A falsification of the thermal specialization paradigm: compensation to elevated temperatures in Antarctic fish by Dr F Seebacher, Dr B Davison, Ms CJ Lowe and Dr CE Franklin
Antarctic fish, living in water that varies by less than 1oC annually and with a body temperature of -1.9oC, are often regarded as the ultimate thermal specialist. Not surprisingly, past research has shown that rapid increases in water temperature of only a few degrees have a negative impact on the performance and survival of Antarctic fish. Here we show that after being exposed to warmer water for several weeks, Antarctic fish compensate for the initial negative impact of elevated temperatures and regain their original performance levels despite being several degrees warmer. These findings indicate that rising temperatures do not necessarily have a long term negative impact, and that the concept of physiological compensation should be included in prognoses of the impact of global warming on biodiversity.
Contact: Dr Frank Seebacher, School of Biological Sciences, University of Sydney, School of Biological Sciences A08, SYDNEY NSW2006, Australia
Macaques (Macaca nemestrina) recognise when they are being imitated by Miss A Paukner, Dr JR Anderson, Miss E Borelli, Dr E Visalberghi and Dr PF Ferrari
Although imitation remains elusive in monkeys, this experiment found that monkeys recognise when they are being imitated. Ten pigtailed macaques were tested by two experimenters. One experimenter imitated the monkeys' actions with an object, the other performed temporally contingent but structurally different object-directed actions. The results show that the monkeys looked significantly longer at the imitating experimenter. However, unlike humans and apes who also recognise imitation, the monkeys did not 'test' the imitator's contingent movements. This suggests that monkeys might recognise matching motor movements, but they do not understand the intentional aspects of the imitator's behaviour.
Contact: Dr Annika Paukner, Department of Psychology, University of Stirling, STIRLING, FK9 4LA, United Kingdom
Selective foraging of fungi by collembolans in soil by Dr HB Jorgensen, Dr T Johansson, Dr B Canback, Dr K Hedlund and Prof A Tunlid
Soils contain highly diverse communities of microorganisms and invertebrates, though, the knowledge of trophic interactions (whom eats whom) is largely unknown. We have developed a molecular technique, based on the analysis of fungal DNA, to investigate the different fungal species eaten by collembolans (springtails) in soil. We discovered that the diversity of fungal species in soil was 33 times higher that the diversity found in the guts of collembolans. This suggests that collembolans can preferentially select certain taxa of fungi for foraging. Furthermore, the developed method presents new possibilities to analyse trophic interactions between fungi and invertebrates in soil-food webs.
Contact: Dr Helene Bracht Jorgensen, Equipe Bioflux, CNRS-CEFE, 1919 Route de Mende, MONTPELLIER, CEDEX 5, 34293, France
Journal of the Royal Society Interface
Age-Dependent Residual Tensile Strains are Present in the Dura Mater of Rats by Dr JH Henderson, Dr RP Nacamuli, Ms B Zhao, Dr MT Longaker and Dr DR Carter
Young children can heal skull injuries, but older children and adults cannot. Skull healing is dependent on the dura mater, a tissue connected to the inside of the skull. This study used computer modelling and surgical experiments on rat dura mater to investigate the physical state of the dura mater. The study shows that dura mater of young rats, but not mature rats, exists in a state of significant tension – the tissue is literally stretched. The tension may give immature dura mater its ability to heal skull injuries. These findings may lead to strategies for repairing adult skull injuries.
Contact: Dr. JH Henderson, Medicine and Biology, Case Western Reserve University, Millis Science Center, CLEVELAND, OH 44106-7080, USA
Comparative Study of Corneal Strip Extensometry and Inflation Tests by Dr AI Elsheikh and Mr K Anderson
Two experimental methods are currently used to test specimens of human cornea. They involve subjecting strips of corneal tissue to tension until rupture, and applying inflation pressure on whole corneal specimens. While the first test is simple to conduct, it is unreliable because of the original spherical nature of the cornea. A mathematical procedure is developed in this paper to address this source of error, and the results of implementing it have been found close to those produced by the more accurate inflation procedure. This work has the potential of simplifying the tests conducted to determine the mechanical properties of the cornea and to improve understanding of its behaviour.
