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1.
PLoS One ; 17(4): e0265339, 2022.
Article in English | MEDLINE | ID: mdl-35385500

ABSTRACT

The nematode genus Bursaphelenchus is a highly divergent group. This genus mainly consists of mycophagous entomophilic species, but some species have specialized as obligate or facultative plant parasites, facultative insect parasites, or exhibit feeding dimorphism (phenotypic plasticity) leading to mycophagous and predatory forms. In the present study, a new Bursaphelenchus species, B. suri n. sp. was isolated from fresh syconia (figs) of Ficus sur and is described and illustrated based on its typological characters and molecular phylogenetic status. The new species is characterized by its highly derived feeding structures found in obligate plant parasites, lip possessing a labial disc and a long and thick stylet with a long conus and extremely well-developed basal swellings. In addition, slender body of both sexes is characteristic of the species. The new species is phylogenetically and typologically closely related to B. sycophilus, i.e., these two species share the characteristic feeding structures and form a well-supported clade within the B. fungivorus group in the genus. Biologically, these two species are both isolated from fresh figs of the section Sycomorus. However, the new species differs from B. sycophilus by the length of the female post-uterine sac and the shape of the male spicule, i.e., the new species has a long post-uterine sac and spicule condylus without dorsal recurvature. Thus, the new species is the second obligate fig parasite of the genus, and the evolutionary relationship between the B. suri n. sp. and B. sycophilus clade and section Sycomorus figs is hypothesized as an example of adaptive radiation with more species to be discovered.


Subject(s)
Ficus , Parasites , Rhabditida , Animals , Biological Evolution , Female , Ficus/parasitology , Male , Phylogeny
2.
Proc Natl Acad Sci U S A ; 118(32)2021 08 10.
Article in English | MEDLINE | ID: mdl-34341115

ABSTRACT

Theory identifies factors that can undermine the evolutionary stability of mutualisms. However, theory's relevance to mutualism stability in nature is controversial. Detailed comparative studies of parasitic species that are embedded within otherwise mutualistic taxa (e.g., fig pollinator wasps) can identify factors that potentially promote or undermine mutualism stability. We describe results from behavioral, morphological, phylogenetic, and experimental studies of two functionally distinct, but closely related, Eupristina wasp species associated with the monoecious host fig, Ficus microcarpa, in Yunnan Province, China. One (Eupristina verticillata) is a competent pollinator exhibiting morphologies and behaviors consistent with observed seed production. The other (Eupristina sp.) lacks these traits, and dramatically reduces both female and male reproductive success of its host. Furthermore, observations and experiments indicate that individuals of this parasitic species exhibit greater relative fitness than the pollinators, in both indirect competition (individual wasps in separate fig inflorescences) and direct competition (wasps of both species within the same fig). Moreover, phylogenetic analyses suggest that these two Eupristina species are sister taxa. By the strictest definition, the nonpollinating species represents a "cheater" that has descended from a beneficial pollinating mutualist. In sharp contrast to all 15 existing studies of actively pollinated figs and their wasps, the local F. microcarpa exhibit no evidence for host sanctions that effectively reduce the relative fitness of wasps that do not pollinate. We suggest that the lack of sanctions in the local hosts promotes the loss of specialized morphologies and behaviors crucial for pollination and, thereby, the evolution of cheating.


Subject(s)
Ficus/parasitology , Host-Parasite Interactions , Wasps/physiology , Animals , Behavior, Animal , Biological Evolution , China , Female , Ficus/physiology , Head/anatomy & histology , Oviposition , Phylogeny , Pollen , Pollination , Seasons , Seeds/growth & development , Symbiosis , Wasps/anatomy & histology
3.
Planta ; 253(2): 37, 2021 Jan 19.
Article in English | MEDLINE | ID: mdl-33464406

