Cognition and reproductive success in cowbirds

Understanding the relationships between cognitive abilities and fitness is integral to an evolutionary study of brain and behavior. However, these relationships are often difficult to measure and detect. Here we draw upon an opportunistic sample of brown-headed cowbird (Molothrus ater) subjects that had two separate research experiences: First, they engaged in a large series of cognitive tests in David Sherry’s Lab in the Advanced Facility for Avian Research (AFAR) at Western University, then subsequently moved to the Field Avian Research Megalab (FARM) at Wilfrid Laurier University where they lived in large breeding flocks in aviaries with other wild-caught cowbirds. Thus, we had extensive measures of cognitive abilities, breeding behavior, and reproductive success for these birds. We report here, for the fist time, the surprisingly strong connections we found among these different measures. Female cowbirds’ spatial cognitive abilities correlated positively with how intensely they were courted by males, and with their overall egg production. Males’ spatial cognition correlated positively with their ability to engage in singing contests (“countersinging”) with other males. In addition, a separate non-spatial cognitive ability correlated positively with the attractiveness of the songs they sung. In sum, these results suggest the cognitive skills assessed in the lab were strongly connected to breeding behavior and reproductive success. Moreover, since certain cognitive abilities related to different aspects of breeding success, it suggests that cognitive modules may have specialized adaptive value, but also that these specialized skills may interact and influence fitness in surprising ways.

Sex Role Reversal and High Frequency of Social Polyandry in the Pheasant-Tailed Jacana (Hydrophasianus chirurgus)

In a few species, males invest more than females in parental care while the females invest in mating competition and producing multiple broods for several mates. Species in the family Jacanidae are commonly used for studying this type of breeding system (called sex-role reversal), and previous studies found discrepancies and variation between species in the expected characteristics of reversed sex roles. Yet, a better understanding of sex role differences in breeding behavior in such species is crucial for disentangling possible evolutionary mechanisms leading to this peculiar breeding system. Sex-role reversal in the pheasant-tailed jacana Hydrophasianus chirurgus has been documented long time ago. Since the very early observation of this species, however, there was no attempt to provide a comprehensive and quantitative description of their breeding. This study aims to fill these knowledge gaps by investigating the sex role differences in the breeding behavior of pheasant-tailed jacanas, by observing and monitoring a breeding population in Taiwan. We focused on three main characteristics of sex-role reversal: (1) competition between females for access to males, such as agonistic and courtship behaviors, (2) polyandrous mating, and (3) male-only care. As expected, we found that females provide most of the territory defense toward conspecifics. Males also participated in agonistic behaviors, although less frequently than females. Furthermore, contrary to what was expected, we found that males spent more time than females on courtship behavior. Polyandrous females performed mating and laying sequentially with different mates but maintained the pair bonds simultaneously with multiple males. For the first time for the species, we could estimate that the average number of mates per female (i.e., degree of polyandry) was 2.4 and that at least 81.8% of the females in the population were polyandrous. Finally, our observations corroborated that brood care is predominantly provided by males, nevertheless females were also participating to some degree in brood attendance but never in direct care (i.e., brooding). This study highlights that some aspects of polyandrous breeding might deviate from stereotyped view on sex-role reversal, and stress the importance of further within species and comparative studies in order to fully understand the mechanisms leading to sex-role reversal.

Does gut microbiota regulate brooding in geese?

Domestic geese can reduce the amount of food intake when brooding. Because of the reduction in food intake, the total number of microorganisms in the gut is also reduced. Will this affect the goose’s thinking and make the goose stop brooding and eat food? We hypothesize that gut microbiota affects the brain through a brain–gut peptide and further regulates the breeding behavior of geese. In this study, we evaluated the microbiome related to the goose and transcription groups of brooding and egg production periods. The changes and differences in gut microbiota and gene expression of female geese in different reproduction periods were analyzed, and the possible interaction between them was explored. The results showed that the relative abundance of Faecalibacterium with a growth-promoting effect in the cecum was higher in the egg production group than in the brooding group. Microbial metabolic pathways with significant differences between the two groups were also enriched in the secondary functional groups with different gut microbiota metabolism. The downregulated genes in the egg production group were mainly related to energy metabolism, such as ATP synthesis-related genes. These results suggest that the brooding group’s gut microbiota can make relevant changes according to the reproduction stage of the goose. Since the amount of food taken in is reduced, it can promote the decomposition of the host’s fat. Simultaneously, insulin is also used to deliver messages to the brain; it is necessary to end the brooding behavior at an appropriate time and for eating to start.

