The Experts below are selected from a list of 153 Experts worldwide ranked by ideXlab platform
Claire N Spottiswoode - One of the best experts on this subject based on the ideXlab platform.
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reciprocal signaling in honeyguide human mutualism
Science, 2016Co-Authors: Claire N Spottiswoode, Keith Egg, Collee EggAbstract:Greater Honeyguides (Indicator indicator) lead human honey-hunters to wild bees’ nests, in a rare example of a mutualistic foraging partnership between humans and free-living wild animals. We show experimentally that a specialized vocal sound made by Mozambican honey-hunters seeking bees’ nests elicits elevated cooperative behavior from Honeyguides. The production of this sound increased the probability of being guided by a honeyguide from about 33 to 66% and the overall probability of thus finding a bees’ nest from 17 to 54%, as compared with other animal or human sounds of similar amplitude. These results provide experimental evidence that a wild animal in a natural setting responds adaptively to a human signal of cooperation.
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The sight of an adult brood parasite near the nest is an insufficient cue for a honeyguide host to reject foreign eggs.
The Ibis, 2015Co-Authors: Wenfei Tong, Nicholas P. C. Horrocks, Claire N SpottiswoodeAbstract:Hosts of brood-parasitic birds typically evolve anti-parasitism defences, including mobbing of parasitic intruders at the nest and the ability to recognize and reject foreign eggs from their clutches. The Greater Honeyguide Indicator indicator is a virulent brood parasite that punctures host eggs and kills host young, and accordingly, a common host, the Little Bee-eater Merops pusillus frequently rejects entire clutches that have been parasitized. We predicted that given the high costs of accidentally rejecting an entire clutch, and that the experimental addition of a foreign egg is insufficient to induce this defence, Bee-eaters require the sight of an adult parasite near the nest as an additional cue for parasitism before they reject a clutch. We found that many Little Bee-eater parents mobbed Greater Honeyguide dummies while ignoring barbet control dummies, showing that they recognized them as a threat. Surprisingly, however, neither a dummy Honeyguide nor the presence of a foreign egg, either separately or in combination, was sufficient to stimulate egg rejection.
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A brood parasite selects for its own egg traits
Biology letters, 2013Co-Authors: Claire N SpottiswoodeAbstract:Many brood parasitic birds lay eggs that mimic their hosts' eggs in appearance. This typically arises from selection from discriminating hosts that reject eggs which differ from their own. However, selection on parasitic eggs may also arise from parasites themselves, because it should pay a laying parasitic female to detect and destroy another parasitic egg previously laid in the same host nest by a different female. In this study, I experimentally test the source of selection on greater honeyguide (Indicator indicator) egg size and shape, which is correlated with that of its several host species, all of which breed in dark holes. Its commonest host species did not discriminate against experimental eggs that differed from their own in size and shape, but laying female Honeyguides preferentially punctured experimental eggs more than host or control eggs. This should improve offspring survival given that multiple parasitism by this species is common, and that honeyguide chicks kill all other nest occupants. Hence, selection on egg size in greater Honeyguides parasitizing bee-eaters appears to be imposed not by host defences but by interference competition among parasites themselves.
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Brain size and morphology of the brood-parasitic and cerophagous Honeyguides (Aves: Piciformes).
Brain behavior and evolution, 2013Co-Authors: Jeremy R. Corfield, Claire N Spottiswoode, Tim R. Birkhead, Andrew N. Iwaniuk, Neeltje J. Boogert, Cristián Gutiérrez-ibáñez, Sarah E. Overington, Douglas R. Wylie, Louis LefebvreAbstract:Honeyguides (Indicatoridae, Piciformes) are unique among birds in several respects. All subsist primarily on wax, are obligatory brood parasites and one species engages in ‘guiding' behavior in which it leads human honey hunters to bees' nests. This unique life history has likely shaped the evolution of their brain size and morphology. Here, we test that hypothesis using comparative data on relative brain and brain region size of Honeyguides and their relatives: woodpeckers, barbets and toucans. Honeyguides have significantly smaller relative brain volumes than all other piciform taxa. Volumetric measurements of the brain indicate that Honeyguides have a significantly larger cerebellum and hippocampal formation (HF) than woodpeckers, the sister clade of the Honeyguides, although the HF enlargement was not significant across all of our analyses. Cluster analyses also revealed that the overall composition of the brain and telencephalon differs greatly between Honeyguides and woodpeckers. The relatively smaller brains of the Honeyguides may be a consequence of brood parasitism and cerophagy (‘wax eating'), both of which place energetic constraints on brain development and maintenance. The inconclusive results of our analyses of relative HF volume highlight some of the problems associated with comparative studies of the HF that require further study.
