The incidence and pattern of copollinator diversification in dioecious and monoecious figs

Differences in breeding system are associated with correlated ecological and morphological changes in plants. In Ficus, dioecy and monoecy are strongly associated with different suites of traits (tree height, population density, fruiting frequency, pollinator dispersal ecology). Although approximately 30% of fig species are pollinated by multiple species of fig‐pollinating wasps, it has been suggested that copollinators are rare in dioecious figs. Here, we test whether there is a connection between the fig breeding system and copollinator incidence and diversification by conducting a meta‐analysis of molecular data from pollinators of 119 fig species that includes new data from 15 Asian fig species. We find that the incidence of copollinators is not significantly different between monoecious and dioecious Ficus. Surprisingly, while all copollinators in dioecious figs are sister taxa, only 32.1% in monoecious figs are sister taxa. We present hypotheses to explain those patterns and discuss their consequences on the evolution of this mutualism.     

Preference of an insular flying fox for seed figs enhances seed dispersal of a dioecious species

Interactions among multiple species form complex networks of interdependences and are considered primary factors in the generation and maintenance of biodiversity. Pteropodid bats are keystone species that provide important ecosystem services of pollination and seed dispersal in the tropics and subtropics. In this study, we investigated the utilization and preference of food resources by the insular frugivorous flying fox Pteropus dasymallus. We found that fig species constituted the major portion of the diet of the flying fox (94.6%). When foraging, the flying fox preferred seed figs from female trees over gall figs from male trees in functionally dioecious fig species. Germination experiments showed a significantly higher percentage of germination for fig seeds in feces than those from pellets and ripe figs (feces: 80.2%, pellets: 23.4%, ripe figs: 32.9%). Considering the active selection of seed figs and avoidance of gall figs by foraging flying foxes, we suggest that the abundance of seed figs accurately represents food availability for dioecy. This preference for seed figs or viable seeds can effectively promote the survival of pollinating wasps and might reinforce the evolution of dioecism in figs. In addition, the effects of gut passage on seed germination, in combination with the capacity of flying foxes to travel long distances, may substantially contribute to the efficiency of flying foxes as seed dispersers.     

Frugivores and seed dispersal: mechanisms and consequences for biodiversity of a key ecological interaction

The 5th Symposium on Frugivores and Seed Dispersal, held in Montpellier (France), 13-18 June 2010, brought together more than 220 researchers exemplifying a wide diversity of approaches to the study of frugivory and dispersal of seeds. Following Ted Fleming and Alejandro Estrada's initiative in 1985, this event was a celebration of the 25th anniversary of the first meeting in Veracruz, Mexico. Frugivory and seed dispersal are active research areas that have diversified in multiple directions since 1985 to include evolution (e.g. phylogenetic diversity and dispersal adaptations), physiology (e.g. sensory cues and digestion), landscape ecology (movement patterns), molecular ecology (e.g. gene flow, genetic diversity and structure), community ecology (e.g. mutualistic interaction networks) and conservation biology (effects of hunting, fragmentation, invasion and extinction), among others. This meeting provided an opportunity to assess conceptual and methodological progress, to present ever more sophisticated insights into frugivory in animals and dispersal patterns in plants, and to report the advances made in examining the mechanisms and consequences of seed dispersal for plants and frugivores.     

Diet of chimpanzees (Pan troglodytes schweinfurthii) at Ngogo, Kibale National Park, Uganda, 1. Diet composition and diversity

Chimpanzees (Pan troglodytes) are ecologically flexible omnivores with broad diets comprising many plant and animal foods, although they mostly eat fruit (including figs). Like other ecologically flexible nonhuman primates (e.g., baboons, Papio spp.) with broad diets, their diets vary across habitats. Much data on diets come from short studies that may not capture the range of variation, however, and data are scant on variation within habitats and populations. We present data on diet composition and diversity for chimpanzees at Ngogo, in Kibale National Park, Uganda, collected over a 15-year period, with a focus on the plant components of the diet. We compare Ngogo data to those on chimpanzees at the nearby Kibale site of Kanyawara, on other chimpanzee populations, and on some other frugivorous-omnivorous primates. Results support the argument that chimpanzees are ripe fruit specialists: Ngogo chimpanzees ate a broad, mostly fruit-based diet, feeding time devoted to fruit varied positively with fruit availability, and diet diversity varied inversely with fruit availability. Comparison of Ngogo and Kanyawara shows much similarity, but also pronounced within-population dietary variation. Chimpanzees fed much more on leaves, and much less on pith and stems, at Ngogo. Figs accounted for somewhat less feeding time at Ngogo, but those of Ficus mucuso were quantitatively the most important food. This species is essentially absent at Kanayawara; its abundance and high productivity at Ngogo, along with much higher abundance of several other important food species, help explain why chimpanzee community size and population density are over three times higher at Ngogo. High inter-annual variation at Ngogo highlights the value of long-term data for documenting the extent of ecological variation among chimpanzee populations and understanding how such variation might affect population biology and social dynamics.     

