Biology subjects

Malausa, T.

Publications and source records attributed to Malausa, T..

3 recordsLinked to original sources

bioRxiv2020

Consistent variations in personality traits and their potential for genetic improvement in the biocontrol agent Trichogramma evanescens

Improvements in the biological control of agricultural pests require improvements in the phenotyping methods used by practitioners to select efficient biological control agent (BCA) populations in industrial rearing or field conditions. Consistent inter-individual variations in behaviour (i.e. animal personality) probably affect BCA efficiency, but have never been taken into account in the development of phenotyping methods, despite having characteristics useful for phenotyping: repeatable (by definition), often heritable, etc. We developed a video-tracking method targeting animal personality traits and evaluated the feasibility of its use for genetic improvement in the BCA Trichogramma evanescens, by phenotyping 1,049 individuals from 24 isogenic lines. We found consistent individual variations in boldness, activity and exploration. Personality differences between the 24 isogenic lines suggested a genetic origin of the variations in activity and exploration (broad-sense heritability estimates of 0.06 to 0.11) and revealed a trade-off between exploration and fecundity.

ecology↗

bioRxiv2019

Rapid and differential evolution of the venom composition of a parasitoid wasp depending on the host strain

Parasitoid wasps rely primarily on venom to suppress the immune response and regulate the physiology of their host. Intraspecific variability of venom protein composition has been documented in some species, but its evolutionary potential is poorly understood. We performed an experimental evolution initiated with crosses of two lines of Leptopilina boulardi of different venom composition to generate variability and create new combinations of venom factors. The offspring were maintained for 10 generations on two strains of Drosophila melanogaster differing in resistance / susceptibility to the parasitoid lines. The venom composition of individuals was characterized by a semi-automatic analysis of 1D SDS-PAGE protein profiles whose accuracy was checked by Western blot analysis of well-characterized venom proteins. Results evidenced a rapid and differential evolution of the venom composition on both hosts and showed that the proteins beneficial on one host can be costly on the other. Overall, we demonstrated the capacity of rapid evolution of the venom composition in parasitoid wasps, important regulators of arthropod populations, suggesting a potential for adaptation to new hosts. Our approach also proved relevant in identifying, among the diversity of venom proteins, those possibly involved in parasitism success and whose role deserves to be deepened.\n\nKey ContributionThe venom protein composition of parasitoid wasps can evolve rapidly and differently depending on the host strain. Studying this evolution can help identify new venom proteins possibly involved in parasitism success on a given host.

evolutionary biology↗

bioRxiv2018

Natural enemies of armored scales (Hemiptera: Diaspididae) and soft scales (Hemiptera: Coccoidae) in Chile: molecular and morphological identification

Scale insects (Hemiptera: Coccoidea) are key pests of agricultural crops and ornamental plants worldwide. Their populations are difficult to control, even with insecticides, due to their cryptic habits. Moreover, there is growing concern over the use of synthetic pesticides for their control, due to deleterious environmental effects and the emergence of resistant populations of target pests. In this context, biological control may be an effective and sustainable approach. Hymenoptera Chalcidoidea includes natural enemies of scale insects that have been successfully used in many biological control programs. However, the correct identification of pest scale species and their natural enemies is particularly challenging because these insects are very small and highly specialized. Integrative taxonomy, coupling DNA barcoding and morphological analysis, has been successfully used to characterize pests and natural enemy species. In this study, we performed a survey of parasitoids and predators of armored and soft scales in Chile, based on 28S and COI barcodes. Fifty-three populations of Diaspididae and 79 populations of Coccidae were sampled over the entire length of the country, from Arica (18{degrees}S) to Frutillar (41{degrees}S), between January 2015 and February 2016. The phylogenetic relationships obtained by Bayesian inference from multilocus haplotypes revealed 40 putative species of Chalcidoidea, five Coccinellidae and three Neuroptera. In Chalcidoidea, 22 species were identified morphologically, resulting in new COI barcodes for 12 species and new 28S barcodes for 14 species. Two predator species (Rhyzobius lophantae and Coccidophilus transandinus) were identified morphologically, and two parasitoid species, Chartocerus niger and Signiphora bifasciata, were recorded for the first time in Chile.

molecular biology↗