Observations on the population genetic structure of the leaf galling nematode, Ditylenchus gallaeformans

2021 ◽  
Author(s):  
Samara Azevedo de Oliveira ◽  
J Antonio Baeza ◽  
Paula Agudelo ◽  
Saara J. DeWalt
Keyword(s):  
Costa Rica ◽  
Host Species ◽  
Biological Control Agent ◽  
Geographical Location ◽  
Geographic Location ◽  
Control Agent ◽  
Genetic Differences ◽  
Host Preferences ◽  
Phylogenetic Reconstructions ◽  
Haplotype Networks

Ditylenchus gallaeformans is a plant parasitic nematode that induces galls on aboveground parts of Melastomataceae plants. It differs from most gall-inducing nematodes in that it is not an endoparasite, and has been considered as a possible biological control agent against invasive species of Miconia . Little is known about D. gallaeformans biology, genetic differences among populations and host preferences. This study examined the genetic differences among D. gallaeformans populations from different locations and host species and the phylogenetic relationships among them. Nematodes were collected from galls in plants from Costa Rica, Dominica, and Trinidad. The Cytochrome c oxidase 1 (cox1) region was sequenced from a total of 33 individual nematodes isolated from 33 different plant individuals, representing 21 species of Melastomataceae. Phylogenetic reconstructions, haplotype networks, and analysis of molecular variance showed that the species is monophyletic and has three major clades, which were mostly consistent with geographic location but not with host species. The first clade was composed by two subclades, one with individuals from Costa Rica and one with individuals from Dominica. The second and third clades comprised nematodes only from Trinidad. Overall, there is no evidence of host-species specialization in D. gallaeformans . Biocontrol efforts using the nematode against invasive Miconia could focus on geographical location matching but likely will not need to match host species.

scholarly journals Wolbachia (Rickettsiales: Alphaproteobacteria) Infection in the Leafhopper Vector of Sugarcane White Leaf Disease

2020 ◽  
Vol 20 (3) ◽  
Author(s):  
Jureemart Wangkeeree ◽  
Panida Tewaruxsa ◽  
Jariya Roddee ◽  
Yupa Hanboonsong
Keyword(s):  
Biological Control Agent ◽  
Insect Pest ◽  
Geographic Location ◽  
Control Agent ◽  
Phylogenic Tree ◽  
Gene Markers ◽  
Leaf Disease ◽  
White Leaf ◽  
White Leaf Disease ◽  
Wsp Gene

Abstract Wolbachia is a maternally inherited bacterium ubiquitous in insects that has attracted interest as a prospective insect pest-control agent. Here, we detected and characterized Wolbachia in the leafhoppers Matsumuratettix hiroglyphicus (Matsumura) (Cicadellidae: Hemiptera) and Yamatotettix flavovittatus Matsumura (Cicadellidae: Hemiptera), insect vectors of the phytoplasma that cause white leaf disease in sugarcane. The 16S rRNA and wsp gene markers revealed that Wolbachia was not present in the M. hiroglyphicus but naturally occurs in Y. flavovittatus. Additionally, the infection rates in adult leafhoppers ranged from 0 to 100% depending on geographic location. Moreover, Wolbachia was detected in the eggs and first- to fifth-instar nymphs of Y. flavovittatus. A phylogenic tree of Wolbachia indicated that it resided in the monophyletic supergroup B clade and clustered in the Ori subgroup. Furthermore, fluorescence in situ hybridization revealed that Wolbachia localized to the egg apices, randomly distributed in the egg cytoplasm, and was concentrated in the nymph and adult bacteriomes, as well as occasional detection in the thorax and abdomen. To the best of our knowledge, the present study is the first to demonstrate the prevalence of Wolbachia in the leafhopper Y. flavovittatus. The obtained results would provide useful information for the future development of Wolbachia as a biological control agent for the leafhopper vectors.

scholarly journals Natural variation in chemoattraction in the gastropod parasitic nematodes Phasmarhabditis hermaphrodita, P. neopapillosa and P. californica exposed to slug mucus

Nematology ◽  
2019 ◽  
Vol 21 (5) ◽  
pp. 479-488 ◽  
Author(s):  
Peter Andrus ◽  
Robbie Rae
Keyword(s):  
Biological Control ◽  
Host Species ◽  
Natural Variation ◽  
Biological Control Agent ◽  
Control Agent ◽  
Parasitic Nematodes ◽  
Natural Isolates ◽  
Volatile Cues ◽  
Phasmarhabditis Hermaphrodita

