Comparison of infant care in family groups of the common marmoset (Callithrix jacchus) and the cotton-top tamarin (Saguinus oedipus)

The involvement of parents and siblings in infant care in similarly composed groups of common marmosets (Callithrix jacchus) and cotton-top tamarins (Saguinus oedipus) was compared during the infants' first 8 weeks of life. The results indicate an earlier infant independence in C. jacchus than in S. oedipus due primarily to a more frequent rejection of carried infants in C. jacchus. There was no species difference in extent of maternal involvment in carrying infants. However, S. oedipus fathers carried infants significantly more often during weeks 5–8 than did C. jacchus fathers. Siblings were generally more involved in infant care at an earlier infant age in C. jacchus than in S. oedipus.     

Systematics of the Saguinus oedipus group of the bare-face tamarins: Evidence from facial morphology

The systematics of the Saguinus oedipus group within the bare-face tamarins remains open to question. Hershkovitz (Living New World Monkeys (Platyrrhini), Vol. 1. Chicago: University of Chicago Press, 1977) places the cotton-top and rufus-naped tamarins as subspecies of Saguinus oedipus (S. o. oedipus and S. o. geoffroyi, respectively). In contrast, several other authors have argued that these two taxa should be considered separate species (S. oedipus and S. geoffroyi). Phylogenetic relationships within the group are also disputed. Resolving these different interpretations has been difficult in part because no study of this group has included an objective measure of expected levels of specific vs. subspecific variation. We used facial measurements from 179 adult crania to address the systematics of this group and included a related species that is known to include multiple subspecies. Our sample included three taxa from the S. oedipus group of the bare-face tamarins (S. oedipus, S. geoffroyi, and S. leucopus) and six subspecies from the related hairy-face tamarin species S. fuscicollis. Comparisons to S. leucopus provided a relative measure of species-level differences. Analyses that included S. fuscicollis provided a measure of subspecific variation. There was no evidence of facial sexual dimorphism in any of these taxa. A variety of multivariate statistical analyses including discriminant function and cluster analysis suggest that S. oedipus and S. geoffroyi differ morphologically at a level consistent with species-level distinctions. The extent of differences between these taxa is large. The differences in their facial morphology was on the order of differences between S. oedipus or S. geoffroyi and S. leucopus rather than the extent of variation among S. fuscicollis subspecies. Furthermore, a comparison of collecting localities revealed that the variation we observed among S. oedipus and S. geoffroyi was not clinal but presented a large morphological discontinuity at the boundary between taxa. Our analyses also suggested that S. leucopus is more similar to S. oedipus than is either to S. geoffroyi. Finally, it may be that there are some distinct species within the S. fuscicollis group. However, this hypothesis, along with other phylogenetic relationships suggested by this study, will require more data and further study. © 1992 Wiley-Liss, Inc.     

Effects of sibling-rearing experience on future reproductive success in two species of callitrichidae

The survival rate for offspring of mothers who either had or did not have previous experience rearing younger siblings was compared in two callitrichid species, Callithrix jacchus and Saguinus oedipus. Offspring of mothers with sibling-rearing experience had a higher survival percentage than offspring of inexperienced mothers in both species. While 50–60% of offspring of inexperienced C. jacchus mothers survived, no offspring of inexperienced S. oedipus mothers survived. The results suggest that sibling-rearing experience is necessary for adequate maternal behavior in S. oedipus, but not necessary to the development of maternal behavior in C. jacchus. Effects of previous sibling-rearing experience of S. oedipus fathers on offspring survival were also examined. Whether the father had rearing experience was not related to the survival of their offspring.     

