The Role of Temperature on the Development of Circadian Rhythms in Honey Bee Workers

Abstract

Circadian rhythms in honey bees are involved in various processes that impact colony survival. For example, young nurses take care of the brood constantly throughout the day and lack circadian rhythms, while foragers use the circadian clock to remember and predict food availability in subsequent days. Previous studies suggested that development of circadian rhythms both in the field and the laboratory began around 7-9 days of age. However, not much is understood about the postembryonic development of circadian rhythms in honey bees. In the current study, we examine the effects of socially regulated colony temperature on the ontogeny of circadian rhythms of young workers under controlled laboratory conditions. We hypothesized that temperature plays a key role in the development of circadian rhythmicity in young workers. Our results show that young workers kept at 35˚C develop circadian rhythmicity faster and in greater proportion than bees kept at 25˚C. In addition, we examine if the effect of colony temperature during the first 48 hours after emergence is enough to observe effects on the rate and proportion of development of circadian rhythmicity. We observed that twice as many individuals that were exposed to 35˚C during the first 48 hours develop circadian rhythms compared to individuals kept at 25˚C. In addition, we observed differences in the average endogenous period length consistent with temperature compensation of the circadian rhythms between the 25˚C and 35˚C cohorts. We also observed differences in the degree of period length variation between the 25˚C and 35˚C cohorts, which combined with the proportion of arrhythmic individuals and survival data suggest that development of circadian rhythms is incomplete in individuals exposed to 25˚C adult emergence. This study shows that temperature, which is socially regulated inside the hive, is a key factor that influences the ontogeny of circadian rhythmicity of workers.

The Compound Eye Regulates Free-Running Period and Stability of the Circadian Locomotor Rhythm in the Cricket Gryllus bimaculatus

“…Although the exact reason is unclear as to why no significant changes in τ and τCV were induced by optic nerve severance at 25°C, it is possible that this particular temperature allows the clock to produce a stable τ, even in the absence of neural information from the compound eye. The crickets were maintained at this temperature throughout their lives and thus could have developed clock characteristics that are suited to this particular temperature, similar to what was found with honey bees (Giannoni-Guzmán et al, 2020). This possibility should be tested by rearing crickets at different temperatures.…”

Relationship Between Inter-individual Variation in Circadian Rhythm and Sociality: A case Study Using Halictid Bees

“…Past studies, such as those of Bloch et al (2001) and Moore et al (1998), revealed that the rhythmicity of honey bees changed with age. Additionally, Giannoni-Guzman et al (2020) showed that foragers in the wild display discrete categories that suggest temporal shift work. An earlier study from Giannoni-Guzman and colleagues (2014) compared the endogenous period of three different variants of honey bees ( Apis mellifera carnica , Apis mellifera caucasica and Apis mellifera gAHB ) as well as similarly sized insects from different orders and families.…”

“…Moreover, it makes us consider that the level of sociality in different organisms may play a role in their daily activity patterns. An important emerging feature is that in social insects, be it groups of individuals as defined by their age and job (Moore et al 1998, Bloch et al 2001), or individuals in the same age and task group (Giannoni-Guzman et al 2014, 2020), exhibit differences in their circadian rhythms with functional significance for their sociality. We hypothesize that with increasing levels of social organization, as can be measured in size of the social group, greater levels of individual variation in circadian rhythms will be observed.…”