Sperm Transfer in Gypsy Moths: Effect of Constant or Cyclic Temperature and Constant Light or Darkness during the Pupal Stage

1997 ◽  
Vol 32 (3) ◽  
pp. 321-331 ◽  
Author(s):  
F. I. Proshold
Keyword(s):  
Light Intensity ◽  
Constant Temperature ◽  
Lymantria Dispar ◽  
Pupal Stage ◽  
Sperm Transfer ◽  
Constant Light ◽  
Constant Darkness ◽  
Gypsy Moths ◽  
Cyclic Temperature ◽  
Full Complement

Sperm transfer and fertility of the gypsy moth, Lymantria dispar (L.), held as pupae under constant temperature and 24-h light, 24-h darkness, or a photoperiod of 16:8 (L:D) h were compared with males held in cyclic temperature and 24-h light, 24-h darkness, or a photoperiod of 16:8 (L:D) h. Constant temperature and constant light or darkness severely reduced its ability to transfer sperm. Males held under constant light were more severely affected than males held in darkness, but sperm transfer was not correlated with light intensity (between 80 and 3960 lux). Nearly all males held under constant light and most held under constant darkness were sterile or partially sterile. In either case, sterility was caused by poor sperm transfer. Females with a full complement of sperm were fertile regardless of holding condition of male pupae. The sterilizing effect of constant light or darkness was overridden by cyclic temperature of 28°C for 16 h and 22°C for 8 h. At a photoperiod of 16:8 h, pupae held in constant 28°C transferred less sperm than those held at 25°C. Pupae held at constant 30°C were sterile, but those held at 30°C for 16 h and 25°C for 8 h transferred similar quantities of sperm as males held at constant 28°C.

Mosquito circadian flight rhythms: differential effects of constant light

1984 ◽  
Vol 247 (6) ◽  
pp. R960-R967 ◽  
Author(s):  
J. R. Clopton
Keyword(s):  
Light Intensity ◽  
Active Phase ◽  
Flight Activity ◽  
Constant Light ◽  
Constant Darkness ◽  
Circadian Pacemaker ◽  
Differential Effects ◽  
Activity Onset ◽  
Culiseta Incidens ◽  
Additional Assumptions

The flight activity of Culiseta incidens was automatically recorded in constant darkness and constant light after entrainment to light:dark 12:12 to determine the usefulness of a formal circadian pacemaker model in which the periods of two oscillators respond reciprocally to light intensity. Period at activity onset lengthened approximately 0.4 h from darkness to 0.1 lx, whereas period at offset shortened approximately 0.4 h. Thus within this range, the onset of the nocturnal active phase obeyed Aschoff's rule for nocturnal animals, and the offset (or onset of diurnal rest phase) obeyed the rule for diurnal animals. These data supported a model in which, as light intensity increases, the period of one oscillator (evening) increases while that of another (morning) decreases. This model, with additional assumptions, also provided a framework for mutually consistent explanations of other features among the data. These included long periods at 3.5 lx, short periods at 35 lx, a progressively earlier occurrence of inactivity with increasing light intensity, and a clear example of circa-bi-dian (approximately 2 days) rhythmicity.

scholarly journals TEMPERATURE CHARACTERISTICS FOR THE GROWTH OF THE SPORANGIOPHORES OF PHYCOMYCES

1928 ◽  
Vol 11 (4) ◽  
pp. 407-413 ◽  
Author(s):  
E. S. Castle
Keyword(s):  
Light Intensity ◽  
Constant Temperature ◽  
Constant Light ◽  
Temperature Characteristics

1. With constant temperature and light intensity, the rate of elongation of a sporangiophore of Phycomyces is constant for many hours. 2. With constant light intensity, values of µ, the "critical thermal increment," have been computed for the elongation of different sporangiophores. These values group themselves closely about the modes 11,000, 16,000, 20,000, 26,000, and 33,000 calories. Sporangiophores from the same culture need not have similar increments. 3. The significance of these results for studies of growth is discussed.