ABSTRACT

MAIN CONCLUSION: Genes of the PLAT protein family, including PLAT and ATS3 subfamilies of higher plants and homologs of liverwort, are involved in plant defense against insects. Laticifer cells in plants contain large amounts of anti-microbe or anti-insect proteins and are involved in plant defense against biotic stresses. We previously found that PLAT proteins accumulate in laticifers of fig tree (Ficus carica) at comparable levels to those of chitinases, and the transcript level of ATS3, another PLAT domain-containing protein, is highest in the transcriptome of laticifers of Euphorbia tirucalli. In this study, we investigated whether the PLAT domain-containing proteins are involved in defense against insects. Larvae of the lepidopteran Spodoptera litura showed retarded growth when fed with Nicotiana benthamiana leaves expressing F. carica PLAT or E. tirucalli ATS3 genes, introduced by agroinfiltration using expression vector pBYR2HS. Transcriptome analysis of these leaves indicated that ethylene and jasmonate signaling were activated, leading to increased expression of genes for PR-1, ß-1,3-glucanase, PR5 and trypsin inhibitors, suggesting an indirect mechanism of PLAT- and ATS3-induced resistance in the host plant. Direct cytotoxicity of PLAT and ATS3 to insects was also possible because heterologous expression of the corresponding genes in Drosophila melanogaster caused apoptosis-mediated cell death in this insect. Larval growth retardation of S. litura occurred when they were fed radish sprouts, a good host for agroinfiltration, expressing any of nine homologous genes of dicotyledon Arabidopsis thaliana, monocotyledon Brachypodium distachyon, conifer Picea sitchensis and liverwort Marchantia polymorpha. Of these nine genes, the heterologous expression of A. thaliana AT5G62200 and AT5G62210 caused significant increases in larval death. These results indicated that the PLAT protein family has largely conserved anti-insect activity in the plant kingdom (249 words).


Subject(s)
Arabidopsis , Gene Expression Regulation, Plant , Insecta , Plant Proteins , Plants , Animals , Arabidopsis/metabolism , Chitinases/metabolism , Drosophila melanogaster/drug effects , Ficus/genetics , Ficus/parasitology , Insecta/drug effects , Larva/drug effects , Plant Proteins/genetics , Plant Proteins/metabolism , Plant Proteins/pharmacology , Plants/genetics , Plants/parasitology , Spodoptera/drug effects , Transcriptome
4.
Genes (Basel) ; 11(10)2020 09 29.
Article in English | MEDLINE | ID: mdl-33003564

ABSTRACT

Chemosensory proteins (CSP) are a class of acidic soluble proteins which have various functions in chemoreception, resistance and immunity, but we still have very little knowledge on this gene family in fig wasps, a peculiar insects group (Hymenoptera, Chalcidoidea) that shelter in the fig syconia of Ficus trees. Here, we made the first comprehensive analysis of CSP gene family in the 11 fig wasps at whole-genome level. We manually annotated 104 CSP genes in the genomes of the 11 fig wasps, comprehensively analyzed them in gene characteristics, conserved cysteine patterns, motif orders, phylogeny, genome distribution, gene tandem duplication, and expansion and contraction patterns of the gene family. We also approximately predicted the gene expression by codon adaptation index analysis. Our study shows that the CSP gene family is conserved in the 11 fig wasps; the CSP gene numbers in pollinating fig wasps are less than in non-pollinating fig wasps, which may be due to their longer history of adaptation to fig syconia; the expansion of CSP gene in two non-pollinating fig wasps, Philotrypesis tridentata and Sycophaga agraensis, may be a species-specific phenomenon. These results provide us with useful information for understanding the evolution of the CSP gene family of insects in diverse living environments.


Subject(s)
Gene Expression Regulation , Insect Proteins/genetics , Multigene Family , Receptors, Odorant/genetics , Wasps/genetics , Animals , Ficus/parasitology , Gene Expression Profiling , Genome-Wide Association Study , Insect Proteins/metabolism , Phylogeny , Receptors, Odorant/metabolism
5.
Sci Rep ; 10(1): 14941, 2020 09 10.
Article in English | MEDLINE | ID: mdl-32913204

