The behaviour of recently hatched Tobago glass frog tadpoles

Egg clutches of the Tobago glass frog Hyalinobatrachium orientale tobagoense were collected from streams around the north-east of Tobago and hatched into tanks of native stream water. Previously unreported behaviour of newly hatched tadpoles was observed. Observations were made through a series of tests for substrate preference (gravel, rocks or leaves), shelter or open water preference, and surfacing behaviour under different depths and turbulence levels. Tests found that tadpoles showed a preference for stream substrates over plastic tank floor, with the highest percentage of tadpoles found in gravel. Tadpoles preferred sheltered areas of the tank, and surfaced significantly less when water was turbulent, with depth having no significant effect on surfacing behaviour

Temporal trends in stillbirth over eight decades in England and Wales:A longitudinal analysis of over 56 million births and lives saved by improvements in maternity care

BACKGROUND: Considering the public health importance of stillbirth, this study quantified the trends in stillbirths over eight decades in England and Wales. METHODS: This longitudinal study utilized the publicly available aggregated data from the Office for National Statistics that captured maternity information for babies delivered in England and Wales from 1940 to 2019. We computed the trends in stillbirth with the associated incidence risk difference, incidence risk ratio, and extra lives saved per decade. RESULTS: From 1940-2019, 56 906 273 births were reported. The stillbirth rate declined (85%) drastically up to the early 1980s. In the initial five decades, the estimated number of deaths per decade further decreased by 67 765 (9.49/1000 births) in 1940-1949, 2569 (0.08/1000 births) in 1950-1959, 9121 (3.50/1000 births) in 1960-1969, 15 262 (2.31/1000 births) in 1970-1979, and 10 284 (1.57/1000 births) in 1980-1989. However, the stillbirth rate increased by an additional 3850 (0.58/1000 births) stillbirths in 1990-1999 and 693 (0.11/1000 births) stillbirths in 2000-2009. The stillbirth rate declined again during 2010-2019, with 3714 fewer stillbirths (0.54/1000 births). The incidence of maternal age 35 years) increased. CONCLUSIONS: The stillbirth rate declined drastically, but the rate of decline slowed in the last three decades. Though teenage pregnancy (<20 years) had reduced, the prevalence of women with a higher risk of stillbirth may have risen due to an increase in advanced maternal age. Improved, more personalised care is required to reduce the stillbirth rate further

Sex-specific thermal constraints on fiddler crab behavior

Sexual selection via endurance rivalry favors increased tenure at the breeding site but can be costly. Here, we investigated thermal constraints on endurance rivalry in fiddler crabs, a group well suited for studies of interactions between sexual and natural selection due to ritualized mating behaviors and extreme sexual dimorphism. Fiddler crab males display in thermally stressful high-intertidal breeding areas. Retreating into burrows, an effective thermoregulatory mechanism, requires a cessation of courtship behaviors. We predicted that males should spend more time on the surface than females and that their ability to do so should decrease with increasing body temperature. In contrast, the amount of time females spend on the surface should be little affected by body temperature. We tested these predictions in the fiddler crab Uca panacea by manipulating body temperatures and monitoring surface activity and habitat choice in large outdoor tanks during the breeding season. Males showed consistently higher surface activity than females. Effects of body temperature on surface activity were sex-specific, occurring in males but not in females, indicating sex-specific thermal constraints on surface behavior and supporting our hypothesized thermal constraints on endurance rivalry.Michael Zachary Darnell, Kenna K. Fowler, and Pablo Mungui