Influence of Habitat and Food Resource Availability on Common Raven Nest Site Selection and Reproductive Success in Mediterranean Forests

Bird nest selection in forests can be influenced by the composition of key structural elements and resources. This has important consequences in terms of species population dynamics since it can determine reproduction success. Here, we assessed Common raven nest-site selection and reproductive success, and how these might be determined by foraging behavior and habitat structure. A previously documented breeding raven population that exerts high predation pressure on young Spur-thighed tortoises (Testudo graeca) in a Mediterranean forest was monitored. Generalized linear mixed models were performed to determine the singularities of the trees with nests and the drivers of reproductive success of breeding pairs of ravens. The results showed a high density of breeding pairs in the study area (0.8 pairs/km2), which selected taller trees in areas with higher bare ground cover and a high density of tortoises for nesting. Nests were spatially aggregated; breeding pairs occupied smaller territories and intraspecific competition seemed relaxed, reflecting the abundance of food resources. Most breeding pairs occasionally predated on young tortoises. Tortoises seem to play a part in raven reproductive success in our study area, which might be associated with the availability/catchability of young tortoises. The study illustrates that Spur-thighed tortoise distribution and abundance plays a role in the breeding behavior of ravens and is mediated by habitat structure. Understanding the drivers of nest-site selection and the breeding behavior of ravens is pivotal to implementing appropriate habitat management and conservation strategies across their distribution range, particularly in areas where ravens potentially affect threatened species.

Breeding behavior, distribution, and conservation of the Sharp-tailed Tyrant Culicivora caudacuta (Vieillot, 1818) (Aves: Tyrannidae), a South American grassland specialist

Culicivora caudacuta occurs in the Cerrado, Pampa and Chaco grasslands of Bolivia, Brazil, Paraguay, Argentina and Uruguay. Its breeding biology is poorly known. Here, I present a summary of the published information and new data gathered between 2003 and 2009 in southeast Brazil at Tapira, Minas Gerais. Breeding occurred during the rainy season (October to March), clutch size being three eggs. Juveniles and immatures show a different plumage from the adults, mostly brownish orange. All nests studied at Tapira showed evidence of cooperative breeding, with one helper engaged in incubation and provisioning the young. This is the first observations of this behavior for the species. The species has a wider range than currently understood and its presence in protected areas is similarly more common.

A neuroendocrine perspective on the origin and evolution of cooperative breeding

Cooperative breeding behavior in birds ranges from inducible to obligate strategies and has evolved across diverse taxa, in species that display a wide range of social and reproductive behavior. It is often thought to evolve when independent breeding is constrained, and cooperation increases fitness. Yet many systems show variable, even maladaptive, fitness effects. This observation, together with the wide range in the form and frequency of cooperative breeding, raises the question of how the recurrent appearance of cooperative breeding and its extensive variation across species—from inducible to obligate—can be explained. Here, we take a proximate perspective on the evolution of cooperative breeding to argue that cooperative strategies are delineated by the history of prior adaptations and emerge through the rearrangement of preexisting neuroendocrine mechanisms underlying social, dispersal, and parental behaviors. Natural selection sorts among the resultant variants to alter regulation of cooperation, producing stabilization through either greater developmental entrenchment or greater reliance on environmental cues. Thus, species showing inducible cooperative behavior may be at a transitory stage in this process. To assess this possibility, we first evaluate evidence that the components of cooperative breeding are common across taxa. Then, we review the neuroendocrine mechanisms that regulate the pathways underlying cooperative strategies. Finally, we assess the evidence for neuroendocrine linkages during development that may channel coexpression of some components of cooperative breeding and facilitate its evolution. We conclude that understanding the mechanistic bases of the behaviors comprising cooperative breeding strategies may provide novel insight into the recurrent emergence of this strategy across disparate environments and avian taxa.

Visiting Potato from a Breeding Perspective: Accomplishments and Prospects

Several enhancements to the conventional potato breeding are possible though they have encouragement as well as limitations. I n this direction, the marker-assisted selection may be utilized to stack major genes as well as QTLs. Whereas the genetic transformation and genome editing methods accelerate the process of ricking of genes/transgenes. Moreover, these methodologies supplemented with the next-generation sequencing (NGS) platforms and pipelines further aid in reaching the potato ideotype. Here, we overviewed the critical topics that are related to potatoes, from general background, breeding behavior, breeding approaches employed to the potato improvement. Overall, this information complied might serve as background information that is important for potato breeders.

Evolution of Reproductive Life History in Mammals and the Associated Change of Functional Constraints

Phylogenetic trees based on multiple genomic loci enable us to estimate the evolution of functional constraints that operate on genes based on lineage-specific fluctuation of the evolutionary rate at particular gene loci, “gene–branch interactions”. Using this information as predictors, our previous work inferred that the common ancestor of placental mammals was nocturnal, insectivorous, solitary, and bred seasonally. Here, we added seven new continuous traits including lifespan, bodyweight, and five reproduction-related traits and inferred the coevolution network of 14 core life history traits for 89 mammals. In this network, bodyweight and lifespan are not directly connected to each other; instead, their correlation is due to both of them coevolving with gestation period. Diurnal mammals are more likely to be monogamous than nocturnal mammals, while arboreal mammals tend to have a smaller litter size than terrestrial mammals. Coevolution between diet and the seasonal breeding behavior test shows that year-round breeding preceded the dietary change to omnivory, while seasonal breeding preceded the dietary change to carnivory. We also discuss the evolution of reproductive strategy of mammals. Genes selected as predictors were identified as well; for example, genes function as tumor suppressor were selected as predictors of weaning age.