ABSTRACT

The fig tree-fig pollinator mutualism is one of the most tightly knit symbiotic systems. The research on the ecology of non-pollinators which exploit the mutualism without providing services to the host is very limited and conclusions about the role they play in the maintenance of this mutualism are full of contradictions. The non-pollinating fig wasps species are highly diverse in their feeding habit and ecological function, which may result in different consequences on the mutualism. Sycophaga testacea is an early-ovipositing galler hosted by Ficus racemosa, which is a potencial competitor to the pollinators as they use the same female flowers in the fig as their ovipositing sites. In this study, we investigate the effect of S. testacea on the production of both pollinator and fig tree with a field control experiment. Seed production is decreased significantly when the figs were parasitized, while the offspring production of the pollinator is not significantly affected, which indicates that this galler species has a harmful effect on the fitness of its host fig tree but not the pollinator. The overall development ratio of the galls is decreased significantly when the figs were parasitized, and we found that the intrinsic low development ratio of S. testacea is responsible for the decrease in the overall development ratio.


Subject(s)
Ficus/parasitology , Host-Parasite Interactions , Trees/parasitology , Wasps/physiology , Animals , Ficus/physiology , Oviposition , Pollination , Symbiosis , Trees/physiology
6.
Int J Biol Macromol ; 164: 1665-1674, 2020 Dec 01.
Article in English | MEDLINE | ID: mdl-32758613

ABSTRACT

Intraspecific male polymorphism exhibiting extreme differences in morphology, behavior and life history presents good opportunities to explore adaptation mechanisms to different environments. In this study, we examined the transcriptomic differences between wingless and winged morphs of a fig wasp species Philotrypesis tridentata to investigate molecular basis to maintain polymorphisms. The winged male adults fly outside fig syconia to mate, while the wingless only stay and mate inside fig syconia where they have developed. We identified 2,391 differentially expressed genes (DEGs) with 1,396 highly expressed in winged morphs and 995 in wingless morphs. We performed Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses on the DEGs and differential alternative splicing genes and analyzed the top ten DEGs with the highest differential expression in each morph. The results showed that genes related to biosynthesis processes, lipid metabolism, energy production, flight and defense of the complex environments outside fig syconia were up-regulated in winged morphs. Genes involved in substance and energy metabolism and chemical reception were up-regulated in wingless morphs which might relate to their living inside fig syconia. The differences in highly expressed genes between two morphs prove adaptation of P. tridentata male polymorphism to different living environments.


Subject(s)
Ficus/parasitology , Polymorphism, Genetic/genetics , Transcriptome/genetics , Wasps/genetics , Animals , Gene Expression Profiling/methods , Gene Ontology , Lipid Metabolism/genetics , Male , Wings, Animal
7.
J Appl Microbiol ; 129(2): 400-410, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32043673

ABSTRACT

AIMS: To isolate and characterize a native strain of Trichothecium roseum infecting the immatures of Pauropsylla buxtoni on fig leaves, to study the morphological features of the isolated strain, then to test the entomopathogenic effect of the isolated strain against the immatures of P. buxtoni on fig leaves. METHODS AND RESULTS: The isolated strain of T. roseum produced pink mycelial growth on culture medium with septate mycelium and conidiophores. It also produced two-celled conidia with elliptical to pyriform shape born at the tip of conidiophores. Molecular characterization of the isolated strain confirmed the identity of the strain as T. roseum. In bioassays, application of conidial suspension of the isolated strain against the 4th instar of P. buxtoni immatures infesting fig leaves showed an obvious entomopathogenic effect of the applied fungus strain against the targeted insect. This effect was exhibited by the death of treated P. buxtoni immatures with the fungus. The dead insects were characterized by the presence of pinkish mycelial growth on the outer surface which is characteristic to the fungus, in addition to the positive isolation of the fungus from internal tissues of treated insects after a proper external disinfection. Moreover, significant differences (at P < 0·018) were obtained between the means of mortality % of P. buxtoni immatures treated with different concentrations of conidial suspension of the fungus. CONCLUSIONS: The overall results confirm the entomopathogenic effect of T. roseum against P. buxtoni immatures infesting fig leaves. Significant mortalities of P. buxtoni immatures were obtained when the different concentrations of the fungus conidial suspension were bio-assessed against the insect. SIGNIFICANCE AND IMPACT OF THE STUDY: The tested strain of T. roseum can be applied as biocontrol agent of P. buxtoni on fig leaves within an integrated control programme to reduce the impact of pest on fig trees.


