Field margins, foraging distances and their impacts on nesting pollinator success

The areas of wild land around the edges of agricultural fields are a vital resource for many species. These include insect pollinators, to whom field margins provide both nest sites and important resources (especially when adjacent crops are not in flower). Nesting pollinators travel relatively short distances from the nest to forage: most species of bee are known to travel less than two kilometres away. In order to ensure that these pollinators have sufficient areas of wild land within reach of their nests, agricultural landscapes need to be designed to accommodate the limited travelling distances of nesting pollinators. We used a spatially-explicit modelling approach to consider whether increasing the width of wild strips of land within the agricultural landscape will enhance the amount of wild resources available to a nesting pollinator, and if it would impact differently on pollinators with differing foraging strategies. This was done both by creating field structures with a randomised geography, and by using landscape data based upon the British agricultural landscape. These models demonstrate that enhancing field margins should lead to an increase in the availability of forage to pollinators that nest within the landscape. With the exception of species that only forage within a very short range of their nest (less than 125 m), a given amount of field margin manipulation should enhance the proportion of land available to a pollinator for foraging regardless of the distance over which it normally travels to find food. A fixed amount of field edge manipulation should therefore be equally beneficial for both longer-distance nesting foragers such as honeybees, and short-distance foragers such as solitary bees.     

Simultaneous character convergence and divergence in Western Australian land snails

Three distantly related genera of land snails, Amplirhagada Iredale, 1933, Quistrachia Iredale, 1939, and Westraltrachia Iredale, 1933, overlap in distributions only in the Napier and Oscar Ranges, east of Derby, Western Australia. The first two remain allopatric, Quistrachia having a more eastern range, while Westraltrachia overlaps both ranges. In the zone of sympatry, with changes proceeding from east to west, Westraltrachia diverges in feeding, and there is massive, gradual convergence in shell size, shape and colour between Amplirhagada and Westraltrachia. Shells of both genera depart markedly from their distinctive allopatric appearances to form a new morphotype in the north-west Napier Ranges. The species there are so similar in appearance that the two genera cannot be identified at a distance of 0.5 m. Thirteen species-level taxa are involved in these changes, four allopatric Amplirhagada , seven allopatric Westraltrachia, Quistrachia monogramma and Rhagada basedowana.
Westraltrachia species, the only large land snails in their main area of distribution (south-east Kimberlcy), are pre-adapted to graze on an occasionally present food resource, algal-fungal blooms on limestone seepage faces. They entered the Oscar and Napier Ranges, where this food resource is more abundant, and large land snails that are generalized feeders, Amplirhagada or Quistrachia , were already present and abundant. Hence feeding divergence occurred. Such specialization by Westraltrachia to minimize competition is readily understandable.
The selective pressures that led to the striking convergence in shell features in north-west Napier taxa are unknown.     

DNA barcodes as a tool in biodiversity research: testing pre-existing taxonomic hypotheses in Delphic Apollo butterflies (Lepidoptera,Papilionidae)

Numerous studies have demonstrated that DNA barcoding is an effective tool for detecting DNA clusters, which can be viewed as operational taxonomic units (OTUs), useful for biodiversity research. Frequently, the OTUs in these studies remained unnamed, not connected with pre-existing taxonomic hypotheses, and thus did not really contribute to feasible estimation of species number and adjustment of species boundaries. For the majority of organisms, taxonomy is very complicated with numerous, often contradictory interpretations of the same characters, which may result in several competing checklists using different specific and subspecific names to describe the same sets of populations. The highly species-rich genus Parnassius (Lepidoptera: Papilionidae) is but one example, such as several mutually exclusive taxonomic systems have been suggested to describe the phenotypic diversity found among its populations. Here we provide an explicit flow chart describing how the DNA barcodes can be combined with the existing knowledge of morphology-based taxonomy and geography (sympatry versus allopatry) of the studied populations in order to support, reject or modify the pre-existing taxonomic hypotheses. We then apply this flow chart to reorganize the taxa within the Parnassius delphius species group, solving long-standing taxonomic problems.     

