scholarly journals Variation and mechanisms of life history evolution in insular dwarfism as revealed by a natural experiment

2020 ◽  
Author(s):  
Shoji Hayashi ◽  
Mugino O. Kubo ◽  
Marcelo R. Sánchez-Villagra ◽  
Hiroyuki Taruno ◽  
Masako Izawa ◽  
...  

AbstractIslands offer a classic topic for evolutionary studies. Few other subjects have historically raised as much fascination as the island large mammals that having evolved into dwarfs. Consensus has been gained that multivariate ecological causes are behind those changes, but what remains largely unexplored are the mechanisms behind them: how life history (age of reproduction, growth rate, longevity) change with insular dwarfism. Previous studies produced contrasting results difficult to compare, as they concerned different species in single islands. The Japanese Archipelago offers worldwide a unique natural experiment, as in its numerous islands of different sizes the same group of organisms, deer, have evolved into different sizes. Using an extensive examination of bone microstructure, statistical modelling of growth rate and demography, we demonstrate different degrees of change in life history in different islands. We discovered how different life parameters amount to a new, K-strategy contrasting to that of the parent population.

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1358 ◽  
Author(s):  
Christian Kolb ◽  
Torsten M. Scheyer ◽  
Kristof Veitschegger ◽  
Analia M. Forasiepi ◽  
Eli Amson ◽  
...  

The interest in mammalian palaeohistology has increased dramatically in the last two decades. Starting in 1849 via descriptive approaches, it has been demonstrated that bone tissue and vascularisation types correlate with several biological variables such as ontogenetic stage, growth rate, and ecology. Mammalian bone displays a large variety of bone tissues and vascularisation patterns reaching from lamellar or parallel-fibred to fibrolamellar or woven-fibred bone, depending on taxon and individual age. Here we systematically review the knowledge and methods on cynodont and mammalian bone microstructure as well as palaeohistology and discuss potential future research fields and techniques. We present new data on the bone microstructure of two extant marsupial species and of several extinct continental and island placental mammals. Extant marsupials display mainly parallel-fibred primary bone with radial and oblique but mainly longitudinal vascular canals. Three juvenile specimens of the dwarf island hippopotamidHippopotamus minorfrom the Late Pleistocene of Cyprus show reticular to plexiform fibrolamellar bone. The island muridMikrotia magnafrom the Late Miocene of Gargano, Italy displays parallel-fibred primary bone with reticular vascularisation and strong remodelling in the middle part of the cortex.Leithiasp., the dormouse from the Pleistocene of Sicily, is characterised by a primary bone cortex consisting of lamellar bone and a high amount of compact coarse cancellous bone. The bone cortex of the fossil continental lagomorphProlagus oeningensisand three fossil species of insularProlagusdisplays mainly parallel-fibred primary bone and reticular, radial as well as longitudinal vascularisation. Typical for large mammals, secondary bone in the giant rhinocerotoidParaceratheriumsp. from the Late Oligocene of Turkey is represented by dense Haversian bone. The skeletochronological features ofSinomegaceros yabei, a large-sized deer from the Pleistocene of Japan closely related toMegaloceros, indicate a high growth rate. These examples and the synthesis of existing data show the potential of bone microstructure to reveal essential information on life history evolution. The bone tissue and the skeletochronological data of the sampled island species suggest the presence of various modes of bone histological modification and mammalian life history evolution on islands to depend on factors of island evolution such as island size, distance from mainland, climate, phylogeny, and time of evolution.


Author(s):  
Christian Kolb ◽  
Torsten M. Scheyer ◽  
Kristof Veitschegger ◽  
Analia M. Forasiepi ◽  
Eli Amson ◽  
...  

The interest in mammalian palaeohistology has increased dramatically in the last two decades. Starting in 1849 via descriptive approaches, it has been demonstrated that bone tissue and vascularisation types correlate with several biological variables such as ontogenetic stage, growth rate, and ecology. Mammalian bone displays a large variety of bone tissues and vascularisation patterns reaching from lamellar or parallel-fibred to fibrolamellar or woven-fibred bone, depending on taxon and individual age. Here we systematically review the knowledge and methods on mammalian bone and palaeohistology and discuss potential future research fields and techniques. We present new data on the bone microstructure of two extant marsupial species and of several extinct continental and island placental mammals. Three juvenile specimens of the dwarf island hippopotamid Hippopotamus minor from the Late Pleistocene of Cyprus show reticular to plexiform fibrolamellar bone. The island murid Mikrotia magna from the Late Miocene of Gargano, Italy displays parallel-fibred primary bone with reticular vascularisation being pervaded by irregular secondary osteons in the central part of the cortex. Leithia sp., the dormouse from the Pleistocene of Sicily, is characterised by a primary bone cortex consisting of lamellar bone and low vascularisation. The bone cortex of the fossil continental lagomorph Prolagus oeningensis and three fossil species of insular Prolagus displays parallel-fibred primary bone and reticular, radial as well as longitudinal vascularisation. Typical for large mammals, secondary bone in the giant rhinocerotoid Paraceratherium sp. from the Miocene of Turkey is represented by dense Haversian bone. The skeletochronological features of Sinomegaceros yabei, a large-sized deer from the Pleistocene of Japan closely related to Megaloceros, indicate a high growth rate. These examples and the critical summary of existing data show how bone microstructure can reveal essential information on life history evolution. The bone tissue and the skeletochronological data of the sampled island species show that there is no universal modification of bone tissue and life history specific to insular species.