Subject(s)
Ficus/parasitology , Hemiptera/microbiology , Hypocreales/pathogenicity , Pest Control, Biological/methods , Plant Diseases/prevention & control , Animals , Hemiptera/growth & development , Hypocreales/classification , Hypocreales/cytology , Hypocreales/growth & development , Larva/growth & development , Larva/microbiology , Plant Diseases/parasitology , Plant Leaves/parasitology , Spores, Fungal/classification , Spores, Fungal/cytology , Spores, Fungal/growth & development
8.
Mol Ecol ; 28(17): 3958-3976, 2019 09.
Article in English | MEDLINE | ID: mdl-31338917

ABSTRACT

Even though speciation involving multiple interacting partners, such as plants and their pollinators, has attracted much research, most studies focus on isolated phases of the process. This currently precludes an integrated understanding of the mechanisms leading to cospeciation. Here, we examine population genetic structure across six species-pairs of figs and their pollinating wasps along an elevational gradient in New Guinea. Specifically, we test three hypotheses on the genetic structure within the examined species-pairs and find that the hypothesized genetic structures represent different phases of a single continuum, from incipient cospeciation to the full formation of new species. Our results also illuminate the mechanisms governing cospeciation, namely that fig wasps tend to accumulate population genetic differences faster than their figs, which initially decouples the speciation dynamics between the two interacting partners and breaks down their one-to-one matching. This intermediate phase is followed by genetic divergence of both partners, which may eventually restore the one-to-one matching among the fully formed species. Together, these findings integrate current knowledge on the mechanisms operating during different phases of the cospeciation process. They also reveal that the increasingly reported breakdowns in one-to-one matching may be an inherent part of the cospeciation process. Mechanistic understanding of this process is needed to explain how the extraordinary diversity of species, especially in the tropics, has emerged. Knowing which breakdowns in species interactions are a natural phase of cospeciation and which may endanger further generation of diversity seems critical in a constantly changing world.


Subject(s)
Ficus/genetics , Ficus/parasitology , Genetic Speciation , Host-Pathogen Interactions/genetics , Wasps/genetics , Animals , Geography , Phylogeny , Species Specificity
9.
Planta ; 249(3): 617-633, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30689053

ABSTRACT

Ficus species have adapted to diverse environments and pests by developing physical or chemical protection strategies. Physical defences are based on the accumulation of minerals such as calcium oxalate crystals, amorphous calcium carbonates and silica that lead to tougher plants. Additional cellular structures such as non-glandular trichomes or laticifer cells make the leaves rougher or sticky upon injury. Ficus have also established structures that are able to produce specialized metabolites (alkaloids, terpenoids, and phenolics) or proteins (proteases, protease inhibitors, oxidases, and chitinases) that are toxic to predators. All these defence mechanisms are distributed throughout the plant and can differ depending on the genotype, the stage of development or the environment. In this review, we present an overview of these strategies and discuss how these complementary mechanisms enable effective and flexible adaptation to numerous hostile environments.


Subject(s)
Ficus/physiology , Ficus/immunology , Ficus/microbiology , Ficus/parasitology , Herbivory , Plant Leaves/immunology , Plant Leaves/physiology
10.
J Food Prot ; 82(2): 184-188, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30667293

ABSTRACT

In this study, microwave heating was employed for controlling Oryzaephilus surinamensis adult beetles infesting stored Iranian dried figs. The dried fig samples were artificially infested with O. surinamensis and then heated in a microwave oven (2,450 MHz) at power outputs of 450, 720, and 900 W for 20, 30, 40, and 50 s. Changes in the color of the samples after these microwave applications were evaluated for lightness (ΔL*), redness (Δa*), and yellowness (Δb*) using an image processing technique. Both parameters of microwave power and exposure time had significant effects on beetle mortality ( P < 0.01). A direct positive relationship was found between the mortality rate and microwave power. Complete mortality was achieved at 900 W and for 50 s. The color parameters of the dried fig samples did not change significantly. These results indicate that microwave irradiation can be introduced as an appropriate alternative to chemical fumigants without affecting product quality.