The ecology,distribution, conservation and management of large old trees

Large old trees are some of the most iconic biota on earth and are integral parts of many terrestrial ecosystems including those in tropical, temperate and boreal forests, deserts, savannas, agro‐ecological areas, and urban environments. In this review, we provide new insights into the ecology, function, evolution and management of large old trees through broad cross‐disciplinary perspectives from literatures in plant physiology, growth and development, evolution, habitat value for fauna and flora, and conservation management. Our review reveals that the diameter, height and longevity of large old trees varies greatly on an inter‐specific basis, thereby creating serious challenges in defining large old trees and demanding an ecosystem‐ and species‐specific definition that will only rarely be readily transferable to other species or ecosystems. Such variation is also manifested by marked inter‐specific differences in the key attributes of large old trees (beyond diameter and height) such as the extent of buttressing, canopy architecture, the extent of bark micro‐environments and the prevalence of cavities. We found that large old trees play an extraordinary range of critical ecological roles including in hydrological regimes, nutrient cycles and numerous ecosystem processes. Large old trees strongly influence the spatial and temporal distribution and abundance of individuals of the same species and populations of numerous other plant and animal species. We suggest many key characteristics of large old trees such as extreme height, prolonged lifespans, and the presence of cavities – which confer competitive and evolutionary advantages in undisturbed environments – can render such trees highly susceptible to a range of human influences. Large old trees are vulnerable to threats ranging from droughts, fire, pests and pathogens, to logging, land clearing, landscape fragmentation and climate change. Tackling such diverse threats is challenging because they often interact and manifest in different ways in different ecosystems, demanding targeted species‐ or ecosystem‐specific responses. We argue that novel management actions will often be required to protect existing large old trees and ensure the recruitment of new cohorts of such trees. For example, fine‐scale tree‐level conservation such as buffering individual stems will be required in many environments such as in agricultural areas and urban environments. Landscape‐level approaches like protecting places where large old trees are most likely to occur will be needed. However, this brings challenges associated with likely changes in tree distributions associated with climate change, because long‐lived trees may presently exist in places unsuitable for the development of new cohorts of the same species. Appropriate future environmental domains for a species could exist in new locations where it has never previously occurred. The future distribution and persistence of large old trees may require controversial responses including assisted migration via seed or seedling establishment in new locales. However, the effectiveness of such approaches may be limited where key ecological features of large old trees (such as cavity presence) depend on other species such as termites, fungi and bacteria. Unless other species with similar ecological roles are present to fulfil these functions, these taxa might need to be moved concurrently with the target tree species.     

What shapes cerambycid beetle communities in a tropical forest mosaic? Assessing the effects of host tree identity,forest structure,and vertical stratification

Due to anthropogenic activities, tropical rain forests face many challenges in sustaining biodiversity and maintaining global climates. This study explores how forest successional stage, tree composition, and stratum affect communities of saproxylic cerambycid beetles—concealed feeders that play important roles in forest nutrient cycling. Forty trees in five families (Fabaceae, Lecythidaceae, Malvaceae, Moraceae, and Sapotaceae) were sampled in a mosaic of old‐growth and secondary forest on the Osa Peninsula, Costa Rica. Bait branches yielded 3549 cerambycid individuals in 49 species. Species richness was almost identical in old‐growth and secondary forest, and both yielded specialists, but abundance was higher in old‐growth forest. Overall community structure was most strongly influenced by host plant species; within most plant families it was also impacted by forest successional status. Moraceae was the exception, presumably because the focal tree species was abundant in both old‐growth and secondary forest. Several host and old‐growth specialist species reached high densities within patches of old‐growth forest, but seldom colonized apparently suitable trees within secondary forest. This suggests that even small areas of old‐growth forest can act as refuges, but that secondary forest may act as a barrier to dispersal. The vulnerability of specialized saproxylic insects to land use change will be linked to the ability of their preferred hosts to disperse to and persist in successional habitats; rearing studies may provide the most accurate method to monitor community changes over time.     

