Circadian rhythm of sex pheromone-releasing behaviour in females of the dermestid beetle,Trogoderma glabrum: Regulation by photoperiod

The effects on sex pheromone-releasing, or calling behaviour, of diel photoperiods of varying daylength, of light cycle phase shifts, and of continuous illumination were investigated in Trogoderma glabrum females. On light régimes with 8 to 20 hr daylengths, calling maxima tended to centre close to photophase midpoints. Although influencing the time of day at which calling occurred, daylength had little effect on the amount of activity or the length of the calling period. When 16 : 8 LD light cycles were advanced or delayed by 4 hr, the time of day at which calling peaks were observed shifted within 2 to 4 cycles so that a constant phase relationship with photoperiod was maintained. Daily calling peaks were evident in groups of females exposed to between 1 and 5 days of continuous illumination, but mean calling time occurred earlier in the day as light exposures were lengthened. It was concluded that a circadian rhythm of calling behaviour exists in T. glabrum females. and that the rhythm can be entrained to 24 hr periodicity by photoperiod.     

The effects of photoperiod and temperature on calling behaviour and egg development of the bertha armyworm,Mamestra configurata (Lepidoptera: Noctuidae)

The effects of photoperiod and temperature on calling behaviour and the effects of temperature on the relationship between egg development and calling of virgin females of Mamestra configurata Walker were examined at 3 photoperiodic regimes and seven constant temperatures. Photoperiod affected the diel periodicity of calling and length of the daily calling period. The mean onset calling times were similar if the preceding scotophase(s) was 6–10 h long, but the onset of calling was delayed by 1–5 h if the preceding scotophase(s) was 12–18 h long. Long-term, constant temperature (from emergence until death) affected 4 aspects of calling: age at first calling, diel periodicity, length of the daily calling period, and percentage of females calling. Short-term temperature changes (during a single scotophase) affected calling in 3 ways: diel periodicity, length of the daily calling period, and percentage of females calling. The optimal temperature range for calling was, at least, 10–25°C; the upper limit and threshold were near 35 and < 5°C. The time of first calling was synchronized closely with the appearance of the first chorionated eggs in the ovaries at 10–35°C. Egg development and calling were adversely affected at 30 and 35°C. The physiological and ecological significance of the data are discussed.     

Light-, nitrogen-, and phosphorus-limited growth of Phaeodactylum tricornutum Bohlin strain TFX-1: Chemical composition,carbon partitioning,and the diel periodicity of physiological processes

Phaeodactylum tricomutum Bohlin (strain TFX-1) was grown under light-, nitrogen-, and phosphorus-limited conditions in continuous or semicontinuous cultures under a 12L-12D light regime. The C, N, and P contents were determined at each steady state, as was the partitioning of cellular organic carbon into protein, lipids, polysaccharides, and metabolic intermediates. All determinations were made at the beginning and again at the end of the light period. The rates of nutrient assimilation and of synthesis of biochemical constituents during the light and dark periods were calculated from the above data, and the periodicities of these processes characterized. The elemental composition of the cells was different under each limitation. In particular, phosphorus limitation severely restricted the ability of the cell to store nitrogen in non-protein forms. Biochemical composition and the diel periodicity of cellular processes also differed between limitations. Nutrient uptake was most strongly periodic under light limitation. Protein synthesis showed increased periodicity under nitrogen limitation, relative to the other limitations, while the periodicity of lipid synthesis was reduced under phosphate limitation. Polysaccharide was synthesized at high rates during the light period and consumed in the dark under all limitations.     

Reanalysis of Filter-Feeding Behavior of Caddis Fly (Brachycentrus) Larvae Reveals Masking and Circadian Rhythmicity

Data published on the subjectively determined presence or absence of circadian periodicity in feeding of Brachycentrus occidentalis Banks, an aquatic insect belonging to the order Trichoptera, were reanalyzed by statistical methods based on the cosine model. The 4h data for 5 days of synchronized environmental conditions followed by 5 days of constant conditions (using original values and purified values after removal of an 8h component attributed to the feeding schedule) were quantified for rhythm characteristics by the least-squares fit of cosines. A circadian rhythm was highly significant during synchronized conditions (light-dark and cycling water temperature) and in continuous light when water temperature continued to cycle. A circadian rhythm in the percentage of larvae feeding during continuous light and constant water temperature, which had not been observed by visual inspection in the original data, was detected in the unmasked data with a “free-running” period not overlapping 24.0h (95% confidence limits from 18.95h to 21.66h). Effects of masking brought about by manually feeding the larvae every 8h were statistically significant under both synchronized and constant environmental conditions. (Chronobiology International, 15(6), 595-606, 1998)     

