Code of ant-plant mutualism broken by parasite

Newly discovered Phyllobaenus beetles are parasites of a mutualism. Piper ant-plants in tropical forests provide lipid and protein-rich food cells and shelter for Pheidok bicornis ants while the ants remove small herbivores and vines from the foliage. In contrast to all other ant-plants, Piper ant-plants produce food bodies only when Pheidole bicornis is present in the plant. However, Phyllobaenus beetles can stimulate the plants to produce food bodies as if ants were present. The beetles then inhabit the plant, exploiting nest sites and food produced by the plants for ants. These beetles may also prey on ant brood, depriving the plants of resources and services provided by the ants.     

Traditional knowledge and rationale for weaver ant husbandry in the Mekong delta of Vietnam

The weaver ant, Oecophylla smaragdina Fabricius (Hymenoptera: Formicidae), has long been known as perhaps the first example of human manipulation of a natural predator population to enhance the natural biological control of insect pests. The practice of ant husbandry in Vietnamese citrus orchards and the knowledge associated with the use of weaver ants in the Mekong delta are described. In contrast to other regions of Asia, where weaver ants are noted for their role in the protection of citrus from insect damage, citrus farmers in the Mekong delta explain the benefits of ant husbandry in terms of an improvement in fruit quality, likened to the influence of fertilizers, that occurs in direct response to excretory products deposited by the weaver ants as they patrol the fruit. A series of tests, carried out in 1993–94, rated the external shine, sweetness, juiciness, and overall appeal, as characteristics of fruit quality, for paired comparisons of sweet orange, mandarin, and pummelo fruit that had been grown in the presence of weaver ants or from which ants had been excluded. The tests indicate a strong influence of the presence of the weaver ant on external shine, juiciness, and overall appeal for each of the citrus fruits, but particularly for mandarin. The significance of these results and ant husbandry practices in the Mekong delta are discussed in relation to the development of citrus production in Vietnam.     

Pseudomyrmex nigropilosa: A Parasite of a Mutualism

Pseudomyrmex nigropilosa is a parasite ofthe ant-acacia mutualism in Central America in that it harvests the resources of swollen-thorn acacias but does not protect the acacias. In the process, it also lowers the rate of occupation by the obligate acacia-ants, species of ants that do protect swollen-thorn acacias. Tenancy ofan acacia by P. nigropilosa must be temporary, since the unoccupied plant is shortly killed by herbivores or competing plants, or is taken over by obligate acacia-ants. As expected of a species of short-lived ant, a P. nigropilosa colony produces reproductives earlier in the life of the colony and maintains fewer grams of workers per gram of brood than does a colony of the long-lived obligate acacia-ants.     

中国蚂蚁资源研究进展

蚂蚁是地球上分布最广、种类和数量最多的社会性昆虫,也是一类食用和药用资源昆虫.从分类研究文献、区系分布调查、生物学特征、生态学、细胞分子生物学、食用和药用价值以及蚂蚁资源的开发利用与保护等方面论述中国蚂蚁的研究进展.     

The evolution of agriculture in ants

Cultivation of fungi for food by fungus-growing ants (Attini: Formicidae) originated about 50 million years ago. The subsequent evolutionary history of this agricultural symbiosis was inferred from phylogenetic and population-genetic patterns of 553 cultivars isolated from gardens of "primitive" fungus-growing ants. These patterns indicate that fungus-growing ants succeeded at domesticating multiple cultivars, that the ants are capable of switching to novel cultivars, that single ant species farm a diversity of cultivars, and that cultivars are shared occasionally between distantly related ant species, probably by lateral transfer between ant colonies.     

不同氮素水平下三七根系分泌物对小麦的化感作用

为探讨三七在不同氮素水平下根系分泌物的化感作用,以三七种苗为供体植物,小麦为受体植物进行生物测定。结果表明,三七根系分泌物对小麦表现出化感抑制作用(敏感指数M3=-004)。从发育时期来看,小麦种子萌发阶段较幼苗生长阶段更易受化感抑制作用影响,且其发芽指数受抑程度随氮素水平的升高而逐渐增强,即过氮>正常>缺氮;在小麦幼苗生长阶段,三七根系分泌物对其地上部化感作用以促进为主,对根部生长则以抑制作用为主;且三七根系分泌物对小麦的化感作用与培养液氮素水平有关。     

Postsecretory hydrolysis of nectar sucrose and specialization in ant/plant mutualism

Obligate Acacia ant plants house mutualistic ants as a defense mechanism and provide them with extrafloral nectar (EFN). Ant/plant mutualisms are widespread, but little is known about the biochemical basis of their species specificity. Despite its importance in these and other plant/animal interactions, little attention has been paid to the control of the chemical composition of nectar. We found high invertase (sucrose-cleaving) activity in Acacia EFN, which thus contained no sucrose. Sucrose, a disaccharide common in other EFNs, usually attracts nonsymbiotic ants. The EFN of the ant acacias was therefore unattractive to such ants. The Pseudomyrmex ants that are specialized to live on Acacia had almost no invertase activity in their digestive tracts and preferred sucrose-free EFN. Our results demonstrate postsecretory regulation of the carbohydrate composition of nectar.     

