Biology subjects

Requier, F.

Publications and source records attributed to Requier, F..

4 recordsLinked to original sources

bioRxiv2023

Experimental evidence of nocturnal pollination services for berry crops

Insect-mediated pollination is essential for crop production but is mainly studied considering diurnal pollinators only. Using pollinator exclusion techniques to prevent either diurnal or nocturnal insect visits we estimate the contribution of day-active and night-active pollinators to fruit set, seed set, fruit weight and fruit volume in three berry crops. We find that nocturnal pollination improves seed set compared to exclusion of all insect visits for one crop (raspberry), confirming the existence and importance of a nocturnal pollination service. Moreover, we found a general pattern where best crop pollination resulted from combined services of diurnal and nocturnal insect visits. These results call for urgent consideration of nocturnal pollination in crop production and management, towards inclusive pollinator-friendly schemes including night-active pollinators.

ecology↗

bioRxiv2023

Nutrient learning, perception and generalization differ among wild pollinator species

Learning is the process through which skills, knowledge, behaviors are acquired and developed. Through life experiences, pollinator insects, learn to associate odor or visual stimuli from flowers with a rewarding food as pollen or nectar. This capability allows them to obtain resources efficiently and provides a valuable pollination service. Here, we compared the learning capability among different wild pollinator insects by mean of experiments based on the recent Free-Moving Proboscis Extension Response (FMPER) technique. Specifically, we evaluated the process of perception, learning and generalization between pollen enriched with different concentrations of fatty acid (which play a critical role in the survival, development and reproduction of many animals). We compared the associative learning in two castes of bumble bees (queens and workers of Bombus terrestris), honey bees (Apis mellifera), solitary bees (Ruizanthedella mutabilis) and non-bee pollinator species (the hoverfly Eristalis tenax). Our results reveal that learning performances differed among bumble bee social castes, with queens acquiring learning odorants more effectively than workers. Likewise, learning performances differed among the four species of insect pollinators. Honey bees acquired odor-sucrose association more rapidly than the other species. Likewise, bumble bees learned better than the solitary bee species and the hoverfly. The pattern of generalization among odorant stimuli as also different among the studied species, with honey bees showing stronger generalization and hoverflies showing more specific response patterns. Studying the learning behavior in insect pollinators provides valuable information for the conservation of these species and services they provide, through adapted pollinator-friendly schemes matching their behavioral performances.

ecology↗

bioRxiv2022

The genome of the bee louse fly reveals deep convergences in the evolution of social inquilinism

The nests of social insects often harbor a rich fauna of intruders known as inquilines.1 Social inquilines are usually closely-related to their host due to potential genetic predispositions,2,3 but how phylogenetically distant non-social inquilines adapt to their hosts remains unclear. Here, we analyzed the genome of the wingless and blind bee louse fly Braula coeca, an inquiline kleptoparasite of the Western honey bee Apis mellifera.4,5 Using large phylogenomic data, we confirmed recent accounts that the bee louse fly is an aberrant drosophilid,6,7 and showed that it had likely evolved from a sap-breeder ancestor associated with honeydew and scale insects wax. Unlike many parasites, such as the human louse, the bee louse fly genome did not show significant erosion or strict reliance on an endosymbiont, likely due to a relatively recent age of inquilinism. However, a striking parallel evolution in a set of gene families was observed between the honey bee and the bee louse fly. Convergences included genes potentially involved in metabolism and immunity and the loss of nearly all bitter-tasting gustatory receptors in agreement with life in a protective nest and a major diet of honey, pollen, and beeswax. Vision-related and odorant receptor genes also exhibited rapid losses. Only genes whose orthologs in the closely related Drosophila melanogaster respond to honey bee pheromones components or floral aroma were retained, whereas the losses included orthologous receptors responsive to the anti-ovarian honey bee queen pheromones. These results indicate that deep genomic convergences can underlie major morphological and neuroethological transitions during the evolution of inquilinism between non-social parasites and their social hosts.

evolutionary biology↗

bioRxiv2020

Measuring ontogenetic shifts in central-place foraging insects: a case study with honey bees

O_LIMeasuring time-activity budgets over the complete individual lifespan is now possible for many animals with the recent advances of life-long individual monitoring devices. Although analyses of changes in the patterns of time-activity budgets have revealed ontogenetic shifts in birds or mammals, no such technique has been applied to date on insects. C_LIO_LIWe tested an automated breakpoint-based procedure to detect, assess and quantify shifts in the temporal pattern of the flight activities in honey bees. We assumed that the learning and foraging stages of honey bees will differ in several respects, to detect the age at onset of foraging (AOF). C_LIO_LIUsing an extensive dataset covering the life-long monitoring of 2,100 individuals, we compared the AOF outputs with the more conventional approaches based on arbitrary thresholds. We further evaluated the robustness of the different methods comparing the foraging time-activity budget allocations between the presumed foragers and confirmed foragers. C_LIO_LIWe revealed a clear-cut learning-foraging ontogenetic shift that differs in duration, frequency, and time of occurrence of flights. Although AOF appeared to be highly plastic among bees, the breakpoint-based procedure seems better able to detect it than arbitrary threshold-based methods that are unable to deal with inter-individual variation. C_LIO_LIWe developed the aof R-package including a broad range of examples with both simulated and empirical dataset to illustrate the simplicity of use of the procedure. This simple procedure is generic enough to be derived from any individual life-long monitoring devices recording the time-activity budgets of honey bees, and could propose new ecological applications of bio-logging to detect ontogenetic shifts in the behaviour of central-place foraging insects. C_LI

ecology↗