The polychaete Streblospio benedicti is unusual in that several field populations consist of individuals that exhibit either planktotrophic or lecithotrophic larval development. Planktotrophy in this species involves production of many small ova that develop into feeding larvae with a two- to three-week planktonic period. Lecithotrophy involves production of fewer, larger ova that develop into nonfeeding larvae that are brooded longer and have a brief planktonic stage. Reciprocal matings were performed to investigate genetic variance components and the correlation structure of life-history traits associated with planktotrophy and lecithotrophy. Our objective was to better understand persistence of this developmental dichotomy in Streblospio benedicti, and among marine invertebrates in general. Substantial additive genetic variation (75-98% of total) was detected for the following characters at first reproduction: female length; position of the first gametogenic setiger and first brood pouch; ovum diameter; three traits related to fecundity (numbers of ova per ovary, larvae per brood pouch, and larvae per brood); median larval planktonic period and the presence of larval swimming setae; but not for total number of brood pouches; larval length; larval feeding; and larval survivorship. Based on the unusual geographic distribution of development modes in this species, we hypothesize that the developmental traits have evolved in allopatry and have only recently come into contact in North Carolina. The high additive contribution to variance observed for many traits may be inflated due to (a) nonrandom breeding in nature, and (b) examination of only one component of an age-structured population at one time. Nuclear interaction variance and maternal variance accounted for 84% of the total variation in larval survivorship. This observation supports other empirical studies and theoretical predictions that nonadditive components of variance will increase in importance in individual traits that are most closely tied to fitness. A network of life-history trait correlations was observed that defines distinct planktotrophic and lecithotrophic trait complexes. Negative genetic correlations were present between fecundity and egg size, between fecundity and position of the first gametes, and between larval survivorship and median planktonic period. Positive genetic correlations were detected between fecundity and female size at first reproduction and between planktonic period and the presence of swimming setae. Intergenerational product-moment correlations were negative for larval length and fecundity, planktonic period and egg size, female size and larval survivorship, and fecundity and larval survivorship. If the genetic correlation structure observed in the laboratory persists in the field, it may constrain responses of individual characters to directional selection, and indirectly perpetuate the dichotomies associated with planktotrophy and lecithotrophy.

Previous studies on the Rice-Millet (foxtail millet and common millet) Blended Zone in Chinese Neolithic have not clearly addressed such questions as the importance of primitive rice-millet mixed agriculture to human lifestyle and livestock managements within this region, the relationship among the development of the agriculture, paleoenvironment, and cultural interactions, and so on. Here stable carbon and nitrogen isotope analysis of human and pig bones from the Qinglongquan site was conducted, covering two cultural phases, namely the Qujialing Culture (3000 BC to 2600 BC) and the Shijiahe Culture (2600 BC to 2200 BC). Based on this analysis, we further discussed the diets of ancient humans and pigs in the site, investigated the importance of rice-millet mixed agriculture to human and pig diets, and explored the relationship among the primitive rice agriculture and millet agriculture, cultural interactions, and paleoenvironment. The δ 13 C values of human bone collagen (−16.7‰ to −12.4‰, averaging −14.6‰ ±1.3‰, n=24) revealed that both C 3 and C 4 foods were consumed, probably from the contribution of rice (C 3 plant) and millets (C 4 plants) due to the coexistence of these crops at this site. In addition, the human mean δ 13 C value suggested that millet agriculture was only minor in human diets. The human δ 15 N values (6.6‰ to 10.8‰, averaging 9.0‰ ±1.2‰, n=24) showed that animal resources played a significant role in human diets, and varied greatly. The mean δ 13 C value of the pigs (−14.3‰ ±2.5‰, n=13) was quite similar to that of the humans, but the mean δ 15 N value of the pigs was slightly less (1.3‰). The similar δ 13 C and δ 15 N values between humans and pigs suggested that the pigs consumed a lot of humans' food remains. No correlations of the δ 13 C and δ 15 N values between humans and pigs showed that both human and pig diets were based mainly on plant foods, which might be related to highly developed rice-millet mixed agriculture at that time. In comparison with the human and pig diets between the two periods, millet agriculture contributed more than 10% in the Shijiahe Culture, if a simple mixing model was used. This apparent dietary shift matched the climatic variation and agricultural development through the time. In warm and humid climate with the expansion of the Qujialing Culture northwards, rice was widely cultivated. However, when the climate was cold and arid, northern culture was expanding southwards. Thus, millet agriculture became more important. paleodiet, the Rice-Millet Blended Zone, stable isotope, cultural interaction, paleoenvironment Citation:Guo Y, Hu Y W, Zhu J Y, et al. Stable carbon and nitrogen isotope evidence of human and pig diets at

Our data suggested grafting AB alone, DBBM/CM, or AB/DBBM/CM resulted in similar periodontal parameters in canine. Furthermore, the AB could accelerate new bone regeneration and mineralization, and promote the biodegradation of DBBM.

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The Qinglongquan site, China, includes materials from the Neolithic Qujialing (3000-2600 BC) and Shijiahe (2600-2200 BC) periods, and lies within the Sui-Zao Corridor that connects the Nanyang Basin in the north and the Hanjiang River Plain in the south. Previous research suggested a dietary shift from rice-based to millet-based agriculture between the Qujialing and Shijiehe periods at this site. The reason for this dietary shift is still unclear, and it is possible because of immigration into the region by people who already had a mainly C 4 -millet-based diet (i.e. from Northern China). In this study, we examine the carbon (δ S results [4.3‰ to 8.8‰, average of 6.6 ± 1.3‰ (n = 31)], no evidence of migration was found for the humans with the different diets at the Qinglongquan site.