Photic Response Parameters of Circadian Rhythms in The Spinifex Hopping Mouse, Notomys alexis.

1996 ◽  
Vol 19 (1) ◽  
pp. 11
Author(s):  
A.J.P. Francis ◽  
G.J. Coleman
Keyword(s):  
Circadian Rhythms ◽  
Phase Relations ◽  
Constant Light ◽  
Constant Darkness ◽  
Biological Clocks ◽  
Circadian Activity ◽  
Activity Rhythms ◽  
Controlled Conditions ◽  
Australian Native Rodent ◽  
Photic Response

Circadian rhythms are generated endogenously by biological clocks or 'pacemakers', which are responsive to significant environmental stimuli termed zeitgebers. Interactions between pacemakers and zeitgebers provide the basis for synchronisation by light-dark (LD) cycles, and the characteristics of each of these elements determines the phase-relations maintained between an animal's circadian activity rhythms and the natural temporal environment. We report here the basic photic response parameters for an Australian native rodent, Notomys alexis. Under controlled conditions of constant darkness or constant light, N. alexis were found to 'free-run', and with periods different from 24 hours. Under LD cycles N. alexis were strictly nocturnal although, compared to other rodents, entrainment to LD cycles was relatively unstable. This may indicate that N. alexis are not strongly dependent on the LD cycle as a zeitgeber.

scholarly journals INFLUENCE OF LIGHT ON THE GROWTH AND MALIGNANCY OF A TRANSPLANTABLE NEOPLASM OF THE RABBIT

1927 ◽  
Vol 45 (4) ◽  
pp. 727-751 ◽  
Author(s):  
Louise Pearce ◽  
Wade H. Brown
Keyword(s):  
Bone Metastases ◽  
Experimental Evidence ◽  
Malignant Disease ◽  
External Factor ◽  
Wave Length ◽  
Continuous Light ◽  
Constant Light ◽  
Constant Darkness ◽  
Special Character

Experiments are reported in which an environment of constant and continuous light with a wave-length of from 3022 to 5790 Ångström units, supplied by mercury arcs in crown glass, and of constant darkness, have influenced the course and character of a malignant disease of rabbits induced by a transplantable neoplasm. Under the influence of constant light the level of malignancy was lower than in control animals living under ordinary conditions of diffused sunlight. Under the influence of constant darkness the level of malignancy was somewhat lower than in control animals but the effect of this environment was modified by the special character of the disease prevailing at this time. The incidence of bone metastases was unusually high, but it was greatly increased in the rabbits kept in constant darkness. These observations furnish experimental evidence in support of the belief that there is a correlation between the external factor of light and the manifestations of an experimental malignant disease.

Does light intensity affect embryonic development of squid (Heterololigo bleekeri)?

2004 ◽  
Vol 84 (6) ◽  
pp. 1215-1219 ◽  
Author(s):  
Yuzuru Ikeda ◽  
Kingo Ito ◽  
Gen Matsumoto
Keyword(s):  
Body Size ◽  
Light Intensity ◽  
Embryonic Development ◽  
Early Stage ◽  
Constant Darkness ◽  
Light Intensities ◽  
Development Duration ◽  
Experimental Group ◽  
Effect Of Light

The effect of light intensity on the course of embryonic development of squid (Heterololigo bleekeri) was examined. Heterololigo bleekeri embryos at an early stage were incubated in the egg cases under six to seven gradients of light intensities which varied from constant darkness to intensive light >1000 lx (12L:12D for all experimental groups except for the constant darkness group). Duration of hatching in every experimental group ranged from seven to 15 days with a peak for ≈30–50% of total number of hatchlings. However, there were no particular relationships between light intensities and duration of embryonic development, duration of hatching, number of hatchlings at hatching peak, and body size of hatchlings. In all groups, body size of hatchlings increased up to seven days post-hatching and thereafter did not change remarkably. Just after hatching, strongly positive photo taxis was observed for H. bleekeri

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