Cathemerality: a key temporal niche

Abstract

Given the marked variation in abiotic and biotic conditions between day and night, many species specialise their physical activity to being diurnal or nocturnal, and it was long thought that these strategies were commonly fairly fixed and invariant. The term ‘cathemeral’, was coined in 1987, when Tattersall noted activity in a Madagascan primate during the hours of both daylight and darkness. Initially thought to be rare, cathemerality is now known to be a quite widespread form of time partitioning amongst arthropods, fish, birds, and mammals. Herein we provide a synthesis of present understanding of cathemeral behaviour, arguing that it should routinely be included alongside diurnal and nocturnal strategies in schemes that distinguish and categorise species across taxa according to temporal niche. This synthesis is particularly timely because (i) the study of animal activity patterns is being revolutionised by new and improved technologies; (ii) it is becoming apparent that cathemerality covers a diverse range of obligate to facultative forms, each with their own common sets of functional traits, geographic ranges and evolutionary history; (iii) daytime and nighttime activity likely plays an important but currently neglected role in temporal niche partitioning and ecosystem functioning; and (iv) cathemerality may have an important role in the ability of species to adapt to human‐mediated pressures.

Widespread temporal niche partitioning in an adaptive radiation of cichlid fishes

“…Furthermore, our work suggests that transitions between diurnal and nocturnal activity patterns are facilitated through an intermediate crepuscular state or “bridge”. This observation confirms and extends previous categorical studies on the temporal activity patterns of skinks 46 , geckos 47 , and mammals 24–26,48 , in which direct evolutionary transitions between diurnal and nocturnal activity patterns are slower than transitions from crepuscular/cathemeral to diurnal and nocturnal patterns. Our study provides high resolution quantitative, rather than categorical, behavioural evidence for species occupying a continuum of behavioural states consistent with this bridge hypothesis.…”

Seeking temporal refugia to heat stress: increasing nocturnal activity despite predation risk

“…Moreover, changes in activity timing can disrupt interspecific interactions such as competition and parasitism [ 60 ]. In this framework, cathemeral species are likely to be favoured as they retain the ability to adapt their activity rhythms to changing environments or better exploit resources [ 8 , 61 ]. Researchers and managers should pay particular attention to strictly diurnal species, as they are expected to suffer the most important impacts.…”

“…To answer these questions, we focused on large ungulates as they frequently exhibit cathemeral activity [ 8 ], are sensitive to global change [ 9 ] and have evolved from nocturnal to diurnal daily pattern as a result of carnivore avoidance [ 7 ]. As a model species, we used Alpine ibex ( Capra ibex ), a cold-adapted diurnal mountain ungulate known to be sensitive to global warming [ 10 , 11 ].…”

The moon’s influence on the activity of tropical forest mammals

“…Species that change their overall activity level in response to nocturnal illumination may be more strongly impacted than species that can maintain their level of activity by adjusting its timing. Along those lines, lunar phobic species could be expected to cope better with artificial light if they follow a cathemeral diel activity pattern as this is indicative of behavioral plasticity that may be advantageous in a changing world ((temperature changes, artificial light; Cox and Gaston 2023). However, in tropical regions cathemerality is less reportedly less common than in higher latitudes (Bennie et al 2014).…”