Increase In Diurnal Activity Research Articles

Effects of the colour of photophase light on locomotor activity in a nocturnal and a diurnal South African rodent.

Many physiological and behavioural responses to varying qualities of light, particularly during the night (scotophase), have been well documented in rodents. We used varying wavelengths of day-time (photophase) lighting to assess daily responses in locomotor activity in the nocturnal Namaqua rock mouse (Micaelamys namaquensis) and diurnal four-striped field mouse (Rhabdomys pumilio). Animals were exposed to three light-dark cycle regimes: a short-wavelength- (SWLC, blue), a medium-wavelength- (MWLC, green) and a long-wavelength light-dark cycle (LWLC, red). Overall, daily locomotor activity of both species changed according to different wavelengths of light: the diurnal species displayed most activity under the SWLC and the nocturnal species exhibited the highest levels of activity under the LWLC. Both species showed an increase in diurnal activity and a decrease in nocturnal activity under the LWLC. These results indicate an attenuated responsiveness to long-wavelength light in the nocturnal species, but this does not appear to be true for the diurnal species. These results emphasize that the effect of light on the locomotor activity of animals depends on both the properties of the light and the temporal organization of activity of a species.

Testicular Steroidogenesis and Locomotor Activity Are Regulated by Gonadotropin-Inhibitory Hormone in Male European Sea Bass.

Gonadotropin-inhibitory hormone (GnIH) is a neurohormone that suppresses reproduction by acting at both the brain and pituitary levels. In addition to the brain, GnIH may also be produced in gonads and can regulate steroidogenesis and gametogenesis. However, the function of GnIH in gonadal physiology has received little attention in fish. The main objective of this study was to evaluate the effects of peripheral sbGnih-1 and sbGnih-2 implants on gonadal development and steroidogenesis during the reproductive cycle of male sea bass (Dicentrarchus labrax). Both Gnihs decreased testosterone (T) and 11-ketotestosterone (11-KT) plasma levels in November and December (early- and mid-spermatogenesis) but did not affect plasma levels of the progestin 17,20β-dihydroxy-4-pregnen-3-one (DHP). In February (spermiation), fish treated with sbGnih-1 and sbGnih-2 exhibited testicles with abundant type A spermatogonia and partial spermatogenesis. In addition, we determined the effects of peripheral Gnih implants on plasma follicle-stimulating hormone (Fsh) and luteinizing hormone (Lh) levels, as well as on brain and pituitary expression of the main reproductive hormone genes and their receptors during the spermiation period (February). Treatment with sbGnih-2 increased brain gnrh2, gnih, kiss1r and gnihr transcript levels. Whereas, both Gnihs decreased lhbeta expression and plasma Lh levels, and sbGnih-1 reduced plasmatic Fsh. Finally, through behavioral recording we showed that Gnih implanted animals exhibited a significant increase in diurnal activity from late spermatogenic to early spermiogenic stages. Our results indicate that Gnih may regulate the reproductive axis of sea bass acting not only on brain and pituitary hormones but also on gonadal physiology and behavior.

Home Range, Habitat Selection and Activity Patterns of an Arid-Zone Population of Temminck's Ground Pangolins,Smutsia temminckii

All previous behavioural studies of Temminck's ground pangolins (Smutsia temminckii) have focused on populations in mesic regions. We examined home range size, activity periods, habitat selectivity and refuge site selection of 13 individuals over three years in the Kalahari Desert of South Africa, near the western edge of the species' range. Kernel home ranges of adults averaged 6.5 ± 5.9 km2, while juveniles had average home ranges of 6.1 ± 4.0 km2. Reliable prediction of 95% of the Kernel home range required 88 ± 67.7 tracking days. No significant habitat selectivity was observed. Earthen burrows were the most frequently used refuge type. The time at which activity commenced varied seasonally as well as among individuals, with an increase in diurnal activity during winter. Young pangolins also displayed more diurnal activity compared to adults. Individuals spent 5.7 ± 2.0 hours per 24-hour cycle outside of refuges, with no significant seasonal variation. Juvenile dispersal peaked during mid-summer, with individuals travelling up to 49 km from their natal areas. We estimate a breeding density of 0.16 individuals/km2 and a total density of 0.31 individuals/km2 for our study area. Our data suggest that activity patterns, movements and refuge selection is similar across the species’ southern African range, but that densities may be higher in the Kalahari compared to populations in more mesic eastern areas.

