Sampling termites in forest habitats: A reply to Roisin and Leponce

Abstract To characterize the structure and species density of termite assemblages in tropical forests, we developed a sampling protocol based on a single large quadrat (belt transect) that standardises sampling effort and area. Emphasizing the estimation of species richness, Roisin and Leponce (2004, Austral Ecology, 29 : 637–46) recommend sampling numerous small quadrats, and varying the number of quadrats depending on local species density. However, their method would result in the loss of standardisation and speed, taking up to four times longer to collect and process the samples. We show that even for a subtropical forest with low species density, our protocol produces robust results.     

Mitochondrial phylogeny of Arvicolinae using comprehensive taxonomic sampling yields new insights

Comprehensive taxonomic sampling can vastly improve the accuracy of phylogenetic reconstruction. Here, we present the most inclusive phylogenetic analysis of Arvicolinae (Mammalia, Rodentia) to date, combining all published cytochrome  b gene sequences of greater than 1097 bp and new sequences from two monotypic genera. Overall, the phylogenetic relationships between 69 species of voles and lemmings, representing 18 genera and 10 tribes, were studied. By applying powerful modern approaches to phylogenetic reconstruction, such as maximum likelihood and Bayesian analysis, we provide new information on the early pulse of evolution within the Arvicolinae. While the position of two highly divergent lineages, Phenacomys and Ondatra , could not be resolved, the tribe Lemmini, appeared as the most basal group of voles. The collared lemmings (Dicrostonychini) grouped together with all of the remaining tribes. The two previously unstudied monotypic genera Dinaromys and Prometheomys form a moderately well-supported monophyletic clade, possibly a sister group to Ellobius (Ellobiusini). Furthermore, with one exception, all tribes ( sensu Musser & Carleton, 2005) proved to be monophyletic and can thus be regarded as meaningful evolutionary entities. Only the tribe Arvicolini emerged as paraphyletic in both analyses because of the unresolved phylogenetic position of Arvicola terrestris . Steppe voles of the genus Lagurus were solidly supported as a sister group to the Microtus and allies clade.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 825–835.     

Assessment of long-term changes in habitat availability for Arctic charr (Salvelinus alpinus) in a temperate lake using oxygen profiles and hydroacoustic surveys

1. Hydroacoustics (2002–04) and long‐term oxygen data (1969–2004) have been used in conjunction to examine the habitat of Arctic charr in the north and south basins of Windermere, U.K., a temperate lake subjected to cultural eutrophication and subsequent nutrient management. 2. Since 1969 there has been a gradual decline in the oxygen concentration in the bottom waters of both basins of 0.03–0.04 mg L^?1year^?1, resulting in up to 43% of the volume of the south basin having an oxygen concentration <5 mg L^?1 in the early autumn. 3. Hydroacoustic data indicate that most Arctic charr routinely avoid the upper 10 m of the water column irrespective of temperature, with the implication that an observed gradual warming of the lake has not yet directly impacted upon their habitat. 4. In recent years there has been a behavioural response of the Arctic charr population to migrate vertically to avoid oxygen concentrations <2.3–3.1 mg L^?1. Further, the depth of the lower bound of the Arctic charr population is shown to be highly correlated with the deep water oxygen concentration throughout the year prior to autumnal overturn.     

Correlates of extinction risk of birds from two Indonesian islands

Size of distributional range, position in the range, body size and diet are some of the ecological traits that may correlate with local abundance. Evolutionary phenomena such as taxon cycles, acting over much greater time periods, may also influence abundance and promote species extinction. This paper assesses which of a wide range of ecological and historic traits best predict the variation in abundance of tropical forest birds on Sumba and Buru islands in Wallacea (Indonesia). In addition we seek to determine which traits predict species' ability to adapt to secondary or logged forest. The most important correlates of both abundance and ability to transfer were those related to the evolutionary history of the species within the Wallacean Archipelago and not the traits that were more directly related to species ecology. These relationships are maintained when allowance is made for phylogenetic relationships. Our interpretation of the results is that recent colonists to an island are initially rare in the indigenous forest habitat but concomitant with an adaptation to local conditions they gradually become more abundant and taxonomically distinct from other populations of the same species. These results apparently contradict the taxon cycle hypothesis but this may be a result of our focus on indigenous forest habitats rather than on a wider range dominated by anthropogenic ones.     