2005 ◽  
Vol 272 (1564) ◽  
pp. 769-773 ◽  
Author(s):  
Valentina Ferretti ◽  
Paulo E Llambías ◽  
Thomas E Martin

Since David Lack first proposed that birds rear as many young as they can nourish, food limitation has been accepted as the primary explanation for variation in clutch size and other life‐history traits in birds. The importance of food limitation in life-history variation, however, was recently questioned on theoretical grounds. Here, we show that clutch size differences between two populations of a neotropical thrush were contrary to expectations under Lack's food limitation hypothesis. Larger clutch sizes were found in a population with higher nestling starvation rate (i.e. greater food limitation). We experimentally equalized clutches between populations to verify this difference in food limitation. Our experiment confirmed greater food limitation in the population with larger mean clutch size. In addition, incubation bout length and nestling growth rate were also contrary to predictions of food limitation theory. Our results demonstrate the inability of food limitation to explain differences in several life-history traits: clutch size, incubation behaviour, parental feeding rate and nestling growth rate. These life-history traits were better explained by inter‐population differences in nest predation rates. Food limitation may be less important to life history evolution in birds than suggested by traditional theory.


2015 ◽  
Author(s):  
Christian Kolb ◽  
Torsten M. Scheyer ◽  
Kristof Veitschegger ◽  
Analia M. Forasiepi ◽  
Eli Amson ◽  
...  

The interest in mammalian palaeohistology has increased dramatically in the last two decades. Starting in 1849 via descriptive approaches, it has been demonstrated that bone tissue and vascularisation types correlate with several biological variables such as ontogenetic stage, growth rate, and ecology. Mammalian bone displays a large variety of bone tissues and vascularisation patterns reaching from lamellar or parallel-fibred to fibrolamellar or woven-fibred bone, depending on taxon and individual age. Here we systematically review the knowledge and methods on mammalian bone and palaeohistology and discuss potential future research fields and techniques. We present new data on the bone microstructure of two extant marsupial species and of several extinct continental and island placental mammals. Three juvenile specimens of the dwarf island hippopotamid Hippopotamus minor from the Late Pleistocene of Cyprus show reticular to plexiform fibrolamellar bone. The island murid Mikrotia magna from the Late Miocene of Gargano, Italy displays parallel-fibred primary bone with reticular vascularisation being pervaded by irregular secondary osteons in the central part of the cortex. Leithia sp., the dormouse from the Pleistocene of Sicily, is characterised by a primary bone cortex consisting of lamellar bone and low vascularisation. The bone cortex of the fossil continental lagomorph Prolagus oeningensis and three fossil species of insular Prolagus displays parallel-fibred primary bone and reticular, radial as well as longitudinal vascularisation. Typical for large mammals, secondary bone in the giant rhinocerotoid Paraceratherium sp. from the Miocene of Turkey is represented by dense Haversian bone. The skeletochronological features of Sinomegaceros yabei, a large-sized deer from the Pleistocene of Japan closely related to Megaloceros, indicate a high growth rate. These examples and the critical summary of existing data show how bone microstructure can reveal essential information on life history evolution. The bone tissue and the skeletochronological data of the sampled island species show that there is no universal modification of bone tissue and life history specific to insular species.


Impact ◽  
2020 ◽  
Vol 2020 (7) ◽  
pp. 56-58
Author(s):  
Naruya Saitou

The ebb and flow of human migration across the planet can nowadays be probed with advanced archaeology, linguistics, anthropology and genomics. Together, these can provide a convincing picture of the various divergences and convergences of different human populations across vast areas. It is now possible to better understand how, why and where a particular group or society arose. Professor Naruya Saitou of the Population Genetics Laboratory at the National Institute of Genetics in Mishima has dedicated his career to the synthesis of these disciplines. The current focus of his research is on understanding the origins and formation of the Yaponesian people. This broad term was coined by writer Toshio Shimao in 1960s to encompass the diverse peoples of the Japanese Archipelago over its many thousands of years of inhabitation. Saitou's research is helping to uncover Japan's ancient past.


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