Mud-puddling: A study of butterfly puddling sites in Catalonia

Abstract

Some butterflies and other insects acquire nutrients from puddles, stream banks, rotting fruit, carrion, excrement and even sweat. This behaviour, which is called mud-puddling, produces a calling effect generating butterfly clusters. It has been widely studied in tropical areas, however, there are still many gaps in knowledge in temperate latitudes. The work presented is a study of this behaviour in two locations in Catalonia, one in the Alpine region and another in the humid Mediterranean region. This work combines censuses of diurnal butterflies in the chosen puddles with data from the Catalan Butterfly Monitoring Scheme (CBMS) and the use of photo-trapping cameras, during the summer 2022. In the censuses, 1462 individuals of 70 species, mainly belonging to Lycaenidae and Hesperiidae, have been observed. Also, Lycaenidae, Hesperiidae and Pieridae prefer puddles and excrement, while Nymphalinae and Satyrinae combine puddles and flora exudates. Our results also show that the participants are mainly young males, that there is an activity peak between 12 a.m. and 2 p.m. in both localities and that butterflies’ activity leaking from puddles increases with the temperature except for extreme temperatures (38-40 ºC). The study highlights many gaps in knowledge related to this behaviour in temperate latitudes that should be taken into account in future works: such as puddles function in drought periods and predation rate suffered by butterflies.