Agricultural land-use and the spatial distribution of granivorous lowland farmland birds

Current agricultural practices are believed to have contributed to the declines of many farmland bird species, especially seed‐eaters, throughout Europe. We investigated associations between the spatial distribution of fourteen granivorous farmland bird species and agricultural land‐use in Britain, using breeding bird atlas data and national agricultural statistics. Analyses were spatially referenced by 10x10 km square and variation due to broad‐scale geography and spatial auto‐correlation was controlled for. Generalized linear modelling analyses were used to select models describing variation in distribution explained by the available land‐use variables. The results show that relationships between distribution and agriculture tend to be species‐specific, but that some general effects can be identified. Features of intensive arable farming including large areas of sugar beet, wheat and oilseed rape tended to be associated with low frequencies of occurrence for 9–11 species, while large areas of younger (re‐seeded) grassland and high sheep stocking densities were associated with low frequencies in pastoral farmland for up to 12 species. One key feature of lower intensity farming, the presence of larger areas of fallow land, was positively related to frequency index for up to 11 species. The proportion of barley sown in spring and agricultural diversity were each associated with a range of complex relationships with frequency index across species, probably reflecting combinations of positive influences and artefacts of scale and geography. A variable describing the heterogeneity of farmland (the extent to which it is a mix of arable and pastoral land‐use) was negatively related to frequency index for eight species, but other results suggested that farming which is mixed at a smaller spatial scale is widely beneficial. The results reveal relationships between agriculture and the occurrence of granivorous farmland bird species which suggest both hypotheses for the causes of population change and directions for management action. However, data on several key features of agricultural practice (such as pesticide use) were unavailable, so their effects could not be tested, and the effects of the variables included could not be separated from those of other factors which are subject to complex geographical variation. Experimental comparisons of the effects of land‐use at the farm scale are needed to investigate such confounded influences on farmland bird occurrence.     

豫西山地传粉昆虫物种多样性对地貌和季节的响应

通过野外试验布设陷阱捕捉传粉昆虫,调查豫西山地春秋两季不同人为强度土地利用下的传粉昆虫多度、丰富度等,并结合实地的植被群落特征,研究传粉昆虫的多样性、群落相似性及物种重要度(重要值).结果表明: 春秋两季累计捕获传粉昆虫23275头,优势类群多为膜翅目、双翅目等.春季捕获传粉昆虫的数量约是秋季数量的1.8倍,且两个季节传粉昆虫的个体多度差异达到极显著水平.春秋季捕获的双翅目、膜翅目相对多度较高,且季节之间变化不大.鳞翅目、鞘翅目个体数量较少,其中春季捕获的鳞翅目数量极少,秋季的鞘翅目数量也偏低.丘陵的Shannon多样性指数、Pielou均匀度指数和Margalef丰富度指数要明显高于其他两种地貌类型;山地的优势度指数和物种的个体数均高于其他两种地貌类型.不同地貌传粉昆虫的多样性和优势度差异达到显著水平,丘陵传粉昆虫多样性与山地和平原均有显著差异,山地的优势度与丘陵有显著差异.季节变化对传粉昆虫群落影响较小,但群落内各物种组成之间存在一定差异.从Morisita-Horn和Sørensen相似系数来看,仅有膜翅目群落在山地和丘陵间有显著差异.春秋季的物种重要值也存在差异,春季中胡蜂科的重要值最高,寄蝇科、果蝇科次之;秋季中花蝇科重要值最高,胡蜂科次之.传粉昆虫与农作物密切相关,影响着作物生长和粮食产量.在种植作物过程中因地制宜,合理规划土地利用方式,根据不同地貌内的植被类型适当调整物种组成,保护其多样性,对维持农业可持续发展和提高生态系统服务意义重大.     