Subject(s)
Coleoptera , Ficus , Insect Control/methods , Microwaves , Animals , Coleoptera/growth & development , Coleoptera/radiation effects , Color , Ficus/parasitology , Ficus/radiation effects , Insecta , Iran
11.
Nat Prod Res ; 33(4): 544-547, 2019 Feb.
Article in English | MEDLINE | ID: mdl-29098872

ABSTRACT

The present study is aimed to evaluate the total phenolic and flavonoid contents, and free phenolic compounds of acetone extract of Cuscuta reflexa grown on five different hosts: Coccinia grandis, Ficus racemosa, Samanea saman, Streblus asper and Zollingeria dongnaiensis, and to explore the antioxidant activities, α-glucosidase and tyrosinase inhibitory properties of the extracts. The highest level of total phenolic and flavonoid contents were observed in the extract of C. reflexa that was grown on S. asper (65.45 mg GAE/g extract) and C. grandis (97.83 mg QE/g extract), respectively. According to HPLC results, vanillic acid, rutin and quercetin were found in all extracts of C. reflexa grown on diversified hosts. The extract of C. reflexa grown on C. grandis possessed the greatest antioxidant activities (DPPH; 251.64 µg/mL, FRAP; 26.44 mg GAE/g extract), α-glucosidase inhibition accounted for 84.36 per cent and antityrosinase activity was at 18.29 mg KAE/g sample.


Subject(s)
Antioxidants/chemistry , Cuscuta/chemistry , Plant Extracts/chemistry , Acetone/chemistry , Antioxidants/isolation & purification , Chromatography, High Pressure Liquid , Ficus/parasitology , Flavonoids/analysis , Glycoside Hydrolase Inhibitors/chemistry , Monophenol Monooxygenase/antagonists & inhibitors , Phenols/analysis , Species Specificity
12.
Biol Lett ; 14(10)2018 10 31.
Article in English | MEDLINE | ID: mdl-30381449

ABSTRACT

Communities in which species are obligately associated with a single host are ideal to test adaptive responses of community traits to host-imposed selection because such communities are often highly insulated. Fig species provide oviposition resources to co-evolved fig-wasp communities. Dispersing fig-wasp communities move from one host plant to another for oviposition. We compared the spatial dispersion of two fig species and the dispersal capacities of their multitrophic wasp communities. Dispersal capacities were assessed by measuring vital dispersal correlates, namely tethered flight durations, somatic lipid contents and resting metabolic rates. We suggest that dispersal-trait distributions of congeneric wasp species across the communities are an adaptive response to host plant dispersion. Larger dispersal capacities of the entire multitrophic community are related to more widely dispersed resources. Our results provide evidence and a novel perspective for understanding the potential role of adaptation in whole-community dispersal-trait distributions.


Subject(s)
Animal Distribution , Ficus/parasitology , Plant Dispersal , Wasps/physiology , Adaptation, Biological , Animals , Biological Coevolution , Female , India , Oviposition , Species Specificity
13.
BMC Evol Biol ; 18(1): 134, 2018 09 04.
Article in English | MEDLINE | ID: mdl-30180795