High frequency of adventitious shoot regeneration from commercial cultivars of evening primrose (Oenothera spp.) using thidiazuron

Evening primrose (Oenothera spp.) is grown commercially for its seed oil that contains gamma linolenic acid (GLA), a valuable food supplement and pharmaceutical. There is considerable interest in the potential of genetic engineering to improve yields of GLA in evening primrose, and attention has focused on the current state of tissue‐culture knowledge in this species which is a prerequisite for genetic transformation. Published protocols for the regeneration of plants from leaf or cotyledon material of Oenothera spp. are available, but these prove unsatisfactory when applied to commercial cultivars used in this study. An efficient method for regenerating three commercial cultivars of evening primrose Rigel, Merlin and Vulcan was developed using thidiazuron (TDZ) as a growth regulator. Explants from one month old seedlings were cultivated in vitro; a large number of buds were induced directly from strips of leaves, cotyledons and stems when cultured on Murashige and Skoog (MS) basal medium containing TDZ and indole‐butyric acid (IBA). Shoots that were excised and placed onto MS basal medium, supplemented with IBA, rooted with 85–90% efficiency. Plantlets were transferred to soil after 6–8 wk. TDZ stimulated the regeneration process, and its effects were enhanced when combined with IBA or indole‐3‐acetic acid (IAA). The methods developed may be a useful advance toward improvement of this oil seed crop through genetic modification.     

北京房山大足鼠耳蝠食鱼性及回声定位信号

大足鼠耳蝠 (Myotisricketti)具有食鱼蝙蝠的形态特征 ,但食鱼习性待考。以北京房山种群为对象 ,夜间在洞口悬挂雾网 ,捕获取食返洞大足鼠耳蝠共 18只 ,胃检发现 7例全为鱼类 (宽鳍 ,鲫鱼和洛氏 ) ,10例以鱼类为主 ,仅 1例全为昆虫。室内实验观察到捕鱼行为 2 5 6次 ,成功率 12 5 %。如此 ,该种具食鱼习性的猜测得到证实。回声定位信号属调频型 ,扫频范围从 6 7 4 0kHz到 2 3 6 3kHz ,主频 (38 2 1± 1 18)kHz ,声信号时程 (2 5 8± 0 34)ms。这些特征具有一定的物种特异性     

用分子标记研究禾本科赖草属植物可溶性碳水化合物、色素积累和生长特性之间的遗传相关性

在低温条件下,冷季草的可溶性碳水化合物通常与紫色素的积累、生长的缓慢性及对寒冷的适应性具有相关性.Vrn-1基因对一年生冬性禾本科物种的春化、生长和可溶性碳水化合物的积累有重要作用.本研究以Leymus cinereus×L. triticoides的杂种F1开放授粉获得的F2群体为材料,用204个未定位的AFLP分子标记和几个基因组特定的与 vrn-1相连锁的DNA标记检测了控制可溶性碳水化合物的积累、紫色素的积累和生长特性等几个数量性状的QTL.根据生长特性和适应性可将 Leymus cinereus和L. triticoides区分开来.研究表明可溶性碳水化合物与紫色素的积累呈正相关,而且有关基因对这两种性状具有多效性.与之相类似,分蘖、叶发育、叶生长、草被剪后的再生长和地下茎的蔓延性这些性状之间也呈正相关,控制这些性状的基因具有多效性.但是可溶性碳水化合物的积累与生长的缓慢性无相关性.有几个分子标记包括与vrn-Xm1 邻近的一个分子标记对叶可溶性碳水化合物的浓度和低温生长具有正效应.而与vrn-Ns1邻近的一个DNA标记对分蘖具有更加特别的效应.我们推测vrn-1对多年生赖草低温下叶可溶性碳水化合物的积累及生长习性具有数量效应.发现几个DNA标记对可溶性碳水化合物的积累及多个生长特性有较强的作用.研究结果暗示在赖草中紫色素的积累可作为可溶性碳水化合物积累的形态标记.     

Quaternary rainforest refugia in south-east Asia: using termites (Isoptera) as indicators

In south-east Asia, during Quaternary glaciations, increased seasonality and sea level decreases of ~120 m caused considerable fragmentation of the rainforest. It is believed that most of the region's core was covered with savannah vegetation, and rainforest was confined to a few refugia. We investigated the geographical extent of the savannah vegetation and the positions of the refugia, using a combination of palynonlogical, geological, fossil and termite data. Our results show that during the Last Glacial Maximum, most of Thailand, Peninsula Malaysia, western and southern Borneo, eastern and southern Sumatra, and Java were probably covered by savannah. Rainforest refugia were probably present in northern and eastern Borneo, northern and western Sumatra and the Mentawai islands. We also discuss a possible complete history of the region. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 453–466.