Circadian rhythmicity and development of the behavioural response to sex pheromone in male brown-banded cockroaches, Supella longipalpa

Abstract The effects of age, time of day and pheromone concentration on the responsiveness of the male brown-banded cockroach, Supella longipalpa (F.), to female volatile sex pheromone were examined. Male response increased with age and peaked 10 days after the imaginal moult. A diel periodicity of responsiveness was observed, with greater responses in the scotophase. The behavioural response was dose-dependent and its diel periodicity was most obvious when intermediate pheromone concentrations (e.g. 0.01 female equivalents) were used. Higher concentrations obscured the periodicity by eliciting greater responses in the photophase, while the lower concentrations did so by decreasing the response in the scotophase. Following entrainment to a LD 12:12 h cycle, the periodicity of response to 0.01 female equivalents of pheromone persisted for at least 54 h under continuous darkness, further demonstrating a true circadian rhythm.     

Clock genes period and timeless are rhythmically expressed in brains of newly hatched, photosensitive larvae of the fly, Sarcophaga crassipalpis

While roles of the clock genes period (per) and timeless (tim) are relatively well understood in relation to circadian clocks, their potential roles in insect photoperiodism remain enigmatic. In this study, the expression of per and tim genes under two contrasting photoperiods is described in the central nervous system of photoperiodically sensitive, newly hatched first instar larvae of the flesh fly, Sarcophaga crassipalpis. Using qPCR, diel oscillations were observed in the mRNA levels of both genes under long-day (15 h light:9 h dark, promotes direct development) and short-day conditions (11 h light:13 h dark, induces pupal diapause). Peak per and tim mRNA oscillations were closely associated with the light/dark transition. The conspicuous difference between the two photoperiodic conditions was that the sharp increase in per and tim mRNA abundance occurred during the light phase under long days but during the dark phase under short days. The diel oscillations were, at least in part, driven by an endogenous component, as demonstrated by transferring larvae to continuous darkness. The cells displaying Tim- and Per-like immunoreactivities (Tim- and Per-LIRs) were localized using anti-Drosophila-Per and anti-Chymomyza-Tim antibodies. Per-LIR and Tim-LIR co-localized in three groups of cells in each brain hemisphere. Two other groups, one in the brain hemispheres and the other in the fused ventral nerve ganglion, expressed only the Per-LIR.     

Diel periodicity of emergence of adult citrus rust mites in central Florida

Emergence of adult citrus rust mites, Phyllocoptruta oleivora (Ashmead) from the imagochrysafis occurred with a diel periodicity that peaked between mid morning and early afternoon. The pattern of emergence did not differ for mites reared from eggs held under different photoperiod regimes. The transition of nymphs to the imagochrysalis stage also showed a diel periodicity, occurring in the evening. The average duration of the imagochrysalis stage at 28 °C was 14–15 h.Wetting by rain or dew was simulated by immersing fruit in water each night, but the transition to the imagochrysalis stage or the subsequent emergence pattern of adults was not affected. Adult mites reared from eggs laid during two, consecutive 12-h periods emerged at the same time of day, but the peaks of emergence were separated by 24 h. Eclosion of larvae from eggs laid during two, consecutive 12-h periods did not show a diel periodicity. Eggs continuously immersed in water during their development did not hatch, whereas there was a small, but significant, reduction in the viability of eggs immersed in water each night. These results are discussed in relation to external cues that may entrain the diel patterns of development and adult emergence, and to the adaptive responses of citrus rust mite to cyclic fluctuations of key environmental variables in central Florida. This revised version was published online in August 2006 with corrections to the Cover Date.     