海洋微生物的化学生态学研究进展

近年来,海洋生物的化学生态学研究已成为国际化学生态学研究的亮点之一.该领域的研究不仅为生物进化研究提供了理论依据,也对海洋生态养殖、海洋生态环境保护以及海洋资源的可持续发展具有重要意义.本文从海洋动物、植物、微生物三方面综述了它们与海洋微生物之间的化学生态学关系.海洋动物与微生物的化学生态学作用主要包括抗菌、抗附着、共生3种关系.以发现具有生态学效应的化学信号物质的分子结构为主线,介绍了海洋植物和微生物方面的研究进展,并对该领域的关键性问题和发展方向进行了展望.     

糖苷生物碱化学生态学研究进展

糖苷生物碱(glycoalkaloid)是主要分布于茄科和百合科植物中的糖苷类次级代谢产物,糖链通常由3或4个单糖组成,苷元通常为三类甾体生物碱:茄次碱烷、螺旋甾碱烷和其他甾体衍生物.糖苷生物碱的主要生物学功能是化学防御,具有阻止昆虫取食、抑制微生物、化感作用和协同进化等重要作用.本文在阐明糖苷生物碱的来源和化学结构的基础上,着重总结了糖苷生物碱化学生态学研究的现状、进展及其生物学意义,分析了今后的发展方向.     

The timing of frugivore‐mediated seed dispersal effectiveness

The seed dispersal effectiveness framework allows assessing mutualistic services from frugivorous animals in terms of quantity and quality. Quantity accounts for the number of seeds dispersed and quality for the probability of recruitment of dispersed seeds. Research on this topic has largely focused on the spatial patterns of seed deposition because seed fates often vary between microhabitats due to differences in biotic and abiotic factors. However, the temporal dimension has remained completely overlooked despite these factors—and even local disperser assemblages—can change dramatically during long fruiting periods. Here, we test timing effects on seed dispersal effectiveness, using as study case a keystone shrub species dispersed by frugivorous birds and with a fruiting period of 9 months. We evaluated quantity and quality in different microhabitats of a Mediterranean forest and different periods of the fruiting phenophase. We identified the bird species responsible for seed deposition through DNA barcoding and evaluated the probability of seedling recruitment through a series of field experiments on sequential demographic processes. We found that timing matters: The disperser assemblage was temporally structured, seed viability decreased markedly during the plant's fruiting phenophase, and germination was lower for viable seeds dispersed in the fruiting peak. We show how small contributions to seed deposition by transient migratory species can result in a relevant effectiveness if they disperse seeds in a high‐quality period for seedling recruitment. This study expands our understanding of seed dispersal effectiveness, highlighting the importance of timing and infrequent interactions for population and community dynamics.     

An invasive tree alters the structure of seed dispersal networks between birds and plants in French Polynesia

Aim We studied how the abundance of the highly invasive fruit‐bearing tree Miconia calvescens DC. influences seed dispersal networks and the foraging patterns of three avian frugivores. Location Tahiti and Moorea, French Polynesia. Methods Our study was conducted at six sites which vary in the abundance of M. calvescens. We used dietary data from three frugivores (two introduced, one endemic) to determine whether patterns of fruit consumption are related to invasive tree abundance. We constructed seed dispersal networks for each island to evaluate how patterns of interaction between frugivores and plants shift at highly invaded sites. Results Two frugivores increased consumption of M. calvescens fruit at highly invaded sites and decreased consumption of other dietary items. The endemic fruit dove, Ptilinopus purpuratus, consumed more native fruit than either of the two introduced frugivores (the red‐vented bulbul, Pycnonotus cafer, and the silvereye, Zosterops lateralis), and introduced frugivores showed a low potential to act as dispersers of native plants. Network patterns on the highly invaded island of Tahiti were dominated by introduced plants and birds, which were responsible for the majority of plant–frugivore interactions. Main conclusions Shifts in the diet of introduced birds, coupled with reduced populations of endemic frugivores, caused differences in properties of the seed dispersal network on the island of Tahiti compared to the less invaded island of Moorea. These results demonstrate that the presence of invasive fruit‐bearing plants and introduced frugivores can alter seed dispersal networks, and that the patterns of alteration depend both on the frugivore community and on the relative abundance of available fruit.     

