Biological Journal of the Linnean Society, 2005, 86, 345–361. With 5 figures © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86, 345–361 345 Blackwell Science, LtdOxford, UKBIJBiological Journal of the Linnean Society0024-4066The Linnean Society of London, 2005? 2005 863 345361 Original Article PATTERNS IN PUDDLING F. MOLLEMAN ET AL . *Corresponding author. Current address: Biodemographic Determinants of Life Span, c/o Department of Entomology, University of California, Briggs 69, One Shields Avenue, Davis, CA 95616, USA. E-mail: freerkmolleman@hotmail.com Is male puddling behaviour of tropical butterflies targeted at sodium for nuptial gifts or activity? FREERK MOLLEMAN*, ROY H. A. GRUNSVEN, MAARTJE LIEFTING, BAS J. ZWAAN and PAUL M. BRAKEFIELD Institute of Biology, Leiden University, PO Box 9516, 2300 RA Leiden, the Netherlands Received 30 November 2003; accepted for publication 1 December 2004 An apparent sexual difference in adult feeding behaviour in many species of Lepidoptera relates to puddling on mud, dung and carrion. In most butterfly species, puddling is exclusively a male behaviour. A possible explanation for this division in feeding behaviour is that nutrients derived from puddling are transferred to the female in the spermato- phore during mating as a nuptial gift. Sodium derived from puddling has been shown to act as a nuptial gift in a few Lepidoptera species. It can also be used for neuromuscular activity in both males and females and may therefore cor- relate with flight morphology. In this study, we examine the generality of these two hypotheses in comparative work on a community of African fruit-feeding butterflies. We investigated puddling behaviour of males and females on car- rion and dung together with sodium preferences, polyandry, relative wing-size, sexual size dimorphism and sodium concentrations in the bodies and spermatophores of several species. The results show that sodium as a nuptial gift can explain the sexual division in puddling in some species, but not in all. Species in which both sexes puddle trans- fer little sodium in the nuptial gift, which is consistent with the nuptial gift theory. Wing loading and puddling are not significantly correlated, but the trend followed the direction predicted by the activity hypothesis. However, the sodium concentration in the species with the smallest wing area to thoracic volume (WA/TV) ratio (the largest Charaxes spp.), was relatively low. Moreover, in all investigated species, the sodium concentration was higher in the abdomen than in the thorax. The results are discussed in the light of differences between the sexes in foraging behav- iour in both larvae and adults, and with respect to alternative explanations for puddling. © 2005 The Linnean Soci- ety of London, Biological Journal of the Linnean Society, 2005, 86, 345–361. ADDITIONAL KEYWORDS: allometry – carrion – Charaxinae – Lepidoptera – Nymphalinae – polyandry – Satyrinae. INTRODUCTION In most sexually reproducing organisms, the sexes dif- fer in the way they achieve reproductive success. In general, males allocate a high proportion of their resources to maximizing the number of eggs they fer- tilize, whilst females invest a significant proportion of their nutritional resources in the offspring (Trivers, 1972). This implies that selection differs for males and females. If the sexual tactics of one sex are costly to the other, counter-strategies can evolve in a process of coevolution of female and male reproductive strate- gies. However, divergent morphology and behaviour are driven not only by mate choice and intrasexual competition, but also by ecological pressures (Temeles et al., 2000; Altshuler & Clark, 2003). In many species, males provide more to female part- ners than gametes. One form of male contribution is the nuptial gift. In Lepidoptera, males transfer a sper- matophore during copulation, which contains sperm and accessory gland products. Since the spermato- phore can contain substances that are useful for the female it is usually considered a nuptial gift (Vahed, 1998). The size and contents of the spermatophore varies between species (Svard & Wiklund, 1989; Bis- soondath & Wiklund, 1995). When females benefit from nutrients in the sper- matophore, it can be advantageous for them to mate with multiple partners (Bergstrom & Wiklund, 2002;