The relationship between locomotor activity rhythm and burying behavior in the wrasse,Suezichthys gracilis

The wrasse,Suezichthys gracilis, is a diurnal fish which buries itself in sand during the night-time. The present paper deals with the locomotor activity rhythms ofS. gracilis, examined by using an actograph with infra-red photo-electric switches in a dark room. The fish were kept in eight experimental tanks (each 30l in capacity), with three different bottom conditions: sand (grain size about 1 mm in diameter and 5 cm deep); 1 or 2 stones (about 10cm in diameter) without sand; and transparent acrylic pellets (2 × 2 × 3 mm in size, 5 cm deep). The light intensities were 550–700 lux just above the water surface, decreasing to 21.3% under the acrylic pellets at a water depth of 20cm. The water temperatures were kept at 22.0–25.0°C during the experiments for 7 to 14 days. In the aquarium with bottom sand, diel activity rhythms ofS. gracilis were mostly synchronized to LD (LD12:12; 06:00–18:00 light, 18:00–06:00 dark), free-running activity rhythms continued distinctly under LL (constant illumination), and locomotor activity was greatly suppressed, with disappearance of the activity rhythm, under DD (constant darkness). In the aquarium without sand, locomotor activity ofS. gracilis could be summarized as follows. The fish moved throughout almost the entire period under LD, though more frequent movements were observed in light conditions than in dark ones. Under LL they showed continuous locomotor activity during the experiment, with no obvious periodicity. Under DD the activity of the species was somewhat suppressed, but irregular movement or indistinct periodicity was observed. In the aquarium with transparent acrylic pellets, locomotor activity under LD and DD, respectively, bore a close resemblance to activity patterns under the same light conditions with sand, whilst activity under LL was identical to that under LL without sand. Accordingly, it seems that maintenance of normal activity rhythms in the wrasse was due not only to the darkness, but also to the presence of bottom sand. It therefore seems that the biological clock inS. gracilis is not related to locomotor activity, but to burying behavior.     

Effects of photoperiod and temperature on pupal diapause induction of grape berry moth Lobesia botrana

Abstract. The grape berry moth, Lobesia botrana Denn. & Sciff. (Lepidoptera: Tortricidae), one of the most injurious pest of grape berries in Greece, is a multivoltine species that overwinters as diapausing pupae. The effects of several diel and non-diel photoperiods and of temperature, experienced by eggs and larvae, on pupal diapause induction were investigated. The diapause response curve was of Type I (long day type) and the determining factor was the duration of scotophase (> 11 h), regardless of the duration of photophase. However, at very short (< 4 h) photoperiods, the incidence of diapause was also high. Diapause was positively and significantly correlated with the egg-larval developmental time, pupal mortality and the duration of the pupal stage. Eggs and larvae reared under LD 12 : 12 h photoperiod and various temperatures (from 12 to 30 °C) produced diapausing pupae (almost 100%), but the duration of the pupal stage (intensity of diapause) increased with increasing temperature. Under continuous darkness, however, the percentage diapause decreased with increasing temperature. Single and double 1-h light pulses were applied systematically at various times during the scotophase of six diapause-inducing diel photoperiods. Two photosensitive points in time (called A and B) were revealed, during which illumination resulted in a significant decrease of diapause induction. The decrease was much greater during the first sensitive period (early in scotophase) rather than in the second (late in the scotophase).     

Effect of daylength and temperature on the larval diapause of the sunflower moth, Homoeosoma electellum

The effect of daylength and temperature on the regulation of the larval diapause of a central Missouri population of the sunflower moth, Homoeosoma electellum, was examined. Fully grown fourth-instar larvae exhibit a facultative diapause. Measurements of the effect of photoperiod on diapause induction revealed critical photoperiods of about 13 h 30 min light/day at 20°C, and between 11 h 45 min and 12 h light/day at 23°C. Third and fourth-instar larvae were shown to be the main sensitive stages for diapause determination. Daylength was also shown to be an important regulator of the rate of diapause development. A short day of LD 10:14 h permitted only a low rate of diapause development, whereas long days of LD 14:10 h and LD 16:8 h accelerated diapause development at 25 and 30°C. When long days were alternated with short days at 30°C the accelerating effect of long days on diapause development was not found. Systematic transfers of chilled diapausing larvae revealed an accelerated diapause development in groups transferred from 10 to 30°C LD 10:14 h, but diapause development was not accelerated in groups transferred from 10 to 30°C LD 16:8 h.     