Sexual differences in weight loss upon eclosion are related to life history strategy in Lepidoptera

Given that immature and adult insects have different life styles, different target body compositions can be expected. For adults, such targets will also differ depending on life history strategy, and thus vary among the sexes, and in females depend on the degree of capital versus income breeding and ovigeny. Since these targets may in part be approximated by loss of substances upon eclosion, comparing sexual differences in such losses upon eclosion among species that differ in life history would provide insights into insect functional ecology. We studied weight loss in eclosing insects using original data on pupal and adult live weights of 38 species of Lepidoptera (mainly Geometridae) and further literature data on 15 species of Lepidoptera and six representatives of other insect orders, and applied the phylogenetic independent contrasts approach. In addition, data on live and dry weights of pupae of four species of Lepidoptera are presented. We documented that Lepidoptera typically lose a large proportion (20-80%) of their pupal weight upon adult eclosion. Sexual differences in weight loss varied between absent and strongly male biased. Most of the weight loss was water loss, and sexual differences in adult water content correlate strongly with differences in weight loss. Using feeding habits (feeds or does not feed as an adult) and female biased sexual size dimorphism as measures of degree of capital breeding, we found that the difference among the sexes in weight loss tends to be more pronounced in capital breeding species. Additionally, females of more pro-ovigenic species (large proportion of eggs mature upon emergence) tend to have higher water contents. Our results suggests that metamorphosis is generally facilitated by a high water content, while adults excrete water upon eclosion to benefit flight unless water has been allocated to eggs, or is treated as a capital resource for adult survival or future allocation to eggs.     

Measuring biodiversity and sustainable management in forests and agricultural landscapes

Most of the world's biodiversity will continue to exist outside protected areas and there are also managed lands within many protected areas. In the assessment of millennium targets, there is therefore a need for indicators to measure biodiversity and suitability of habitats for biodiversity both across the whole landscape/seascape and in specific managed habitats. The two predominant land uses in many inhabited areas are forestry and agriculture and these are examined. Many national-level criteria and indicator systems already exist that attempt to assess biodiversity in forests and the impacts of forest management, but there is generally less experience in measuring these values in agricultural landscapes. Existing systems are reviewed, both for their usefulness in providing indicators and to assess the extent to which they have been applied. This preliminary gap analysis is used in the development of a set of indicators suitable for measuring progress towards the conservation of biodiversity in managed forests and agriculture. The paper concludes with a draft set of indicators for discussion, with suggestions including proportion of land under sustainable management, amount of produce from such land, area of natural or high quality semi-natural land within landscapes under sustainable management and key indicator species.     

Rarity,geography, and plant exposure to global change in the California Floristic Province

Aim

Rarity and geographic aspects of species distributions mediate their vulnerability to global change. We explore the relationships between species rarity and geography and their exposure to climate and land use change in a biodiversity hotspot.

Location

California, USA.

Taxa

One hundred and six terrestrial plants.

Methods

We estimated four rarity traits: range size, niche breadth, number of habitat patches, and patch isolation; and three geographic traits: mean elevation, topographic heterogeneity, and distance to coast. We used species distribution models to measure species exposure—predicted change in continuous habitat suitability within currently occupied habitat—under climate and land use change scenarios. Using regression models, decision-tree models and variance partitioning, we assessed the relationships between species rarity, geography, and exposure to climate and land use change.

Results

Rarity, geography and greenhouse gas emissions scenario explained >35% of variance in climate change exposure and >61% for land use change exposure. While rarity traits (range size and number of habitat patches) were most important for explaining species exposure to climate change, geographic traits (elevation and topographic heterogeneity) were more strongly associated with species' exposure to land use change.

Main conclusions

Species with restricted range sizes and low topographic heterogeneity across their distributions were predicted to be the most exposed to climate change, while species at low elevations were the most exposed to habitat loss via land use change. However, even some broadly distributed species were projected to lose >70% of their currently suitable habitat due to climate and land use change if they are in geographically vulnerable areas, emphasizing the need to consider both species rarity traits and geography in vulnerability assessments.     

