Biology subjects

Gomez-Moracho, T.

Publications and source records attributed to Gomez-Moracho, T..

3 recordsLinked to original sources

bioRxiv2022

Supplementation in vitamin B3 counteracts the negative effects of tryptophan deficiencies in bumble bees

Increasing evidence highlights the importance of diet content in 9 essential amino acids for bee physiological and behavioral performance. However, the tenth essential amino acid, tryptophan, has been overlooked as its experimental measurement requires a specific hydrolysis. Tryptophan is the precursor of serotonin and vitamin B3, which together modulate cognitive and metabolic functions in most animals. Here, we investigated how tryptophan deficiencies influence the longevity and behavior of bumble bees. Tryptophan-deficient diets led to a moderate increase in food intake, aggressiveness and mortality compared to the control diet. Vitamin B3 supplementation in tryptophan-deficient diets tended to buffer these effects on food intake and survival, and significantly reduced workers aggressiveness. Considering that the pollens of major crops and common plants, such as corn and dandelion, are deficient in tryptophan, these effects could have a strong impact on bee populations and their pollination service.

physiology↗

bioRxiv2021

The gut parasite Nosema ceranae impairs olfactory learning in bumblebees

Pollinators are exposed to numerous parasites and pathogens when foraging on flowers. These biological stressors may affect critical cognitive abilities required for foraging. Here, we tested whether exposure to Nosema ceranae, one of the most widespread parasite of honey bees also found in wild pollinators, impacts cognition in bumblebees. We investigated different forms of olfactory learning and memory using conditioning of the proboscis extension reflex. Seven days after feeding parasite spores, bumblebees showed lower performance in absolute and differential learning, and reversal learning than controls. Long-term memory was also slightly reduced. The consistent effect of N. ceranae exposure across different types of olfactory learning indicates that its action was not specific to particular brain areas or neural processes. We discuss the potential mechanisms by which N. ceranae impairs bumblebee cognition and the broader consequences for populations of pollinators.

animal behavior and cognition↗

bioRxiv2020

Artificial diets modulate infection rates of bumblebees by Nosema ceranae

Parasites alter the physiology and behaviour of their hosts. In domestic honey bees, the microsporidia Nosema ceranae induces an energetic stress and impairs the behaviour of foragers, potentially leading to colony collapse. Whether this emerging parasite similarly affects wild pollinators is little understood because of the low success rates of experimental infection protocols. Here we established a new apporach for infecting bumblebees (Bombus terrestris) with controlled amounts of N. ceranae, by briefly exposing individual bumblebees to a sucrose solution containing parasite spores, before feeding them with artificial diets. We validated our protocol by testing the effect of two spore dosages and two diets varying in their protein to carbohydrate ratio, on the prevalence of the parasite (proportion of infected bees), the intensity of infection (spore count in the gut), and the survival of bumblebees. Insects fed a low-protein high-carbohydrate diet showed highest parasite prevalence (up to 70%) but lived longest, suggesting that immunity and survival of bumblebees are maximised at different protein to carbohydrate ratios. Spore dosage had no effect on parasite infection rate and host survival. The identification of experimental conditions for successfully infecting bumblebees with N. ceranae in the lab will facilitate investigations of the sub-lethal effects of this parasite on the behaviour and cognition of wild pollinators.

physiology↗