Age of epiphyseal closure in tamarins and marmosets

Estimates of the chronological age for animals of unknown age provide useful information for medical, demographic, and evolutionary studies. Skeletal development, as indicated by epiphyseal closure, can be used to estimate an animal's chronological age or specify its stage of development. Many studies of Primate skeletal development have used animals of unknown age, with the order of epiphyseal closure providing a relative age for each animal. This study examines the age of epiphyseal closure at 22 epiphyseal sites using animals of known age at death in three calitrichid species (Saguinus fuscicollis, Saguinus oedipus, and Callithrix jacchus). The observed average age of epiphyseal closure is similar in these tamarins and marmosets. There is a significant difference in rate of development between the species. Regression equations can predict the age of unknown animals to within 4.8 months for S. fuscicollis, 8.6 months for S. oedipus, and 7.6 months for C. jacchus (twice the standard error of the estimate). These age estimates allow us to determine if an animal is relatively mature or immature, but are largely unacceptable for studies in which precise age estimates are necessary. The order of epiphyseal closure is similar across 11 monkey species (using additional data from published literature) and supports the suggestion of a general pattern in Primate skeletal development. Am. J. Primatol. 41:129–139, 1997. © 1997 Wiley-Liss, Inc.     

Diurnal variations in physiology and behaviour of the noble crayfish Astacus astacus and the signal crayfish Pacifastacus leniusculus

Heart rate, locomotor activity, and oxygen consumption were recorded simultaneously and continuously in seven individuals of the noble crayfish Astacus astacus (Linneus 1758) and seven individuals of the signal crayfish Pacifastacus leniusculus (Dana 1852). The recordings were made in the laboratory over 7 days at 15°C under a 12?:?12?h dark?:?light regime. Circadian rhythms in heart rate, locomotor activity and oxygen consumption were found both in A. astacus and P. leniusculus. Increased heart rate, locomotor activity, and oxygen consumption levels during night time in both A. astacus and P. leniusculus illustrated expression of nocturnal behaviour. No differences in oxygen consumption levels were observed between A. astacus and P. leniusculus. Also, no significant difference between heart rate levels or heart rate variances was found in A. astacus and P. leniusculus at night. During day, however, heart rate levels, heart rate variances and locomotor activity were higher in P. leniusculus than in A. astacus. The higher activity level in P. leniusculus than in A. astacus during daytime indicates that P. leniusculus is less strictly nocturnal than is A. astacus.     

Light-dependent damage to photosynthesis in olive leaves during chilling and high temperature stress

Abstract The leaves of olive are long lived and likely to experience both chilling and high temperature stress during their life. Changes in photosynthetic CO₂ assimilation resulting from chilling and high temperature stress, in both dim and high light, are investigated. The quantum yield (φ) of photosynthesis at limiting light levels was reduced following chilling (at 5°C for 12 h), in dim light by approximately 10%, and in high light by 75%; the difference being attributed to photoinhibition. Similar reductions were observed in the light-saturated rate of CO₂ uptake (A_max). Decrease in A_max correlated with a halving of the leaf internal CO₂ concentration (c_i), suggesting an increased limitation by stomata following photoinhibition. Leaves were apparently more susceptible to photoinhibitory damage if the whole plant, rather than the leaf alone, was chilled. On return to 26 °C, I he photosynthetic capacity recovered to pre-stress levels within a few hours if leaves had been chilled in high light for 8 h or less, but did not fully recover from longer periods of chilling when loss of chlorophyll occurred. Leaves which were recovering from chilling in high light showed far more damage on being chilled a second time in high light. Three hours in high light at 38 °C reduced φ by 80%, but φ recovered within 4h of return to 26 °C. Although leaves of Olive are apparently less susceptible to photoinhibitory damage during chilling stress than the short-lived leaves of chilling-sensitive annual? crops, the results nevertheless show that photoinhibition during temperature stress is potentially a major factor influencing the photosynthetic productivity of Olive in the field.     

Stem Extension Rate in Light-Grown Plants : Effects of Photo- and Thermoperiodic Treatments on the Endogenous Circadian Rhythm in Chenopodium rubrum

Low temperature pulses have two effects on the circadian rhythm exhibited by stem extension rate of green Chenopodium rubrum plants. First, low temperature pulses have the same effect on the phasing of the rhythm as a dark period interrupting continuous light. Second, low temperature pulses stimulate stem extension rate during the 10 hours immediately following the end of the pulse. A difference in temperature between soil and air increases this effect. In any case, it is the change in temperature which is essential and not a specific temperature. Effects of light and temperature on phasing and amplitude of the rhythm explain why the maximal stem growth is observed under normal photo-thermoperiodic conditions, i.e. a high temperature during the photoperiod and a low temperature during the dark period.     