Home range, habitat selection and activity patterns of an arid-zone population of Temminck’s ground pangolins, Smutsia temminckii

All previous behavioural studies of Temminck’s ground pangolins (Smutsia temminckii) have focused on populations in mesic regions. We examined home range size, activity periods, habitat selectivity and refuge site selection of 13 individuals over three years in the Kalahari Desert of South Africa, near the western edge of the species’ range. Kernel home ranges of adults averaged 6.5 ± 5.9 km2, while juveniles had average home ranges of 6.1 ± 4.0 km2. Reliable prediction of 95% of the Kernel home range required 88 ± 67.7 tracking days. No significant habitat selectivity was observed. Earthen burrows were the most frequently used refuge type. The time at which activity commenced varied seasonally as well as among individuals, with an increase in diurnal activity during winter. Young pangolins also displayed more diurnal activity compared to adults. Individuals spent 5.7 ± 2.0 hours per 24–hour cycle outside of refuges, with no significant seasonal variation. Juvenile dispersal peaked during mid-summer, with individuals travelling up to 49 km from their natal areas. We estimate a breeding density of 0.16 individuals/km2 and a total density of 0.31 individuals/km2 for our study area. Our data suggest that activity patterns, movements and refuge selection is similar across the species’ southern African range, but that densities may be higher in the Kalahari compared to populations in more mesic eastern areas.

The effects of lighting conditions and food restriction paradigms on locomotor activity of common spiny mice, Acomys cahirinus.

BackgroundAn endogenous circadian clock controls locomotor activity in common spiny mice (Acomys cahirinus). However, little is known about the effects of constant light (LL) on this activity or about the existence of an additional food entrainable clock. A series of experiments were performed to investigate the effects of LL and DD on tau and activity levels.MethodsSpiny mice were housed individually and their running wheel activity monitored. One group of mice was exposed to LD, DD and several intensities of LL. Another group was exposed to a restricted feeding (RF) paradigm in light: dark (LD) during one hour before the L to D transition. Significance of rhythmicity was assessed using Lomb-Scargle periodograms.ResultsIn LD all animals exhibited nocturnal activity rhythms that persisted in DD. When animals were exposed to RF (during L), all of these animals (n = 11) demonstrated significant food anticipatory activity as well as an increase in diurnal activity. This increase in diurnal activity persisted in 4/11 animals during subsequent ad libitum conditions. Under LL conditions, the locomotor rhythms of 2/11 animals appeared to entrain to RF. When animals were exposed to sequentially increasing LL intensities, rhythmicity persisted and, while activity decreased significantly, the free-running period was relatively unaffected. In addition, the period in LL was significantly longer than the period in DD. Exposure to LL also induced long-term changes (after-effects) on period and activity when animals were again exposed to DD.ConclusionsOverall these studies demonstrate clear and robust circadian rhythms of wheel-running in A. cahirinus. In addition, LL clearly inhibited activity in this species and induced after-effects. The results also confirm the presence of a food entrainable oscillator in this species.

Ethologisch fundierte Empfehlungen für eine artgemäße Zoohaltung von Schwarzfußkatzen Felis nigripes Burchell, 1824

The Blackfooted Cat ( Felis nigripes), also called Small Spotted Cat, is a species endemic to the drier areas of Southern Africa. Ethological observations can give insight into their specialised adaptations to their environment. The investigations were carried out at the base of Karoo Cat Research. The large nature-type enclosures allow the cats to show a wide range of their natural behaviour. This study was done in the hope that it will lead to improved zoo-keeping and husbandry of the Blackfooted Cat in zoological gardens. It is alarming to note that worldwide the zoo populations of these cats, having always been quite low, have dramatically decreased recently, especially in Europe, where at present only 5 males and 2 females are kept at 3 different sites. Worldwide, most cats die at a rather young age from either Amyloidosis, a kidney disease, or from respiratory tract infections. The possibility is discussed that both diseases are, at least partly, due to inadequate keeping conditions. It is imperative, though not always easily accomplished, that these cats are kept in enclosures that, at least in part, provide desert conditions: a dry climate (relative air humidity of 30 to 40%), and a preponderantly sandy substrate with fitting vegetation. As Blackfooted Cats habitually cover large distances during their nightly prowls, they would require larger enclosures than other cats of the Genus Felis. The enclosures should also give the cats adequate shelter to allow them to hide from disturbances caused by the public. Failing to provide this may be the cause of numerous, possibly lethal, stress-related diseases. Due to the Blackfooted Cat's extremely shy nature and solitary way of living, especially in respect of keeping their progeny healthy, the choice of the right curator is of utmost importance. The experiment of having young Blackfooted Cats reared simultaneously by their own mother and by humans aimed to avoid an imprinting-like bond but at the same time to create the basis for a lasting relationship of trust towards the human carers. The Karoo Cat Research Station proved to be a suitable observation area, offering the possibility of caring for three young Blackfooted Cats from the age of 6 to 16 weeks together with their mother. The behaviour patterns defining the opposites “tame” and “shy” were evaluated numerically and presented in diagram form. The result of this experiment was a stress-free and relaxed relationship between the animals and their carers that was not only observed in the kittens but was also maintained with the adult cats. The activity rhythm of seven Blackfooted Cats in human care in South Africa was studied throughout two seasons with considerable temperature variations. In graphic representations, data are presented, such as the weather or sexual differences, which could not be influenced by humans but have a clearly recognisable effect on the activity rhythm. Altered keeping conditions had an important influence on the divergence of the rest periods of the three young Blackfooted Cats from the usual diaphasic activity pattern of most felid species. The behaviour of wild-caught animals was studied and compared with that of well integrated or zoo-born individuals. Here too an important reduction in activity was noted. The effect of behavioural enrichment measures, such as play, feeding methods, olfactory stimuli, as well as the rearing of young, on a positive increase in diurnal activity is discussed.

