Female signalling to male song in the domestic canary, Serinus canaria

Most studies on sexual selection focus on male characteristics such as male song in songbirds. Yet female vocalizations in songbirds are growing in interest among behavioural and evolutionary biologists because these vocalizations can reveal the female's preferences for male traits and may affect male display. This study was designed to test whether male song performance influences the different female signals in the domestic canary ( Serinus canaria ). Female canaries were exposed to three types of song performance, differing in the repetition rate of sexy syllables. This experiment demonstrates that female birds are engaged in multimodal communication during sexual interaction. The results support the copulation solicitation hypothesis for female-specific trills: these trills were positively correlated and had a similar pattern to the copulation solicitation displays; responses were higher to the songs with higher performance and responses decreased with the repetition of the stimulation. Also, we observed a sensitization effect with the repetition of the song of the highest performance for the simple calls. Simple trills and other calls were more frequent during the broadcast of canary songs compared with the heterospecific control songs. The differential use of female signals in response to different song performance reveals a highly differentiated female signalling system which is discussed in light of the role of female traits to understand sexual selection in a broader perspective.

Female rock sparrows (Petronia petronia), not males, respond differently to simulations of different courtship interaction outcomes

Animals communicate in networks which spread beyond the classic sender-receiver dyad. Researchers have often concentrated on networks of signalling males, but the network-level effects of male-female signalling interactions are largely unexplored, even though these can contain information when individuals of both sexes have access to a range of mating strategies. We tested whether rock sparrows (Petronia petronia) behave differently after hearing playbacks of vocal interactions simulating a successful courtship as opposed to playback of an unsuccessful courtship. We found no support for our prediction that males which heard a successful courtship simulation would increase the frequency of sexual behaviours compared with those which heard the unsuccessful courtship. Females which heard the successful courtship simulation stayed longer at the nest site and inside the nest box compared with those which heard the unsuccessful courtship simulation. Therefore, females responded to the treatments as if these represented different degrees of competition for either mates or nest sites. This is, to the best of our knowledge, among the first experimental demonstrations that female birds intercept signalling interactions between males and females and suggests that information available through communication networks can be relevant for an animal's choice of breeding strategy.

Sexual behaviour of Bosca's newt, Triturus boscai

The sexual behaviour of Bosca's newt, Triturus boscai is characterized by an extended phase of static display, during which tail fanning is the main display. This behaviour is similar to that of another species, T. italicus. During the static display phase males may also push the females' throat with the snout, and perform tail flicking movements. Unlike the other small-bodied Triturus species, T. boscai males receive very little or no indication on the part of the female signalling them to begin the spermatophore transfer phase, and do not perform retreat display. As in T. italicus, the tail-touch behaviour by the female of T. boscai appears to be less stereotyped than in the T vulgaris-helveticus-montandoni group. Spermatophore transfer success was highest at the beginning of the sexual encounters, the so-called early sequences. These sequences had little or no fanning behaviour before the spermatophore transfer. Luring behaviours are often performed, mainly during the spermatophore transfer phase.