The influence of daylength,light intensity and temperature on the growth rates of planktonic blue-green algae

The in vitro growth rates under continuous light of the four dominant blue-green algae in Lough Neagh, Anabaena flos-aquae Bréb., Aphanizomenon flos-aquae Ralfs fa. gracile Lemm., Oscillatoria agardhii Gom. and Oscillatoria redekei van Goor were slower than in situ rates from Lough Neagh that had been corrected for hours of light received by the algae. However, by culturing on a 6: 18 light-dark cycle in vitro growth rates were obtained that were similar to the in situ rates. Under continuous light small species showed the fastest growth with Oscillatoria redekei the dominant species. However, this pattern was almost completely reversed under the light-dark cycle with Oscillatoria redekei only exhibiting the fastest growth rate under low light conditions. This observation showed agreement with Lough Neagh field data which showed that Oscillatoria redekei reached its maximum crop in April while the other three species were dominant during the summer months. Compared to the generally assumed high thermal tendency of blue-green algae the temperature maxima of the four species were low. No growth was observed at 35°C for any species while Anabaena flos-aquae was severely inhibited at 25°C.     

Diving behaviour of a reptile (Crocodylus johnstoni) in the wild: interactions with heart rate and body temperature

The differences in physical properties of air and water pose unique behavioural and physiological demands on semiaquatic animals. The aim of this study was to describe the diving behaviour of the freshwater crocodile Crocodylus johnstoni in the wild and to assess the relationships between diving, body temperature, and heart rate. Time-depth recorders, temperature-sensitive radio transmitters, and heart rate transmitters were deployed on each of six C. johnstoni (4.0-26.5 kg), and data were obtained from five animals. Crocodiles showed the greatest diving activity in the morning (0600-1200 hours) and were least active at night, remaining at the water surface. Surprisingly, activity pattern was asynchronous with thermoregulation, and activity was correlated to light rather than to body temperature. Nonetheless, crocodiles thermoregulated and showed a typical heart rate hysteresis pattern (heart rate during heating greater than heart rate during cooling) in response to heating and cooling. Additionally, dive length decreased with increasing body temperature. Maximum diving length was 119.6 min, but the greatest proportion of diving time was spent on relatively short (<45 min) and shallow (<0.4 m) dives. A bradycardia was observed during diving, although heart rate during submergence was only 12% lower than when animals were at the surface.     

Further Observations on Light and Spore Discharge in Certain Pyrenomycetes

A ‘spore-clock’ for studying the hourly rate ofspore discharge over a 24-hour period is described. A numberof the experiments reported in this paper have involved theuse of this apparatus. In Sordaria fimicola there is a distinct positive light-dischargereaction in a dark-conditioned culture, the rate of spore dischargeincreasing steeply to a peak 2–3 hours after brief stimulationby bright light. Although darkening a light-conditioned cultureleads to an immediate decrease in the rate of discharge, thereis no evidence of a delayed negative dark-discharge reaction. In S. verruculosa with a 12-hours light: 12-hours dark dailyreëgime, more spores are discharged in the dark than inthe light periods if the intensity of illumination is low. Withhigher light intensity there is no significant difference betweenthe number of spores discharged in light and dark periods. Asin S. fimicola there is a positive light-discharge reaction,the interval between stimulus and maximum response being muchlonger (8–12 hours). When a dark-conditioned culture istransferred to light for 48 hours and then returned to darknessfor a further 48 hours it is apparent that not only is therea positive light-discharge reaction but also a negative dark-dischargeresponse. The ‘plateau’ level of discharge is essentiallythe same in light and darkness. It is confirmed that in Hypoxylon fuscum light inhibits discharge.     