Timing is everything? Phenological synchrony and population variability in leaf‐chewing herbivores of Quercus

Abstract.  1. Specialization on ephemeral resources (e.g. new leaves) should produce large annual variation in herbivore population size when the timing of availability of those resources is unpredictable. Despite considerable evidence for impacts of synchrony with budburst on survival of larval Lepidoptera, previous studies of adult Geometridae and Noctuidae found no correlations between insect phenology and population variability.
2. We surveyed larval Lepidoptera feeding on Quercus alba and Q. velutina in Missouri from 1993 to 2003 and examined population variability, measured as the coefficient of variation of population density (CV), in a subset of abundant species. We compared CV values among species whose larvae feed only in spring, early summer, mid-summer, late summer, or all season. We predicted that univoltine species whose larvae eclose and complete development in spring during leaf expansion would have higher variability than species feeding later in the season, having multiple generations, or having longer development times.
3. As predicted and consistent with hypotheses, spring-feeding species had CV values 32% higher than species feeding in summer months. Coefficients of variation were also 34% higher in leaf-rolling and mining guilds compared with free-feeders, suggesting that mobile species may compensate for asynchrony with budburst by dispersing to higher quality plants or plant parts. Multivoltine species, however, did not differ from univoltine species in population variability.
4. Our results suggest that asynchrony with plant phenology and factors that might exacerbate it, such as climate change, will have the largest impacts on the dynamics of spring-feeding Lepidoptera, particularly species with limited mobility.     

Reproductive endocrinology of Syngnathidae

Few studies have examined the underlying hormonal mechanisms that mediate reproductive cyclicity, male pregnancy and reproductive behaviour in syngnathids. Progress in these areas has been hampered by the small size of most species in the family and a lack of validated techniques for assessing endocrine function. Research on a relatively small number of species has suggested that androgens are likely regulators of spermatogenesis and the development of the male brood pouch prior to pregnancy whereas prolactin and corticosteroids synergistically promote brood pouch function during pregnancy. No evidence supports a reversal of reproductive steroid hormone function in sex-role reversed behaviour, but neuropeptides such as arginine vasotocin or isotocin should be examined for their role in regulating parturition and mating behaviour. The diversity of reproductive patterns exhibited by syngnathids suggests that they will provide a unique opportunity to assess how hormonal regulation of integumentary function, gametogenesis and reproductive behaviour have evolved within a teleost lineage. Additionally, their coastal distribution and embryo retention make them potentially important subjects for studies on the effect of endocrine disruption on fitness.     

Ten challenges for 2010 and beyond to conserve Lepidoptera in Europe

Butterflies and moths have undergone a serious decline in most European countries following rapid changes in land use in recent decades. The main drivers of loss have been agricultural and forestry intensification, abandonment of marginal land (especially in mountainous regions), loss of traditional management of grasslands and woodlands, and urban spread. Over the same period the science and practice of Lepidoptera conservation has developed considerably and concerted action to save biodiversity has been taken in many countries, with vast areas designated as nature reserves or national parks. Despite this effort, Lepidoptera are still declining at an alarming rate and it is clear that the 2010 target of halting biodiversity loss will not be met. We suggest ten challenges that conservationists in Europe need to address if we are to be successful in halting these losses over coming decades. In this continent, Lepidoptera and their habitats often rely on traditional farming and forestry systems. How can these be brought together in harmony to create a healthier environment in which both humans and wildlife can thrive? The ten challenges include reform of agricultural support, identifying and supporting beneficial forestry systems, managing the matrix between habitats, managing habitats on a landscape scale, mitigating for climate change, creating a robust planning system that protects key sites, developing a comprehensive monitoring programme for Europe, securing long term funding for nature conservation, and ensuring both political and public support.     

