Sexual Difference in Color Sense in a Lycaenid Butterfly, Narathura japonica

The spectral sensitivity of a lycaenid butterfly, Narathura japonica, was investigated by electroretinography using an integrating sphere that could illuminate the compound eye from almost all directions. Samples were collected from three locations. Butterflies from different locations showed a similar pattern; the first, second, and third peaks (or a shoulder) were located at about 380, 460, and 560 nm, respectively. Males clearly showed the highest sensitivity at the first peak point. In contrast, females showed a higher relative sensitivity than males at the second and third peak points in all samples, and showed broad spectral sensitivity. This male-specific UV-sensitivity is discussed in terms of ecological factors

Asymmetrical morphology and growth of the hermit crab Pagurus filholi (Decapoda, Anomura, Paguridae) reared in non-dextral shell conditions

The body of a hermit crab shows asymmetrical morphology, which may be related to utilization of the dextral shell. To examine the effect of the shell, we reared Pagurus filholi (De Man, 1887) from the glaucothoe stage to full-sized adults, in a sinistral shell, in a straight tusk shell, without a shell, and in a normal dextral shell as a control. Body parts that show the most conspicuous asymmetry, uropods, pleopods and chelipeds, were checked at the time of the shedding of exuviae during rearing. No inversion of laterality on these characters was observed. However, in crabs subjected to conditions other than a dextral shell, the otherwise rather short right uropod became somewhat extended, and in those reared in sinistral shells, the right major cheliped was more enlarged

PERISTALSIS IN THE MONOPOLYPID STAGE OF THE SEA-PEN, CAVERNULARIA OBESA VALENCIENNES

Peristalsis in the monopolypid stage of the sea-pen, Cavernularia obesa, was studied experimentally as to the change in light, temperature and pH of the sea water. (1) The monopolypid of this sea-pen shows two types of peristalses: downward and upward peristalses. (2) Downward peristalsis occurs more frequently in the light phase, while upward peristalsis is mostly limited to the dark phase. (3) Downward peristalsis is induced by sudden illumination at night, with the frequency depending on the absolute light intensity as well as the variation in light intensity. (4) The frequency of downward peristalsis is seemingly temperature-dependent. (5) The frequency of downward peristalsis is more or less decreased in the sea water of lowered pH, but increased in the sea water of raised pH, while the frequency of upward peristalsis seems to be rather insensitive to pH change. (6) On the basis of these results, peristalses of the monopolypid of this sea-pen are discussed in comparison with those of the adult colonies

ON THE MECHANISM OF THE ACTIVITY RHYTHM OF THE SEA-PEN, CAVERNULARIA OBESA VALENCIENNES

Efforts have been paid in the present experiments to clarify the mechanism of the expansion-contraction rhythm of the sea-pen. Results are summarized as follows: (1) The hydrogen ion concentration of the body fluid at the beginning of expansion was slightly lower at higher temperatures in the regular rhythm as well as in the case of omission of an expansion. (2) Injection of alkalized, acidified or natural sea water or saline solution induced the contracted colony to expand to a certain extent. (3) Injection of alkalized sea water did not make the expanded colony contract. (4) The expansion-contraction rhythm was affected by both the injection of alkalized sea water and the mechanical stimulation. As far as the results obtained are concerned, it is concluded that the rhythmic behavior of the sea-pen is under the control of a time-keeping mechanism independent of the rhythmic behavior itself, and that the mechanism is susceptible in this sea-pen to influences from the inside and outside

ACTIVITY RHYTHM OF THE SEA-PEN, CAVERNULARIA OBESA VALENCIENNES, UNDER TEMPERATURE AND LIGHT CYCLES

Circadian rhythms are generally known to be entrained to light cycles, and in some poikilothermic animals living in terrestrial region also to temperature cycles. The entraining effect of temperature cycles may be attributable to the fact that the daily fluctuation of temperature on the land is rather clear and regular closely related to the natural light change. On the other hand, the daily fluctuation of temperature in the sea is not so clear as in the terrestrial region, being generally very small or perfectly null depending on the depth. So, it is interesting to examine the effect of temperature cycle on the circadian rhythm of marine organisms, to make it clear whether the effect of temperature cycle is dependent on species, or generally seen on the circadian rhythms of different species of poikilothermic animals. The author made an experiment concerning this problem in a series of experiments with using of the sea-pen, Cavernularia obesa, a marine colonial coelenterate living on the sand bottom of shallow water, and obtained data somewhat unclear with difference among colonies in behavior under the temperature cycle (Imafuku, 1973). Thus, he repeated the experiment on the same species, recording its behavior continuously for about four months through under temperature cycles of various levels of temperature, and also examining the effect of light cycle

TIDAL ACTIVITY RHYTHM OF THE HERMIT CRAB, PAGURUS GEMINUS MCLAUGHLIN

Tidal rhythms are known in many animal and plant species living in intertidal zone (Palmer, 1974). One of interesting aspects concerning tidal rhythms is that animals living under the influence of an ordinary change of tide possess tidal rhythms while ones inhabiting shores of a small change of tide do not have rhythms of tidal frequency but of circadian frequency. This has been shown in the relative species of green crabs (Naylor, 1958; 1961), blennies (Gibson, 1965; 1969) and in the same species of fiddler crabs (Barnwell, 1968). The present paper deals with the activity rhythm of the hermit crab, Pagurus geminus, which is one of the commonest inhabitants of Japanese littoral zone and is distributed all over Japan including the Pacific coast with the ordinary change of tide and the japan Sea coast with the small change of tide

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京都大学0048新制・課程博士理学博士甲第1695号理博第384号新制||理||221(附属図書館)UT51-61-I168京都大学大学院理学研究科動物学専攻(主査)教授 加藤 勝, 教授 森 主一, 教授 日高 敏隆学位規則第5条第1項該当Kyoto UniversityDFA

ON SOME PHYSIOLOGICAL ASPECTS IN THE DAILY RHYTHMIC ACTIVITY OF THE SEA-PEN, CAVERNULARIA OBESA VALENCIENNES

Some efforts have been made in these experiments to see whether or not the fluctuation of hydrogen ion concentration of the body fluid can truly be a driving force of the rhythmic behavior, by injection of acidified sea water or changing of the metabolic rate by thermal treatments. The results are as folllows: (1)A phase-shift was induced by the injection of acidified sea water. (2)The temperature coefficients of oxygen-consumption and the period of rhythm were 2.53 and 1.00 respectively from 20 to 30℃. (3)The phase of rhythm was shifted by a sudden temperature change in a certain range. (4)Rarely, an active expanded state was omitted without a phase-shift. As far as the results obtained are concerned it seems difficult to attribute the rhythmic behavior definitely to the fluctuation of hydrogen ion concentration of the body fluid