Thermal acclimation of swimming performance in newt larvae: the influence of diel temperature fluctuations during embryogenesis

1.  Thermal acclimation is one of the basic strategies by which organisms cope with thermal heterogeneity of the environment. Under predictable variation in environmental temperatures, theory predicts that selection favours acclimation of thermal performance curves over fixed phenotypes.
2.  We examined the influence of diel fluctuations in developmental temperatures on the thermal sensitivity of the maximal swimming capacity in larvae of the alpine newt, Triturus alpestris .
3.  We incubated newt eggs under three thermal regimes with varying daily amplitudes (1, 5 and 9 °C) and similar means (17·6–17·9 °C), and accordingly we measured the swimming speed of hatched larvae at three experimental temperatures (12, 17 and 22 °C), which they would normally experience in their natural habitat.
4.  Embryonic development under low and middle temperature fluctuations produced larvae with similar swimming speeds across experimental temperatures. In contrast, the most fluctuating regime induced development of phenotypes, which at 12 °C swam faster than larvae developed under moderate diel fluctuations.
5.  Our results provide evidence that diel temperature fluctuations induce acclimation of thermal dependence of locomotor performance. In ectotherms experiencing diel cycles in environmental temperatures, this plastic response may act as an important pacemaker in the evolution of thermal sensitivity.     

Spore discharge in Entomophthora grylli

Entomophthora grylli Fres. has been found on larvae of Bradysia (Sciaridae, Diptera) on wood in Kansas State University greenhouses since November 1967. Infected larvae crawled to an exposed site in the night and by morning spores of E. grylli were being discharged. In the greenhouse and under controlled environments spore discharge showed a marked periodicity; spore discharge occurred in the light with peaks in the first 1–4 h; discharge then gradually declined but extended into the dark. On the second and third days peaks occurred in the light but were progressively smaller. In a greenhouse under fluctuating conditions twin peaks occurred at 10·00 and 22·00; in a growth chamber, at constant 21° C. 90% r.h., alternating 12 h light and dark periods, spore discharge was similar, with maximum numbers about 21/2 h after the onset of the photo-period. In continuous dark and continuous light no endogenous pattern was evident. Temperature range for spore discharge was 2–28·, with optimum at 15·. Decreasing humidities resulted in decreased spore production and cessation of discharge below 40% r.h.     

Exogenous control of diel locomotor activity in the whitefish Coregonus clupeaformis: effects of light and temperature

Summary Data on factors determining activity cycles of nearctic fishes are scarce overall, and nonexistent for Coregoniae (family Salmonidae), a group with closely related and somewhat better known palaearctic species. We studied effects of photoperiodicity, light intensity and temperature on diel locomotor activity of lake whitefish Coregonus clupeaformis (Mitchill). Under LD 12:12, a day-active pattern was evident. Under continuous light (LL) and continuous dark (DD), rhythmicity was greatly suppressed or absent, respectively. Day-time activity levels were positively correlated with illuminance over the range tested (0.005 to 500 lux). At the three temperatures tested, activity was lowest at 7° C, highest at 12° C (a reported temperature optimum), and intermediate at 17° C. Our results suggest that level and diel pattern of lake whitefish activity are under overriding external control, and we find similarities with published data on the European species Coregonus lavaretus.     

Diel drift of Chironomidae in a large lowland river (Central Poland)

The diel drift patterns of Chironomidae larvae were investigated in a seventh order section of the Warta River (Central Poland) over two diel cycles during May 1989. Three nets (mesh size 400 m) were installed in a cross section of the Warta River.The estimated drift density was low, but was comparable to that calculated for other large rivers. Spatio-temporal fluctuations in abundance and composition of macroinvertebrate drift, including Chironomidae, were observed with the highest density of drifting macrobenthos recorded near the depositional bank of this river. The ratio benthosdrift indicated differing propensities for of the older instars of a given chironomid taxon to drift. Orthocladiinae larvae were the most abundant subfamily of Chironomidae in drift but not in benthos, reaching up to 73% of the total drifting chironomid larvae. More taxa but fewer individuals (about 20% of the chironomid larvae collected) belonged to the tribe Chironomini, the dominant group in benthos.A major part of chironomid drift collection may represent behavioural drift because the net mesh size used in the Warta River was insufficient to catch the earliest instars (distributional drift). Both at the family and subfamily level chironomid larvae exhibited a distinct nocturnal drift periodicity. Nocturnal periodicity was documented for the dominant species, but due to the low density of many chironomid species, it was impossible to determine their diel drift pattern. Some Chironomidae appeared to be aperiodic.     

