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Diverse life histories have been documented in terrestrial pulmonates, which inhabit different regions in climate. Life history traits are often phenotypically plastic and vary depending on the environment. Thus, surveys using designs that control for the confounding effects of environment are needed to evaluate the evolutionary differences between populations of closely related species in the wild. We examined the life histories of sibling species of terrestrial pulmonate within two regions of similar climates. Bradybaena pellucida (BP) is endemic to Japanese islands, and has recently been expanding its distribution northeastward, whereas B. similaris (BS) has been introduced by humans into temperate and tropical regions worldwide. We found that these species exhibit discrete differences in population dynamics and life cycle, despite their close relatedness. The annual life cycle of BP is synchronized among individuals in a population. Thus, BP is univoltine with discontinuous generation. In contrast, BS individuals do not synchronize their growth or reproduction, and thus exhibit overlapping generations. Our results indicate that synchronized and non-synchronized population dynamics diverge relatively rapidly in semelparous pulmonates. This type of difference has not been documented in pulmonate life history, and may have been overlooked because only a few studies have explicitly compared life cycles of closely related species within the same climate. Our results provide a basis for further studies of life history evolution in pulmonates.Key words: life cycle, life history, population dynamics, land snail, Bradybaena, Gastropoda INTRODUCTIONThe life histories of animals and plants can be categorized as iteroparous or semelparous; iteroparity refers to repeated reproduction over separate periods in individual lifetime, whereas semelparity is characterized by death after reproduction in a single period (Roff, 1992;Young, 2010). This way of contrasting different life histories provides useful insights into the evolution of reproductive strategies. Among diverse organisms, however, distinctions between these categories may not necessarily be generally applicable, and remain controversial (Kirkendall and Stenseth, 1985;Hughes and Simons, 2014).In land gastropods including snails and slugs, Heller (2001) reviewed literature of 20 iteroparous and 15 semelparous genera. Since then, probable iteroparity in the genus Helicodonta (Maltz, 2003) and semelparity in Pupilla (Pokryszko, 2001) and Trochulus (Kuznik-Kowalska et al., 2013a) have been reported. Populations of Xerolenta obvia vary from iteroparity to semelparity, perhaps depending on environment (Lazaridou and Chatziioannou, 2005). Even among terrestrial pulmonates, wide ranges of variation have been documented in life span and cycle and other reproductive traits across diverse climatic ranges (Heller, 1990(Heller, , 2001Maltz, 2003;Kramarenko, 2013).To elucidate the processes and mechanisms of ecology and evolution responsible for the diversity of life history, t...

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The rate of whole body protein synthesis in mice was obtained by a newly modified large dose method. A large amount of alanyltyrosine was injected intraperitoneally together with a tracer dose of [14C]tyrosine into mice. The animals were sacrificed at 10, 17, 24 and 31 min after the injection. The specific radioactivity of free tyrosine in the whole body was slightly higher than in the serum at 10 min and then decreased linearly. The two straight lines from the serum and whole body crossed each other at about 20 min after the injection. The specific radioactivity of the bound tyrosine in the whole body homogenate increased linearly from zero. Assuming the specific radioactivity of free tyrosine at the crossover point represents that of the site of protein synthesis, we estimated the fractional rate of whole body protein synthesis in mice receiving diets containing egg white hydrolysate, or an aminoacid mixture simulating egg white protein, by measuring the specific radioactivity of the free and proteinbound tyrosine at 20 min after the injection in another set of experiments. The fractional synthesis rate of whole body protein was 26.5 %per day in the peptide-fed animals, and 19.7 % per day in the amino acid-fed ones. The former value was significantly higher than the latter one.

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