A new and potentially more revealing way of studying how animal evolution is affected by the geography of climate has been designed by researchers at The University of Nottingham and Harvard University.
The research, published in the prestigious journal, The American Naturalist, uses a new approach to investigate how animals across (inter-specific) and within (intra-specific) species change in size along temperature gradients, shedding light on a 150-year-old evolutionary puzzle.
Bergmann’s rule — the tendency for warm-blooded animal body size to increase in colder environments — has long been controversial with debate around whether it applies to cold-blooded animals and how the rule applies within or among species.
Now, the team from Nottingham and Harvard has created a unified model to simultaneously study how inter-specific and intra-specific patterns of animal size change through space. The researchers focused on two groups of Anolis lizard, one on Cuba and the other on nearby Hispaniola, the island occupied by Haiti and the Dominican Republic. They found that the size of lizards decreases with elevation on both islands, but their model revealed that different ecological and evolutionary processes are responsible on each island.
Re-examining Bergmann's rule
Dr Adam Algar, from The University of Nottingham’s School of Geography, said: “Our new approach allows for the separation of intra- and inter-specific components of the relationships between animal traits and the environment. We found that the similar body size gradients in the lizards on both islands are constructed in very different ways. Even though lizards are smaller at high elevations on both islands, these body size patterns are underlain by very different processes. On Hispaniola, interspecific processes dominate, while on Cuba, intraspecific processes drive the pattern.”
Martha Muñoz from Harvard University’s Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, said: “Our results suggest that restricting analyses to either the intra-specific or inter-specific levels can miss important patterns. Both must be considered. We believe our approach can help integrate a divided research programme by focusing on how the combined effects of intra- and inter-specific processes can enhance or erode trait-environment relationships at large bio-geographic scales”.
The researchers think the different geographies of Cuba and its neighbour Hispaniola may account for some of the varying patterns observed on each island. Hispaniola’s highland areas and their associated climatic gradients are far more extensive than on Cuba. Hispaniola has nearly 8,000 km² of habitat above 1,000m whereas Cuba has only 271 km² of highland habitat.
The greater extent of climatically extreme habitats suggests a greater potential for reduced dispersal of lizards and isolation by environment along tropical elevational gradients in Hispaniola. Conversely, climatically extreme habitat is more rare on Cuba so higher gene flow across elevations may limit the role of interspecific processes on this island.
The full paper, 'Untangling intra- and interspecific effects on body size clines reveals divergent processes structuring convergent patterns in Anolis lizards', is available here.
Emma Rayner | Eurek Alert!
Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz
Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences