Unimodal Activity Pattern Research Articles

Activity pattern of the Lorenz’s tree iguana <i>Liolaemus lorenzmuelleri</i> in Coquimbo, Chile

Liolaemus lorenzmuelleri is a lizard endemic to Chile. Some authors indicated that its activity pattern was unimodal; however, no evidence was found to support this statement. The objective of this study was to verify the unimodal activity pattern of L. lorenzmuelleri, based on quantitative data. Thirty-five videos recorded between August and December 2022 of an individual of the species were examined. The times and dates of recording were analyzed with the Kernel density function. It was concluded that the species exhibited a unimodal activity pattern for the study period.

Autecology of the gecko Phyllopezus periosus (Squamata: Phyllodactylidae) inhabiting rock cliffs of a waterfall canyon from the semi-arid region of northeastern Brazil

Phyllopezus periosus is the largest phyllodactilid in Brazil, with a relictual distribution in the Caatinga Domain. Herein, we investigated the autecology of P. periosus, describing activity patterns, microhabitat use (spatial niche dimension), foraging mode, body temperature, reproduction, diet (trophic niche dimension), and temperature. Also, we tested the influence of seasonality and ontogeny on these biological aspects. Geckos (n = 116, 54 females, 33 males, and 29 juveniles) were sampled from October 2013 to September 2014. Phyllopezus periosus has an unimodal activity pattern, with peak activity in the early hours of the night. Males are more robust than females, and forelimbs in females are longer than in males. The body temperatures of this thermoconformer gecko are higher in the dry season. The reproductive season begins in the early dry season, with a fixed clutch of two eggs. Although we did not find evidence of more than one clutch per year, the studied population of P. periosus reproduces for an extended period throughout the dry season, as highlighted by the presence of juveniles all year. Phyllopezus periosus is saxicolous and presents a generalist diet composed mainly of arthropods, also including vertebrates such as frogs and lizards.

Unimodal activity pattern of stone marten in a Mediterranean island habitat

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Seasonal variation in the diurnal activity pattern of Eurasian blackbirds (Turdus merula) in the forest

Camera traps are increasingly used to estimate the density of animals as well as their activity patterns. As camera traps allow monitoring of animals over long periods of time without disturbance, they are especially useful to observe changes in diurnal activity patterns over time. In ornithology, camera trapping is still in its infancy. To our knowledge, no study has yet investigated the activity pattern of a songbird over the full annual cycle. We used camera traps in the Rammert, a small mountainous forest area near Rottenburg in Southwest Germany to monitor the diurnal activity pattern of forest-dwelling Eurasian blackbirds (Turdus merula). As the activity level of animals is known to be affected by day light, we used double-anchoring transformation of day times to account for the variation in sunrise and sunset across the different seasons. By generating activity models, we investigated the pattern of blackbird activity during the four seasons of the year and compared the patterns of male and female birds, respectively. A significant difference between a unimodal activity pattern in spring and a bimodal pattern for the rest of the year was found which might be related to breeding and territorial behaviour in spring. Moreover, we observed that the activity pattern of males and females overlapped greatly but still showed some variation in the number and timing of density peaks.

Natural History and Morphology of Crotalus ehecatl (Serpentes: Viperidae)

The Tehuantepec Isthmus rattlesnake (Crotalus ehecatl) is a poorly known species endemic to Mexico. We describe its diet, morphological variation, life history traits and activity patterns based on data from field encounters, museum specimens, and published data. Its diet consists almost exclusively of mammals, with no detected ontogenetic shift or sexual differences in prey type, and with feeding happening mainly in the rainy season. As the first detailed study on the feeding ecology of C. ehecatl, it adds six new prey species and suggests a homogeneous diet among age classes and sexes, but not among seasons. Crotalus ehecatl does not present sexual dimorphism in snout-vent length, head length or total length, but males have significantly longer tails than females, possess fewer ventral scales, more subcaudal and anterior intersupraocular scales. Crotalus ehecatl showed a unimodal activity pattern with peak activity in the summer, with crepuscular and nocturnal activity during the warmer months, and diurnal activity during the cooler months. The timing of C. ehecatl reproductive events, is similar to other rattlesnakes from temperate and tropical zones. Additional studies on this and related species would help to understand how the ecology of Neotropical rattlesnakes differs from rattlesnakes of more temperate zones.

