0000000000165199
AUTHOR
Pekka Lankinen
Latitudinal clines in the timing and temperature‐sensitivity of photoperiodic reproductive diapause in Drosophila montana
Reproductive diapause is a primary mechanism used by arthropods to synchronize their life cycle with seasonal changes in temperate regions. Our study species, Drosophila montana, represents the northern insect species where flies enter reproductive diapause under short day conditions and where the precise timing of diapause is crucial for both survival and offspring production. We have studied clinal variation in the critical day length for female diapause induction (CDL) and their overall susceptibility to enter diapause (diapause incidence), as well as the temperature sensitivity of these traits. The study was performed using multiple strains from four latitudinal clines of the species – …
Northern Drosophila montana flies show variation both within and between cline populations in the critical day length evoking reproductive diapause
Reproductive diapause, and its correct timing, plays an important role in the life cycle of many insect species living in a seasonally varying environment at high latitudes. In the present paper we have documented variation in the critical day length (CDL) for adult reproductive diapause and the steepness of photoperiodic response curves (PPRCs) in seven clinal populations of Drosophila montana in Finland between the latitudes 61 and 67°N, paying special attention to variation in these traits within and between cline populations. The isofemale lines representing these populations showed a sharp transition from 0% to 100% in females' diapause incidence in the shortening day lengths, indicate…
sj-pdf-1-jbr-10.1177_0748730421997265 – Supplemental material for Nanda-Hamner Curves Show Huge Latitudinal Variation but No Circadian Components in Drosophila Montana Photoperiodism
Supplemental material, sj-pdf-1-jbr-10.1177_0748730421997265 for Nanda-Hamner Curves Show Huge Latitudinal Variation but No Circadian Components in Drosophila Montana Photoperiodism by Pekka Lankinen, Chedly Kastally and Anneli Hoikkala in Journal of Biological Rhythms
Selection for reproduction under short photoperiods changes diapause-associated traits and induces widespread genomic divergence.
The work has been supported by the Academyof Finland to A.H. (project 267244) and Natural Environment Research Council (NERC) funding (NE/J020818/1 to M.G.R.; NE/L501852/1 to R.A.W.W.). The incidence of reproductive diapause is a critical aspect of life history in overwintering insects from temperate regions. Much has been learned about the timing, physiology and genetics of diapause in a range of insects, but how the multiple changes involved in this and other photoperiodically regulated traits are inter-related is not well understood. We performed quasinatural selection on reproduction under short photoperiods in a northern fly species, Drosophila montana, to trace the effects of photoper…
Nanda-Hamner Curves Show Huge Latitudinal Variation but No Circadian Components in Drosophila Montana Photoperiodism
Insect species with a wide distribution offer a great opportunity to trace latitudinal variation in the photoperiodic regulation of traits important in reproduction and stress tolerances. We measured this variation in the photoperiodic time-measuring system underlying reproductive diapause in Drosophila montana, using a Nanda-Hamner (NH) protocol. None of the study strains showed diel rhythmicity in female diapause proportions under a constant day length (12 h) and varying night lengths in photoperiods ranging from 16 to 84 h at 16°C. In the northernmost strains (above 55°N), nearly all females entered diapause under all photoperiods and about half of them even in continuous darkness, while…
Nanda-Hamner Curves Show Huge Latitudinal Variation but No Circadian Components in Drosophila Montana Photoperiodism
Insect species with a wide distribution offer a great opportunity to trace latitudinal variation in the photoperiodic regulation of traits important in reproduction and stress tolerances. We measured this variation in the photoperiodic time-measuring system underlying reproductive diapause in Drosophila montana, using a Nanda-Hamner (NH) protocol. None of the study strains showed diel rhythmicity in female diapause proportions under a constant day length (12 h) and varying night lengths in photoperiods ranging from 16 to 84 h at 16°C. In the northernmost strains (above 55°N), nearly all females entered diapause under all photoperiods and about half of them even in continuous darkness, whil…
Plasticity in Photoperiodism : Drosophila montana Females Have a Life-Long Ability to Switch From Reproduction to Diapause
Photoperiodic reproductive diapause is an essential part of female life cycle in several insect species living on high latitudes, where overwintering in reproductive stage involves high risks for survival and progeny production. The sensitive period (SP), during which photoperiodic cues can trigger the switch from direct development to diapause, can last from a few hours or days after emergence to the entire life span of females. Moreover, in some species, sexually mature females can enter post-reproductive diapause as a response to decreasing day length and/or temperature. We studied the duration of SP for diapause induction and the females’ ability to enter post-reproductive diapause at s…
sj-pdf-1-jbr-10.1177_0748730421997265 – Supplemental material for Nanda-Hamner Curves Show Huge Latitudinal Variation but No Circadian Components in Drosophila Montana Photoperiodism
Supplemental material, sj-pdf-1-jbr-10.1177_0748730421997265 for Nanda-Hamner Curves Show Huge Latitudinal Variation but No Circadian Components in Drosophila Montana Photoperiodism by Pekka Lankinen, Chedly Kastally and Anneli Hoikkala in Journal of Biological Rhythms