Ayumu Mukai - Academia.edu (original) (raw)

Papers by Ayumu Mukai

Research paper thumbnail of Juvenile hormone as a causal factor for maternal regulation of diapause in a wasp

Insect Biochemistry and Molecular Biology, 2022

Research paper thumbnail of Environmental parameters in the semi-natural condition and diapause incidence of flesh fly

Seasonal changes in temperature and day length are distinct between rural and urban areas due to ... more Seasonal changes in temperature and day length are distinct between rural and urban areas due to urban warming and the presence of artificial light at night. Many studies have focused on the impacts of these ubiquitous signatures on daily biological events, but empirical studies on their impacts on insect seasonality are limited. In the present study, we used the flesh fly Sarcophaga similis as a model insect to determine the impacts of urbanisation on the incidence and timing of diapause (dormancy), not only in the laboratory but also in rural and urban conditions. In the laboratory, diapause entry was affected by night-time light levels as low as 0.01 lux. We placed fly cages on outdoor shelves in urban and rural areas to determine the timing of diapause entry; it was retarded by approximately four weeks in urban areas relative to that in rural areas. Moreover, almost all flies in the site facing an urban residential area failed to enter diapause, even by late autumn. Although an ...

Research paper thumbnail of Figure S1; Figure S2 from Urban warming and artificial light alter dormancy in the flesh fly

Spectra of the fluorescent light used for the laboratory diapause induction (A) and the residenti... more Spectra of the fluorescent light used for the laboratory diapause induction (A) and the residential light at site 2 in Experiment 2 (18:30 on 30 January 2018, 1-h after sunset) (B). Spectral irradiance (mW/m2/min) in each wavelength (nm) was recorded by the colour rendering illuminometer CL-70F (Konica Minolta, Tokyo, Japan). Note that the irradiance of A and B was different (972 lux and 17. 6 lux in A and B, respectively).; Night illuminance at site 1 and site 2 in Experiment 2, 23 September – 22 November 2016. Mean values of illuminance during the astronomical nights (from sunset to sunrise) obtained from the National Astronomical Observatory of Japan website (eco.mtk.nao.ac.jp) were calculated. Error bars indicate standard deviations. Shaded areas (5 and 6 October) indicate no data due to the incidence of a typhoon.

Research paper thumbnail of Supplementary material from "Urban warming and artificial light alter dormancy in the flesh fly

Seasonal changes in temperature and day length are distinct between rural and urban areas due to ... more Seasonal changes in temperature and day length are distinct between rural and urban areas due to urban warming and the presence of artificial light at night. Many studies have focused on the impacts of these ubiquitous signatures on daily biological events, but empirical studies on their impacts on insect seasonality are limited. In the present study, we used the flesh fly <i>Sarcophaga similis</i> as a model insect to determine the impacts of urbanization on the incidence and timing of diapause (dormancy), not only in the laboratory but also in rural and urban conditions. In the laboratory, diapause entry was affected by night-time light levels as low as 0.01 lux. We placed fly cages on outdoor shelves in urban and rural areas to determine the timing of diapause entry; it was retarded by approximately four weeks in urban areas relative to that in rural areas. Moreover, almost all flies in the site facing an urban residential area failed to enter diapause, even by late a...

Research paper thumbnail of Molecular dissection of the photoperiodic and maternal induction of diapause in the jewel wasp, Nasonia vitripennis

Research paper thumbnail of Cell cycle arrest in the jewel wasp Nasonia vitripennis in larval diapause

Journal of insect physiology, Jan 26, 2016

Insects enter diapause to synchronise their life cycle with biotic and abiotic environmental cond... more Insects enter diapause to synchronise their life cycle with biotic and abiotic environmental conditions favourable for their development, reproduction, and survival. One of the most noticeable characteristics of diapause is the blockage of ontogeny. Although this blockage should occur with the cessation of cellular proliferation, i.e. cell cycle arrest, it was confirmed only in a few insect species and information on the molecular pathways involved in cell cycle arrest is limited. In the present study, we investigated developmental and cell cycle arrest in diapause larvae of the jewel wasp Nasonia vitripennis. Developmental and cell cycle arrest occur in the early fourth instar larval stage of N. vitripennis under short days. By entering diapause, the S fraction of the cell cycle disappears and approximately 80% and 20% of cells arrest their cell cycle in the G0/G1 and G2 phases, respectively. We further investigated expression of cell cycle regulatory genes and some housekeeping ge...