Leaf herbivores decrease fitness of a tropical plant

Damage by insect herbivores to neighboring individuals of the shrub Piper arieianum in a neotropical wet forest varies greatly. This differential damage has a genetic basis and results in a 2-year decrease in growth, seed production, and seed viability, with larger plants recovering before smaller plants. The results provide evidence that leaf herbivores represent a potentially strong selective force for the evolution of plant defenses.     

Insects as selective agents on plant vegetative morphology: egg mimicry reduces egg laying by butterflies

Experiments show that Heliconius butterflies are less likely to oviposit on host plants that possess eggs or egglike plant structures. These egg mimics are an unambiguous example of a plant trait evolved in response to a host-restricted group of insect herbivores.     

Comment on "A keystone mutualism drives pattern in a power function"

Vandermeer and Perfecto (Reports, 17 February 2006, p. 1000) maintain that a mutualist ant disrupts the power law distribution of scale insect abundances. However, reanalysis of the data reveals that ants cause an increase in the range of the power law and modify its exponent. We present a tentative, but more realistic, model that is suitable for quantitative predictions.     

Evolution of the gene network underlying wing polyphenism in ants

Wing polyphenism in ants evolved once, 125 million years ago, and has been a key to their amazing evolutionary success. We characterized the expression of several genes within the network underlying the wing primordia of reproductive (winged) and sterile (wingless) ant castes. We show that the expression of several genes within the network is conserved in the winged castes of four ant species, whereas points of interruption within the network in the wingless castes are evolutionarily labile. The simultaneous evolutionary lability and conservation of the network underlying wing development in ants may have played an important role in the morphological diversification of this group and may be a general feature of polyphenic development and evolution in plants and animals.     

Species coextinctions and the biodiversity crisis

To assess the coextinction of species (the loss of a species upon the loss of another), we present a probabilistic model, scaled with empirical data. The model examines the relationship between coextinction levels (proportion of species extinct) of affiliates and their hosts across a wide range of coevolved interspecific systems: pollinating Ficus wasps and Ficus, parasites and their hosts, butterflies and their larval host plants, and ant butterflies and their host ants. Applying a nomographic method based on mean host specificity (number of host species per affiliate species), we estimate that 6300 affiliate species are "coendangered" with host species currently listed as endangered. Current extinction estimates need to be recalibrated by taking species coextinctions into account.     

模拟根系分泌物输入对森林土壤氮转化的影响研究综述

在全球气候变化加速植物生长和生物量积累的背景下,氮素是森林生态系统初级生产力的主要限制因子之一。根系分泌物所介导的根际微生物过程在驱动森林生态系统土壤养分循环和增加氮素有效性方面具有重要意义。基于此,本研究综述了模拟根系分泌物输入对森林土壤氮素矿化、硝化与反硝化过程的影响及其机制。发现根系分泌物中的有机酸、糖类和氨基酸等物质均能促进有机质的分解和氮素矿化,在一定程度上能缓解植物对氮的需求。不同碳含量和碳氮比的根系分泌物输入驱动根际微生物行使不同养分利用策略,通过生物和非生物作用,根系分泌物矿化有机质中的氮素供给植物吸收利用;根系分泌物中的生物硝化抑制剂能抑制土壤硝化作用,减少氮素的淋溶;根系分泌物还通过控制根际与氮转化相关的反硝化细菌群落来促进土壤反硝化作用。综上,植物通过增加根系分泌物的输入能提高地下碳分配,影响根际土壤氮素转化,在维持森林土壤氮素循环和缓解养分限制等方面具有重要作用。表2参70     

Territorial strategies in ants

Several features in social insects, particularly in ants, make the behavioral organization of territoriality considerably more complex than that of solitary animals. The establishment and maintenance of territories are based on a division of labor and a complex communication system. The analyses of territorial strategies in ants comprise the study of the design and spatiotemporal structure of the territory, as well as the social mechanisms through which the insect society pursues its territorial strategy. The geometric and behavioral organization of the absolute territories of the African weaver ants (Oecophylla longinoda) and harvester ants (Pogonomyrmex), and of the "spatiotemporal territories" of honey ants (Myrmecocystus mimicus) are described, and simple cost-benefit models are developed to illustrate the economic defensibility of each type of territory.     