ABSTRACT

BACKGROUND: While the communities constituted by phytophageous insects and their parasites may represent half of all terrestrial animal species, understanding their diversification remains a major challenge. A neglected idea is that geographic phenotypic variation in a host plant may lead to heterogeneous evolutionary responses of the different members of the associated communities. This could result in diversification on a host plant by ecological speciation in some species, leading to geographic variation in community composition. In this study we investigated geographic variation of inflorescence receptacle size in a plant, Ficus hirta, and how the hymenopteran community feeding in the inflorescences has responded. Our predictions were: 1) Inflorescence size variation affects wasp species differently depending on how they access oviposition sites. 2) In some affected lineages of wasps, we may observe vicariant, parapatric species adapted to different inflorescence sizes. RESULTS: We show that fig (the enclosed inflorescence of Ficus) wall thickness varies geographically. The fig-entering pollinating wasp was not affected, while the parasites ovipositing through the fig wall were. Two parapatric species of Philotrypesis, exhibiting strikingly different ovipositor lengths, were recorded. One species of Sycoscapter was also present, and it was restricted, like the shorter-ovipositor Philotrypesis, to the geographic zone where fig walls were thinner. CONCLUSIONS: Previous work on fig wasps suggested that parapatric geographic ranges among congenerics were due to adaptation to variation in abiotic factors, complemented by interspecific competition. Our results show that parapatric ranges may also result from adaptation to variation in biotic factors. Within an insect community, differences among species in their response to geographic phenotypic variation of their host plant may result in geographically heterogeneous community structure. Such heterogeneity leads to heterogeneous interaction networks among sites. Our results support the hypothesis that plant geographic phenotypic variation can be a driver of diversification in associated insect communities, and can complement other diversification processes.


Subject(s)
Biological Variation, Population , Ficus/parasitology , Geography , Parasites/physiology , Wasps/physiology , Wasps/parasitology , Animals , Female , Ficus/anatomy & histology , Ficus/genetics , Inflorescence/anatomy & histology , Inflorescence/physiology , Microsatellite Repeats/genetics , Oviposition/physiology , Pollination , Sample Size
14.
PLoS One ; 13(7): e0199417, 2018.
Article in English | MEDLINE | ID: mdl-29995895

ABSTRACT

A new nematode species of the genus Parasitodiplogaster was recovered from syconia of Ficus religiosa at the Guangxiao Temple, Guangzhou, China. It is described herein as P. religiosae n. sp. and is characterised by possessing the longest and thinnest spicule of all currently described males in the genus, an elongated laterally "ε-shaped" and ventrally rhomboid-like gubernaculum, a stoma without teeth, consisting of a ring-like cheilostom with indistinct anteriolateral projections, a tube-like gymnostom and a funnel-like stegostom, monodelphic with a mean vulval position of 66%. There are three pre-cloacal and six post-cloacal male genital papillae with the arrangement P1, P2, P3, (C, P4), P5, P6d, P7, P8, P9d, Ph. This new species was easily differentiated from other members of the genus by DNA sequences of partial small subunit rRNA gene (SSU) and the D2-D3 expansion segments of the large subunit rRNA gene (LSU). Phylogenetic analysis also corroborated its reasonable placement within a well-supported monophyletic clade with other Parasitodiplogaster species and within the australis-group that includes P. australis and P. salicifoliae that are all associates of fig wasp pollinators (Platyscapa sp.) of figs of the subsection Urostigma.


Subject(s)
Ficus/parasitology , Nematoda/anatomy & histology , Nematoda/genetics , Animals , Bayes Theorem , China , Female , Genes, Protozoan , Male , Nematoda/classification , Phylogeny
15.
PLoS One ; 13(6): e0198018, 2018.
Article in English | MEDLINE | ID: mdl-29864131

ABSTRACT

The interplay with bacteria is of crucial importance for the interaction of multicellular organisms with their environments. Studying the associations between the nematode model organisms Caenorhabditis elegans and Pristionchus pacificus with bacteria constitutes a powerful system to investigate these interactions at a mechanistic level. P. pacificus is found in association with scarab beetles in nature and recent studies revealed the succession and dynamics of this nematode and its microbiome during the decomposition of one particular host species, the rhinoceros beetle Oryctes borbonicus on La Réunion Island. However, these studies were performed using culture-free methods, with no attempt made to establish bacterial cultures from the beetle-nematode ecosystem and to investigate the effects of these microbes on life history traits in P. pacificus. Here, we establish and characterize a collection of 136 bacterial strains that have been isolated from scarab beetles and figs, another Pristionchus-associated environment, as a resource for studying their effect on various nematode traits. Classification based on 16S sequencing identified members of four bacterial phyla with the class of Gammaproteobacteria representing the majority with 81 strains. Assessing the survival of P. pacificus on individual bacteria allowed us to propose candidate groups of pathogens such as Bacillaceae, Actinobacteria, and Serratia. In combination with chemoattraction data, it was revealed that P. pacificus is able to recognize and avoid certain groups of pathogens, but not others. Our collection of bacterial strains forms a natural resource to study the effects of bacterial diet on development and other traits. Furthermore, these results will form the basis of future studies to elucidate the molecular mechanisms of recognition and pathogenicity.


