Revised stratigraphy and chronology for Homo floresiensis at Liang Bua in Indonesia

Homo floresiensis, a primitive hominin species discovered in Late Pleistocene sediments at Liang Bua (Flores, Indonesia)1,2,3, has generated wide interest and scientific debate. A major reason this taxon is controversial is because the H. floresiensis-bearing deposits, which include associated stone artefacts2,3,4 and remains of other extinct endemic fauna5,6, were dated to between about 95 and 12 thousand calendar years (kyr) ago2,3,7. These ages suggested that H. floresiensis survived until long after modern humans reached Australia by ~50 kyr ago8,9,10. Here we report new stratigraphic and chronological evidence from Liang Bua that does not support the ages inferred previously for the H. floresiensis holotype (LB1), ~18 thousand calibrated radiocarbon years before present (kyr cal. BP), or the time of last appearance of this species (about 17 or 13–11 kyr cal. BP)1,2,3,7,11. Instead, the skeletal remains of H. floresiensis and the deposits containing them are dated to between about 100 and 60 kyr ago, whereas stone artefacts attributable to this species range from about 190 to 50 kyr in age. Whether H. floresiensis survived after 50 kyr ago—potentially encountering modern humans on Flores or other hominins dispersing through southeast Asia, such as Denisovans12,13—is an open question

Anti-brood parasite defences : the role of individual and social learning

In this chapter, we consider the ways in which learning is involved in the antibrood parasitism defences that hosts deploy across the nesting cycle. Brood parasitism varies in space and through time, and hosts have accordingly evolved plastic defences that can be tuned to local conditions. Hosts can achieve their defence plasticity by individual and social learning, as well as by experienceindependent mechanisms. While these mechanisms can profoundly affect the coevolutionary dynamics between hosts and their brood parasites, our understanding of how they feature across the host nesting cycle is far from complete. Hosts can actively defend themselves against brood parasitism via a variety of behaviours, including nest defence, egg discrimination and chick discrimination. Such anti-brood parasite defences rely on the host ’ s ability to recognise and then defend against the parasitic threat, and there is good evidence that both these components of discrimination can be in fl uenced by learning. To date, most research has focused on the function of learning in nest defence, but the learning mechanisms underlying egg discrimination are much better understood; and despite some notable exceptions, the role of learning in chick discrimination remains largely unexplored. An important challenge now is to understand the observed plasticity of anti-brood parasite defences in the context of environmental heterogeneity and speci fi cally in terms of variation in the presence, detection and reliability of parasitism cues

Anti-brood Parasite Defences: The Role of Individual and Social Learning

In this chapter, we consider the ways in which learning is involved in the antibrood parasitism defences that hosts deploy across the nesting cycle. Brood parasitism varies in space and through time, and hosts have accordingly evolved plastic defences that can be tuned to local conditions. Hosts can achieve their defence plasticity by individual and social learning, as well as by experienceindependent mechanisms. While these mechanisms can profoundly affect the coevolutionary dynamics between hosts and their brood parasites, our understanding of how they feature across the host nesting cycle is far from complete. Hosts can actively defend themselves against brood parasitism via a variety of behaviours, including nest defence, egg discrimination and chick discrimination. Such anti-brood parasite defences rely on the host’s ability to recognise and then defend against the parasitic threat, and there is good evidence that both these components of discrimination can be influenced by learning. To date, most research has focused on the function of learning in nest defence, but the learning mechanisms underlying egg discrimination are much better understood; and despite some notable exceptions, the role of learning in chick discrimination remains largely unexplored. An important challenge now is to understand the observed plasticity of anti-brood parasite defences in the context of environmental heterogeneity and specifically in terms of variation in the presence, detection and reliability of parasitism cues