Contact: Dr AI El-Sheikh, Civil Engineering, University of Dundee, Dundee, DD1 4HN
Proceedings of the Royal Society B: Biological Sciences
Swimming porpoises acoustically inspect areas that lie ahead by Dr TA Akamatsu, Dr DW Wang, Mr KW Wang and Dr YN Naito
Free-ranging finless porpoises scan ahead in advance by using their sonar before swimming silently. The inspection distance reaches several tens of metres, providing a sufficient 'safety margin' for the animal before it has to face real risks or rewards. Once the porpoise detects a potential prey, it keeps focusing its sonar on the target as it approaches. When we are driving a car whilst listening to music, we should check ahead in advance before changing a compact disk, otherwise we can crash easily. Detecting objects in their path is a fundamental perceptional function of moving organisms.
Contact: Dr Tomonari Akamatsu, Fisheries Information Science Division, National Research Institute of Fisheries Engineering, Ebidai, Hasaki, IBARAKI, 314-0421, Japan
Scaling of mammalian ethmoid bones predicts olfactory organ size and performance by Dr H Pihlstrom, Dr M Fortelius, Dr S Hemila, Dr R Forsman and Dr T Reuter
We introduce the concept of an organ of smell consisting of the sensory epithelium in the nose and the olfactory bulb in the brain. We found that the ethmoid bone in the skull is a good measure of the size of this organ, and thus we could estimate olfactory organ size in 150 mammalian species, from mice to elephant. Much is known about the relation between eye size and visual acuity, and between ear size and the frequency range of hearing. It is now possible to investigate the relation between the size of the organ of smell and olfactory performance.
Contact: Dr H Pihlstrom, Dept of Biosciences, University of Helsinki, PO Box 65, FIN-00014, Finland
The geological history of deep-sea colonization by echinoids: roles of surface productivity and deep-water ventilation by Dr AB Smith and Dr B Stockley
Echinoids are a diverse and important component of deep-sea benthic communities in Today's oceans, but when did they first move into this environment? By combining information about their fossil record and using a molecular clock, we are able to demonstrate that there was a short time interval between about 75 and 55 Ma when a large number of lineages specialising in deposit feeding independently migrated off-shelf. This coincides with a marked increase in surface water productivity, and suggests that changes in the availability of food delivered to ocean basins over geological time had a more important role in controlling the colonization of deep-sea environments than deep-water circulation patterns.
Contact: Dr AB Smith, Department of Palaeontology, The Natural History Museum, London SW7 5BD, UK
Density-dependent dispersal and spatial population dynamics by Professor RA Ims and Dr HP Andreassen
How synchronized are population fluctuations across space and which are the causes of such synchrony is considered to be fundamental questions in population biology. The issue of spatial population synchrony has also an applied interest since it affects both the likelihood of extinction of endangered species and our ability to control pest organisms. Dispersal movements have been claimed to be a universal cause of population synchrony. However, our study, which for the first time combines experimental data and mathematical modelling revealed that dispersal could interact with population density in a way that eliminates its synchronising effect.
Contact: Professor RA Ims, Department of Biology, University of Tromso, TROMSO, N-9037, Norway
Limited genetic exchanges between populations of an insect pest living on wild and related cultivated host plants by Mrs A. Vialatte, Dr CA Dedryver, Dr JC Simon, Mrs M Galman and Dr M Plantegenest
We assessed the role of non-crop habitats as reservoirs or refuges for the aphid pest Sitobion avenae that attacks cereals by investigating genetic structure of populations collected on both several cereal crops and uncultivated hosts at the landscape scale. Analyses indicated that genetic differentiation was high between populations on uncultivated hosts and on crops, indicating relatively limited gene flow between these two habitat types. Nevertheless certain uncultivated hosts showed greater exchange of aphid populations with the crops. These could act as reservoir of genetic diversity that could enhance the adaptive potential of S. avenae, in particular in response to the modification of agricultural practices.
Contact: Dr Manuel Plantegenest, Bio3P, INRA, Equipe "Biologie et Génétique des Populations, LE RHEU, 35327, France
Sperm competition and the evolution of male reproductive anatomy in rodents by Mr SA Ramm, Professor GA Parker and Dr P Stockley
Female mammals often mate with multiple males, leading to competition between the ejaculates of rival males over the fertilization of ova. Such sperm competition accounts for many aspects of reproductive morphology and behaviour. Here, a correlation is reported in rodents between the size of the sperm-producing testes and the prevalence of multiple paternity within litters, together with an association between sperm competition intensity and the size of the seminal fluid-producing accessory reproductive organs (seminal vesicles and prostate). These comparative findings thus suggest that sperm competition underlies variation in male reproductive anatomy in this, the largest and most diverse mammalian group.
Contact: Mr SA Ramm, Animal Behaviour Group, Faculty of Veterinary Science, University of Liverpool, Leahurst, NESTON, CH64 7TE
Journal
Proceedings of the Royal Society of London