Habitat Selection, Ambient Light and Colour Patterns in Some Lek-Displaying Birds

The effects of handling time, ambient light intensity, and anaesthetic method, on the collection of spectral reflectance data were assessed in two species of Malawi cichlids ( Melanochromis auratus and Metriaclima zebra ). Using spectrometry, colour patches were measured over 10 min, under increasing ambient light levels, and using three anaesthetic methods. As time elapsed, maximum percent reflectance (Rmax) decreased across all anaesthetic methods and species, suggesting that measurements should be taken immediately after capture and anaesthetization. With increasing light intensity, Rmax increased significantly, suggesting that measurements should be taken under natural ambient conditions when possible. Finally, we found that anaesthetizing fish using an ice bath produced significantly higher Rmax than using either MS-222 (tricaine methanesulphonate) or clove oil (eugenol). However, the highest proportion of ultraviolet (UV) colouration was recorded while fish were anaesthetized with clove oil. Our results highlight the variation involved in measuring fish colour patterns using two related species, and thus indicate the need for a standardized approach to collecting spectral reflectance data in fish.

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Contrast to background influences predation on aposematic but not cryptic artificial caterpillars in a Brazilian coastal shrubland

Journal of Tropical Ecology ◽

10.1017/s026646742000005x ◽

2020 ◽

Vol 36 (3) ◽

pp. 109-114

Author(s):

Rayane S. Oliveira ◽

Pedro Diniz ◽

Vitor Araujo-Lima ◽

Gabriela Rosário ◽

Charles Duca

Keyword(s):

Habitat Selection ◽

Natural Variation ◽

Relative Effectiveness ◽

Mimic Model ◽

Defensive Strategies ◽

Mimic Models ◽

Arthropod Predators ◽

Risk Of Predation ◽

Colour Patterns ◽

Predation Rates

AbstractAposematism and crypticity are visual defensive strategies against predation; however, the relative effectiveness of these two strategies to reduce the risk of predation is not yet fully understood. We evaluated the risk of predation for caterpillars with cryptic and aposematic colouration as well as the probability of predation relative to the natural variation of contrast with the substrate. We expected that the two models would experience similar predation attempts and that the contrast with the substrate would be negatively related to the predation on aposematic mimic models and positively to the predation of cryptic models. Overall, 224 models were laid out along a transect and exposed to predation for five consecutive days during winter and autumn. Daily predation was 11.0% (winter) and 4.8% (autumn). Significant differences were not observed between predation rates on the two model types (50.6% aposematic). Most of the predated models had arthropod marks (86.4%) and only 13.6% had bird marks. The chance of predation was higher the greater the contrast between the aposematic mimic model and the substrate, although no relationship was observed for the cryptic model. Our results suggest that the two colour patterns do not differ in their defensive effectiveness and that micro-habitat selection might define the predation risk on aposematic mimic caterpillars in environments dominated by arthropod predators.

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Hierarchical habitat selection by woodland caribou: its relationship to limiting factors

Ecography ◽

10.1034/j.1600-0587.2000.230409.x ◽

2000 ◽

Vol 23 (4) ◽

pp. 466-478 ◽

Cited By ~ 66

Author(s):

W. James Rettie ◽

Francois Messier

Keyword(s):

Habitat Selection ◽

Limiting Factors ◽

Woodland Caribou

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Does food-searching ability determine habitat selection? Foraging in sand of three species of gerbilline rodents

Ecography ◽

10.1034/j.1600-0587.2000.230113.x ◽

2000 ◽

Vol 23 (1) ◽

pp. 122-129 ◽

Cited By ~ 1

Author(s):

Boris R. Krasnov ◽

Georgy I. Shenbrot ◽

Luis E. Rios ◽

Maria E. Lizurume

Keyword(s):

Habitat Selection ◽

Searching Ability

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Design, Development and Practical Realization of a VLC Supportive Indoor Lighting System

Light & Engineering ◽

10.33383/2019-048 ◽

2020 ◽

pp. 87-97

Author(s):

Sourish Chatterjee ◽

Biswanath Roy

Keyword(s):

Data Communication ◽

Cost Effective ◽

Ambient Light ◽

Lighting System ◽

Design Development ◽

Led Driver ◽

Communication Performance ◽

Good Communication ◽

Simulink Model ◽

Light Interference

In an office space, an LED-based lighting system allows you to perform the function of a data transmitter. This article discusses the cost-effective design and development of a data-enabled LED driver that can transmit data along with its receiving part. In addition, this paper clearly outlines the application of the proposed VLC system in an office environment where ambient light interference is a severe issue of concern. The result shows satisfactory lighting characteristics in general for this area in terms of average horizontal illuminance and illuminance uniformity. At the same time, to evaluate real-time and static communication performance, Arduino interfaced MATLAB Simulink model is developed, which shows good communication performance in terms of BER (10–7) even in presence of ambient light noise with 6 dB signal to interference plus noise ratio. Our designed system is also flexible to work as a standalone lighting system, whenever data communication is not required.

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