Mate Choice in Double-Breeding Female Great Tits (Parus Major): Good Males or Compatible Males

Producing two broods within the same season may be a good strategy by which short-lived species can maximize reproductive success. To produce two clutches in the same breeding season and to ensure offspring quality, choosing a good mate is important for females. Previous studies on double breeding focused on the associated influencing factors, and few studies examined how females choose social mates. Good genes and genetic compatibility are the two main hypotheses of the genetic benefit that females obtain from choosing mates. Uncovering the method used in mate choice for genetic benefits adopted by double-breeding females would provide a better understanding of the life history and rules of female choice. The great tit is an optionally double-breeding species in temperate-latitude populations. Here, we used a dataset for a Chinese population monitored between 2014 and 2016 to test two hypotheses on double-breeding female mate choice. A total of 30.1% of the breeding pairs initiated second breeding attempts, always remating with the same mate. The date of the first egg of the first brood did not affect initiation of a second brood, and female individual heterozygosity slightly influenced initiation of a second breeding. Female great tits choose males with both compatible genes and good genes in double-breeding mating. Double-breeding females prefer males with large breast stripes, high heterozygosity, and lower relatedness, while tarsus length, repertoire size, and individual F are not the main factors considered by females when selecting males for double breeding. The number of offspring of the first clutch did not affect the pairing status of male great tits in double breeding. The genetic quality of offspring from double-breeding pairs was higher than that of those from single-breeding pairs (higher heterozygosity and lower individual F). Taken together, our results showed that double breeding female great tits adopt multiple methods for genetic benefits to choose mates.

Ordu İlindeki Koyunculuk İşletmelerinde Damızlık Hayvan Temin Yollarının Belirlenmesi

In this study, it was aimed to determine the ways of supplying breeding animals for sheep enterprises in Ordu. In the research, enterprises with a minimum size of 80 heads have been taken into consideration. Random selection method was used in determining the enterprises and face-to-face surveys were conducted in 86 enterprises. 37.21% of the enterprise owners met their breeding coach needs from their own enterprises, while 33.72% met from their own enterprise + neighboring enterprises. Moreover, it was determined that 52.33% of the enterprise owners met their breeding female animal needs from their own enterprise, whereas 22.08% and 12.79% met from their own enterprise + neighboring enterprise and from their own enterprise + state enterprise, respectively. According to the results, 58.14% of breeders (50 enterprises) keep breeding female animals for more than 5 years in the herd and 41.86% of breeders (36 enterprises) keep them between 3-5 years. Breeding male animals are kept in the herd for more than 5 years in 47.67% of enterprises (41 enterprises) and for 3-5 years in 41.86% of enterprises (36 enterprises). In only 10.47% of enterprises, breeding male animals are used in the herd as breeding for less than 3 years.

Is the Mahali mole-rat (Cryptomys hottentotus mahali) a spontaneous or induced ovulator?

The Mahali mole-rat (Cryptomys hottentotus mahali (Roberts, 1913)) is a social, cooperatively breeding subterranean rodent that breeds aseasonally. Only one female in a colony breeds and the remaining females are reproductively suppressed. When the opportunity arises, these non-reproductive females disperse from the natal colony to escape reproductive suppression and pair up with an unrelated male to start a new colony. This study set out to determine whether female Mahali mole-rats are induced or spontaneous ovulators once separated from the reproductive suppression of the breeding female. Fifteen separated females were subjected to three treatments: housed separately without a male (A), allowed chemical, but not physical, contact with a vasectomised male (NPC), and placed in direct contact with a vasectomised male (PC). Urine was collected from all females under each treatment every 2 days for 40 days. Only females housed in the PC treatment exhibited heightened progesterone concentrations and corpora lutea of ovulation in the ovaries. Furthermore, males possessed epidermal spines on the shaft of the penises that may be used to stimulate the cervix of the female during copulation. These findings suggest that the Mahali mole-rat is an induced ovulator.