Temporal resource partitioning mediates vertebrate coexistence at carcasses: The role of competitive and facilitative interactions

Temporal resource partitioning mediates vertebrate coexistence at carcasses: The role of competitive and facilitative interactions

Resource partitioning between Microlophus occipitalis and Stenocercus puyango (Sauria: Tropiduridae) in Cerros de Amotape National Park, Tumbes, Peru

Activity, microhabitat use, and diet are patterns commonly used to define the saurian community structure, because of differential exploitation allowing coexistence at the same time and place. We analyze resource partitioning between two sympatric saurian species, Stenocercus puyango and Microlophus occipitalis, in the transitional area of the Pacific Tropical Forest and the Dry Forest inside Cerros de Amotape National Park (PNCA) in Tumbes, northwestern of Peru. Microlophus occipitalis and S. puyango both showed a unimodal activity pattern with higher activity around 13:00 h, with a mean body temperature of 34.83 °C and 32.17 °C respectively, observing a significant relationship between body and environmental (air and substrate) temperatures. Rocks and tree trunks were the most frequent microhabitats used by M. occipitalis while S. puyango were registered more frequently over leaf litter. The diets of both tropidurids were composed by arthropods, ants, and insect larvae mainly. Similarities in activity times (temporal niche) and diet (trophic niche) should be related to phylogenetic relationship and environmental characteristics of PNCA (seasonality, vegetal composition) meanwhile differences in space use and microhabitat thermal quality will be related to thermal quality in the area.

Diel activity patterns of urban Woodchucks (<i>Marmota monax</i>) revealed by camera traps at burrows in southwestern Ontario, Canada

Animals display a range of diurnal and nocturnal activity patterns and, among mammals, a high proportion of species are crepuscular or nocturnal. Daily activities are often endogenous and oscillate on a light:dark regime. Such cycles are referred to as ‘circadian’ and are generally influenced by biotic and abiotic factors. I investigated the daily activity of urban Woodchucks (Marmota monax) by using 24-hour camera traps at backyard burrows in London, Ontario, Canada, in June. Cameras enabled the collection of data that would otherwise have been labour intensive by direct observation. Statistical modelling showed that Woodchucks exhibited a strictly diurnal activity pattern. The unimodal activity pattern started at sunrise and ended before sunset. The general daily activity trend was similar to the pattern described by others who used direct observations and telemetry to monitor Woodchucks in more rural settings. Temperature and wind were not included in the best-fit model. Camera trapping is a non-invasive method that could give insight to diel activity as it can easily monitor extended periods and reduce the effort required by direct observation.

Does social thermal regulation constrain individual thermal tolerance in an ant species?

In ants, social thermal regulation is the collective maintenance of a nest temperature that is optimal for individual colony members. In the thermophilic ant Aphaenogaster iberica, two key behaviours regulate nest temperature: seasonal nest relocation and variable nest depth. Outside the nest, foragers must adapt their activity to avoid temperatures that exceed their thermal limits. It has been suggested that social thermal regulation constrains physiological and morphological thermal adaptations at the individual level. We tested this hypothesis by examining the foraging rhythms of six populations of A. iberica, which were found at different elevations (from 100 to 2,000m) in the Sierra Nevada mountain range of southern Spain. We tested the thermal resistance of individuals from these populations under controlled conditions. Janzen's climatic variability hypothesis (CVH) states that greater climatic variability should select for organisms with broader temperature tolerances. We found that the A. iberica population at 1,300m experienced the most extreme temperatures and that ants from this population had the highest heat tolerance (LT50=57.55°C). These results support CVH's validity at microclimatic scales, such as the one represented by the elevational gradient in this study. Aphaenogaster iberica maintains colony food intake levels across different elevations and mean daily temperatures by shifting its rhythm of activity. This efficient colony-level thermal regulation and the significant differences in individual heat tolerance that we observed among the populations suggest that behaviourally controlled thermal regulation does not constrain individual physiological adaptations for coping with extreme temperatures.

Abundance and Diurnal Activity Rhythm of Stomoxys spp. in a Wildlife-human Interface in Makokou (North East-Gabon)

The aim of the study was to determine the abundance and diurnal activity rhythm of Stomoxyinae at the Ivindo National park and its environs, 14 Vavoua traps were set-up during the rainy season (25th Sept-5th Oct and 21st Oct-9th Nov 2018), in two habitats: the forest, a part of the Ivindo National Park (INP) and village-Town. In the Village-Town habitat, 62141 Stomoxys were caught and regrouped under five species notably 36502 S. omega (58.74%), 24045 S. n. niger (38.69%), 1312 S. xanthomelas (2.11%), 265 S. n. bilineatus (0.43%) and 17 S. calcitrans (0.03%). At the INP, 4645 Stomoxys were caught and regrouped under four species notably 2364 S. n. niger (50.89%), 2153 S. omega (46.35%), 114 S. xanthomelas (2.45%) and 14 S. n. bilineatus (0.30%). Stomoxys were more abundant in the village (517.84 s/t/d) as compared to the INP (44.24 s/t/d). There was a statistically significant difference (P<0.05) in apparent density of Stomoxys in the prospected biotopes. Stomoxys spp. showed a unimodal activity pattern in Village-Town environments and forest sites of the INP. The diurnal activity trend of Stomoxys spp. was sex dependent. This base line data will be used in Stomoxys spp. management in the environs of the INP.

