EUROPEAN JOURNAL OF ENTOMOLOGYENTOMOLOGY ISSN (online): 1802-8829 Eur. J. Entomol. 116: 158–172, 2019 http://www.eje.cz doi: 10.14411/eje.2019.017 ORIGINAL ARTICLE Circadian rhythms in the locomotor activity of the spiders Carrhotus xanthogramma (Salticidae) and Philodromus cespitum (Philodromidae): Temporal patterns and sexual differences LÁSZLÓ MEZŐFI 1, GÁBOR MARKÓ 2, 3, PÉTER KOVÁCS 4 and VIKTOR MARKÓ 1 1 Department of Entomology, Szent István University, Ménesi út 44, Budapest 1118, Hungary; e-mails: mezofi
[email protected],
[email protected] 2 Department of Plant Pathology, Szent István University, Ménesi út 44, Budapest 1118, Hungary; e-mail:
[email protected] 3 Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány P. sétány 1/C, Budapest 1117, Hungary 4 Mining and Geological Survey of Hungary, Columbus utca 17-23, Budapest 1145, Hungary; e-mail:
[email protected] Key words. Araneae, Carrhotus xanthogramma, Philodromus cespitum, diel activity, circadian rhythm, activity profi le, ultradian rhythmicity, locomotor activity, sexual differences, natural photoperiod, temporal niche, benefi cial arthropods Abstract. Circadian rhythms play an essential role in the adaptation of organisms to the environment and may show species-spe- cifi c or sex-specifi c differences even within a closely related taxonomic group. Although spiders (Araneae) are sexually dimorphic in several morphological and behavioural features, there are very few studies on the sex-specifi c differences in their biological rhythms. This study evaluated the circadian rhythm in the locomotor activity of two agrobiont hunting species of spider, Carrho- tus xanthogramma (Latreille, 1819) (Salticidae) and Philodromus cespitum (Walckenaer, 1802) (Philodromidae), under natural photoperiod conditions.