Notice bibliographique
Résumé
Humans can be forgiven for assuming that successful reproduction requires both partners to be alive. Amazingly, this isn't the case for the Trinidadian guppy. Under laboratory conditions, female guppies are able to store sperm for up to a year, potentially allowing them to produce offspring even if the males are no longer around. However, several other studies have suggested that the last male to mate with a female ends up fertilizing the bulk of her offspring. This last-male-in advantage may mean that stored sperm is rarely used by guppies in nature. Studying this phenomenon in natural surroundings poses many logistical problems, but in a recent report, Andrés López-Sepulcre and his international team of collaborators not only proved that they were up to the challenge of tackling this problem in the wild but also discovered just how often female guppies use the sperm of deceased mates.Undertaking a year-long mark–recapture study in Trinidad, the team introduced individually marked guppies with known genetic ‘fingerprints’ to a short stretch of the Guanapo River, which is isolated from existing downstream guppy populations by a swiftly flowing waterfall. Then, each month, the researchers painstakingly caught and identified almost every guppy longer than 13 mm present in the study site. These monthly assessments were used to determine when each guppy died, and also allowed the researchers to collect a few scales from each guppy born at the field site so that their mother and father could be determined using genetic fingerprinting. López-Sepulcre and colleagues then developed a complex mathematical model to estimate the reproductive contributions of dead males to the introduced guppy population.The research team found that almost 50% of reproductively active males sired young after they had died and, amazingly, over 30% of reproductive males were successful only after they were dead. Some offspring were even fathered by males that had been dead for 8 months. Perhaps this allows relatively short-lived males (with an average lifespan of 3 months) to continue to mate with females over their much longer lives (15 months). The researchers also suggested that sperm storage would allow the genetic material of male guppies to survive the rainy season, when males die in much higher numbers than females. From the female perspective, the researchers proposed that using sperm from many males, both dead and alive, would produce offspring with higher genetic diversity. In a fluctuating habitat like a Trinidadian stream, this should increase the odds of producing some offspring that are genetically well suited to whatever environmental conditions the future has in store.By the end of their year-long study, the researchers found that posthumously conceived guppies comprised almost 25% of the total reproductive population. This both highlights the importance of stored sperm to female guppies in nature and also raises red flags for measurements of genetic diversity in other species where females can store sperm: if the potential genetic contributions of dead males are not assessed, population sizes may be significantly underestimated. Apparently, you won't hear, ‘Till death do us part’, at a guppy wedding.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,003 | 0,001 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,000 | 0,002 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,010 | 0,007 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».