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Army ant invasion of leatherback nests in Gabon

Egg mortality is one of the main factors affecting life history and conservation of oviparous species. A massive and cryptic colonisation of many leatherback turtle (Dermochelys coriacea) eggs is presented in the most important rookery for the species in Gabon. A total of 163 nests were exhumed at Kingere beach, revealing that only 16.7% of eggs produced hatchlings. In the 59% of the nests, more than half of the eggs were dead and attacked by invertebrates and 94% had at least one egg affected by invertebrates. The rate of eggs and SAGs (yolkless eggs) affected by invertebrates within a clutch ranged from 0% to 100%, with an average proportion of 39% and 52%, respectively. The most common invertebrates interacting with the eggs were ghost crabs and insects that affected 51% and 82% of the nests, respectively. Crab and insect co-occurred in 33% of the affected nests. Ants, identified as Dorylus spininodis (Emery 1901) were found in 56% of the excavated nests. However, it was not possible to determine if the ants predated alive eggs or scavenged dead eggs. Very often, hundreds of ants were found drowned within dead eggs. Termites and other invertebrates were associated with the clutch environment and identified as opportunistic feeders, being this is the first record of interaction between termites and sea turtle eggs. An unusual ecological interaction within the leatherback clutches between termites and ants was found in 11% of the nests. The abrupt transition between the soil forest and the beach might be favouring a thriving microbial and invertebrate activity in the sand profile that colonises the nests. informacion[at]ebd.csic.es: Ikaran et al (2020) Cryptic massive nest colonisation by ants and termites in the world's largest leatherback turtle rookery Ethol Ecol Evol 2020. Doi 10.1080/03949370.2020.1715487


https://www.tandfonline.com/doi/abs/10.1080/03949370.2020.1715487
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Asymmetric iris heterochromia in birds

Asymmetric iris heterochromia in birds

For the first time the unique coloured pattern of the iris of buttonquails (Turnicidae) is described. This unique pattern is due to the presence of a dark-brown crescent in the iris below the pupil, whose form and extent varies in response to light conditions. This dark crescent is present in the eyes of all individuals of Turnix species at every life stage, a consistency that has not been previously observed for the iridal marks found in other avian groups. This consistency suggests that the crescent-shaped spot in buttonquails' eyes is a character subjected to natural selection, probably related to light regulation. Although there is no direct evidence for the function of the dark crescent in the iris of buttonquails, since these birds usually live under the shady cover of low and partly open scrubland, grassland and farmland, it can be argued that the dark crescent may be an adaptation to exposure to sudden changes in light when the birds are foraging between dark shade beneath full cover and sunny conditions in the open. This hypothesis seems to be supported by the adaptability of the size and form of the dark crescent, and thus its suggested functionality, in response to changes in light intensity. In summary, the dark crescent of the iris may be a sophisticated system for improved vision under certain light exposure. informacion[at]ebd.csic.es: Gutiérrez-Expósito (2018) Asymmetric iris heterochromia in birds: the dark crescent of buttonquails. J Ornithol https://doi.org/10.1007/s10336-018-1606-4


https://link.springer.com/article/10.1007/s10336-018-1606-4#citeas