Subject(s)
Caenorhabditis elegans/microbiology , Coleoptera/microbiology , Culture Techniques , Escherichia coli/physiology , Ficus/microbiology , Host-Pathogen Interactions , Microbiota , Animals , Caenorhabditis elegans/physiology , Chemotaxis , Coleoptera/parasitology , Escherichia coli/cytology , Escherichia coli/growth & development , Ficus/parasitology
16.
Sci Rep ; 8(1): 1833, 2018 01 30.
Article in English | MEDLINE | ID: mdl-29382931

ABSTRACT

Different types of mutualisms may interact, co-evolve and form complex networks of interdependences, but how species interact in networks of a mutualistic community and maintain its stability remains unclear. In a mutualistic network between treehoppers-weaver ants and fig-pollinating wasps, we found that the cuticular hydrocarbons of the treehoppers are more similar to the surface chemical profiles of fig inflorescence branches (FIB) than the cuticular hydrocarbons of the fig wasps. Behavioral assays showed that the cuticular hydrocarbons from both treehoppers and FIBs reduce the propensity of weaver ants to attack treehoppers even in the absence of honeydew rewards, suggesting that chemical camouflage helps enforce the mutualism between weaver ants and treehoppers. High levels of weaver ant and treehopper abundances help maintain the dominance of pollinating fig wasps in the fig wasp community and also increase fig seed production, as a result of discriminative predation and disturbance by weaver ants of ovipositing non-pollinating fig wasps (NPFWs). Ants therefore help preserve this fig-pollinating wasp mutualism from over exploitation by NPFWs. Our results imply that in this mutualistic network chemical camouflage plays a decisive role in regulating the behavior of a key species and indirectly shaping the architecture of complex arthropod-plant interactions.


Subject(s)
Ants/physiology , Biological Mimicry/physiology , Hemiptera/physiology , Symbiosis/physiology , Wasps/physiology , Animals , Biological Evolution , Ficus/parasitology , Host-Parasite Interactions/physiology , Hydrocarbons/metabolism , Inflorescence/physiology , Pollination/physiology , Predatory Behavior/physiology , Seeds/parasitology
17.
BMC Ecol ; 17(1): 35, 2017 11 14.
Article in English | MEDLINE | ID: mdl-29137616

ABSTRACT

BACKGROUND: Figs are widely distributed key resources to many tropical-subtropical animals, and flying-foxes are major consumers and seed dispersers of figs. Bat-fig interrelationships, however, may vary among species differing in fruiting traits, i.e., bat- versus bird-dispersed figs. We examined Ryukyu flying-fox foraging dispersion and the relationships with tree species composition and fig abundance in forests of Iriomote Island. RESULTS: Bat foraging dispersion showed no spatial patterns with respect to different areas of the island, and was not explained by heterogeneity, density, or basal area (BA) of total trees, nor by relative density or BA of fruiting trees or total fruiting figs among sites. Instead, bat densities were positively dependent on the relative density of total figs, and particularly the relative BA of bat-dispersed figs Ficus septica and F. variegata. Both species were dominant figs in forests, fruiting asynchronously with long crop seasons, and were used as predominant foods. Bats foraged mostly solitarily and the mean density was in a hump-shaped relationship with crop sizes of the dominant bat-figs. These two species and Ficus benguetensis are larger-sized bat-figs, all contained more seeds, higher dry-pulp mass and water mass, but not necessarily water content. By approximate estimation, higher proportions of seeds of these bat-figs would have been removed from fruits through the bat consumption, than that of small-sized bird-figs like F. virgata, F. superba, and F. microcarpa. CONCLUSIONS: The foraging dispersion of Ryukyu flying-foxes in forests depends on the availability of the most abundant bat-figs that serve as predominant foods. Intermediate levels of crop sizes of theses figs appear most fit with their solitary foraging. Our results suggest that as density and BA coverage of these dominant bat-figs are below a certain level, their effectiveness to attract bats may dwindle and so would their chance of dispersal by bats.