Species Composition and Diurnal Activity Rhythm of Tabanids (Diptera: Tabanidae) at the Ivindo National Park and Its Environs

An entomological prospection to show the species composition and diurnal activity of tabanids was carried out using 15 Vavoua traps, during the rainy season (25th Sept-5th Oct and 21st Oct-9th Nov 2018), in the secondary forest [Ivindo National Park (INP)] and Village-Town sites in and around the biosphere reserve Ipassa-IRET Makokou in Gabon. In total, 839 tabanids were caught with 747 recorded at INP and regrouped under 11 species of the genus Tabanus [T. taeniola (57.76%), T. ricardae (26.32%), T. par (5.54%), T. ruficrus (3.74%), T. socius (3.74%), T. disjunctus (2.49%), T. marmorosus (0.28%) and T. obscurehirtus (0.14%)]. However, two species of the genus Chrysops [C. dimidiatus (70.83%) and C. silaceus (29.17%)] and one species of the genus Haematopota [H. pluvialis (100%)] were only identified at INP. While in the Village-Town sites, 92 tabanids were caught and regrouped under five species of the genus Tabanus [T. ruficrus (14.13%), T. taeniola (9.78%), T. ricardae (73.91%), T. par (1.09%), and T. marmorosus (1.09%)]. Tabanids were more abundant in the forest (7.12 tabanid/trap/day) as compared to the Village-Town (0.77 t/t/d) with a statistically significant difference (P<0.05). At INP, tabanids showed a unimodal activity pattern with peak attained between 12-14H and in the anthropized milieu (14-16H) and dominated by females.

Fish thermoregulation and the promotion of cellular antimicrobial defenses

Fish thermoregulation and the promotion of cellular antimicrobial defenses

Diversity, ecology, and seasonality of hard ticks (Acari: Ixodidae) in eastern Croatia.

The diversity of hard tick fauna was studied in different forest communities in 48 localities of eastern Croatia using the dragging-flagging method and by hand from ten different vertebrate hosts. A total of 2,225 specimens comprising seven species in three genera were identified. Ixodes ricinus, the most abundant species (72.8% of all collected specimens) was recorded in 44 localities, followed by Dermacentor reticulatus in 19 localities, while the other five species (D. marginatus, H. concinna, H. inermis, I. canisuga, and I. hexagonus) were recorded in fewer localities. The highest ratio (67% of collected ticks) was in the adult stage with the predominance of females. The numbers of collected females, males, and nymphs of I. ricinus and H. concinna differed significantly. Ten new tick-host associations in Croatia were recorded. Fifty-three animals were infested with one tick species. Single species infestation with I. ricinus was found in 45.8% of animals, followed by D. reticulatus with 25.4%, D. marginatus with 10.2%, H. inermis and I. hexagonus with 3.4%, and I. canisuga with 1.7%. Coinfestation with two species of ticks were recorded in six animals. Ixodes ricinus, H. inermis, and D. reticulatus showed bimodal seasonal activity; for other species unimodal activity patterns were recorded.

Summer activity patterns of four resident south Texas bat species

Summer activity patterns of four resident south Texas bat species

Tick species diversity and population dynamics of Ixodes ricinus in Galicia (north-western Spain)

Tick species diversity and population dynamics of Ixodes ricinus in Galicia (north-western Spain)

Temporal patterns in the activity density and sex ratio of isopods (Oniscidea, Isopoda) along an urbanization gradient in Denmark

Urbanization effects on terrestrial isopod (Isopoda, Oniscidea) populations were studied in forested areas along a rural-to-urban gradient including a native beech forest, suburban and urban forest fragments in Sorø, Denmark. The seasonal activity patterns of the dominating species (Oniscus asellus, Philoscia muscorum and Porcellio scaber) indicated differences among the areas, but these patterns were idiosyncratic. There were more females than males in most areas. The seasonal patterns of males and non-gravid females were similar and often bimodal; gravid females showed markedly different, usually unimodal activity patterns. Temporal changes of sex ratios were — in each species — characterized by an early summer activity peak of males, followed by the activity peak of gravid females. We suggest that these trends might indicate a reproduction-driven surface activity of males. The small response of the three isopod species to urbanization may reflect their wide ecological tolerance as well as the “soft management” of the urban park.

Daily Activity and Nest Occupation Patterns of Fox Squirrels (Sciurus niger) throughout the Year.

