Worker size and seed size selection by harvester ants in a neotropical forest

Oecologia ◽  
1996 ◽  
Vol 105 (3) ◽  
pp. 397-404 ◽  
Author(s):  
M. Kaspari
Primates ◽  
2008 ◽  
Vol 49 (4) ◽  
pp. 239-245 ◽  
Author(s):  
Britta Kerstin Kunz ◽  
Karl Eduard Linsenmair

2017 ◽  
Vol 190 (3) ◽  
pp. 430-441 ◽  
Author(s):  
Qiaoqiao Huang ◽  
Martin Burd ◽  
Zhiwei Fan

1999 ◽  
Vol 26 (1) ◽  
pp. 53-56 ◽  
Author(s):  
W. D. Branch ◽  
A. K. Culbreath

Abstract The major peanut (Arachis hypogaea L.) producing regions in the U.S. are currently faced with an increasing tomato spotted wilt tospovirus (TSWV) problem, and the most effective control is the use of resistant cultivars. This study was conducted to compare the field performance and TSWV disease intensity among different seed sizes of two runner-type cultivars. For three consecutive years, 1995–97, the effect of continuous seed size selection on yield, grade, and TSWV intensity among the two runner cultivars Georgia Green and Florunner was evaluated at the Univ. of Georgia Coastal Plain Exp. Sta. Sound mature kernels from both cultivars were divided into four seed sizes (jumbo, medium, No. 1, and the combined mill run check). Seed size selection pressure was applied to both cultivars each year. Seed stock for planting each year was obtained from the corresponding seed size produced the previous year. The results showed that the Georgia Green cultivar significantly out-performed the Florunner cultivar in yield, grade, dollar value, and had significantly less TSWV. Georgia Green had a similar percentage of jumbo seed, more medium seed, and fewer No. 1 seed than Florunner. Both runner-type cultivars responded similarly to continuous selection pressure with small but significant changes in seed size distribution over a relatively short 3-yr period.


2006 ◽  
Vol 22 (6) ◽  
pp. 685-693 ◽  
Author(s):  
Martin Pfeiffer ◽  
Jamili Nais ◽  
K. Eduard Linsenmair

‘Size matching’ of forager size and prey size is an ecological mechanism that should partition diets both within ant colonies and ensembles. We studied the relationship between ant body size and food size in tropical leaf-litter ant ensembles at different levels. In three plots of primary rain forest in Sabah, Malaysia, we observed altogether 50 species of 18 genera of ants (e.g. Pheidole, Recurvidris, Lophomyrmex, Paratrechina, Odontoponera) that harvested seed particles from baits of milled rice of various particle size. At colony level ‘size matching’ of individual foragers with their load was found only in one of 12 tested species, viz. Pheidole lucioccipitalis. However, ant species differed considerably with respect to ‘seed’ size used: on average, foragers of larger species transported significantly larger ‘seed’ fragments. This was highly significant in a subset of ant species with at least 12 records of size choice per species. But when we investigated resource partitioning within each of the three ant ensembles with a null model, analysis proved that there was a significant overlap in seed size selection of species at two of the sites, thus indicating that food size choice of foragers had little influence on niche patterns and community structure of ants. Ant species with workers that were not matched with their seed resources (viz. Oligomyrmex or Pheidologeton) engaged in cooperative ‘seed’ transport, mass recruitment to and in situ mastication of rice fragments. Mean ‘seed’ transport distance was 38.4 cm.


Author(s):  
Е. Шукис ◽  
С. Шукис

Просо посевное — одна из ценных продовольственных и кормовых культур. Его активное внедрение невозможно без научного сопровождения в области селекции. Особый интерес вызывают отборы по крупности семян, что существенно влияет на продуктивность. С целью выяснения результативности отбора крупнозёрных форм на ранних этапах селекционного процесса были заложены специальные опыты. В результате исследований выявлено, что в гибридных популяциях третьего поколения (F3) продолжалось расщепление по массе 1000 зёрен. У отдельных популяций этот признак по величине превосходил родительские формы. То же самое наблюдалось при анализе таких элементов структуры урожая, как размеры и озернённость метёлки, а также масса зерна. В первом поколении эти показатели, благодаря реализации эффекта гетерозиса, имели более высокие значения, во втором и в меньшей степени — в третьем поколении показатели продуктивности несколько снижались, и значительно возрастало разнообразие гибридов. В качестве объектов изучения использовались три гибридных популяции: Саратовское 10 × Барнаульское 80М, Саратовское 10 × Тувинское и Барнаульское 98П × Кр.з.кф. Разделение семян по фракциям на крупную и мелкую осуществляли с помощью продолговатых сит размером 1,5–1,7 мм, при этом соотношение фракций составляло 50:50 %, а масса 1000 семян у крупной фракции — от 7,1 до 7,9 г, у мелкой — от 6,3 до 6,9 г. В последующих поколениях проводили отборы линий, их оценку и браковку. После достижения относительной константности выделившиеся линии подлежали испытанию. В ходе исследований выявлено, что выделение крупной фракции в F3 позволяло сконцентрировать в гибридной популяции ценные генотипы и тем самым повысить эффективность отборов. Лучшей гибридной комбинацией при реализации селекционной программы оказалась комбинация Саратовское 10 × Барнаульское 80М. В её крупной фракции были выделены перспективные линии, сочетающие высокую продуктивность с крупнозёрностью, устойчивостью к пыльной головне и хорошим качеством крупы. Wide cultivation of common millet — valuable food and fodder crop —requires preliminary breeding data. Seed size selection is of great interest, since it is closely connected to productivity. The investigation evaluated the selection effectiveness of large-kernel genotypes at the early breeding time. Hybrid F3 populations showed segregation of 1000 kernel weight. Some populations exceeded their parental lines in this trait as well as in grain size, weight and content in crop head. F1 population gave higher trait values due to heterosis. F2 and F3 populations showed slight reduction in those values, and hybrid diversity significantly grew. Three hybrid populations were studied: “Saratovskoe 10” × “Barnaulskoe 80M”, “Saratovskoe 10” × “Tuvinskoe” and “Barnaulskoe 98P” × “Kr.z.kf.”. Seed fractionation into large and small seeds resulted in fraction ratio of 50:50 %. 1000 kernel weight of large grain varied from 7.1 to 7.9 g, the small one — from 6.3 to 6.9 g. Relatively stable lines of further generations were selected and tested. Large grains, chosen in F3 gave valuable hybrid genotypes, improving selection efficacy. The best hybrid combination was “Saratovskoe 10” × “Barnaulskoe 80M”. It produced promising lines, having high productivity, large kernels, resistance to kernel smut and good grain quality.


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