The ecology of seed dispersal in two species of callitrichid primates (Saguinus mystax and Saguinus fuscicollis)

Data collected during a 12-month field investigation of mixed species troops of Saguinus mystax and Saguinus fuscicollis in the Amazon Basin of north-eastern Peru indicate that callitrichid primates play an important role in tropical forest seed dispersal. Moustached and saddle-back tamarins were observed to ingest seeds from a variety of tree and liana species and pass them unharmed. These seeds tended to be large and heavy, and passed through the tamarin digestive tract in one to three hours. Experimental plantings of defecated seeds yielded a germination success rate of 70%. The specific gravity of these seeds (weight/volume) was inversely correlated with passage time and apparently had an indirect influence on the distance that seeds were dispersed from the parent tree. In the case of three preferred fruiting species, Leonia glycycarpa, Pourouma sp., and Hippocrateaceae #283, the present distribution of adult trees closely resembled the pattern of the seed shadow created by Saguinus. Moustached and saddle-back tamarins appeared to be reliable and high-quality dispersal agents for a number of tree and liana species. In this role, they are likely to exert an important influence on the composition, distribution, and regeneration patterns of Amazonian rain forest.     

国际化学生态学文献、实验室网络资源评介

本文介绍了国际上化学生态学的文献和网络资源 ,包括重要著作简介、杂志的特点和网址、实验室的工作内容和网址 ,一些网络讨论组 ,以及主要的组织机构和会议等。     

Directed vertebrate-mediated seed dispersal of a fleshy-fruited amaryllid in a heterogenous habitat

Most plants with fleshy fruits have seeds that are ingested by animals, but a less well-understood mode of seed dispersal involves fleshy fruits containing seeds that are discarded by frugivorous animals because they are too large or toxic to be ingested. We studied the seed dispersal biology of Haemanthus deformis, an amaryllid lily species found in a mosaic of bush clumps in a grassland matrix in South Africa. We asked whether seed dispersal is directed in and among bush clumps and whether germination and survival are greater for seeds dispersed to bush clumps than for those dispersed into grassland. Using camera trapping, we found that fruits are consumed mainly by birds and rodents. The pulp was removed from the seeds which were then discarded without ingestion. While many seeds were dispersed close to the parent plant, most (c. 78.5%) were dispersed further than 1 m away from the parent plant. Longer distance dispersal resulted mainly from birds flying off with fruits in their bill or from rodents engaging in scatter-hoarding behavior. Seedling survival was most successful within bush clumps as compared to grasslands and shade was identified as a primary requirement for seedling survival. Seeds from which the fruit pulp had been removed germinated faster than those in intact fruits. Haemanthus deformis deploys a system of directed seed dispersal, whereby both birds and rodents contribute to the dispersal of seeds within patchy bush clumps that are favorable for seedling survival.     

果实生态学的概念、研究现状及研究方向

总结了果实生态学的概念及主要研究内容,对国内外的果实生态学研究领域的进展进行了综述,分析了这些研究尚存在的不足之处,并指出了未来研究的科学问题.迄今为止,果实生态学在果实与种子的关系、果实颜色与环境、果实化学成分与环境、群落果实构成式样的地理分布特征、果实及食果动物的协同进化等方面已经取得了若干进展.果实重量谱等物理性状的空间分异格局及机理、果实化学成分的时空变异格局、果实类型的组成式样及大尺度地理分布格局及其机制的探讨、果实传播与食果动物的协同进化等是未来亟待开展的工作.     

Avian fruit consumption and seed dispersal in a temperate Australian woodland

Abstract The effectiveness of avian fruit consumers as seed dispersers of fleshy‐fruited plants was studied in a temperate woodland community. As a consequence of the short and overlapping fruiting phenologies of fleshy‐fruited plant species in temperate regions of Australia, there are very few avian species that are true specialist frugivores. The relative importance of bird species as fruit consumers was investigated, and how their foraging activities, movements and gut treatment of seeds affected dispersal of viable seeds away from the parent plant was examined. Fruit consumption and consumer seed dispersal capacity were assessed in this study through faecal analyses and by testing the viability of seeds that had passed through the gut of avian consumers. Behavioural observations enabled us to determine the consumption rates of, and quantities of fruit consumed by, various bird species and the amount of time spent feeding. Silvereyes (Zosterops lateralis) were the dominant fruit consumers in the community, although 19 bird species were either observed consuming fruit or provided faecal samples that contained fruit. Silvereyes had a high local abundance at the site and more than 90% of silvereyes’faecal samples contained the seeds of fruiting plants (n = 409). Large numbers of fruit were consumed per visit by silvereyes, particularly for Rhagodia parabolica (fragrant saltbush). Silvereyes consumed an average of four R. parabolica fruit per 5 s and up to a maximum 40 fruit per visit. Viability was high for seeds recovered from silvereyes’faeces (R. parabolica, 94.4% viable; Hymenanthera dentata, 100% viable). However, the number of seeds per faecal sample was high for R. parabolica, which may result in density‐dependent seed mortality. Gut passage rate for silvereyes fed R. parabolica fruit in captivity was 31.5 ± 1.9 min. Silvereyes remained at fruiting plants for very short periods (average 50‐60 s) and in most cases moved away from the parent plant, primarily toward canopy trees. Given the short visit duration of silvereyes, individuals would have left the parent plant well before seeds passed through the gut. Rhagodia parabolica fruit was consumed by a large number of bird species in the community, including species often thought of as exclusively insectivorous or nectarivorous. These species are likely to disperse viable R. parabolica seeds into microhabitats different from those visited by silvereyes.     