Research paper thumbnail of Effect of light intensity in urban night on insect seasonality: A case study in a flesh fly

Hikaku seiri seikagaku(Comparative Physiology and Biochemistry)

Research paper thumbnail of Urban warming and artificial light alter dormancy in the flesh fly

Royal Society Open Science

Seasonal changes in temperature and day length are distinct between rural and urban areas due to ... more Seasonal changes in temperature and day length are distinct between rural and urban areas due to urban warming and the presence of artificial light at night. Many studies have focused on the impacts of these ubiquitous signatures on daily biological events, but empirical studies on their impacts on insect seasonality are limited. In the present study, we used the flesh fly Sarcophaga similis as a model insect to determine the impacts of urbanization on the incidence and timing of diapause (dormancy), not only in the laboratory but also in rural and urban conditions. In the laboratory, diapause entry was affected by night-time light levels as low as 0.01 lux. We placed fly cages on outdoor shelves in urban and rural areas to determine the timing of diapause entry; it was retarded by approximately four weeks in urban areas relative to that in rural areas. Moreover, almost all flies in the site facing an urban residential area failed to enter diapause, even by late autumn. Although an ...

Research paper thumbnail of RNAi targeted to the circadian clock geneperioddisrupts photoperiodism of the jewel wasp,Nasonia vitripennis

2016 International Congress of Entomology

Research paper thumbnail of The clock gene period is essential for the photoperiodic response in the jewel wasp Nasonia vitripennis (Hymenoptera: Pteromalidae)

Applied Entomology and Zoology

The role of the clock gene period (per) in photoperiodism was investigated in the jewel wasp Naso... more The role of the clock gene period (per) in photoperiodism was investigated in the jewel wasp Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae). Typically, females reared under long days lay eggs that develop to adulthood without developmental interruption, whereas those reared under short days lay eggs that enter larval diapause. We found that RNA interference (RNAi) of per disrupts the photoperiodic response; RNAi wasps failed to produce diapause-destined eggs in response to short days. This indicates that per is essential for the photoperiodic response in this species. Exposure to low temperature swiftly affects maternal physiology and prompts N. vitripennis females to lay diapause-destined eggs. Interestingly, per RNAi females also laid diapause-destined eggs in response to the low temperature treatment in the current study. This finding indicates that per RNAi did not disrupt the maternal physiology that was directly involved in production of diapause-destined eggs, but it did affect photoperiodic perception. We also investigated the expression patterns of several clock genes, per, mammalian-type cryptochrome (cry-m), cycle (cyc), PAR domain protein 1 (Pdp1), and clockwork orange (cwo), to determine whether their expression patterns were affected by different photoperiods.

Research paper thumbnail of Juvenile hormone as a causal factor for maternal regulation of diapause in a wasp

Insect Biochemistry and Molecular Biology, 2022

Research paper thumbnail of Environmental parameters in the semi-natural condition and diapause incidence of flesh fly

Seasonal changes in temperature and day length are distinct between rural and urban areas due to ... more Seasonal changes in temperature and day length are distinct between rural and urban areas due to urban warming and the presence of artificial light at night. Many studies have focused on the impacts of these ubiquitous signatures on daily biological events, but empirical studies on their impacts on insect seasonality are limited. In the present study, we used the flesh fly Sarcophaga similis as a model insect to determine the impacts of urbanisation on the incidence and timing of diapause (dormancy), not only in the laboratory but also in rural and urban conditions. In the laboratory, diapause entry was affected by night-time light levels as low as 0.01 lux. We placed fly cages on outdoor shelves in urban and rural areas to determine the timing of diapause entry; it was retarded by approximately four weeks in urban areas relative to that in rural areas. Moreover, almost all flies in the site facing an urban residential area failed to enter diapause, even by late autumn. Although an ...

Research paper thumbnail of Figure S1; Figure S2 from Urban warming and artificial light alter dormancy in the flesh fly

Spectra of the fluorescent light used for the laboratory diapause induction (A) and the residenti... more Spectra of the fluorescent light used for the laboratory diapause induction (A) and the residential light at site 2 in Experiment 2 (18:30 on 30 January 2018, 1-h after sunset) (B). Spectral irradiance (mW/m2/min) in each wavelength (nm) was recorded by the colour rendering illuminometer CL-70F (Konica Minolta, Tokyo, Japan). Note that the irradiance of A and B was different (972 lux and 17. 6 lux in A and B, respectively).; Night illuminance at site 1 and site 2 in Experiment 2, 23 September – 22 November 2016. Mean values of illuminance during the astronomical nights (from sunset to sunrise) obtained from the National Astronomical Observatory of Japan website (eco.mtk.nao.ac.jp) were calculated. Error bars indicate standard deviations. Shaded areas (5 and 6 October) indicate no data due to the incidence of a typhoon.