The authors investigated the general activity and nest occupation patterns of fox squirrels in a natural setting using temperature-sensitive data loggers that measure activity as changes in the microenvironment of the animal. Data were obtained from 25 distinct preparations, upon 14 unique squirrels, totaling 1385 recording days. The animals were clearly diurnal, with a predominantly unimodal activity pattern, although individual squirrels occasionally exhibited bimodal patterns, particularly in the spring and summer. Even during the short days of winter (9 hours of light), the squirrels typically left the nest after dawn and returned before dusk, spending only about 7 hours out of the nest each day. Although the duration of the daily active phase did not change with the seasons, the squirrels exited the nest earlier in the day when the days became longer in the summer and exited the nest later in the day when the days became shorter in the winter, thus tracking dawn along the seasons. During the few hours spent outside the nest each day, fox squirrels seemed to spend most of the time sitting or lying. These findings suggest that fox squirrels may have adopted a slow life history strategy that involves long periods of rest on trees and short periods of ground activity each day.

Unimodal activity pattern in forest-dwelling chamois: typical behaviour or interspecific avoidance?

Daily activity rhythms in mammals are influenced by a range of biotic and abiotic factors. During warm periods, mountain ungulates living in open areas typically show a bimodal pattern of activity rhythms, with peaks at dawn and dusk. To date, however, little is known about the activity patterns of mountain ungulates living in forested habitats and in areas where large predators are present. Using camera traps over a 6-month period between May and October of 2012, we investigated the activity pattern of a chamois population dwelling in the forests of the northern Mount Velebit region (Croatia) and its overlap with the activity patterns of potential predators (brown bear, grey wolf) and competitors (wild boar). Chamois showed a peak of activity between 5:00 a.m. and 7:00 a.m., when 65 % of individuals were photographed. Contrary to previous literature on chamois, we found evidence for a unimodal pattern of activity with a peak in the early morning hours: At a seasonal level, this pattern remained fairly consistent, though the activity at dusk increased in the warmest months. The main peak of activity occurred during periods of decreased activity of potential predators and competitors, and chamois exhibited the least tolerance for overlap with grey wolf. Further studies are needed to clarify whether this pattern is typical of forest-dwelling populations or if it reflects a temporal niche shift, possibly as a strategy to avoid predators.

The relationship between external temperature and daily activity in a large rodent (Dasyprocta azarae) in the Brazilian Pantanal

Abstract:Daily activity patterns reflect interactions between circadian mechanisms and environmental stimuli. Among these stimuli, temperature can be an important factor affecting activity budgets. To sample the agouti (Dasyprocta azarae), a systematic camera-trap grid was established with 50 independent sampling sites. A circular kernel function was used to characterize the activity patterns of the agouti population. To evaluate shifts in activity as a function of mean daily temperature, the entire set of records was subdivided into smaller sets covering different temperature ranges. The activity pattern belonging to each set was characterized and compared through the overlap of their full activity (95% isopleth) and activity core (50% isopleth). Based on 400 independent records, agoutis were predominately diurnal. They shifted their activity core, while keeping their activity range (the amount of time a population remains active during the 24-h cycle) constant through the temperature gradient. The agouti demonstrated a unimodal activity pattern at lower temperatures, which became more bimodal at higher temperatures. Nevertheless, it kept its activity range constant, regardless of temperature. These results likely reflect a trade-off between activity time and thermoregulation during the diurnal period and demonstrate how the agouti can change its behaviour to achieve thermal comfort.

Light loggers reveal weather-driven changes in the daily activity patterns of arboreal and semifossorial rodents

Measuring daily and seasonal patterns of activity is useful for understanding the ecological and evolutionary drivers of behavior. We used collar-mounted light loggers to examine how nest attendance in arboreal squirrels and aboveground activity in semifossorial ground squirrels are affected by weather-driven changes in thermoregulatory conditions. Activity of lactating red squirrels (Tamiasciurus hudsonicus) had a diurnal pattern showing 3 daily peaks of activity with time spent outside the nest increasing with increasing ambient temperature, but decreasing with increasing relative humidity and wind. Despite the persistence of daylight during midsummer in the arctic environment, female arctic ground squirrels (Urocitellus parryii) also exhibited diurnal activity patterns with time spent above ground each day decreasing in response to precipitation but increasing with increasing ambient temperature and incident solar radiation. On cooler days, ground squirrels exhibited a unimodal activity pattern. However, on warm days, ground squirrels spent less time above ground when solar radiation and ambient temperature were both at their daily maxima, which resulted in a bimodal activity pattern. Our results highlight the utility of light loggers as a cost-effective means of addressing questions related to foraging behavior, parental care, thermoregulation, energetics, and timing of activity in arboreal and semifossorial small mammals.