The network structure of myrmecophilic interactions

1. Ants establish mutualistic interactions involving a wide range of protective relationships (myrmecophily), in which they provide defence against enemies and partners provide food rewards and/or refuge. Although similar in the general outcome, myrmecophilic interactions differ in some characteristics such as quantity and quality of rewards offered by partners which may lead to different specialisation levels and, consequently, to different network properties. 2. The aim of this study was to identify structural patterns in myrmecophilic interaction networks, focusing on aspects related to specialisation: network modularity, nestedness and taxonomic relatedness of interaction ranges. To achieve this, a database of networks was compiled, including the following interactions: ants and domatia‐bearing plants (myrmecophytes); ants and extrafloral nectary‐bearing plants (EFNs); ants and floral nectary‐bearing plants (FNs); ants and Lepidoptera caterpillars; and ants and Hemiptera. 3. Myrmecophilic networks differed in their topology, with ant–myrmecophyte and ant–Lepidoptera networks being similar in their structural properties. A continuum was found, ranging from highly modular networks and phylogenetically structured interaction ranges in ant–myrmecophyte followed by ant–Lepidoptera networks to low modularity and taxonomically unrelated interaction ranges in ant–Hemiptera, EFN and FN networks. 4. These results suggest that different network topologies may be found across communities of species with similar interaction types, but also, that similar network topologies can be achieved through different mechanisms such as those between ants and myrmecophytes or Lepidoptera larvae. This study contributes to a generalisation of myrmecophilic network patterns and a better understanding of the relationship between specialisation and network topology.     

Contrasting Patterns of Species Richness and Composition of Solitary Wasps and Bees (Insecta: Hymenoptera) According to Land‐use

Several species of arthropods inhabiting forest fragments interact with managed areas. The importance of such areas to biodiversity conservation, however, is not well established. Communities of solitary wasps and bees (Insecta: Hymenoptera) play a key role in agroecosystem functioning and they have been used in studies of biodiversity assessment in different land‐use types. We aimed to assess patterns of species richness and composition of solitary wasps and bees over a 1‐yr period in a gradient of decreasing land‐use intensity formed by pastures, alley croppings, young fallows, and old fallows using trap nests. Old fallows had the highest species richness of wasps and bees, harboring all bee species and 86 percent of wasp species occurring in the region, while the remaining land‐uses had similar species richness. Vegetation structure (tree richness) and relative humidity explained most of the variance for the species richness of wasps. For bees, however, there was no influence of environmental factors on the community among land‐use types, indicating better adaptability of this group to environmental variations related to land‐use. The composition of solitary wasp communities (but not those of bees) differed among land‐use types, and the occurrence of rare species in most cases was restricted to old fallow sites. In conclusion, the community of solitary wasps and bees is contingent on land‐use, with solitary wasps more sensitive to anthropized areas. For both groups, less anthropized areas harbor a greater richness and number of rare species while more intensively managed land‐use types harbor higher abundances.     

Development and implementation of a high nature value (HNV) farming indicator for Denmark

During the latest decades, conservation awareness have increased and conservation of biodiversity is no longer an agenda restricted to pristine natural areas of high value but is being integrated in cultivated landscapes characterized by increasing fragmentation and anthropogenic pressures. Conservation of species has become relevant even in agricultural areas especially in countries heavily influenced by intensive farming and ubiquitous infrastructure. Based on the UN biodiversity convention all EU membership countries are obliged to develop a high nature value (HNV) farming indicator. The purpose of such an indicator is to provide a basis for informed decisions in prioritizing agricultural subsidies allocating these to high nature value areas. Here, the development of a national HNV farming indicator for Denmark is presented and its application in the Danish government-controlled agricultural subsidy system is outlined. The Danish HNV farming indicator is based on landscape structural parameters, known occurrences of natural and semi-natural habitats, current land use and the distributions of rare and threatened species. It covers all agricultural areas as well as Natura 2000 areas and nationally protected sites in Denmark, ranking them on a 0–13 point scale from low to high nature value according to their estimated value for threatened and rare biodiversity. The Danish government recognizes areas reaching at least 5 points as HNV farming areas eligible to subsidy and from 2015 and onwards the HNV farming indicator will be implemented for allocating part of the agricultural subsidies under the Rural Development Program in Denmark. The indicator will be updated annually to include the growing knowledge of species occurrence and land use changes.     