Research paper thumbnail of Supplementary material from "Urban warming and artificial light alter dormancy in the flesh fly

Seasonal changes in temperature and day length are distinct between rural and urban areas due to ... more Seasonal changes in temperature and day length are distinct between rural and urban areas due to urban warming and the presence of artificial light at night. Many studies have focused on the impacts of these ubiquitous signatures on daily biological events, but empirical studies on their impacts on insect seasonality are limited. In the present study, we used the flesh fly <i>Sarcophaga similis</i> as a model insect to determine the impacts of urbanization on the incidence and timing of diapause (dormancy), not only in the laboratory but also in rural and urban conditions. In the laboratory, diapause entry was affected by night-time light levels as low as 0.01 lux. We placed fly cages on outdoor shelves in urban and rural areas to determine the timing of diapause entry; it was retarded by approximately four weeks in urban areas relative to that in rural areas. Moreover, almost all flies in the site facing an urban residential area failed to enter diapause, even by late a...

Research paper thumbnail of Molecular dissection of the photoperiodic and maternal induction of diapause in the jewel wasp, Nasonia vitripennis

Research paper thumbnail of Cell cycle arrest in the jewel wasp Nasonia vitripennis in larval diapause

Journal of insect physiology, Jan 26, 2016

Insects enter diapause to synchronise their life cycle with biotic and abiotic environmental cond... more Insects enter diapause to synchronise their life cycle with biotic and abiotic environmental conditions favourable for their development, reproduction, and survival. One of the most noticeable characteristics of diapause is the blockage of ontogeny. Although this blockage should occur with the cessation of cellular proliferation, i.e. cell cycle arrest, it was confirmed only in a few insect species and information on the molecular pathways involved in cell cycle arrest is limited. In the present study, we investigated developmental and cell cycle arrest in diapause larvae of the jewel wasp Nasonia vitripennis. Developmental and cell cycle arrest occur in the early fourth instar larval stage of N. vitripennis under short days. By entering diapause, the S fraction of the cell cycle disappears and approximately 80% and 20% of cells arrest their cell cycle in the G0/G1 and G2 phases, respectively. We further investigated expression of cell cycle regulatory genes and some housekeeping ge...

Research paper thumbnail of Effect of light intensity in urban night on insect seasonality: A case study in a flesh fly

Hikaku seiri seikagaku(Comparative Physiology and Biochemistry)

Research paper thumbnail of Urban warming and artificial light alter dormancy in the flesh fly

Royal Society Open Science

Seasonal changes in temperature and day length are distinct between rural and urban areas due to ... more Seasonal changes in temperature and day length are distinct between rural and urban areas due to urban warming and the presence of artificial light at night. Many studies have focused on the impacts of these ubiquitous signatures on daily biological events, but empirical studies on their impacts on insect seasonality are limited. In the present study, we used the flesh fly Sarcophaga similis as a model insect to determine the impacts of urbanization on the incidence and timing of diapause (dormancy), not only in the laboratory but also in rural and urban conditions. In the laboratory, diapause entry was affected by night-time light levels as low as 0.01 lux. We placed fly cages on outdoor shelves in urban and rural areas to determine the timing of diapause entry; it was retarded by approximately four weeks in urban areas relative to that in rural areas. Moreover, almost all flies in the site facing an urban residential area failed to enter diapause, even by late autumn. Although an ...

Research paper thumbnail of RNAi targeted to the circadian clock geneperioddisrupts photoperiodism of the jewel wasp,Nasonia vitripennis

2016 International Congress of Entomology

Research paper thumbnail of The clock gene period is essential for the photoperiodic response in the jewel wasp Nasonia vitripennis (Hymenoptera: Pteromalidae)

Applied Entomology and Zoology

The role of the clock gene period (per) in photoperiodism was investigated in the jewel wasp Naso... more The role of the clock gene period (per) in photoperiodism was investigated in the jewel wasp Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae). Typically, females reared under long days lay eggs that develop to adulthood without developmental interruption, whereas those reared under short days lay eggs that enter larval diapause. We found that RNA interference (RNAi) of per disrupts the photoperiodic response; RNAi wasps failed to produce diapause-destined eggs in response to short days. This indicates that per is essential for the photoperiodic response in this species. Exposure to low temperature swiftly affects maternal physiology and prompts N. vitripennis females to lay diapause-destined eggs. Interestingly, per RNAi females also laid diapause-destined eggs in response to the low temperature treatment in the current study. This finding indicates that per RNAi did not disrupt the maternal physiology that was directly involved in production of diapause-destined eggs, but it did affect photoperiodic perception. We also investigated the expression patterns of several clock genes, per, mammalian-type cryptochrome (cry-m), cycle (cyc), PAR domain protein 1 (Pdp1), and clockwork orange (cwo), to determine whether their expression patterns were affected by different photoperiods.