Summary Phasmarhabditis hermaphrodita is a lethal parasite of several slug species and has been formulated into a biological control agent for farmers and gardeners. Phasmarhabditis hermaphrodita responds to slug faeces, mucus and volatile cues to find hosts in soil. However, these results have only focused on one strain of P. hermaphrodita (DMG0001). We exposed four strains of P. hermaphrodita (and DMG0001), three strains of P. neopapillosa and two strains of P. californica to mucus from seven common slug species. Furthermore, we investigated whether there was a relationship between chemoattraction and the numbers of offspring that were produced on each host species. Natural isolates of P. hermaphrodita differed in their preference of slug species whereas P. neopapillosa tended to prefer Arion sp. and strains of P. californica displayed striking differences in their responses. The reasons for positive chemoattraction to mucus were not due to higher numbers of offspring produced on these hosts.

scholarly journals Effects of host species identity and diet on biodiversity of oral and rectal microbiomes of Puerto Rican bats

2020 ◽  
Author(s):  
Steven J. Presley ◽  
Joerg Graf ◽  
Ahmad F. Hassan ◽  
Anna R. Sjodin ◽  
Michael R. Willig
Keyword(s):  
Host Species ◽  
Geographical Location ◽  
Geographic Location ◽  
Oral Microbiome ◽  
Host Immune System ◽  
Species Identity ◽  
Symbiotic Relationships ◽  
Vital Functions ◽  
Host Sex ◽  
Host Characteristics

AbstractMicrobiomes perform vital functions for their mammalian hosts, making them potential drivers of host evolution. Understanding effects of environmental factors and host characteristics on the composition and biodiversity of microbiomes may provide novel insights into the origin and maintenance of these symbiotic relationships. Our goals were to (1) characterize biodiversity of oral and rectal microbiomes of bats in Puerto Rico; and (2) determine the effects of geographic location and host characteristics on that biodiversity. We collected bats and their microbiomes from 3 sites, and used 4 metrics (species richness, Shannon diversity, Camargo evenness, Berger-Parker dominance) to characterize biodiversity. We evaluated the relative importance of site, host sex, host species identity, and host foraging guild on microbiome biodiversity. Microbiome biodiversity was highly variable among conspecifics. Geographical location exhibited consistent effects, whereas host sex did not do so. Within each host guild, host species exhibited consistent differences in oral and rectal microbiome biodiversity. Oral microbiome biodiversity was indistinguishable between guilds, whereas rectal microbiome biodiversity was significantly greater in carnivores than in herbivores. The high intraspecific and spatial variation in microbiome biodiversity necessitate a large number of samples to isolate the effects of environmental or host characteristics on microbiomes. Species-specific biodiversity of oral microbiomes suggests these communities are structured by direct interactions with the host immune system via epithelial receptors. In contrast, the number of microbial taxa that a host gut supports may be contingent on the number and kinds of functions a host requires of its microbiome.

scholarly journals Description, Biology, and Impact of the Fruit-Feeding Moth, Mompha luteofascia sp. n. (Lepidoptera: Momphidae), on Miconia calvescens (Melastomataceae) in Costa Rica

2019 ◽  
Author(s):  
Manuel Antonio Alfaro-Alpízar ◽  
Sjaak J C Koster ◽  
M Tracy Johnson ◽  
Francisco Rubén Badenes-Pérez
Keyword(s):  
Biological Control ◽  
Costa Rica ◽  
Seed Germination ◽  
Biological Control Agent ◽  
Control Agent ◽  
Feeding Damage ◽  
Miconia Calvescens ◽  
Fruit Maturity ◽  
Fruit Damage ◽  
Study Sites

Abstract Fruits of Miconia calvescens DC. (Melastomataceae) were dissected to study insect frugivory in this plant in its native habitat in Costa Rica. Larvae of an unknown Mompha species (Lepidoptera: Momphidae), Anthonomus monostigma Champion (Coleoptera: Curculionidae), and unidentified Diptera and Hymenoptera were found in M. calvescens fruits. The Mompha species, described here as new as Mompha luteofascia Koster & Badenes-Pérez, was the most abundant insect frugivore in M. calvescens, infesting up to 38.1% of the fruits sampled. Feeding damage by M. luteofascia was positively correlated with fruit maturity, and resulted in significantly reduced numbers of seeds and rates of seed germination. Miconia calvescens fruits with medium damage (50–75% of the pulp missing) and high damage (75–100% of the pulp missing) had an average of 96 and 99 seeds, respectively, whereas undamaged fruits contained an average of 127 seeds per fruit. In fruits with medium and high fruit damage, only 1.9 and 0.1% of the seeds germinated, respectively, whereas 34.8% of the seeds germinated in undamaged fruits. Mompha luteofascia developed through three instars, as determined from measurement of head capsules. Larvae usually fed as one individual per each fruit attacked, exiting fruit to pupate in foliage or litter. Parasitism of M. luteofascia larvae was substantial, averaging 64 and 38% at the two study sites. Although host specificity of M. luteofascia has not been evaluated, the significant reductions in seed numbers and seed germination caused by its larvae indicate that this species deserves further assessment as a potential biological control agent of M. calvescens.

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