Microsporidia-host interactions in beneficial lady beetles : factors that influence chronic disease
Notice bibliographique
Résumé
Lady beetles produce species-specific defensive compounds (alkaloids) that are toxic to some predators and deters others with their foul taste.Some lady beetle alkaloids, such as harmonine from Harmonia axyridis, exhibit antimicrobial activity and may provide the beetle protection against pathogens.Convergine and hippodamine are the major and minor alkaloids produced by the convergent lady beetle, Hippodamia convergens.Adaline and adalinine are produced by the two-spotted lady beetle, Adalia bipunctata.Although the defensive chemistry of these lady beetles has received some attention, the role of their alkaloids with respect to pathogen virulence is poorly understood.Microsporidia, intracellular spore-forming parasites, have been reported in several coccinellid species, including Tubulinosema hippodamiae from H. convergens and Vairimorpha (Nosema) adaliae from A. bipunctata.These pathogens delay larval development but have no other observable effect on the host.However, previous studies were performed under optimal laboratory conditions and did not take into consideration challenges (stress factors) beetles would face in the natural environment.The objective of this study is to determine the relationship between alkaloids and microsporidiosis in H. convergens and A. bipunctata, and to examine the effects of different stress factors (limited food availability, rearing temperatures above optimal, and physical agitation) on the development of microsporidiosis and production of alkaloids in these beetles.During all three research trials, larval development was delayed for microsporidia-infected beetles when compared to uninfected beetles.In Chapter Two, limited food availability for microsporidia-infected A. bipunctata further delayed larval development compared to uninfected beetles, increased pathogen load and reduced adaline content.An irregular, unpredictable food supply acts as a stressor to further amplify the negative effects of microsporidiosis for A. bipunctata.No further development delays were observed for H. convergens when provided an irregular diet and no conclusions could be made regarding H. convergens alkaloid content.In Chapter Three, rearing A. bipunctata at temperatures above 25 °C shortened development, decreased pathogen load, and increased adaline content.Temperatures above 25 °C mitigate the microsporidian infection.In the final chapter, adaline content increased as A. bipunctata development progressed, uninfected adults produced more adaline than infected beetles when exposed to physical agitation on alternate days, and spore counts were highest when beetles were exposed to daily shaking.As with limited food availability, physical agitation further amplified the negative effects of microsporidiosis in A. bipunctata and had an influence on alkaloid production.Many plants produce antimicrobial secondary metabolites (phytoalexins) that can inhibit the germination and/or growth of bacteria and fungi.Alkaloids present in lady beetles may act as the animal equivalent of phytoalexins and play a larger role in the coccinellid immune system than previously thought.These findings provide some preliminary insight into the relationship between adaline, V. adaliae and A. bipunctata, including certain factors that influence this relationship.However, adalinine, hippodamine and convergine, alkaloids not examined in this study, may also influence infection and could be the focus of future studies.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».