Temperature‐dependent phagotrophy and phototrophy in a mixotrophic chrysophyte

The roles of temperature and light on grazing and photosynthesis were examined for Dinobryon sociale, a common freshwater mixotrophic alga. Photosynthetic rate was determined for D. sociale adapted to temperatures of 8, 12, 16, and 20°C under photosynthetically active radiation light irradiances of 25, 66, and 130 μmol photons · m^?2 · s^?1, with concurrent measurement of bacterial ingestion at all temperatures under medium and high light (66 and 130 μmol photons · m^?2 · s^?1). Rates of ingestion and photosynthesis increased with temperature to a maximum at 16°C under the two higher light regimes, and declined at 20°C. Although both light and temperature had a marked effect on photosynthesis, there was no significant difference in bacterivory at medium and high irradiances at any given temperature. At the lowest light condition (25 μmol photons · m^?2 · s^?1), photosynthesis remained low and relatively stable at all temperatures. D. sociale acquired the majority of carbon from photosynthesis, although the low photosynthetic rate without a concurrent decline in feeding rate at 8°C suggested 20%–30% of the carbon budget could be attributed to bacterivory at low temperatures. Grazing experiments in nutrient‐modified media revealed that this mixotroph had increased ingestion rates when either dissolved nitrogen or phosphorus was decreased. This work increases our understanding of environmental effects on mixotrophic nutrition. Although the influence of abiotic factors on phagotrophy and phototrophy in pure heterotrophs and phototrophs has been well studied, much less is known for mixotrophic organisms.     

CONTROL OF GERMINATION OF ALEXANDRIUM TAMARENSE (DINOPHYCEAE) CYSTS FROM THE LOWER ST. LAWRENCE ESTUARY (CANADA)

Cysts of the toxic dinoflagellate Alexandrium tamarense (Lebour) Balech 1992 from the lower St. Lawrence estuary were used in a test of the following hypotheses: (1) cyst germination is triggered by a change in temperature, and (2) germination rate varies throughout the year and is controlled by a circannual internal biological clock. Results show that cyst germination was not affected significantly by temperature of incubation over the range 1°–16° C, and light showed no significant stimulation of germination. This is supported by the lack of effect of cyst incubation conditions during evaluation of the seasonal changes in germination rate (two temperatures: 4° and 15° C, and two light conditions: darkness and 150 μmol photons·m^?2·s^?1). Thus, direct environmental control through short-term increases in temperature and exposure to light has no effect on the germination of the cysts tested. The rate of germination, observed monthly over a 16-month period, showed low germination (<20%) over most of the period tested, except for a maximum reaching more than 50% germination in August to October of the second year of the experiment. This pattern was observed for cysts both from monthly field collections and from laboratory-stored cysts kept under constant environmental conditions (4° C, in the dark). The peak in germination observed under constant environmental conditions (in the laboratory), the almost coincidental increase in cyst germination observed for the field-collected cysts, and the absence of effects of temperature and light during incubation could be explained either by a temperature-controlled cyst maturation period (the time-temperature hypothesis of Huber and Nipkow 1923) or by the presence of an internal biological clock. However, the large decline in the rate of germination 2 months after the maximum provides strong support for the biological clock hypothesis. The ca. 12-month maturation (dormancy) period observed for the laboratory-stored cysts is the longest reported for this species to our knowledge; this might be related to the low storage temperature (4° C), which is close to bottom temperatures generally encountered in this environment (0° to 6° C). Similar field and laboratory storage temperatures could explain the coincidental increase in germination rate in the fall of the second year if cyst maturation is controlled by temperature. A fraction of the laboratory-stored cysts did not follow a rhythmic pattern: A rather constant germination rate of about 20% was observed throughout the year. This continuous germination of likely mature cysts may supplement the local blooms of this toxic dinoflagellate, as these often occur earlier than peak germination observed in late summer. It seems that two cyst germination strategies are present in the St. Lawrence: continuous germination after cyst maturation, with temperature controlling the length of the maturation period, and germination controlled by a circannual internal rhythm.     