Ontogenetic Behavior, Migration, and Social Behavior of Pallid Sturgeon, Scaphirhynchus albus, and Shovelnose Sturgeon, S. platorynchus, with Notes on the Adaptive Significance of Body Color

We conducted laboratory studies on the ontogenetic behavior of free embryos (first life interval after hatching) and larvae (first feeding interval) of pallid and shovelnose sturgeon. Migration styles of both species were similar for timing of migration (initiation by embryos on day 0 after hatching and cessation by larvae on days 12–13 at 236–243 cumulative temperature degree units), migration distance (about 13km), life interval when most distance was moved (embryo), and diel behavior of embryos (diurnal). However, the species differed for two behaviors: movement characteristics of embryos (peak movement rate of pallid sturgeon was only one-half the peak rate of shovelnose sturgeon, but pallid sturgeon continued the lower rate for twice as long) and diel behavior of larvae (pallid sturgeon were diurnal and shovelnose sturgeon were nocturnal). Thus, the species used different methods to move the same distance. Migrating as poorly developed embryos suggests a migration style to avoid predation at the spawning site, but moving from spawning habitat to rearing habitat before first feeding could also be important. Migrants of both species preferred bright habitat (high illumination intensity and white substrate), a behavioral preference that may characterize the migrants of many species of sturgeon. Both species were remarkably similar for swimming height above the bottom by age, and day 7 and older migrants may swim far above the bottom and move far downstream. A migration of 12 or 13 days will probably not distribute larvae throughout the population's range, so an older life interval likely initiates a second longer downstream migration (2-step migration). By day 2, individuals of both species were a black-tail phenotype (light grey body with a black-tail that moved conspicuously during swimming). Aggregation behavior suggests that black-tail is a visual signal used for group cohesion.     

Laboratory spawning cues in Menidia beryllina,and M. peninsulae (Pisces,Atherinidae) with notes on survival and growth of larvae at different salinities

Synopsis Spawning patterns of inland silversides, Menidia beryllina, and tidewater silversides, Menidia peninsulae, were examined in the laboratory under several combinations of ‘tidal’ and diel light cycle cues. M. beryllina showed a high frequency of spawning throughout the day when held under constant conditions (24L: OD, current velocity 8 cm sec⁻¹) and when ‘tidal’ and diel light cycles were presented singly or in combination. In contrast, M. peninsulae demonstrated a high frequency of spawning only when presented a combination of ‘tidal’ and diel light cycle cues and spawned predominantly at night. Menidia beryllina embryos were euryhaline. Hatching ranged from 73 to 78% at salinities of 5,15 and 30‰ M. peninsulae embryos showed an inverse relationship between the percentage hatch and the incubation salinity, 90% at 5‰ and only 65% at 30‰ Survival and growth of larval M. beryllina from the day of hatching through 16 days old was optimal at 15‰ Although survival of M. peninsulae larvae was optimal at 30%, no trend was apparent in growth of larvae held for 16 days at 5, 15 or 30‰ salinity. Contribution No. 508 from the Gulf Breeze Environmental Research Laboratory     

DIEL PATTERNS IN LIGHT ABSORPTION AND ABSORPTION EFFICIENCY FACTORS OF ISOCHRYSIS GALBANA (PRYMNESIOPHYCEAE)1

The chl a specific absorption coefficients [a* (λ), m²·mg chl a ^{? 1}] were examined in chemostat culture of the Prymnesiophyceae Isochrysis galbana (Parke) under a 12:12‐h light:dark cycle at low light (75 μmol photons·m ^{? 2}·s ^{? 1}) and high light (500 μmol photons· m ^{? 2}·s ^{? 1}) conditions. Other associated measurements such as pigment composition, cell density, and diameter as the measure of cell size were also made at the two light regimes every 2 h for 2 days to confirm the periodicity. A distinct diel variability was observed for the a* (λ) with maxima near dawn and minima near dusk. The magnitude of diel variation in a* (440) was 15% at low light and 22% at high light. Pronounced diel patterns were observed for cell size with minima near dawn and maxima near dusk. The magnitude of diel variation in cell size was 9.3% at low light and 21% at high light. The absorption efficiency factors [Q _a (440)] were determined by reconstruction using intracellular concentrations of pigments and cell size. The Q _a (440) also showed a distinct diel variability, with minima near dawn and maxima near dusk. The diel variation in a* (λ) and Q _a (λ) was primarily caused by changes in cell size due to growth, although there was some influence from diel variations in the intracellular pigment concentrations. The results presented here indicated that diel variation in a* (λ) was an important component of the optical characterization of phytoplankton.     

