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P J Fonseca

Publications and source records attributed to P J Fonseca.

3 recordsLinked to original sources
PubMed2002

Temperature dependence of cicada songs (Homoptera, Cicadoidea).

The songs of male Portuguese cicadas Tettigetta argentata, T. josei and Tympanistalna gastrica were recorded at five to seven temperatures within the range 24-38.5 degrees C. To investigate the temperature dependence of the neuromuscular apparatus involved in song production, different temporal elements of the calling songs were measured. We report a strong temperature dependence for the syllable and the echeme rates in T. josei and Ty. gastrica. This suggests that in these species the neuromuscular structures involved in the timbal cycle and in generating the echeme succession of the song are strongly temperature dependent. In T. argentata, the syllable rate was again significantly temperature dependent; the echeme rate, however, increased between 25.5 degrees C and 33.5 degrees C but decreased with the highest temperature. This indicates that at least in T. argentata two separate neuronal networks control both song parameters. Other temporal elements of the song with potential behavioural significance were also measured and found to be temperature dependent (e.g. echeme duration and interval). The possible implications for intraspecific communication are discussed. We also demonstrate that the temperature of these small cicadas is not significantly influenced by the muscle activity involved in song production. On the other hand, exposure to sunlight can be used by these cicadas to elevate their body temperature by more than 10 degrees C.

Animals↗
PubMed2002

Song discrimination by male cicadas Cicada barbara lusitanica (Homoptera, Cicadidae).

Cicada barbara lusitanica males presented a stereotyped singing response behaviour when exposed to a playback of the conspecific song. Males preferred (as measured by the time taken to sing) the conspecific signal to heterospecific songs that differed markedly in temporal pattern. Manipulation of the gross temporal pattern of C. barbara calling song significantly reduced stimulus attractiveness. Indeed, C. barbara males stopped responding to stimuli in which the temporal pattern approached the characteristic C. orni song, a sympatric and closely related species. If present in females, the preference for stimuli with pauses not exceeding 30 ms could reflect the evolution of a behavioural pre-copulatory isolating mechanism based on song analysis. Males discriminated frequencies within 3-15 kHz, clearly preferring 6 and 9 kHz; both these frequencies matched the main spectral peaks of the song. The preference for specific frequencies was not associated with maximum neuronal excitation as estimated by auditory nerve recordings, which suggests that this frequency-dependent behaviour is not based on the strength of the auditory system's response to different frequencies. Rather, it is likely to reflect fine frequency resolution in the central nervous system.

Acoustic Stimulation↗