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Ancient host specificity within a single species of brood parasitic bird
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: Claire N Spottiswoode, John F. R. Colebrook-robjent, Katherine Faust Stryjewski, Suhel Quader, Michael D. SorensonAbstract:Parasites that exploit multiple hosts often experience diversifying selection for host-specific adaptations. This can result in multiple strains of host specialists coexisting within a single parasitic species. A long-standing conundrum is how such sympatric host races can be maintained within a single parasitic species in the face of interbreeding among conspecifics specializing on different hosts. Striking examples are seen in certain avian brood parasites such as cuckoos, many of which show host-specific differentiation in traits such as host egg mimicry. Exploiting a Zambian egg collection amassed over several decades and supplemented by recent fieldwork, we show that the brood parasitic Greater Honeyguide Indicator indicator exhibits host-specific differentiation in both egg size and egg shape. Genetic analysis of honeyguide eggs and chicks show that two highly divergent mitochondrial DNA lineages are associated with ground- and tree-nesting hosts, respectively, indicating perfect fidelity to two mutually exclusive sets of host species for millions of years. Despite their age and apparent adaptive diversification, however, these ancient lineages are not cryptic species; a complete lack of differentiation in nuclear genes shows that mating between individuals reared by different hosts is sufficiently frequent to prevent speciation. These results indicate that host specificity is maternally inherited, that host-specific adaptation among conspecifics can be maintained without reproductive isolation, and that host specificity can be remarkably ancient in evolutionary terms.
Kenji Kono - One of the best experts on this subject based on the ideXlab platform.
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Honeyguide: A VM Migration-Aware Network Topology for Saving Energy Consumption in Data Center Networks
IEICE Transactions on Information and Systems, 2013Co-Authors: Hiroki Shirayanagi, Hiroshi Yamada, Kenji KonoAbstract:Current network elements consume 10-20% of the total power in data centers. Today's network elements are not energy-proportional and consume a constant amount of energy* regardless of the amount of traffic. Thus, turning off unused network switches is the most efficient way of reducing the energy consumption of data center networks. This paper presents Honeyguide, an energy optimizer for data center networks that not only turns off inactive switches but also increases the number of inactive switches for better energy-efficiency. To this end, Honeyguide combines two techniques: 1) virtual machine (VM) and traffic consolidation, and 2) a slight extension to the existing tree-based topologies. Honeyguide has the following advantages. The VM consolidation, which is gracefully combined with traffic consolidation, can handle severe requirements on fault tolerance. It can be introduced into existing data centers without replacing the already-deployed tree-based topologies. Our simulation results demonstrate that Honeyguide can reduce the energy consumption of network elements better than the conventional VM migration schemes, and the savings are up to 7.8% in a fat tree with k = 12.
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ISCC - Honeyguide: A VM migration-aware network topology for saving energy consumption in data center networks
2012 IEEE Symposium on Computers and Communications (ISCC), 2012Co-Authors: Hiroki Shirayanagi, Hiroshi Yamada, Kenji KonoAbstract:Network elements consume 10–20% of the total power in data centers. Today's network elements are not energy-proportional and consume constant energy1 regardless of the traffic amounts. Thus, turning off unused network switches is the most efficient way of saving energy consumption of data center networks. This paper presents Honeyguide, an energy optimizer for data center networks that not only turns off inactive switches but also increases the number of inactive switches for energy-efficiency. To this end, Honeyguide combines two techniques: 1) virtual machine (VM) and traffic consolidation, and 2) a slight extension to existing tree-based topologies. Honeyguide has the following advantages. VM consolidation, which is gracefully combined with traffic consolidation, can handle severe requirements on fault tolerance. It can be introduced into existing data centers without replacing already-deployed tree-based topologies. Our simulation results demonstrate that Honeyguide can save more energy consumption of network elements than conventional VM migration schemes, and the savings are up to 7.8% in a fat tree with k = 12.
Hiroki Shirayanagi - One of the best experts on this subject based on the ideXlab platform.
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Honeyguide: A VM Migration-Aware Network Topology for Saving Energy Consumption in Data Center Networks
IEICE Transactions on Information and Systems, 2013Co-Authors: Hiroki Shirayanagi, Hiroshi Yamada, Kenji KonoAbstract:Current network elements consume 10-20% of the total power in data centers. Today's network elements are not energy-proportional and consume a constant amount of energy* regardless of the amount of traffic. Thus, turning off unused network switches is the most efficient way of reducing the energy consumption of data center networks. This paper presents Honeyguide, an energy optimizer for data center networks that not only turns off inactive switches but also increases the number of inactive switches for better energy-efficiency. To this end, Honeyguide combines two techniques: 1) virtual machine (VM) and traffic consolidation, and 2) a slight extension to the existing tree-based topologies. Honeyguide has the following advantages. The VM consolidation, which is gracefully combined with traffic consolidation, can handle severe requirements on fault tolerance. It can be introduced into existing data centers without replacing the already-deployed tree-based topologies. Our simulation results demonstrate that Honeyguide can reduce the energy consumption of network elements better than the conventional VM migration schemes, and the savings are up to 7.8% in a fat tree with k = 12.
