i DOI: https://doi.org/10.3318/BIOE.2020.22 Biology and Environment: Proceedings of the Royal Irish Academy,Vol. 120, No. 3, i–ii (2020). © Royal Irish Academy Cite as follows: Osborne, B. In this issue 2020 Biology and Environment: Proceedings of the Royal Irish Academy 2020. DOI: 10.3318/ BIOE.2020.22 IN THIS ISSUE Bruce Osborne Harbour seal pups and weaning The shift from parental dependence to individual responsibility is clearly an important stage in the life of a vast range of organisms, not just humans. Weaning, the gradual transition from a dependence on milk supplied by the mother, to individuals foraging for alternative food sources on their own, involves several complex behavioural and dietary changes and may even involve the mother rejecting its young. Whilst we know a lot about weaning in humans, less information is available for other animals, one of which is the harbour seal. Wilson and Jones, in this issue, address this deficiency in our understanding of the weaning process in harbour seals and add another dimension to this: namely, the influence of local habitat conditions. The authors examined the behaviour of pups in the absence of their mothers at two pupping sites in Dundrum bay in north east Ireland. Far from rejecting their young, mothers and pups often reunited for short periods even after the pups became more dependent on foraged food, indicating that some parental care continued even up to seven years of age. Although the reason(s) for the continued parental contact is not known, this flexibility in the weaning process may relate to food availability and/or the presence of predators.Clearly,the weaning process in harbour seals is not always abrupt, as often thought, nor is it common for mothers to reject their young, so a variety of factors will determine the duration of the weaning process. Pollen as a food source for stoneflies Stoneflies are an ancient order of insects with a fossil history extending back over 250 million years. Globally there are currently approximately 3,500 species, around 15% of which are found in Europe, with 20 species recorded in Ireland. Stoneflies (nymphs and adults) are invariably associated with water bodies, forming a large proportion of the invertebrate fauna particularly in headwater streams, and are an important food source for fish and terrestrial vertebrates. Although the winged adults live and survive out of water it was once believed that all adult stoneflies were, unlike their nymphs, incapable of feeding due to their limited mouth parts, and therefore only able to drink water. However, it was subsequently shown that many do feed when out of water. Unlike nymphs, which may be predators or feed on dead plant material and algal biofilms, the winged adults probably depend largely on pollen grains. This raises some interesting questions about whether there are any preferences for the pollen of particular plant species and if so, why? McGonigley et al., in this issue, investigated this by rearing captured stoneflies in the laboratory prior to exposing them to pollen from different tree species. Their results showed that there was a significant preference for the pollen from birch trees over that of spruce, supporting the authors’ contention that riverside vegetation and its conservation could have important implications for stonefly biology and ecology, with knock-on effects on riverine food webs.Whilst the reason(s) for this food preference was not identified pollen is a particular rich source of protein and vitamins and this could have had a significant influence on food choice. Pollen can also vary considerably in its digestibility and this too could have contributed to the selection of birch pollen over that of spruce. Zebra fish-again! Zebra fish have featured several times in Biology and Environment and have become the go-to organism for bioassays of a wide range of potential toxic chemicals, as well as providing a means of testing for the presence of environmental contaminants, including herbicides and pesticides present in water. Although the role of many synthetic herbicides may be diminishing with steady progress being made on the development of more environmentally compatible alternatives,they are still widely used and associated with several—albeit hotly contested— disadvantages, including...
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Mar 2, 2020
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