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The first breeding of osprey (Pandion haliaetus) on Jeju Island, South Korea, were observed in 2015, and ospreys bred on three sites. We found a total of three nests and observed that A site nest bred on successfully from 2017 to 2020. The number of eggs per clutch ranged from two to four, with a mean ± SD of 3.16 ± 0.75. The nesting period varied from 71 days to 79 days, with an average duration of 76.2 ± 3.18 days. The incubation period ranged from 34 days to 38 days, averaging 35.8 ± 1.72 days. Fledging dates ranged from July 4th to 13th. The nest tree species was Pinus thunbergii, and the average tree height was 16.2 ± 3.12 m. On average, the nest height from the ground was 14.8 ± 2.57 m. The average diameter at breast height of the nesting trees was 36.1 ± 2.02 cm. Of the total 19 eggs produced, the hatching rate was 91.4% ± 10.2%, fledgling rate was 68.6% ± 26.9%, and breeding success was 65.6% ± 25.1%. Little ecological information is available on osprey living in South Korea; therefore, this study makes a meaningful contribution to provide baseline ecological data from South Korea for this species.

Insect-associated microorganisms play important roles in the health and development of insects. This study aimed to investigate the similarities and differences in bacterial community structure and composition between the larval gut of Osmia excavata, nest soil, and brood provision from the nest tube. We sequenced larvae gut and their environments' microorganisms of O. excavata from four locations based on full-length 16S rRNA gene amplicons. The results showed 156, 280, and 366 bacterial OTUs from gut, brood provision, and nest soil, respectively, and three groups shared 131 bacterial OTUs. In the gut, the top two dominant bacteria were Sodalis praecaptivus (68.99%), Lactobacillus micheneri (17.95%). In the brood provision, the top two dominant bacteria were S. praecaptivus (26.66%), Acinetobacter nectaris (13.05%), and in the nest soil, the two most abundant bacteria were Gaiella occulta (4.33%), Vicinamibacter silvestris (3.88%). There were significant differences in diversity between the brood provision groups and the nest soil groups, respectively. Three of the four locations did not differ for gut microbial diversity. Bacteria similar to other solitary bees also existed in the gut of the larvae. Results indicated when the habitat environments were similar, the bacterial community diversity of the gut of O. excavata was similar, despite significant differences among brood provisions and soils, respectively. [ABSTRACT FROM AUTHOR]

The nest environment may limit the ability of nest-bound birds to hear sounds from the outside world. In vocal learning species, such as humans and songbirds, it is vital for young animals to hear the voices of conspecific animals early in life. In songbirds, nest structure varies considerably across species, and the resulting impact on sound transmission may have consequences for vocal learning in nestlings. In this study, we tested the hypothesis that the nest environment attenuates song of Savannah Sparrows (Passerculus sandwichensis), grassland songbirds that build nests on the ground under cover of dense vegetation. We recorded live Savannah Sparrows singing at variable distances from 21 nests. We recorded songs using one microphone inside the nest (the typical position of a nestling) and another placed 1 m directly above the nest (a typical position of an adult). We found a substantial reduction in signal-to-noise ratio, where songs recorded inside the nest were an average of 11 dB lower than songs recorded directly above the nest. We estimate that the attenuation imposed by the nest reduced the maximum acoustic environment from 117.7 m (for recordings above the nest), to 78.6 m (for recordings within the nest), which is analogous to listening from a position 39.1 m farther away from the singer. Previous research estimated that song transmits up to 100 m in this species, so any adult male within 100 m of a young bird was previously considered a potential vocal tutor. By reducing the nestling acoustic environment from 100 m to 78.6 m, the number of male tutors available to nestlings is reduced by an average of 27%. Given the growing evidence that song learning begins very early in life, future research on vocal development should account for how the structural properties of the natal environment affect the songs that nestlings hear.

