Laboratory studies on the larval food habits of the ground beetle Amara (Curtonotus) gigantea (Motschulsky) (Coleoptera: Carabidae: Zabrini)

Ground beetles (Coleoptera: Carabidae) are important components of soil ecosystems in temperate zones, but our knowledge regarding the ecology of many species is limited. This study examined larval food habits in the ground beetle Amara (Curtonotus) gigantea (Motschulsky) using laboratory‐rearing experiments. Because this beetle is a member of the tribe Zabrini, which includes several species that exhibit granivory during larval and/or adult stages, three diet types were tested, with starvation as a control: Tenebrio larvae, mixed seeds (Bidens pilosa (Asteraceae), Setaria spp., Digitaria ciliaris (both Poaceae), and Humulus scandens (Moraceae)), and Tenebrio larvae + mixed seeds. Because of high larval mortality during overwintering under laboratory‐rearing conditions, survival and the duration of development through pre‐overwintering stages (first and second instars) were compared. Larvae fed the diet of Tenebrio larvae + mixed seeds showed the highest survival (89%), followed by the diet of Tenebrio larvae (83%), but the difference between the two treatments was not significant; similarly, developmental durations did not differ between these two diets. Larvae fed the mixed‐seeds diet showed markedly lower survival, and no larvae reached the second instar. Therefore, for A. gigantea larvae, animal food results in high larval performance, whereas seeds provide a low value diet; animal food is essential for larval development, but seeds provide no benefit, even as a dietary supplement. Overall, the present results suggest that A. gigantea larvae are omnivorous but with a mainly carnivorous food habit.     

Preliminary results of a fertilization-irrigation experiment in a Quercus ilex L. forest in relation to leaves and twigs characteristics

A multifactorial ANOVA experiment was designed for a Quercus ilex forest in the Prades mountains in Tarragona (NE Spain). The purpose of this study was to clarify the relative importance of water, nitrogen and phosphorus as factors controlling primary production.Eight plots comprising all possible combinations of the three factors (including a control) were laid out in three replicate blocks. Fertilizers were applied to the appropriate treatments in March 1989 with a dosage of 125 kg of P/ha and 250 kg N/ha. Irrigation was applied with a rate of 20 mm per week during the warm season.To evaluate the effects on canopy structure we measured specific leaf weight (mg/cm²), average leaf weight (mg), average twig height and average twig length. These variables were selected as they are the most likely to manifest changes over short time periods following changes in environmental conditions.The values of these parameters before initial treatments (autumn 1988) and after treatments (summer 1990) were analyzed. The results obtained show that water and nitrogen have a greater effect than phosphorus on tree canopy structure, at least during initial development.     

A comparison of zygote survival of native and non-native walleye stocks in two Georgian Bay rivers

Synopsis Poor natural recruitment of a Georgian Bay walleye stock that spawns in the Shawanaga River has been attributed to poor survivorship of early life stages. I investigated whether low zygote survival was part of the problem by conducting an in-situ incubation experiment with artificially fertilized eggs from the Shawanaga and the nearby Magnetawan River stocks. Both rivers have low buffering capacity (5–6.5 mg·l^–1 alkalinity), but moderately low pH (5.5) had only been recorded in the Shawanaga. Zygotes were reared in both rivers. Minimum pH during incubation was 6.2 in the Shawanaga and 6.8 in the Magnetawan River. Mean survival rate to hatching strongly favoured the native stock in both rivers (86 vs. 25 % in the Shawanaga River and 80 vs. 40% in the Magnetawan River), and these differences were statistically significant. The results suggest that viability of Shawanaga zygotes is not a problem, but a low pH effect on zygote survival could not be inferred from the relatively high pH of Shawanaga water in the spring of 1990. The large difference in hatching success between native and non-native stocks was unexpected, and may have been the result of stock-specific adaptation to differing cation: anion and/or metal concentrations in the two rivers, or to some other factor.     

Competitive effects of Rattus lutreolus presence on food resource use by Pseudomys gracilicaudatus

Abstract We examined faecal samples of the eastern chestnut mouse (Pseudomys gracilicaudatus) that were collected during a removal experiment conducted in a coastal heathland at Myall Lakes National Park to see whether removal of the swamp rat (Rattus lutreolus) had any effects on food resource use by P. gracilicaudatus. The results showed that, at the young successional stage of vegetation (1. 5 years since last fire), the diet of P. gracilicaudatus changed significantly after the number of R. lutreolus was significantly reduced on the experimental sites. Two months after the removal treatment was terminated there were no significant differences between the control and experimental sites. Factor analysis showed that seasonal change was significant for all three food factors on the control sites, whereas on experimental sites the change was significant only for factor 1. At the middle successional stage (3.5 years since last fire), P. gracilicaudatus showed relatively small seasonal changes on both control and experimental sites, and significant differences between the control and experimental sites did not occur until after the removal manipulation was completed, showing a delayed response. Comparisons of the young and the middle successional stages on both control and experimental sites showed that P. gracilicaudatus used proportionally different food when R. lutreolus was present, but consumed similar food when R. lutreolus was removed. These results suggest that R. lutreolus might have restricted the access of P. gracilicaudatus to better microhabitats, and hence to a better food supply. The ecological implication of these results is that the interpretation of observed population and community patterns must take into account the direct effects of species interactions.     

Intimate Territories and the Experimental Subject in Ladakh,India

Abstract

This paper explores the management of reproduction and sexuality as experimental political practice. In Leh District of India's Jammu and Kashmir State, vote bloc politics and a tenuous geopolitical context highlight the reproductive body's potential to maintain political and territorial control through demographic trends. Conflict between the Buddhist majority and Muslim minority is articulated partly through the regulation of fertility and sexuality. Population is described as a zero-sum game in which each side acquires or cedes territory; activists and religious leaders experiment with the body as a territorial tool. These projects collide with the hopes and fears of women and men considering love, marriage, pregnancy, and contraceptive use. This paper draws on research conducted in 2004 and 2007–2009 to explore how women's desiring and reproductive bodies are folded into geopolitical experiments, how women cope under this experimental regime, and the ways that they turn to a tactic of ‘not knowing.’     

基于能力培养的分子生物学实验教学改革与探索

分子生物学技术已成为生命科学领域普遍运用的方法和手段,分子生物学实验课是一门让学生理解、掌握分子生物学技术的课程。系统总结了近年来我们以学生的能力培养为宗旨,在分子生物学实验教学中进行的建立“3＋1”的新课程体系、更新教学内容、尝试新的教学方法和手段、改革考核方式等探索,并就下一步改革进行了展望。