scholarly journals Night of the hunter: using cameras to quantify nocturnal activity in desert spiders

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10684
Author(s):  
Tamara I. Potter ◽  
Aaron C. Greenville ◽  
Christopher R. Dickman

Invertebrates dominate the animal world in terms of abundance, diversity and biomass, and play critical roles in maintaining ecosystem function. Despite their obvious importance, disproportionate research attention remains focused on vertebrates, with knowledge and understanding of invertebrate ecology still lacking. Due to their inherent advantages, usage of camera traps in ecology has risen dramatically over the last three decades, especially for research on mammals. However, few studies have used cameras to reliably detect fauna such as invertebrates or used cameras to examine specific aspects of invertebrate ecology. Previous research investigating the interaction between wolf spiders (Lycosidae: Lycosa spp.) and the lesser hairy-footed dunnart (Sminthopsis youngsoni) found that camera traps provide a viable method for examining temporal activity patterns and interactions between these species. Here, we re-examine lycosid activity to determine whether these patterns vary with different environmental conditions, specifically between burned and unburned habitats and the crests and bases of sand dunes, and whether cameras are able to detect other invertebrate fauna. Twenty-four cameras were deployed over a 3-month period in an arid region in central Australia, capturing 2,356 confirmed images of seven invertebrate taxa, including 155 time-lapse images of lycosids. Overall, there was no clear difference in temporal activity with respect to dune position or fire history, but twice as many lycosids were detected in unburned compared to burned areas. Despite some limitations, camera traps appear to have considerable utility as a tool for determining the diel activity patterns and habitat use of larger arthropods such as wolf spiders, and we recommend greater uptake in their usage in future.

1985 ◽  
Vol 63 (4) ◽  
pp. 843-846 ◽  
Author(s):  
B. M. Culik ◽  
D. J. McQueen

The activities of individual burrowing wolf spiders were continuously recorded with time-lapse television and respiration rates were simultaneously recorded. Five categories of activity and rest were differentiated and it was found that resting rates on the surface of the burrow and in the burrow were indistinguishable and similar to measures recorded in other studies. On average, in-burrow activity required 55% more energy than resting, surface activity required 220% more energy, and vertical activity (moving up the burrow) required 1780% more energy than resting. These data were analyzed with respect to the periodicity of activity patterns observed in the field and it was found that respiration rates that relate to periods of field activity are 40% higher than rates recorded for spiders assumed to be at rest.


Crustaceana ◽  
1996 ◽  
Vol 69 (1) ◽  
pp. 101-112 ◽  
Author(s):  
G. Guerao ◽  
C. Ribera

AbstractDiel activity rhythms of the prawn Palaemon serratus from Alfacs Bay, Ebro Delta, Spain, were studied under laboratory conditions by time-lapse video recording. The activity pattern showed endogenous rhythmicity of a circadian period with maximum activity at night. The feeding habits of P. serratus were studied using the frequency-of-occurrence method and the points method. The food of this species mainly consists of molluscs and crustaceans, and the remains of gastropods, amphipods, isopods, bivalves, mysids, copepods, and decapods were identified. The remaining items consisted of cnidarians, polychaetes, ophiuroids, plant material, sand, and unidentified organic debris. Results indicate that P. serratus is a predator of benthic invertebrates rather than a scavenger or detritus feeder. Diet composition changes with the size of the prawn.


Author(s):  
Piotr Indykiewicz ◽  
Dariusz Jakubas ◽  
Julita Gerke

AbstractMany vertebrates exhibit a diel activity, steered by light–dark cycle. However, some colonial waterbirds, in that several species of gulls, are active not only in day hours but also at night. In this study, we aimed to investigate 24 h cycle of black-headed gulls (BHG) Chroicocephalus ridibundus activity with focus on sleep behaviour. We expected that 24 h patterns of activity differ between colonies located in various habitats, and within a colony between nests located in the centre vs at the edge. We studied behaviour based on 9600 of 30 s videos from camera-traps taken in six colonies and data from 10 GPS-tracked individuals from one colony recorded during incubation. BHGs stayed active on average during 48.1% of a night, mainly spent on passive and active nest defence, and on nest maintenance. BHGs spent similar time on these activities in day hours. Individuals breeding in the colony centre slept at night longer than those at its edge. BHGs stayed active during on average 76.5% of daytime. In two urban colonies with the highest nest densities and highest level of light pollution birds slept less during the day than in other studied colonies (three rural and one urban) characterized by lower densities and light intensity after sunset near the colony. Knowledge of nocturnal behaviour is crucial to comprehend 24 h activity patterns of an organism, especially to understand flexibility of behaviour crucial for restoration, like sleep.