Insect-associated microorganisms play important roles in the health and development of insects. This study aimed to investigate the similarities and differences in bacterial community structure and composition between the larval gut of Osmia excavata, nest soil, and brood provision from the nest tube. We sequenced larvae gut and their environments’ microorganisms of O. excavata from four locations based on full-length 16S rRNA gene amplicons. The results showed 156, 280, and 366 bacterial OTUs from gut, brood provision, and nest soil, respectively, and three groups shared 131 bacterial OTUs. In the gut, the top two dominant bacteria were Sodalis praecaptivus (68.99%), Lactobacillus micheneri (17.95%). In the brood provision, the top two dominant bacteria were S. praecaptivus (26.66%), Acinetobacter nectaris (13.05%), and in the nest soil, the two most abundant bacteria were Gaiella occulta (4.33%), Vicinamibacter silvestris (3.88%). There were significant differences in diversity between the brood provision groups and the nest soil groups, respectively. Three of the four locations did not differ for gut microbial diversity. Bacteria similar to other solitary bees also existed in the gut of the larvae. Results indicated when the habitat environments were similar, the bacterial community diversity of the gut of O. excavata was similar, despite significant differences among brood provisions and soils, respectively.

Social insects are well known for their high level of cooperation. Workers of the primitively eusocial bumblebee Bombus terrestris are able to produce male offspring in the presence of a queen. Nonetheless, they only compete for reproduction, in the so-called competition phase, when the workforce is large enough to support the rearing of reproductives. So far, little is known about the proximate mechanisms underlying the shift between altruism and selfish behaviour in bumblebee workers. In this study, we have examined the influence of chemical cues from the nest wax on the onset of worker reproduction. Chemical analyses of wax extracts have revealed that the patterns and amounts of cuticular lipids change considerably during colony development. These changes in wax scent mirror worker abundance and the presence of fertile workers. In bioassays with queen-right worker groups, wax affects the dominance behaviour and ovarian development of workers. When exposed to wax from a colony in competition phase, workers start to compete for reproduction. We suggest that wax scent enables workers to time their reproduction by providing essential information concerning the social condition of the colony.

The nest environment may limit the ability of nest-bound birds to hear sounds from the outside world. In vocal learning species, such as humans and songbirds, it is vital for young animals to hear the voices of conspecific animals early in life. In songbirds, nest structure varies considerably across species, and the resulting impact on sound transmission may have consequences for vocal learning in nestlings. In this study, we tested the hypothesis that the nest environment attenuates song of Savannah Sparrows (Passerculus sandwichensis), grassland songbirds that build nests on the ground under cover of dense vegetation. We recorded live Savannah Sparrows singing at variable distances from 21 nests. We recorded songs using one microphone inside the nest (the typical position of a nestling) and another placed 1 m directly above the nest (a typical position of an adult). We found a substantial reduction in signal-to-noise ratio, where songs recorded inside the nest were an average of 11 dB lower than songs recorded directly above the nest. We estimate that the attenuation imposed by the nest reduced the maximum acoustic environment from 117.7 m (for recordings above the nest), to 78.6 m (for recordings within the nest), which is analogous to listening from a position 39.1 m farther away from the singer. Previous research estimated that song transmits up to 100 m in this species, so any adult male within 100 m of a young bird was previously considered a potential vocal tutor. By reducing the nestling acoustic environment from 100 m to 78.6 m, the number of male tutors available to nestlings is reduced by an average of 27%. Given the growing evidence that song learning begins very early in life, future research on vocal development should account for how the structural properties of the natal environment affect the songs that nestlings hear. [ABSTRACT FROM AUTHOR]

