Correspondence ISSN 2336-9744 The journal is available on line at www.ecol-mne.com

Strange affection: male Bufo bufo (Anura: Bufonidae) passionately embracing a bulge of mud

SONJA ĐOR ĐEVI Ć1,2,* and ALEKSANDAR SIMOVI Ć2

1University of Belgrade, Faculty of Biology, Institute of Zoology. Studentski trg 16, 11000 Belgrade, Serbia 2Serbian Herpetological Society “Milutin Radovanovi ć”. Bulevar despota Stefana 142, 11000 Belgrade, Serbia. E- mail: [email protected] *Corresponding author. E-mail: [email protected]

Received 13 March 2014 │ Accepted 20 March 2014 │ Published online 21 March 2014.

On March 11 th 2014, app. between 10 AM and noon, we visited a pond on the Avala Mt. (44°40.879 ′ N, 20°33.098 ′ E, 230 m a.s.l.). Its north–northeastern portion, overgrown with reeds, was crowded with common toads, Bufo bufo (Linnaeus, 1758). Males were vocalizing, chasing females (and males), struggling to clasp them in firm grip; we observed several “mating balls” – three to ten males were vigorously fighting over a single female. On the margin of that mating frenzy, at the edge of the pond, we observed a silent, lonely male holding on to a bulge of mud (Fig. 1). He was literally motionless in that position for at least half an hour (recorded time).

Figure 1. Male common toad firmly grasping a muddy protuberance (Photo: S. Đor đevi ć)

Anurans are notorious for making mistakes during mating. Their erroneous amplexuses include conspecific males, dead conspecifics of both sexes, other anuran species, caudates, fish, small tortoises, etc., and even inanimate floating objects (Banta, 1914; Davies & Halliday, 1979; Pearl et al., 2005; Simovi ć et al., 2014; Storm, 1952). Explosively breeding, scramble competing common toads are no exception (Davies & Halliday, 1979; Marco & Lizana, 2002; Mollov et al., 2010; Wells, 1977).

Ecol. Mont., 1 (1), 2014, 15-17

MALE BUFO BUFO EMBRACING A BULGE OF MUD

In anurans, courting/mating errors sometimes result from search for a larger among the available females (e.g. Schmeller et al., 2005). Sex ratio at breeding sites is often male-biased: males arrive there earlier and stay longer than females (Davies & Halliday, 1979). Large males often choose their mates and take them in amplexus on land: when they reach the breeding pond, most females are already paired; amplexus lasts from several hours to few days (Davies & Halliday, 1979; Reading & Clarke, 1983). Smaller males are usually rejected by females or displaced by larger males during fierce fights over females (Arak, 1988; Davies & Halliday, 1979; Lamb, 1984). Overall, for male anurans, courtship and mating are expensive in terms of energy, time and predation risk (e.g. McCauley et al., 2000). Despite extensive literature search, we could not find any previous report of a toad holding on to a piece of soil. Wet soil is huge, and is more toad-like than, e.g. a plastic cup (Mollov et al., 2010), but it is not floating or moving. We find it hard to imagine how a piece of the pond bank – although probably soaked with various hormones – could resemble a living, gravid female (Banta, 1914; Yu & Lu, 2013). Numerous seasonally oscillating hormones (similar/identical to those of other vertebrates) were shown to dictate reproductive behaviour in male and female anurans (Propper & Dixon, 1997; Wilczynski et al., 2005; Wilczynski & Lynch, 2011). During the reproductive season, potential mates communicate via pheromones as well as through visual, tactile and auditory signals (Belanger & Corkum, 2009; Pearl et al., 2000; Wabnitz et al., 1999). Male mating hormones and behaviours were more widely studied than those of females (Pearl et al., 2000, but see Wilczynski & Lynch, 2011). Also, information concerning roles of various other factors (environmental conditions, social interactions, personalities of individual males, female mate choice, etc.) and their interplay with acoustic and chemical communication is still scarce (Han & Brooks, 2013; Propper & Dixon, 1997; Smith & Blumstein, 2008; Wilczynski et al., 2005). In short, a pond in which anurans court and mate becomes a highly complex arena, a thick soup packed with pheromones, over which hovers an cacophony of mating offers and invitations. One can easily get confused. Especially if you are not among the largest, strongest and loudest in the crowd of males, you may “decide” to seek for something you could hug, for a bit of cold comfort.

References

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