Artificial light affects the foraging behavior in greater white‐toothed shrews (CROCIDURA RUSSULA)

• Published in: Ethology Vol. 129; no. 2; pp. 88 - 98
• Main Authors: Aparício, Guilherme, Carrilho, Maílis, Oliveira, Flávio, Mathias, Maria da Luz, Tapisso, Joaquim T., Merten, Sophie
• Format: Journal Article
• Language: English
• Published: Hamburg Blackwell Publishing Ltd 01.02.2023
• Subjects: activity; ALAN; Ecological effects; Food; Food preferences; Food quality; Foraging behavior; Insectivores; Light; Light pollution; Light sources; Metabolic rate; Metabolism; Nocturnal; Predation; Risk perception; small mammals; Soricidae; Urban environments; urbanization
• ISSN: 0179-1613; 1439-0310
• DOI: 10.1111/eth.13347

Light pollution is one of the forms by which human‐induced alterations are changing natural environments. Artificial light at night (ALAN) has been increasing over the past decades and it is already known that ALAN can have a major influence on the ecology, behavior, and physiology of different taxa. Nocturnal small mammals are particularly vulnerable, as ALAN can increase their predation risk while foraging. The aim of this study was to investigate foraging strategies under different light conditions in a nocturnal small insectivore, the greater white‐toothed shrew (Crocidura russula). Compared with rodents, shrews have a higher metabolic rate and thus present a good model for a foraging study. In three laboratory experiments with wild‐caught shrews we tested (i) food preference under dark conditions as well as the effect of different light conditions on (ii) foraging strategies and (iii) food choice. The results showed that shrews had a clear food preference under dark conditions. They also preferred to forage under dark over light conditions when presented with the same food in both conditions. However, when presented with the choice of foraging their preferred food under illuminated conditions or a lower food quality in the dark, the food preference of shrews overruled their preference for feeding in the dark. It seems that food preference, rather than risk perception, is the main driver determining the foraging strategy of the greater white‐toothed shrews. This study suggests that ALAN does not necessarily prevent high‐metabolic nocturnal insectivores from achieving their energetic needs, which might help explain their persistence in urban environments. In our study, we made three cafeteria tests. First, we tested their food preference, resulting in mealworms being their favorite food item, fly pupae their less favorite and minced meat not being eaten. When shrews' favorite food item (mealworms) was offered in darkness and under bright white light, they avoided the illuminated condition. However, when they had to choose between their preferred and less preferred food items (mealworms and fly pupae, respectively) under different light conditions, their food preference prevailed.