Many temperate animals spend half their lives in a non-active, overwintering state, and multiple adaptations have evolved to enable winter survival. One notable vertebrate model is Chrysemys picta, whose hatchlings display dichotomous overwintering strategies: some hatchlings spend their first winter aquatically after nest emergence in the autumn, whereas others overwinter terrestrially within their natal nest with subsequent emergence in the spring. The occurrence of these strategies varies among populations and temporally within populations; however, factors that determine the strategy employed by a nest in nature are unknown. We examined potential factors that influence intra-population variation in the overwintering strategy of C. picta hatchlings over two winters in Algonquin Park, Ontario. We found that environmental factors may be a trigger for the hatchling overwintering strategy: autumn-emerging nests were sloped towards the water and were surrounded by a relatively higher percentage of bare ground compared with spring-emerging nests. Autumn-emerging hatchlings were also relatively smaller. Overwintering strategy was not associated with clutch oviposition sequence, or mammalian or avian predation attempts. Instead, autumn emergence from the nest was associated with the direct mortality threat of predation by sarcophagid fly larvae. Body condition and righting response, measured as proxies of hatchling fitness, did not differ between overwintering strategies. Costs and benefits of overwintering aquatically versus terrestrially in hatchling C. picta are largely unknown, and have the potential to affect population dynamics. Understanding winter survival has great implications for turtle ecology, thus we emphasize areas for future research on dichotomous overwintering strategies in temperate hatchling turtles. [ABSTRACT FROM AUTHOR]

Carefully controlled gas exchange across the eggshell is essential for the development of the avian embryo. Water vapour conductance (GH2o) across the shell, typically measured as mass loss during incubation, has been demonstrated to optimally ensure the healthy development of the embryo while avoiding desiccation. Accordingly, eggs exposed to sub-optimal gas exchange have reduced hatching success. We tested the association between eggshell GH2o and putative life-history correlates of adult birds, ecological nest parameters and physical characteristics of the egg itself to investigate how variation in GH2o has evolved to maintain optimal water loss across a diverse set of nest environments. We measured gas exchange through eggshell fragments in 151 British breeding bird species and fitted phylogenetically controlled, general linear models to test the relationship between GH2o and potential predictor parameters of each species. Of our 17 life-history traits, only two were retained in the final model: wet-incubating parent and nest type. Eggs of species where the parent habitually returned to the nest with wet plumage had significantly higher GH2o than those of parents that returned to the nest with dry plumage. Eggs of species nesting in ground burrows, cliffs and arboreal cups had significantly higher GH2o than those of species nesting on the ground in open nests or cups, in tree cavities and in shallow arboreal nests. Phylogenetic signal (measured as Pagel's γ) was intermediate in magnitude, suggesting that differences observed in the GH2o are dependent upon a combination of shared ancestry and speciesspecific life history and ecological traits. Although these data are correlational by nature, they are consistent with the hypothesis that parents constrained to return to the nest with wet plumage will increase the humidity of the nest environment, and the eggs of these species have evolved a higher GH2o to overcome this constraint and still achieve optimal water loss during incubation. We also suggest that eggs laid in cup nests and burrows may require a higher GH2o to overcome the increased humidity as a result from the confined nest microclimate lacking air movements through the nest. Taken together, these comparative data imply that species-specific levels of gas exchange across avian eggshells are variable and evolve in response to ecological and physical variation resulting from parental and nesting behaviours. [ABSTRACT FROM AUTHOR]

Social insects are well known for their high level of cooperation. Workers of the primitively eusocial bumblebee Bombus terrestris are able to produce male offspring in the presence of a queen. Nonetheless, they only compete for reproduction, in the so-called competition phase, when the workforce is large enough to support the rearing of reproductives. So far, little is known about the proximate mechanisms underlying the shift between altruism and selfish behaviour in bumblebee workers. In this study, we have examined the influence of chemical cues from the nest wax on the onset of worker reproduction. Chemical analyses of wax extracts have revealed that the patterns and amounts of cuticular lipids change considerably during colony development. These changes in wax scent mirror worker abundance and the presence of fertile workers. In bioassays with queen-right worker groups, wax affects the dominance behaviour and ovarian development of workers. When exposed to wax from a colony in competition phase, workers start to compete for reproduction. We suggest that wax scent enables workers to time their reproduction by providing essential information concerning the social condition of the colony.