Considering evolutionary processes in the use of single-locus genetic data for conservation,with examples from the Lepidoptera

The increasing popularity of molecular taxonomy will undoubtedly have a major impact on the practice of conservation biology. The appeal of such approaches is undeniable since they will clearly be an asset in rapid biological assessments of poorly known taxa or unexplored areas, and for discovery of cryptic biodiversity. However, as an approach for diagnosing units for conservation, some caution is warranted. The essential issue is that mitochondrial DNA variation is unlikely to be causally related to, and thus correlated with, ecologically important components of fitness. This is true for DNA barcoding, molecular taxonomy in general, or any technique that relies on variation at a single, presumed neutral locus. Given that natural selection operates on a time scale that is often much more rapid than the rates of mutation and allele frequency changes due to genetic drift, neutral genetic variation at a single locus can be a poor predictor of adaptive variation within or among species. Furthermore, reticulate processes, such as introgressive hybridization, may also constrain the utility of molecular taxonomy to accurately detect significant units for conservation. A survey of published genetic data from the Lepidoptera indicates that these problems may be more prevalent than previously suspected. Molecular approaches must be used with caution for conservation genetics which is best accomplished using large sample sizes over extensive geography in addition to data from multiple loci. Matthew L. Forister, Chris C. Nice and James A. Fordyce contributed equally to this paper.     

The Conservation Value of Secondary Forests for Vascular Epiphytes in Central Panama

Secondary forests that develop following land abandonment could compensate for the losses of diversity and structure that accompany deforestation of old‐growth forests in tropical regions. Whether secondary forests can harbor similar species richness, density, and composition of old‐growth forests for vascular epiphytes remains largely unknown for secondary forests older than 50 yr. We examined community structure (species richness, density, and species composition) of vascular epiphytes in older secondary forests between 35 and 115 yr after land abandonment and nearby old‐growth forests to determine if the community structure of epiphytes in secondary forests approaches that of old‐growth forests over time. The recovery of epiphyte species richness was rapid with 55‐year‐old forests containing 65 percent of old‐growth epiphyte species richness. Secondary forest epiphyte communities were found to be statistically nested within secondary forests older in age and within old‐growth forests. Similarity of epiphyte communities to old‐growth forests increased to 75 percent, 115 yr after abandonment. This study suggests that secondary forests will likely recover old‐growth epiphyte richness and composition given enough time. Epiphyte densities did not recover quickly with 55‐year‐old forests having 14 percent and 115‐year‐old forests having only 49 percent of the density of old‐growth forest epiphytes. The low density of epiphytes in secondary forests could impact rainforest diversity and function. We conclude that in less than 115 yr, although secondary moist forests have high conservation value for some aspects of community structure, they are unlikely to compensate biologically for the loss of diversity and ecosystem function that high epiphyte densities provide.     

啮齿动物分子系统地理学研究进展

系统地理学是研究种间及种内不同种群的形成、现有分布格局的历史原因和演化过程的一门学科。基于分子水平,能够更准确地界定物种分布格局,促进分子系统地理学的形成和发展。近年来,分子系统地理研究的开展,促进了对啮齿动物物种分布格局形成机制的理解。对啮齿动物的种内及种上分类阶元的系统演化关系、起源中心与演化历程、影响系统地理格局的因素、鼠害防控和保护生物学等分子系统地理学方面的研究进行了综述。并提出了啮齿动物分子系统地理学未来发展的四点展望:1)综合性系统地理学研究;2)区域系统地理学研究;3)物种演化的全面系统研究;4)新型分子标记和分析方法的发展。     

Isolation and characterization of polymorphic microsatellites in the Potato Tuber Moth Tecia solanivora (Povolny, 1973) (Lepidoptera: Gelechiidae)

Nine polymorphic microsatellite markers were isolated from Tecia solanivora, one of the most serious pests of potato tubers in Central and South America. As found in other studies of Lepidoptera, development of microsatellites is a difficult task: in our case, despite the large number of clones sequenced (796), of which 70 were unique, only nine loci were found to be both variable, and in Hardy-Weinberg equilibrium, No null alleles were detected. The loci were tested in three other co-occurring Gelechiidae species, one of which was variable. These loci will be used to provide a greater understanding of the genetic changes occurring during the invasive process in this species.