The influence of previous host age on current host acceptance in Trichogramma

AbstractEggs of Sepedon fuscipennis (Diptera: Sciomyzidae) < 1, 1–2, 2–3, and 3–4 days old were offered to inexperienced female Trichogramma sp. near californicum in a laboratory experiment. Exposure period (2 h) and number of host eggs offered at one time (10) were held constant. Percentage of hosts parasitized, total number of parasitoid progeny found in a group of hosts, percentage of parasitized hosts yielding adult parasitoids, and survivorship of parasitoid progeny to adulthood all decreased significantly with increased host age. Younger hosts yielded more than one adult parasitoid more often than did older hosts. Over 50% of the adult parasitoids emerging from hosts < 1, or 1–2 days old were female. Hosts 2–3 days old produced only males. The data show a somewhat different relationship of host age to host acceptance and suitability than do some published data on lepidopteran hosts of Trichogramma.

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Faculty Opinions recommendation of Retaliatory mafia behavior by a parasitic cowbird favors host acceptance of parasitic eggs.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1069804.522739 ◽

2007 ◽

Author(s):

Michael Siva-Jothy

Keyword(s):

Host Acceptance

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Identification of Epidemiological Traits by Analysis of SARS−CoV−2 Sequences

Viruses ◽

10.3390/v13050764 ◽

2021 ◽

Vol 13 (5) ◽

pp. 764

Author(s):

Bohu Pan ◽

Zuowei Ji ◽

Sugunadevi Sakkiah ◽

Wenjing Guo ◽

Jie Liu ◽

...

Keyword(s):

Clustering Analysis ◽

Phylogenetic Trees ◽

Sequence Similarity ◽

Host Age ◽

Hierarchical Clustering Analysis ◽

Genome Sequences ◽

Geographic Patterns ◽

Rapid Spread ◽

Pairwise Sequence Similarity ◽

Sequence Similarity Analysis

Severe acute respiratory syndrome coronavirus 2 (SARS−CoV−2) has caused the ongoing global COVID-19 pandemic that began in late December 2019. The rapid spread of SARS−CoV−2 is primarily due to person-to-person transmission. To understand the epidemiological traits of SARS−CoV−2 transmission, we conducted phylogenetic analysis on genome sequences from >54K SARS−CoV−2 cases obtained from two public databases. Hierarchical clustering analysis on geographic patterns in the resulting phylogenetic trees revealed a co-expansion tendency of the virus among neighboring countries with diverse sources and transmission routes for SARS−CoV−2. Pairwise sequence similarity analysis demonstrated that SARS−CoV−2 is transmitted locally and evolves during transmission. However, no significant differences were seen among SARS−CoV−2 genomes grouped by host age or sex. Here, our identified epidemiological traits provide information to better prevent transmission of SARS−CoV−2 and to facilitate the development of effective vaccines and therapeutics against the virus.

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Sheep nemabiome diversity and its response to anthelmintic treatment in Swedish sheep herds

Parasites & Vectors ◽

10.1186/s13071-021-04602-y ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Peter Halvarsson ◽

Johan Höglund

Keyword(s):

Species Richness ◽

Diversity Index ◽

Nematode Species ◽

Abundant Species ◽

Anthelmintic Treatment ◽

Host Age ◽

Larval Culture ◽

Nematode Parasites ◽

South Central ◽

Nematode Diversity

Abstract Background A novel way to study the species composition and diversity of nematode parasites in livestock is to perform deep sequencing on composite samples containing a mixture of different species. Herein we describe for the first time the nematode community structures (nemabiomes) inhabiting Swedish sheep and how these are/were affected by host age and recent anthelmintic treatments. Methods A total of 158 fecal samples were collected (n = 35 in 2007 and n = 123 in 2013–2016) and cultured from groups of sheep on 61 commercial farms in the south-central part of the country where most animals are grazed. Among the samples, 2 × 44 (56%) were paired collections from the same groups pre- and post-treatment with anthelmintics such as macrocyclic lactones, benzimidazoles or levamisole. Samples were analyzed for their nemabiome using the PacBio platform followed by bioinformatic sequence analysis with SCATA. Species richness and diversity were calculated and analyzed in R. Results Nematode ITS2 sequences were found in all larval culture samples except two, even though the fecal egg counts were below the McMaster threshold in 20 samples. Sequencing yielded, on average, 1008 sequences per sample. In total, 16 operational taxonomical units (OTU), all with ≥ 98 % identity to sequences in the NCBI database, were recognized. The OTUs found represented nematode species of which ten are commonly associated with sheep. Multiple species were identified in all pre-anthelmintic treatment larval culture samples. No effects on nematode diversity were found in relation to host age. On the other hand, recent anthelmintic treatment lowered species richness, especially after use of ivermectin and albendazole. Interestingly, despite zero egg counts after use of levamisole, these samples still contained nematode DNA and especially H. contortus. Conclusions Our findings provide evidence that nemabiome analysis combined with diversity index analysis provides an objective methodology in the study of the efficacy of anthelmintic treatment as both high and low abundant species were detected.

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Assortments of Digestive Enzymes Induced in First Instar Larvae of Busseola fusca Feeding on Different Plants

International Journal of Insect Science ◽

10.1177/1179543319843521 ◽

2019 ◽

Vol 11 ◽

pp. 117954331984352 ◽

Cited By ~ 1

Author(s):

Gérald Juma ◽

Bruno Le Ru ◽

Paul-André Calatayud

Keyword(s):

Plant Species ◽

Digestive Enzymes ◽

Host Plants ◽

Feeding Habits ◽

Busseola Fusca ◽

Stem Borer ◽

Sub Saharan Africa ◽

Host Acceptance ◽

First Instar ◽

Sub Saharan

The stem borer Busseola fusca (Fuller) (Lepidoptera: Noctuidae) is an important pest of maize and sorghum in sub-Saharan Africa. This insect has oligophagous feeding habits, feeding mostly on maize and sorghum with a narrow range of wild Poaceous plant species. We hypothesised that first instar B. fusca larvae, the critical stage for successful establishment on a host plant, can establish and then grow on a particular plant as a result of induction of a complement of digestive enzymes that mediates host acceptance at first instars. A fast semi-quantitative analysis of potentially digestive enzymatic activities present in the first larvae previously fed for 4 days on leaves of host and non-host plants was performed using the API-ZYM kit system able to detect a multiplex of enzyme activities. Regardless of the plant species, the larvae exhibited higher activities of the carbohydrate metabolising enzymes than of aminopeptidases and proteases. In addition, highest activities of carbohydrates degrading enzymes were exhibited by larvae that consumed leaves of the most preferred plant species of B. fusca. Conversely, esterases were only detected in neonate larvae that consumed leaves of the less preferred and non-host plants. No alkaline phosphatase and lipase activities were detected. The significance of these results was discussed in terms of food requirements of first instar larvae when settling on a plant.

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