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ISCC - Honeyguide: A VM migration-aware network topology for saving energy consumption in data center networks
2012 IEEE Symposium on Computers and Communications (ISCC), 2012Co-Authors: Hiroki Shirayanagi, Hiroshi Yamada, Kenji KonoAbstract:Network elements consume 10–20% of the total power in data centers. Today's network elements are not energy-proportional and consume constant energy1 regardless of the traffic amounts. Thus, turning off unused network switches is the most efficient way of saving energy consumption of data center networks. This paper presents Honeyguide, an energy optimizer for data center networks that not only turns off inactive switches but also increases the number of inactive switches for energy-efficiency. To this end, Honeyguide combines two techniques: 1) virtual machine (VM) and traffic consolidation, and 2) a slight extension to existing tree-based topologies. Honeyguide has the following advantages. VM consolidation, which is gracefully combined with traffic consolidation, can handle severe requirements on fault tolerance. It can be introduced into existing data centers without replacing already-deployed tree-based topologies. Our simulation results demonstrate that Honeyguide can save more energy consumption of network elements than conventional VM migration schemes, and the savings are up to 7.8% in a fat tree with k = 12.
Skead C J John) - One of the best experts on this subject based on the ideXlab platform.
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Looking up uMthaleni Valley towards Kei Road
1Co-Authors: Skead C J John)Abstract:"Where Lesser, Greater and Scaly-throated Honeyguides had regular call-sites for 20 years and more. 'A' is field workers' camp-site. 'B' was main call-site of Lesser Honeyguide; 'C' was a minor call-site of Lessers; 'D' was the main call-site of Greater Honeyguide. The Scaly-throated's call-site was in the forest valley just off the bottom of the photograph.
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Looking down on the lower reaches of uMthaleni Valley, Kei Road, King William's Town
1Co-Authors: Skead C J John)Abstract:The Scaly-throated Honeyguides call-site was in the dense tall patch in the stream bed
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uMthaleni Valley, Kei Road, King William's Town
1Co-Authors: Skead C J John)Abstract:The open thorn-tree scattered hillside across the bushy valley contain the favourate Acacia karroo tree used successively for many years by Lesser Honeyguides as their call-site
Hiroshi Yamada - One of the best experts on this subject based on the ideXlab platform.
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Honeyguide: A VM Migration-Aware Network Topology for Saving Energy Consumption in Data Center Networks
IEICE Transactions on Information and Systems, 2013Co-Authors: Hiroki Shirayanagi, Hiroshi Yamada, Kenji KonoAbstract:Current network elements consume 10-20% of the total power in data centers. Today's network elements are not energy-proportional and consume a constant amount of energy* regardless of the amount of traffic. Thus, turning off unused network switches is the most efficient way of reducing the energy consumption of data center networks. This paper presents Honeyguide, an energy optimizer for data center networks that not only turns off inactive switches but also increases the number of inactive switches for better energy-efficiency. To this end, Honeyguide combines two techniques: 1) virtual machine (VM) and traffic consolidation, and 2) a slight extension to the existing tree-based topologies. Honeyguide has the following advantages. The VM consolidation, which is gracefully combined with traffic consolidation, can handle severe requirements on fault tolerance. It can be introduced into existing data centers without replacing the already-deployed tree-based topologies. Our simulation results demonstrate that Honeyguide can reduce the energy consumption of network elements better than the conventional VM migration schemes, and the savings are up to 7.8% in a fat tree with k = 12.
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ISCC - Honeyguide: A VM migration-aware network topology for saving energy consumption in data center networks
2012 IEEE Symposium on Computers and Communications (ISCC), 2012Co-Authors: Hiroki Shirayanagi, Hiroshi Yamada, Kenji KonoAbstract:Network elements consume 10–20% of the total power in data centers. Today's network elements are not energy-proportional and consume constant energy1 regardless of the traffic amounts. Thus, turning off unused network switches is the most efficient way of saving energy consumption of data center networks. This paper presents Honeyguide, an energy optimizer for data center networks that not only turns off inactive switches but also increases the number of inactive switches for energy-efficiency. To this end, Honeyguide combines two techniques: 1) virtual machine (VM) and traffic consolidation, and 2) a slight extension to existing tree-based topologies. Honeyguide has the following advantages. VM consolidation, which is gracefully combined with traffic consolidation, can handle severe requirements on fault tolerance. It can be introduced into existing data centers without replacing already-deployed tree-based topologies. Our simulation results demonstrate that Honeyguide can save more energy consumption of network elements than conventional VM migration schemes, and the savings are up to 7.8% in a fat tree with k = 12.