Benefits of cooperation in captive Damaraland mole-rats

Although the social mole-rats are commonly classified as eusocial breeders on the grounds that groups include a single breeding female (the “queen”) and a number of nonbreeding individuals (“helpers”) of both sexes, alloparental care is not highly developed in these species and there is no direct evidence that the presence or number of nonbreeders is associated with reductions in the workload of the “queen.” An alternative interpretation of mole-rat groups is that the social mole-rats are cooperative foragers rather than cooperative or eusocial breeders. Here, in captive colonies of Damaraland mole-rats (Fukomys damarensis), we provide the first evidence that increases in the number of nonbreeding subordinates in mole-rat groups are associated with reductions in the workload of “queens” and with increases in their fecundity.

The estrogenic pathway modulates non-breeding female aggression in a teleost fish

Aggressive behaviors are widespread among animals and are critical in the competition for resources. The physiological mechanisms underlying aggression have mostly been examined in breeding males, in which gonadal androgens, acting in part through their aromatization to estrogens, have a key role. There are two alternative models that contribute to further understanding hormonal mechanisms underlying aggression: aggression displayed in the non-breeding season, when gonadal steroids are low, and female aggression. In this study we approach, for the first time, the modulatory role of estrogens and androgens upon non-breeding aggression in a wild female teleost fish. We characterized female aggression in the weakly electric fish Gymnotus omarorum and carried out acute treatments 1 h prior to agonistic encounters with either an aromatase inhibitor or an antagonist of androgen receptors. Aromatase inhibition caused a strong distortion of aggressive behavior whereas anti-androgen treatment had no effect on behavior. Territorial non-breeding aggression in female G. omarorum is robust and depended on rapid estrogen actions to maintain high levels of aggression, and ultimately reach conflict resolution from which dominant/subordinate status emerged. Our results taken together with our own reports in males and the contributions from non-breeding aggression in bird and mammal models, suggest a conserved strategy involving fast-acting estrogens in the control of this behavior across species. In addition, further analysis of female non-breeding aggression may shed light on potential sexual differences in the fine tuning of social behaviors.HighlightsFemale Gymnotus omarorum displayed robust territorial aggression in lab settings.Acute treatment with aromatase inhibitor lowered aggression levels.Aromatase inhibition increased first attack latency and decreased conflict resolution.Acute treatment with anti-androgens showed no effects.This is the first report of estrogens underlying teleost non-breeding female aggression.

Responses to pup vocalizations in subordinate naked mole-rats are induced by estradiol ingested through coprophagy of queen’s feces

Naked mole-rats form eusocial colonies consisting of a single breeding female (the queen), several breeding males, and sexually immature adults (subordinates). Subordinates are cooperative and provide alloparental care by huddling and retrieving pups to the nest. However, the physiological mechanism(s) underlying alloparental behavior of nonbreeders remains undetermined. Here, we examined the response of subordinates to pup voice and the fecal estradiol concentrations of subordinates during the three reproductive periods of the queen, including gestation, postpartum, and nonlactating. Subordinate response to pup voice was observed only during the queen’s postpartum and was preceded by an incremental rise in subordinates’ fecal estradiol concentrations during the queen’s gestation period, which coincided with physiological changes in the queen. We hypothesized that the increased estradiol in the queen’s feces was disseminated to subordinates through coprophagy, which stimulated subordinates’ responses to pup vocalizations. To test this hypothesis, we fed subordinates either fecal pellets from pregnant queens or pellets from nonpregnant queens amended with estradiol for 9 days and examined their response to recorded pup voice. In both treatments, the subordinates exhibited a constant level of response to pup voice during the feeding period but became more responsive 4 days after the feeding period. Thus, we believe that we have identified a previously unknown system of communication in naked mole-rats, in which a hormone released by one individual controls the behavior of another individual and influences the level of responsiveness among subordinate adults to pup vocal signals, thereby contributing to the alloparental pup care by subordinates.