Subject(s)
Chiroptera/physiology , Ficus/parasitology , Animals , Birds/physiology , Asia, Eastern , Feeding Behavior , Female , Ficus/growth & development , Ficus/physiology , Forests , Islands , Male , Seasons , Seed Dispersal , Trees/growth & development , Trees/parasitology , Trees/physiology
18.
J Exp Biol ; 220(Pt 9): 1554-1557, 2017 05 01.
Article in English | MEDLINE | ID: mdl-28468812

ABSTRACT

We show that the insect ovipositor is an olfactory organ that responds to volatiles and CO2 in gaseous form. We demonstrate this phenomenon in parasitic wasps associated with Ficus racemosa where ovipositors, as slender as a human hair, drill through the syconium (enclosed inflorescences) and act as a guiding probe to locate highly specific egg-laying sites hidden inside. We hypothesize that olfaction will occur in the ovipositors of insects such as parasitic fig wasps where the hosts are concealed and volatile concentrations can build up locally. Relevant stimuli such as herbivore-induced fig volatiles and CO2 elicited electrophysiological responses from the ovipositors. Silver nitrate staining also revealed pores in ovipositor sensilla, indicating their olfactory nature. Insects could use volatile sensors on their ovipositors to evaluate ecologically relevant stimuli for oviposition. Further investigations on the sensory nature of ovipositors can provide designs for development of ovipositor-inspired micro-chemosensors.


Subject(s)
Wasps/physiology , Animals , Carbon Dioxide/metabolism , Female , Ficus/parasitology , Oviposition/physiology , Sensilla/physiology , Sensory Receptor Cells/physiology , Volatile Organic Compounds/metabolism , Wasps/anatomy & histology , Wasps/ultrastructure
19.
Zootaxa ; 4196(4): zootaxa.4196.4.6, 2016 Nov 24.
Article in English | MEDLINE | ID: mdl-27988656

ABSTRACT

A new species group, the brevis-group, is established for two new species of the fig wasp genus Sycophaga Westwood (Hymenoptera: Agaonidae) reared from the monoecious fig tree Ficus orthoneura (Moraceae, Ficus, subgenus Urostigma) in China. The two new species, S. brevis n. sp. and S. diutius n. sp. are described and illustrated, supplemented by COI sequence data. In contrast with two other species groups newly recognized in Sycophaga, the explorator-group for species previously classified in Apocryptophagus Ashmead and the sycomori-group for other species previously classified in Sycophaga, the brevis-group is uniquely defined by the long pronotum of females and a Ficus host within the subgenus Urostigma.


Subject(s)
Wasps/anatomy & histology , Wasps/classification , Animals , China , Female , Ficus/parasitology , Male , Sequence Analysis, DNA , Species Specificity , Wasps/genetics
20.
Zootaxa ; 4138(1): 189-94, 2016 Jul 14.
Article in English | MEDLINE | ID: mdl-27470760

ABSTRACT

In summer 2014, the bark beetle Hypocryphalus scabricollis (Eichhoff) and the ambrosia beetle Xyleborus bispinatus Eichhoff, species new to Italy and Europe, respectively, were found for the first time in south-eastern Sicily (Italy). Large infestations of the two species were recorded in many plantations of common fig (Ficus carica L.) both in 2014 and 2015. Data concerning insect characteristics, taxonomy, and distribution are briefly reported.


Subject(s)
Coleoptera/classification , Ficus/parasitology , Plant Diseases/parasitology , Animal Distribution , Animal Structures/anatomy & histology , Animal Structures/growth & development , Animals , Body Size , Coleoptera/anatomy & histology , Coleoptera/growth & development , Female , Male , Organ Size , Seasons , Sicily
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