Detoxication enzymes in the guts of caterpillars: an evolutionary answer to plant defenses?

Higher activity of midgut microsomal oxidase enzymes in polyphagous than in monophagous species indicates that the natural function of these enzymes is to detoxify natural insecticides present in the larval food plants. Differing strategies of adaptation to plant defenses may partly account for the great diversity of insect herbivores.     

瑞丽市 3 种类型柠檬园地表蚂蚁群落多样性研究

为探讨覆膜对柠檬园地表蚂蚁群落的影响,于2016年4月和7月采用陷阱法对云南省瑞丽市覆膜种植和常规种植模式下3种类型柠檬园地表蚂蚁群落进行调查。结果表明,柠檬园RG采集地表蚂蚁17种276头;柠檬园RH采集地表蚂蚁22种527头;柠檬园RI采集地表蚂蚁16种273头。3种类型柠檬园间地表蚂蚁相对多度和物种丰富度均有显著差异,柠檬园RH中地表蚂蚁的相对多度和物种丰富度均显著高于柠檬园RG和柠檬园RI。3种类型柠檬园间地表蚂蚁群落结构互不相似。覆膜降低了柠檬园地表蚂蚁群落的相对多度和物种丰富度,除草剂对柠檬园地表蚂蚁的相对多度和物种丰富度无影响,但可以改变地表蚂蚁群落结构。     

基于认知程度评估的红火蚁 管理策略与方式探讨

采用问卷调查的方法对南沙区132 个社区/村当地居民对红火蚁认知程度进行调查。结果发现、南沙区 居民对红火蚁的了解程度较高、其中65.2%居民知道红火蚁;对红火蚁的了解途径中、野亲眼所见冶所占比例最高、为 57.78%、其次是从电视上得知、为14.43%;86.84%居民所在地区发现有红火蚁、90.93%居民周围有人知道红火蚁。在 发现红火蚁后、52.35%居民会向相关部门反映、38.01%居民会使用工具进行破坏;68.78%居民3 年前就已经听说当 地有红火蚁发生;48.08%居民认为红火蚁入侵对人身健康产生影响;59.59%居民被红火蚁叮咬过、且86.32%居民会 有痛痒、红肿、脓包的症状;69.50%居民在被叮咬后知道处理方法、其中53.88%居民会涂抹药膏、30.53%会去医;就 医;62.09%居民会关心入侵生物相关的信息;56.37%居民了解红火蚁相关工作内容;89.95%居民对红火蚁的宣传、防 治工作感到基本满意;在红火蚁相关工作中、37.47%居民建议应该加强防控力度、21.98%居民认为应该加强宣传。通 过调查所反映的问题、提出解决的方法和建议。     

Vein-cutting behavior: insect counterploy to the latex defense of plants

Many mandibulate insects that feed on milkweeds, or other latex-producing plants, cut leaf veins before feeding distal to the cuts. Vein cutting blocks latex flow to intended feeding sites and can be viewed as an insect counteradaptation to the plant's defensive secretion. Experimental vein severance renders milkweed leaves edible to generalist herbivores that do not show vein-cutting behaviors and ordinarily ignore milkweeds in nature.     

Competition for dispersal in ant-dispersed plants

Two closely related and coexisting plants (Chenopodiaceae) of the Australian arid zone are adapted for seed dispersal by ants. These facultatively perennial shrubs persist in saltbush communities largely as a result of highly directional dispersal to ant mounds, where conditions are favorable for establishment and growth. The two species grow predominantly on mounds and compete for dispersal to these favorable microhabitats.     

Opposing effects of native and exotic herbivores on plant invasions

Exotic species are widely assumed to thrive because they lack natural enemies in their new ranges. However, a meta-analysis of 63 manipulative field studies including more than 100 exotic plant species revealed that native herbivores suppressed exotic plants, whereas exotic herbivores facilitated both the abundance and species richness of exotic plants. Both outcomes suggest that plants are especially susceptible to novel, generalist herbivores that they have not been selected to resist. Thus, native herbivores provide biotic resistance to plant invasions, but the widespread replacement of native with exotic herbivores eliminates this ecosystem service, facilitates plant invasions, and triggers an invasional "meltdown."