Transgenerational effects of ungulates and pre-dispersal seed predators on offspring success and resistance to herbivory

Abstract Arabidopsis thaliana is a highly selfing plant that nevertheless appears to undergo substantial recombination. To reconcile its selfing habit with the observations of recombination, we have sampled the genetic diversity of A. thaliana at 14 loci of ~500 bp each, spread across 170 kb of genomic sequence centered on a QTL for resistance to herbivory. A total of 170 of the 6321 nucleotides surveyed were polymorphic, with 169 being biallelic. The mean silent genetic diversity (πs) varied between 0.001 and 0.03. Pairwise linkage disequilibria between the polymorphisms were negatively correlated with distance, although this effect vanished when only pairs of polymorphisms with four haplotypes were included in the analysis. The absence of a consistent negative correlation between distance and linkage disequilibrium indicated that gene conversion might have played an important role in distributing genetic diversity throughout the region. We tested this by coalescent simulations and estimate that up to 90% of recombination is due to gene conversion.

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Sublethal and transgenerational effects of spinetoram on the biological traits of Plutella xylostella (L.) (Lepidoptera: Plutellidae)

Ecotoxicology ◽

10.1007/s10646-021-02385-7 ◽

2021 ◽

Author(s):

R. Tamilselvan ◽

J. S. Kennedy ◽

A. Suganthi

Keyword(s):

Plutella Xylostella ◽

Biological Traits ◽

Transgenerational Effects

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Transgenerational Effects of a Neonicotinoid and a Novel Sulfoximine Insecticide on the Harlequin Ladybird

Insects ◽

10.3390/insects12080681 ◽

2021 ◽

Vol 12 (8) ◽

pp. 681

Author(s):

Changchun Dai ◽

Michele Ricupero ◽

Zequn Wang ◽

Nicolas Desneux ◽

Antonio Biondi ◽

...

Keyword(s):

Nicotinic Acetylcholine Receptors ◽

Harmonia Axyridis ◽

Biocontrol Agent ◽

Insect Pests ◽

Negative Influence ◽

Management Approach ◽

Generalist Predator ◽

Cotton Aphid ◽

Transgenerational Effects ◽

Harlequin Ladybird

The harlequin ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), is a generalist predator and an effective biocontrol agent of various insect pests that has been exploited for the control of aphid pests in the greenhouse and field. However, insecticides are widely used to control aphid pests worldwide and the potential non-target effects of sulfoxaflor and imidacloprid for controlling aphid pests towards this biocontrol agent are little known. Although both sulfoxaflor and imidacloprid act on nicotinic acetylcholine receptors of insects, sulfoxaflor has a novel chemical structure compared with neonicotinoids. We assessed the lethal, sublethal and transgenerational effects of sulfoxaflor and imidacloprid on H. axyridis simultaneously exposed via ingestion of contaminated prey and via residual contact on the host plant at LC20 and LC50 doses estimated for the cotton aphid. Imidacloprid significantly reduced the survival of H. axyridis adults compared to sulfoxaflor at the same lethal concentration against cotton aphid. Both concentrations of imidacloprid and sulfoxaflor reduced the proportion of ovipositing females, and both concentrations of imidacloprid and sulfoxaflor, except LC20 dose of sulfoxaflor, reduced the fecundity and fertility of the parental generation. In the progeny of imidacloprid- and sulfoxaflor-exposed parents, both tested LC50 concentrations significantly decreased the juvenile survival rate, and both concentrations of imidacloprid and sulfoxaflor, except LC20 dose of sulfoxaflor, prolonged the development time. Our findings provide evidence of the negative influence of imidacloprid and sulfoxaflor at low lethal concentrations on the harlequin ladybird and on the progeny of exposed individuals, i.e., transgenerational effects. Hence, these findings stress the importance of optimizing the applications of imidacloprid and sulfoxaflor for the control of aphid pests, aiming at preserving the biocontrol services provided by H. axyridis throughout the integrated pest management approach.

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Individual crop size increases predispersal predation by beetles in a tropical palm

Seed Science Research ◽

10.1017/s0960258520000380 ◽

2020 ◽

pp. 1-4

Author(s):

Morgana Maria Arcanjo Bruno ◽

Klécia Gili Massi ◽

Alexander V. Christianini ◽

John du Vall Hay

Keyword(s):

Seed Predation ◽

Positive Influence ◽

Reproductive Phenology ◽

Individual Plant ◽

Crop Size ◽

Seed Predators ◽

Plant Trait ◽

Predispersal Seed Predation ◽

Total Seed ◽

Number Of Seeds

Abstract Predispersal seed predation is one of the main causes of seed mortality in plant populations, contributing to decreased plant recruitment. Seed loss has previously been found to be related to crop size. Thus, we examined the influence of individual crop size on predispersal seed predation by beetles in the palm Syagrus flexuosa in the Brazilian savanna. The study was carried out in three tropical woodland savanna sites, where we sampled the total seed crop of 46 fruiting palms and checked the presence of beetle larvae inside all seeds per plant. We observed predispersal seed predation of S. flexuosa from all sites and a high variation in the number of seeds preyed on per individual palm. Crop size had a positive influence on the number of seeds lost to predispersal seed predators. Variations in levels of predispersal seed predation may also be accounted for by the reproductive phenology of S. flexuosa. If fruits are not available at the same time, less resource is available for predators and therefore a high proportion of seeds may be preyed on. Thus, our study demonstrates that an individual plant trait, crop size, is an important predictor of beetle seed damage per palm and a driver of the number of seeds lost to predispersal seed predators.

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