. Therefore, the net indirect benefits of a specific behaviour may largely depend on the existence of mechanisms dampening the fitness costs of competing with kin. In lekking species, males may increase the mating success of their close relatives (and hence gain indirect fitness benefits) because female prefer large leks. Yet kin selection may also lead to the evolution of avoidance mechanisms dampening the costs of kin competition. As this mechanism has largely been ignored to date, we used detailed behavioural and genetic data collected in the black grouse to test whether males mitigate the costs of kin competition through the modulation of their fighting behaviours according to kinship and the avoidance of close relatives when establishing a lek territory. We found that neighbouring males’ fighting behaviour was unrelated to kinship and males did not avoid settling down with close relatives on leks. As males’ current and future mating success are strongly related to their behaviour on the lek (including fighting behaviour and territory position), the costs of kin competition may be negligible relative to the direct benefits of successful male-male contests. As we previously showed that the indirect fitness benefits of group membership were very limited in this black grouse population, such a lack of mechanisms dampening the potential costs associated with kin competition makes the evolution and maintenance of the lekking behaviour through indirect effects unlikely

Data from: Simultaneous age-dependent and age-independent sexual selection in the lekking black grouse (Lyrurus tetrix)

Individuals' reproductive success is often strongly associated with their age, with typical patterns of early-life reproductive improvement and late-life senescence. These age-related patterns are due to the inherent trade-offs between life-history traits competing for a limited amount of resources available to the organisms. In males, such trade-offs are exacerbated by the resource requirements associated with the expression of costly sexual traits, leading to dynamic changes in trait expression throughout their life span. Due to the age dependency of male phenotypes, the relationship between the expression of male traits and mating success can also vary with male age. Hence, using longitudinal data in a lekking species with strong sexual selection – the black grouse Lyrurus tetrix – we quantified the effects of age, life span and age of first lek attendance (AFL) on male annual mating success (AMS) to separate the effects of within-individual improvement and senescence on AMS from selective (dis)appearance of certain phenotypes. Then, we used male AMS to quantify univariate and multivariate sexual selection gradients on male morphological and behavioural traits with and without accounting for age and age-related effects of other traits. Male AMS increased with age, and there was no significant reproductive senescence. Most males never copulated, and of the ones that did, the majority had only one successful year. Life span was unrelated to AMS, but early AFL tended to lead to higher AMS at ages 1–3. AMS was related to most morphological and behavioural traits when male age was ignored. Accounting for age and age-specific trait effects (i.e. the interaction between a trait and age) reduced the magnitude of the selection gradients and revealed that behavioural traits are under consistent sexual selection, while sexual selection on morphological traits is stronger in old males. Therefore, sexual selection in black grouse operates primarily on male behaviour and morphological traits may act as additional cues to supplement female choice. These results demonstrate the multifaceted influence of age on both fitness and sexual traits and highlight the importance of accounting for such effects when quantifying sexual selection

Characterisation of sixteen additional polymorphic microsatellite loci for the currently spreading but locally rare butterfly Brenthis ino (Lepidoptera: Nymphalidae

Whilst the overall geographic range of the lesser marbled fritillary, Brenthis ino (Rottemburg, 1775), is currently expanding, this species is patchily distributed at a local spatial scale due to its use of flower rich semi-natural meadows and the aggregated distribution of its host plant. Therefore, understanding the dispersal patterns of this butterfly and the effect of increasing fragmentation of the landscapes in central and Western Europe on its population dynamics is key to determining whether this patchy distribution can lead to metapopulation structuring and dynamics. One way to determine the degree to which local populations are isolated from one another is to use high resolution molecular genetic markers and thence quantify gene flow and genetic drift. Eleven microsatellite loci have previously been developed for this species, but six showed evidence of null alleles, effectively violating key assumptions of the models used to infer gene flow. We therefore developed a set of new primer pairs to amplify a suite of 16 highly polymorphic microsatellite loci (number of alleles ranged from 2-30) of which nine were found to conform to the Hardy-Weinberg's expectations, whilst at the same time not showing any clear signature for the presence of null alleles. We further describe how these primers were optimized for landscape and metapopulation genetics studies in Belgian Ardenne