Activity rhythms and cyclical changes of microhabitat preferences in the intertidal pipefish Nerophis lumbriciformis (Pisces: Syngnathidae)

As an inhabitant of the intertidal zone, Nerophis lumbriciformis predictably should show a clear rhythmic activity, with its maximum closely correlated with the high tide period, as observed in several other rocky intertidal fish species. We investigated the rhythmic activity patterns of N. lumbriciformis and analysed to what extent specific substratum preferences may be linked to water level and, ultimately, to the particular activity rhythm patterns of the fish. To determine N. lumbriciformis substratum preferences, two different experiments were conducted. The first evaluated substratum preferences from among a group of the four most common substrates found in the sample area. The second experiment evaluated the fish's maintenance of that substratum preference, after alteration of the water level in a simulated ebb tide. From the available substrata, N. lumbriciformis displayed a clear preference for algae until the water level began to decrease. Then, the preference radically shifted from algae to boulders. N. lumbriciformis showed a clear rhythmic activity, affected by both tidal and circadian periodicity, producing asymmetrical activity peaks. Unlike the rhythms of other rocky intertidal fish species, the maximum activity peaks were not centred at the expected high tide period. The adaptive explanation for the apparently peculiar activity peaks appears to be related to the particular substratum preferences of N. lumbriciformis. The detected circatidal period seems, consequently, closely related to small migrations between substrata, whilst the observed increase in diurnal activity, independent of the tidal cycle, may be related to predatory activity, since N. lumbriciformis is a visual feeder.

Winter activity of a population of greater horseshoe bats (Rhinolophus ferrumequinum)

AbstractActivity patterns of greater horseshoe bats Rhinolophus ferrumequinum were investigated at caves in Cheddar (south‐west England) during the hibernation season. An ultrasound detector and datalogger were used to monitor and record the number of echolocation calls in a single cave. Activity of R. ferrumequinum remained largely nocturnal throughout winter, and the mean time of activity over 24 h was 88 to 369 min after sunset. There was an increase in diurnal activity from late May to early June, probably because bats remained active after foraging at dawn towards the end of the hibernation season. Visits to the cave did not increase bat activity. Cave air temperature reflected external climatic temperature, although there was variation in cave temperature and its range within and among caves. Individual R. ferrumequinum are usually dispersed in caves in regions where temperature fluctuations correlate with climatic variations in temperature. There was a positive correlation between the number of daily bat passes monitored by the bat detector and datalogger (= daily activity) and cave temperature. Nocturnal activity may be sometimes associated with winter feeding. Neither date nor barometric pressure had a significant effect on daily activity. Activity patterns largely reflected the findings from individual R. ferrumequinum studied by telemetry (Park, 1998), in that bat activity increased with cave and climatic temperatures, and the temporal pattern of activity remained consistently nocturnal throughout winter, starting at dusk.

Seasonal changes in the level and diel pattern of activity in the European lobster Homarus gammarus

European lobsters are large, mobile crustaceans of ecological and commercial significance. Until recently, the lack of a reliable technique for long-term, in situ monitoring of activity has hindered study of seasonal variation in activity and its determinants. Electromagnetic telemetry has been used to measure seasonal changes in locomotor activity and body movements of lobsters on an artificial reef in Poole Bay, southern England. Both measures of activity showed marked seasonal variation, related primarily to water temperature, with greatest activity in late summer and minimum values in winter. Subsidiary effects of water movement and seabed illumination were also indicated. Throughout the spring and summer, excursions outside shelter were almost exclusively nocturnal, with movement peaking in the early part of the night. Body movements followed a similar pattern, but with less abrupt changes, suggesting a degree of activity within shelters during the day. Diet timing of lobster activity appeared to be mainly governed exogenously by light level, since the length of the nocturnal active period and the timing of the activity peak varied seasonally with the times of sunset and sunrise, and there was a relative increase in diurnal activity during periods of low seabed light levels caused by increased turbidity. During low temperatures in lid to late winter, activity was low throughout the 24 h cycle. These findings suggest that there are likely to be significant seasonal changes in the relationship between fishing effort and fishing mortality that need to be taken into account in lobster stock assessment.

Diurnal and Nocturnal Patterns of Activity in Resident and Migrant SilvereyesZosterops lateralis

This study examined diurnal and nocturnal activity patterns from 40 hours of continuous activity recordings of individually caged resident and migrant Silvereyes Zosterops lateralis. Elevated night activity (= Zugunruhe) was displayed by migrants in autumn and spring but not by residents. Zugunruhe commonly commenced in the dark portion of the morning and continued to about 2-3 h beyond the onset of light. Migrants were more night restless than residents in winter and in the migratory seasons of autumn and spring. They were also more diurnally active in the winter months than residents. The increase in diurnal activity in the latter period is related to winter migratory movements.