Diurnal rhythms of body temperature, heart rate, and behaviour in the stanchioned adult Shiba goats

Using a data logger system, body temperature (dorsal subcutaneous temperature), heart rate, ingestive or ruminating behaviour and posture in adult Shiba goats tied to a stanchion were recorded automatically during 24 hours, to obtain basic information on the biological rhythms. A 600 g of usual ration mixed with hay cube, hay, beet pulp and wheat bran was fed twice a day (morning; 9:00-9:30, evening; 16:00-16:30). Animals kept under an artificial photoperiod (12L-12D, light period; 5:30-17:30) and about 10 degrees C room temperature. 1) Diurnal patterns of the above-mentioned items were recorded, mutual relationships relationships between these items were revealed. 2) The heart rate was higher after morning feeding, or during a light period and decreased gradually from midnight to early morning. Twice feeding greatly increased the heart rate. 3) The body temperature was lower in the early morning and increased gradually after morning feeding and showed the highest level during 1 to 1.5 hours after evening feeding. After that it decreased gradually till the early morning. 4) The numbers of jaw movement (bites/min) were a 70-90 bites in the ingestive behaviour and a 80-90 bites in the ruminating behaviour at dark period. 5) The total heart rate was a 110000 to 120000 beats/day, the total biting time was a 9.5 hours/day, and the mean standing time was a 9.3 to 11.7 hours/day. The standing time during light period (12 hours) was a 7.3 to 9.9 hours and that during dark period (12 hours) was a 1.8 to 2 hours.     

Temperature-metabolism relations in the cotton-top tamarin (Saguinus oedipus) model for ulcerative colitis

Examination of temperature-metabolism relations found no significant differences between thermoregulation of temperature housed laboratory cotton-top tamarins (Saguinus oedipus) and wild tamarins in Colombia, S.A. The results indicate that tamarins do not acclimate to a temperate environment and are metabolically stressed at T_a less than 32°C. This is consistent with an hypothesis of chronic metabolic stress as a factor in the etiology of cotton-top tamarin colitis, which is restricted to captive populations and not found in wild tamarins.     

Tail Regeneration in Normal,Blinded and Pinealectomized Gekkonid Lizards,Hemidactylus flaviviridis,Exposed to Four Different Light Conditions During Three Seasons (Temperatures)

Tail regeneration was followed for 60 days in 1470 normal (NL), blinded (BL) and pinealectomized (PX) gekkonid lizards, Hemidactylus flaviviridis, fed on cockroaches ad libitum and exposed to continuous light of high intensity (2500 lux), continuous light of low intensity (638 lux), 12 h of light (high intensity) and 12 h of darkness and continuous darkness in summer (March – May; cage temperature 30°C) monsoon (August – October; cage temperature 26°C) and winter (November – January; cage temperature 17°C) seasons. A comparative assessment of the new growth (regenerate) showed that the initiation of regeneration, the daily growth, the total length of tail replaced at the end of regeneration and the total percentage replacement of the lost (autotomized) tails were all enhanced by continuous light and depressed by continuous darkness. Furthermore, there was no significant difference between any of the parameters in NL and BL Hemidactylus; however, PX lizards generally showed retardation in the regeneration process. Seasonal differences in tail regeneration were noted—the best regenerative performance was obtained during the summer months and the worst during the winter months, with the regenerative performance during the monsoon season in between. Thermal and photoperiodic influences on tail regeneration in lizards are discussed.     

Photosynthetic Activity during the Life Cycle of Synchronous Skeletonema Cells

A culture of Skeletonema costatum grown at a light intensity of 3 klux and at 20°C was synchronized in diurnally intermittent illumination of 12 hour light and 12 hour dark. The culture was hardly fully synchronous as the cell division period lasted about 9 hours. The cell division started in the middle of the light period. The concentration of the pigments: chlorophyll a, chlorophyll 6 and fucoxanthin and the rate of light-saturated photosynthesis were followed every hour during the 24 hour period. Both the concentration of pigments and the photosynthetic activity showed a rhythmical variation. The concentration per cell of all three pigments examined increased during the development of the cells and decreased automatically during the period of cell division. An increase in the pigment concentration was found only in the light period. The rate of light-saturated photosynthesis calculated per unit of cell number increased during the cell development and decreased during the division period. The increase in the photosynthetic activity at light-saturation started about 4 hours after the end of cell division, which was 4 hours before the light was turned on while the increase in the concentration of chlorophyll a first started 1–2 hours after this moment. The variation in photosynthetic activity was compared with that found by other workers. The results found with Chlorella ellipsoidea by Japanese scientists (Nihci et al.) was explained as an inhibition phenomenon because the cells were not adapted to the experimental conditions.     