Absence of consistent diel rhythmicity in mated honey bee queen behavior

Relatively little is known about the temporal control of behavior of honey bee queens under natural conditions. To determine if mated honey bee queens possess diel rhythmicity in behavior, we observed them in glass-sided observation hives, employing two focal studies involving continuous observations of individual queens as well as a scan-sampling study of multiple queens. In all cases, all behaviors were observed at all times of the day and night. In four of the five queens examined in focal studies, there were no consistent occurrences of diel periodicity for any of the individual behaviors. A more encompassing measure for periodicity, in which the behaviors were characterized as active (walking, inspecting, egg-laying, begging for food, feeding, and grooming self) or inactive (standing), also failed to reveal consistent diel rhythmicity. Furthermore, there were no consistent diel differences in the number of workers in the queen's retinue. Behavioral arrhythmicity persisted across seasons and despite daily changes in both light and temperature levels. Both day and night levels of behavioral activity were correlated with daytime, but not with nighttime, ambient temperatures. The behavior of the one exceptional queen was not consistent: diurnal activity patterns were present during two 24-h observation sessions but arrhythmicity during another. Based on the behavior observed by all but one of the queens examined in this work, the arrhythmic behavior by the mated honey bee queen inside the colony appears to be similar to that exhibited by worker bees before they approach the age of onset of foraging behavior.     

Entrainment of the circadian rhythm in larval release of the crab Dyspanopeus sayi by temperature cycles

Marine and estuarine crabs brood attached eggs, which hatch synchronously releasing larvae at precise times relative to environmental cycles. The subtidal crab Dyspanopeus sayi has a circadian rhythm, in which larvae are released within the 4-h interval after the time of ambient sunset. Previous studies demonstrated that the rhythm can be entrained by the light:dark cycle. Since subtidal crabs are also exposed to temperature fluctuations, an unstudied question was whether the circadian rhythm could be entrained by the diel temperature cycle. To answer this question, ovigerous D. sayi were entrained in darkness to 2.5, 5, and 10 °C temperature cycles that were reverse in phase from the ambient temperature cycle. After entrainment, larval release times were monitored in constant conditions of temperature and darkness with a time-lapse video system. The effectiveness of a temperature cycle to shift the timing of larval release increased as the magnitude of the temperature cycle increased and as crabs were exposed to increasing numbers of entrainment cycles. However, entrainment to a 10 °C cycle only lasted 2 days in constant conditions. When crabs were entrained to a light:dark vs. a 10 °C temperature cycle, the light:dark cycle was dominant for entrainment. Nevertheless, ovigerous crabs do sense temperature cycles and in areas where daylight is too low for entrainment, temperature cycles can be used to regulate the time of larval release.     

Photoperiod induced developmental effects on silkmoth,Bombyx mori

Bombyx mori is most common silkmoth used for the commercial production of the silk. The different environmental conditions may affect development of silkmoth and hence the output of silkworm. Present study investigated effects of different photoperiodic conditions on the development of silkmoth. Three experiments were performed on newly hatched larvae. In experiment1, larvae were divided into three groups; group 1, 8L:16D (8 h light and 16 h dark), group 2, 12L:12D (12 h light and 12 h dark) and group 3, 16L:8D (16 h light and 8 h dark). In experiment 2, larvae were exposed to either continuous light or continuous dark. In experiment 3, larvae were divided into three groups. Each group received light of similar duration (16L:8D) and intensity (1.1 ± 0.1 PAR) but of different wavelengths; i.e. long wavelength red light (640 nm), short wavelength blue light (450 nm) and white light. Larvae were fed on young mulberry (Morus alba) leaves. Temperature and humidity were maintained at 26 (±2) °C and 75 (±5)%, respectively, throughout the study. Observations on change in body length of larvae were made on every alternate day. We also calculated the shell ratio, time taken in cocoon formation and emergence. Results from experiment show that the larvae underwent significant change in body length but with faster growth rate under 12L:12D photoperiod in comparison to 8L:16D and 16L:8D. Time taken in cocoon formation and hatching was significantly less, while shell ratio was significantly higher in 12L:12D in comparison to other groups. We did not observe much effect of monochromatic light on the development of silkmoth.