Vocal communication regulates sibling competition over food stock

Animals resolve conflicts over the share of resources by competing physically or signalling motivation with honest signals of need. In some species, young siblings vocally signal to each other their hunger level and the most vocal individual deters its siblings from competing for the non-divisible food item delivered at the next parental visit. This so-called sibling negotiation for forthcoming food has been studied only in this context. It therefore remains unclear whether siblings could also negotiate access to a pool of divisible resources, a situation that is similar to a group of individuals competing for an accessible food resource. To tackle this issue, we placed barn owl (Tyto alba) nestlings singly in artificial nests containing several mice, and we simulated the presence of a sibling calling at low or high rate using playback experiments. If nestling barn owls vocally negotiate over a divisible food stock, we propose the following two predictions. First, nestlings would vocally signal before eating from this stock of food, and second, numerous playback vocalizations would inhibit feeding. Accordingly, singleton nestlings vocalized just before consuming food stored in their artificial nest and they delayed the consumption of the food stock if hearing many playback calls. The production of such food-associated vocalizations has been observed in foraging adults in various birds and mammals, but never in young animals and when resource is divisible and easily accessible. Our study raises the possibility that vocal communication could evolve in a variety of competitive contexts. We present here the first experimental evidence that sibling barn owls use food-associated vocalizations to compete over the preys stored in the nest. Owlets emit calls just before consuming an available food item and broadcasting calls induces nestlings to temporarily refrain from eating from the food stock. This raises the possibility that vocal communication can mediate the share of a food stock accessible to all competitors

Responsiveness to siblings' need increases with age in vocally negotiating barn owl nestlings

In animal societies, individuals should optimize the way they behave in relation to the behavior displayed by their conspecifics. This social competence, i.e., the ability to adjust behavior to the social context, can vary between individuals, but also improve with age and experience. This aspect, although important, has rarely been studied. We tested whether the ability to adjust behavior to siblings develops with age in barn owl nestlings (Tyto alba). In this species, young siblings show intense social interactions referred to as Bsibling negotiation. Indeed, because parents bring a single indivisible food item at each visit to the nest, all the effort invested in sibling competition is only paid back in the nestling that is able to monopolize the food item. Therefore, before the arrival of parents, siblings vocally inform each other about their relative hunger level so that they can optimally invest in sibling competition, with the most vocal, and hence hungry, nestling momentarily deterring its siblings from competing. This process implies that siblings have the ability to adjust their behavior in relation to the behavior of their siblings, a process that could change with age. In a series of experiments, we examined how nestlings of different ages respond to the vocal behavior of siblings. We show here that older nestlings adjusted their vocal behavior more finely than younger nestlings in relation to the behavior of their siblings. Elders also more readily refrained from eating in front of a hungry sibling. These patterns could arise because owlets' social competence develops with age or because they adopt different competitive and cooperative strategies according to their age. Significance statement In sibling barn owls, competition for food brought by parents is settled by vocalization. Highly vocal owlets induce their siblings to call less and to let them eat in priority once parents are back with a prey item, a process referred to as Bsibling negotiation." Nestling barn owls adjust their investment in sibling competition according to two parameters: their hunger level and the vocal behavior of their siblings. We analyzed the relative importance of these two parameters in differently aged owlets. Younger owlets adjusted the intensity of vocalizing primarily in relation to their own hunger level, which was efficient in modifying older nestlings' behavior, as older nestlings readily withdrew from vocal contest and refrained from eating in front of highly vocal siblings. Hence, social adjustment changed with age in owlets, older ones being more sensitive to the signals of need of their siblings

[Radiocrystallography and Spectral-analysis of Dihydroxymalonic Acid and its Potassium-salts]

The structures of the potassium salts of ketomalonic acid were determined on the basis of radiocrystallographic measurement. The Raman and infrared spectra of the acid and its potassium salts in aqueous solution were recorded from 4000 to 200 cm-1. An assignment of the observed lines as fundamental is proposed. The analysis of the Raman lines indicated that the salts belong to the C(s) group, whereas the acid belongs to the C2 group. Comparison between the solid state and aqueous solution is proposed

Structure of Potassium Hydrogen Diethylmalonate Monohydrate

[K(C7H11O4)].H2O, M(r) = 216.27, tetragonal, P4(3), a = 9.251 (3), c = 13.123 (4) angstrom, V = 1123 (1) angstrom 3, Z = 4, D(x) = 1.29 Mg m-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 0.45 mm-1, F(000) = 456, T = 293 K, R = 0.041 for 1121 observed reflections. The asymmetric unit contains one formula unit of potassium hydrogen diethylmalonate linked by a hydrogen bond to the water molecule. Each molecule is intramolecularly hydrogen bonded and the carboxylic and carboxylate groups lying in the same plane of symmetry are equivalent

“Are You Serious About This Spanish Thing?”

My title comes from remarks made to the then-President and Chief Operating Officer of NBC, Andrew Lack, on the links of corporate America in 2002..