2021 ◽  
Vol 134 (4) ◽  
pp. 353-360
Author(s):  
Ronny Steen

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.


PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254254
Author(s):  
Milaja Nykänen ◽  
Hannu Pöysä ◽  
Sari Hakkarainen ◽  
Tuomas Rajala ◽  
Juho Matala ◽  
...  

Taiga bean goose (Anser fabalis fabalis) is an endangered subspecies that breeds sporadically in remote habitats in the arctic and boreal zones. Due to its elusive behaviour, there is a paucity of knowledge on the behaviour of taiga bean goose during the breeding season, and survey methods for monitoring numbers in the breeding areas are lacking. Camera traps are a useful tool for wildlife monitoring, particularly when there is a need for non-invasive methods due to the shy nature of the species. In this study, we tested the use of camera traps to investigate seasonal and diel activity patterns of taiga bean goose in Finland over two successive breeding seasons, 2018 and 2019. We did this by modelling counts of geese from images with generalized linear and additive mixed models. The camera type (cameras placed by experts specialized in bean goose ecology vs randomly placed cameras) did not influence the count of taiga bean goose (p = 0.386). However, the activity varied significantly by region, Julian day, time of day and temperature, with the study site (individual peatland) and year adding substantial random variation and uncertainty in the counts. Altogether, the best fitting model explained nearly 70% of the variation in taiga bean goose activity. The peak in activity occurred about a month later in the southernmost region compared to the more northern regions, which may indicate behaviours related to migration rather than breeding and moulting. Our results show that long-term monitoring with game camera traps provide a potential unobtrusive approach for studying the behavioural patterns of taiga bean goose and can increase our ecological knowledge of this little-known subspecies. The results can be applied to planning of the annual censuses and finding the optimal time frame for their execution.


2021 ◽  
Vol 8 ◽  
Author(s):  
Anne-Sophie Bonnet-Lebrun ◽  
Maria P. Dias ◽  
Richard A. Phillips ◽  
José P. Granadeiro ◽  
M. de L. Brooke ◽  
...  

Every year, billions of birds undertake extensive migrations between breeding and non-breeding areas, facing challenges that require behavioural adjustments, particularly to flight timing and duration. Such adjustments in daily activity patterns and the influence of extrinsic factors (e.g., environmental conditions, moonlight) have received much more research attention in terrestrial than marine migrants. Taking advantage of the widespread deployment in recent decades of combined light-level geolocator-immersion loggers, we investigated diel organisation and influence of the moon on flight activities during the non-breeding season of 21 migrant seabird species from a wide taxonomic range (6 families, 3 orders). Migrant seabirds regularly stopped (to either feed or rest) during migration, unlike some terrestrial and wetland birds which fly non-stop. We found an overall increase for most seabird species in time in flight and, for several species, also in flight bout duration, during migration compared to when resident at the non-breeding grounds. Additionally, several nocturnal species spent more of the day in flight during migration than at non-breeding areas, and vice versa for diurnal species. Nocturnal time in flight tended to increase during full moon, both during migration and at the non-breeding grounds, depending on species. Our study provides an extensive overview of activity patterns of migrant seabirds, paving the way for further research on the underlying mechanisms and drivers.


2018 ◽  
Vol 45 (8) ◽  
pp. 706 ◽  
Author(s):  
Helen R. Morgan ◽  
Guy Ballard ◽  
Peter J. S. Fleming ◽  
Nick Reid ◽  
Remy Van der Ven ◽  
...  