粉蚧化学生态学研究进展

粉蚧是农林经济作物的一类重要害虫,由于体表覆盖一层蜡粉,化学防治常需要大剂量反复用药该虫才能得以控制,易造成环境污染及害虫再猖獗。本文从昆虫化学生态学的角度综述了粉蚧类害虫的寄主植物范围、天敌应用以及三重营养关系研究进展,归纳已鉴定粉蚧性信息素化学结构特点及其在综合防治中应用概况,探讨粉蚧类害虫化学生态学未来研究方向,为其绿色防控提供理论基础。     

Studying the quantity component of seed dispersal effectiveness from exclosure treatments and camera trapping

The quantity component of effectiveness of seed dispersal by animals is determined by two events: fruit removal (intensity of the interaction) and animal visitation to the plant (frequency of interactions). Considering dispersal of Prosopis flexuosa seeds as case study, this work aimed at investigating the strengths and weaknesses of the two methods for assessing the quantity component of seed dispersal effectiveness: exclosures and camera traps. Prosopis fruits were offered for 48 hr. Exclosure treatments were performed using two types of wire‐screen cages, allowing access to ants (“closed exclosure”) and to small mammals up to 100 g (“open to small mammals”), and a treatment without exclosure (“open to all removers”). The camera trapping experiment was carried out using vertically oriented cameras placed at approximately 1.80 m height and focused on the fruits. The cameras were set in “motion detect mode,” taking series of three consecutive photographs. The exclosures largely allowed estimation of fruit removal by size‐based groups of animals, but did not provide information on species identity. In contrast, camera traps were able to identify all visitors to species level and could not only determine the number of visits by each species but also the proportion of visits, which resulted in removal of fruits. Camera trapping allowed discriminating among small mammals playing different roles, without underestimating fruit removal by scatter‐hoarding species. The quality of estimation of the quantity component of seed dispersal is remarkably better when the camera trapping method is applied. Additional information obtained, such as activity patterns of visitors, can contribute to a better understanding of the seed dispersal process.     

Feeding ecology and seed dispersal of sympatric cheirogaleid lemurs (Microcebus murinus, Cheirogaleus medius, Cheirogaleus major) in the littoral rainforest of south-east Madagascar

The lemurs of Madagascar are known for their extraordinary species diversity. The mechanisms that allow the coexistence of these species are still poorly known. Here feeding patterns were investigated for three small nocturnal lemur species of Cheirogaleidae ( Microcebus murinus , Cheirogaleus medius and Cheirogaleus major ) occurring sympatrically in a littoral rainforest in south-east Madagascar. During three rainy seasons, the plant species eaten by these three lemurs were described in relation to morphological and biochemical characteristics. All three species were mainly frugivorous and fed on 68 different plant species with small- and medium-sized fruits. A total of 91% of these forage plant species was visited by all three lemur species. Fruits larger than 25–30 mm were avoided. Seeds of a total of 51 food plant species were swallowed and passed the gut unharmed. Thus, even these smaller lemur species play an important role in seed dispersal. There were no differences in the morphological and biochemical characteristics of fruits eaten between the three species, but the feeding height was significantly different between the species. Thus, competition avoidance and niche separation are presumably not based on different feeding patterns of M. murinus , C. medius and C. major in the littoral rainforest, but on different habitat utilization.     

Reversal of height dimorphism promotes pollen and seed dispersal in a wind-pollinated dioecious plant

Variation in the timing of reproductive functions in dioecious organisms may result in adaptive changes in the direction of sexual dimorphism during the breeding season. For plants in which both pollen and seeds are wind-dispersed, it may be advantageous for male plants to be taller when pollen is dispersed and female plants to be taller when seeds are dispersed. We examined the dynamics of height dimorphism in Rumex hastatulus, an annual, wind-pollinated, dioecious plant from the southern USA. A field survey of seven populations indicated that females were significantly taller than males at seed maturity. However, a glasshouse experiment revealed a more complex pattern of height growth during the life cycle. No dimorphism was evident prior to reproduction for six of seven populations, but at flowering, males were significantly taller than females in all populations. This pattern was reversed at reproductive maturity, consistent with field observations. Males flowered later than females and the degree of height dimorphism was greater in populations with a later onset of male flowering. We discuss the potential adaptive significance of temporal changes in height dimorphism for pollen and seed dispersal, and how this may be optimized for the contrasting reproductive functions of the sexes.