Further observations on drift in two brooks in Auvergne (France)

In two brooks, at about 1000 m altitude, drift rates were measured at hourly intervals during 48 hours.Hydracarina were day-active with a maximum drift rate coincidently starting with the increasing phase of the sinusoidal water temperature curve. Nymphs ofEphemeroptera andPlecoptera as well as gammarids were night-active with maximum numbers of animals caught that start and end shortly after the greatest changes in light intensity during resp. sunset and sunrise. Analysis of the activity during 48 hours of a drifting ephemeroptean and a non-drifting trochopteran did not reveal a periodical pattern. The results have been discussed. The relationship between periodically occurring increases in drift and activity, with attention to exogenous control and endogenous rhythms, deserves thorough experimental studies.     

Changes of fluorescence and xanthophyll pigments during dehydration in the resurrection plantSelaginella lepidophylla in low and medium light intensities

The changes in photosynthetic efficiency and photosynthetic pigments during dehydration of the resurrection plantSelaginella lepidophylla (from the Chiuhahuan desert, S.W. Texas, USA) were examined under different light conditions. Changes in the photosynthetic efficiency were deduced from chlorophyll a fluorescence measurements (F_o, F_m, and F_v) and pigment changes were measured by HPLC analysis. A small decrease in F_v/F_m was seen in hydrated stems in high light (650 μmol photons·m⁻²·s⁻¹) but not in low light (50 μmol photons·m⁻²·s⁻¹). However, a pronounced decline in F_v/F_m was observed during dehydration in both light treatments, after one to two hours of dehydration. A rise in F_o was observed only after six to ten hours of dehydration. Concomitant with the decrease in photosynthetic efficiency during dehydration a rise in the xanthophyll zeaxanthin was observed, even in low-light treatments. The increase in zeaxanthin can be related to previously observed photoprotective non-photochemical quenching of fluorescence in dehydrating stems ofS. lepidophylla. We hypothesize that under dehydrating conditions even low light levels become excessive and zeaxanthin-related photoprotection is engaged. We speculate that these processes, as well as stem curling and self shading (Eickmeier et al. 1992), serve to minimize photoinhibitory damage toS. lepidophylla during the process of dehydration.     

Genetic Differentiation among Populations of the Cave Fish Schistura Oedipus (Cypriniformes: Balitoridae)

DNA sequences were determined for portions of the mitochondrial control region and 16S rRNA genes in five populations of Schistura oedipus, a troglobitic fish from northwestern Thailand. Based on variation at seven sites out of 593 sequenced, the five populations fall into three groups, apparently isolated by altitude and distance. Nucleotide diversity within groups is on the order of 1.0×10^–3 while the extra increment of diversity among groups is on the order of 5.0×10^–3. While the groups are distinct, the level of differentiation among them is low enough to accept provisionally that the five populations represent a single species. On the basis of 16S sequence, Schistura oedipus appears to be more closely related to S. poculi than to S. reidi, a proposed sister taxon.     

Microclimate and production of peat moss Sphagnum palustre L. in the warm‐temperate zone

Sphagnum palustre L. is one of the few Sphagnum species distributed in the warm‐temperate zone. To elucidate the mechanisms that enable S. palustre to maintain its productivity under warm climatic conditions, we examined the temperature conditions and photosynthetic characteristics of this species in a lowland wetland in western Japan. Moss temperatures during the daytime were much lower than the air temperature, particularly during summer. The optimum temperature for the net photosynthetic rate was approximately 20°C, irrespective of the season, but summer and autumn samples maintained high rates at higher temperatures as well. The net photosynthetic rate at near light saturation was much higher during summer–autumn than during spring–winter. A model estimation in which net production was calculated from the photosynthetic characteristics and microclimatic data showed that both the low temperature of the moss colony and the seasonal shift in photosynthetic characteristics are among the mechanisms that enable this species to maintain its productivity under warm climatic conditions.