Context When measuring grazing impacts of vertebrates, the density of animals and time spent foraging are important. Traditionally, dung pellet counts are used to index macropod grazing density, and a direct relationship between herbivore density and foraging impact is assumed. However, rarely are pellet deposition rates measured or compared with camera-trap indices. Aims The aims were to pilot an efficient and reliable camera-trapping method for monitoring macropod grazing density and activity patterns, and to contrast pellet counts with macropod counts from camera trapping, for estimating macropod grazing density. Methods Camera traps were deployed on stratified plots in a fenced enclosure containing a captive macropod population and the experiment was repeated in the same season in the following year after population reduction. Camera-based macropod counts were compared with pellet counts and pellet deposition rates were estimated using both datasets. Macropod frequency was estimated, activity patterns developed, and the variability between resting and grazing plots and the two estimates of macropod density was investigated. Key Results Camera-trap grazing density indices initially correlated well with pellet count indices (r2=0.86), but were less reliable between years. Site stratification enabled a significant relationship to be identified between camera-trap counts and pellet counts in grazing plots. Camera-trap indices were consistent for estimating grazing density in both surveys but were not useful for estimating absolute abundance in this study. Conclusions Camera trapping was efficient and reliable for estimating macropod activity patterns. Although significant, the relationship between pellet count indices and macropod grazing density based on camera-trapping indices was not strong; this was due to variability in macropod pellet deposition rates over different years. Time-lapse camera imagery has potential for simultaneously assessing herbivore foraging activity budgets with grazing densities and vegetation change. Further work is required to refine the use of camera-trapping indices for estimation of absolute abundance. Implications Time-lapse camera trapping and site-stratified sampling allow concurrent assessment of grazing density and grazing behaviour at plot and landscape scale.


Author(s):  
Daniel A Crawford ◽  
L Mike Conner ◽  
Gail Morris ◽  
Michael J Cherry

Abstract Prey species often mitigate predation risk through alteration of spatiotemporal diel activity patterns whereby prey access high-quality resources in risky areas during predator downtimes. However, dominance hierarchies exist in some prey species, and temporal partitioning is a mechanism thought to reduce aggressive intraspecific interactions. How demographic-specific responses to predation risk influence intraspecific temporal partitioning in prey are largely unknown and could be key to understanding the effects of predators on intraspecific interactions in prey. To assess the effects of predation risk on intraspecific interactions in white-tailed deer (Odocoileus virginianus), we monitored deer diel activity during the fawning season in four pairs of predator exclusion and control plots (~40 ha) from 2015 to 2018 using 16 camera traps. We examined the effect of predation risk on diel activity of males, females, and nursery groups by comparing the within-group coefficient of activity overlap (d̂) across predator exclusion and control plots. We then examined within-treatment activity overlap between groups in the predator exclosure and control plots. All groups maintained different diel activity patterns in safe and risky areas. Unconstrained by predation risk, all groups behaved more similarly, and interspecific group overlap was greater in the predator exclusion plots than control plots. Male-nursery group overlap exhibited the strongest treatment effect, increasing 24% in predator exclusion plots (d̂ = 0.91, confidence interval [CI]: 0.87–0.95) relative to control plots (d̂ = 0.67, CI: 0.57–0.76). Our results suggest predators increase heterogeneity in prey behavior and may be important drivers of behavioral processes, such as temporal partitioning, that minimize antagonistic intraspecific interactions of prey.


2015 ◽  
Vol 72 (suppl_1) ◽  
pp. i147-i154 ◽  
Author(s):  
Jason S. Goldstein ◽  
Elizabeth A. Dubofsky ◽  
Ehud Spanier

Abstract Although the natural history for Mediterranean slipper lobsters (Scyllarides latus) is well established, there exists a disproportionate lack of important biological and physiological data to verify many key traits, including to what extent endogenous rhythms modulate aspects of their behaviour. Although Scyllarids appear nocturnally active, few studies exist that quantify this tendency. Our overall objective was to test the hypothesis that adult slipper lobsters are nocturnal and to determine if their diel activity rhythms are under the influence of an endogenous circadian clock. In the laboratory, we exposed a total of 16 animals (CLavg = 92.6 ± 6.6 mm; CL, carapace length) to a 12 : 12 light : dark (LD) cycle for 7–10 d, followed by ***constant dark (DD) for 15–20 d. Activity was assessed using a combination of time-lapse video and accelerometers. Of a total of 16 lobsters, we analysed data from 15 (one mortality). All 15 lobsters were evaluated using video. Thirteen of these lobsters were also evaluated using accelerometers. All lobsters were more active during night-time than during daytime and synchronized their activity to the LD cycle, expressing a diel activity pattern (τ = 24.04 ± 0.13 h). In DD, lobsters maintained a circadian rhythm with a τ of 23.87 ± 0.07 h. These findings may provide insight into the behaviour of these animals in their natural habitat and help explain their ability to anticipate dawn and dusk.


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