Environmental cycles regulate development time via circadian clock mediated gating of adult emergence

Abstract

BackgroundPrevious studies have implicated a role for circadian clocks in regulating pre-adult development of organisms. Among them two approaches are most notable: 1) use of insects whose clocks have different free-running periods and 2) imposition of artificial selection on either rate of development, timing of emergence or circadian period in laboratory populations. Using these two approaches, influence of clock on rate of development has been elucidated. However, the contribution of circadian clocks in determining time taken for pre-adult development has remained unclear. Here we present results of our studies aimed to understand this influence by examining populations of fruit flies carrying three different alleles of the period gene and hence having different free-running periods. We tried to achieve similarity of genetic background among the three strains while also ensuring that they harbored sufficient variation on loci other than period gene.ResultsWe find that under constant conditions, flies with long period have slower development whereas in presence of light-dark cycles (LD) of various lengths, the speed of development for each genotype is influenced by whether their eclosion rhythms can entrain to them. Under LD 12:12 (T24), where all three strains entrain, they do not show any difference in time taken for emergence, whereas under LD 10:10 (T20) where long period flies do not entrain and LD 14:14 (T28) where short period flies do not entrain, they have slower and faster pre-adult development, respectively, compared to the controls. We also show that a prior stage in development namely pupation is not rhythmic though time taken for pupation is determined by both the environmental cycle and period allele.ConclusionWe discuss how in presence of daily time cues, interaction of the cyclic environmental factors with the clock determines the position and width of the gate available for a fly to emerge (duration of time within a cycle when adult emergence can occur) resulting in an altered developmental duration from that observed under constant conditions. We also discuss the relevance of genetic background influencing this regulation.Electronic supplementary materialThe online version of this article (10.1186/s12861-018-0180-6) contains supplementary material, which is available to authorized users.

Obesogenic Effect of Sulfamethoxazole on Drosophila melanogaster with Simultaneous Disturbances on Eclosion Rhythm, Glucolipid Metabolism, and Microbiota

“…That is to say, it is not yet clear whether antibiotics first disturbed eclosion rhythm, then changed microbiota, and finally resulted in obesity or whether the disruptions in microbiota and metabolism occur prior to the alterations in eclosion rhythm. It was previously reported that the pigment-dispersing factor (pdf) and ecdysone-induced protein 74EF ( Eip74EF , also known as E74 ) are essential in controlling eclosion rhythm, , and period (per) and timeless (tim) are core clock genes . Future studies can employ the gal4 -UAS binary system to manipulate gene functions to provide evidence for whether eclosion dysrhythmia is necessary for disturbances on lipid metabolism.…”

Impact of disabled circadian clock on yellow fever mosquito Aedes aegypti fitness and behaviors

“…Several earlier studies have shown that pupation is gated in mosquitoes such as Anopheles gambiae 32 and Aedes taeniorhynchus 33 , and is regulated by the duration of the photoperiod via the secretion of the prothoracicotropic hormone that stimulates ecdysone secretion 34 . Also, study showed that importance of the light cycle and the period gene in developmental time memory specifically pupation and adult emergence in fruit flies D. melanogaster is under circadian clock control 35 , 36 . The environmental cycle and period allele both determines the time taken for each pre-adult developmental stages such as time taken for pupation 37 .…”

Disabling the Circadian Clock in the Yellow Fever Mosquito Aedes Aegypti Reduces Adult Life Span, Attraction to Host Odor and Mating Success

“…Several earlier studies have shown that pupation is gated in mosquitoes such as Anopheles gambiae [34] and Aedes taeniorhynchus [35], and is regulated by the duration of the photoperiod via the secretion of the prothoracicotropic hormone that stimulates ecdysone secretion [36]. Also, it showed that importance of the light cycle and the period gene in developmental time memory specifically pupation and adult emergence in fruit flies D. melanogaster is under circadian clock control [37,38]. The environmental factors with circadian clock (eg: light input pathways regulate the period gene expression) determines the stage of development and duration of time (width of the gate) within a cycle available for an insect to emerge into an adult [39].…”