Department of Zoology

Current Biology, 17th November 2009

Are Bigger Brains Better? Lars Chittka and Jeremy Niven

Jeremy Niven and his colleague Lars Chittka from Queen Mary University London question the commonly held assumption that animals with bigger brains are more intelligent. Drawing on research from over the last 20 years they argue that in many ways the behaviour of insects, which possess some of smallest brains of any animal, are as sophisticated as that of animals with much larger brains. They question what the much larger brains of other animals, including our own, are for in an article published in Current Biology on the 17th of November.

“Many insects produce remarkable behaviour that only a few decades ago many scientists thought were beyond them despite having brains no bigger than a pin head.” Niven says. “They do this with small numbers of neurons suggesting that when it comes to brains, size may not be everything.” Niven and Chittka argue that researcher must move away from simply considering brain size and focus instead on circuits. Big brains often contain far greater numbers of neurons than the brains of their smaller counterparts but these extra neurons often only provide finer resolution, higher sensitivity or greater precision: in other words, more of the same. They argue that it’s what neurons do rather than simply the number of them that’s important.

The authors point out that even Darwin was impressed by the brains of tiny insects, in The Descent of Man he writes “…the brain of an ant is one of the most marvellous atoms of matter in the world, perhaps more so than the brain of man.”

Science, 5th June 2009

Social Transmission of a Host Defense Against Cuckoo Parasitism by Nicholas B. Davies, and Justin A. Welbergen

Reed Warblers mobbing fake cuckoo from Cambridge University on Vimeo.

Nick Davies and Justin Welbergen have demonstrated that reed warblers can use social information to fine-tune their defences against brood parasitism from cuckoos. Their previous work showed that reed warblers distinguished cuckoos from other nest enemies and adjusted their defences according to local parasitism risk. New experiments show that inexperienced warblers can learn to defend themselves against cuckoos by observing the mobbing behaviour of their neighbours. This social learning was specific to cuckoos but not to harmless control birds, such as parrots, suggesting that the warblers are primed to learn defensive behaviour but only in response to true threats. Such enemy-specific social transmission of defences provides a mechanism by which hosts can respond rapidly to changes in parasitism, and may influence the coevolutionary trajectories and population dynamics of brood parasites and hosts.

Proceedings of the Royal Society B, May 2009

Prenatal environmental effects match offspring begging to parental provisioning by Camilla A. Hinde, Katherine L. Buchanan, Rebecca M. Kilner

Camilla Hinde, Kate Buchanan and Rebecca Kilner have discovered that canary mothers communicate with their unhatched chicks by using a signal in the egg. The signal tells the developing chick how much food it can expect to receive after hatching and the chick responds by adjusting the development of its begging behaviour. After hatching, chicks that are destined to be born to generous parents beg vigorously for food, while those whose parents are meaner are correspondingly less demanding.

Animal Conservation, March 2009

Rangeland degradation is poised to cause Africa's first recorded avian extinction, by C. N.Spottiswoode, M.Wondafrash, M. N.Gabremichael, Y. Dellelegn Abebe, M. A. K. Mwangi, N. J. Collar & P. M. Dolman

Claire Spottiswoode and her team became interested in the Sidamo lark after a BirdLife International report estimated that only 1600 to 2000 individuals of this little known bird were left on Ethiopia's Liben plain, occupying an area of 760 km2. However, once the team began to map the vegetation and count larks along transects, they quickly discovered that the population is actually much smaller. Changes to traditional ways of life mean that much of the rangeland has disappeared. In areas where the Liben plain has been overgrown by bush, converted into farmland or destroyed by overgrazing, the team rarely found Sidamo larks. They conclude that the range of the bird is now down to only 35 km2 and that the remaining patch hosts 250 adult larks at best. "If the situation does not improve rapidly, this species will be gone in four years or even sooner," says Spottiswoode, who is calling for the bird's status to be moved to critically endangered on the IUCN Red List

Further Coverage: African Lark soon to be extinct, BBC (15.04.09)

Philosophical Transactions of the Royal Society, B - February 2009

Animal Camouflage: Current Issues and New Perspectives

A new issue of Philosophical Transactions of the Royal Society, B has been published on animal camouflage. The issue, guest edited by Martin Stevens and Sami Merilaita, discusses the importance of camouflage in survival, with contributions from zoologists and computer scientists through to art historians.

Current Biology - 29th January 2009

Social Feedback and the Emergence of Leaders and Followers by Jennifer L. Harcourt, Tzo Zen Ang, Gemma Sweetman, Rufus Johnstone and Andrea Manica

Colleagues in the Evolutionary Ecology Group and the Behaviour and Evolution Group showed how leadership in fish arises when pairs respond to each others movements. Individual behavioural differences influenced foraging initiative but shy fish also elicited greater leadership in their bold partners, showing that leadership can be reinforced by positive social feedback.

Further coverage: Hey, Fish, Got My Back?, Science Journal (29.01.09)