Full Description

"Breeding Lusitanian toadfish males defend nests from intruders with sounds."

"Lusitanian toadfish males (Halobatrachus didactylus) are highly territorial during the breeding season and use sounds (boatwhistles, BW) to defend nests from intruders. BW present most energy in either the fundamental frequency, set by the contraction rate of the sonic muscles attached to the swimbladder, or in the harmonics, which are multiples of the fundamental frequency."

"Type I males nest under rocks or in crevices, are territorial, vocalize to attract mates and provide parental care to the eggs in the nest. In contrast, Type II males are not territorial and sneak fertilizations [20]."

"Also, in the course of similar experiments (e.g. [16]) we have observed that only nest-holders produce sounds. In one exception (unpublished data), the intruder entered the nest and also made BW but these could clearly be distinguished from the nest-holder's sounds due to spectral differences."

"These nest-holders made an average of 10.4 ± 6.4 (4–22) BW during a 1 h trial."

"The number of BW was correlated with the number of interactions (r = 0.61, p < 0.05) but not with male features."

"Agonistic BW Dur averaged 640 ms (range 437–933 ms) and presented a relatively high coefficient of variation (mean = 0.3, range 0.1–0.5). PP averaged 23 ms (range 19.7–26.9 ms) and was more stereotyped (mean CV = 0.05, range 0.01–0.07). DH was most commonly found on the first harmonic (DH mean = 89 Hz, range 41–146 Hz), and on average males maintained a particular dominant frequency band in 70% of BW, i.e. DH variability averaged 0.7 (range 0.5–1.0). Only three out of 13 males produced BW always with the same dominant frequency, i.e. with DH variability = 1."

"The Lusitanian toadfish used BW as the primary response to intruders, both during approaches and while facing actual intrusions in the nest (Fig. 1). Nest-holders typically only resorted to escalated fight when opponents did not flee after first receiving BW, and only after the intruder entered the nest. These results are consistent with BW signalling territorial ownership and serving as a warning of a possible attack."

"In this context, low and stable BW dominant harmonics are informative of androgen driven traits, such as sonic muscle mass, and likely of the individuals foraging competitive ability."

"In summary, agonistic BW not only function to fend off potential nest intruders but also potentially convey relevant information for male assessment."

Observation Environment Quotes

"We used plastic round swimming-pools (2.5 m diameter, 0.5 m water depth) as stock and experimental tanks."

Behaviour Description Quotes

"Breeding Lusitanian toadfish males defend nests from intruders with sounds."

"Lusitanian toadfish males (Halobatrachus didactylus) are highly territorial during the breeding season and use sounds (boatwhistles, BW) to defend nests from intruders. BW present most energy in either the fundamental frequency, set by the contraction rate of the sonic muscles attached to the swimbladder, or in the harmonics, which are multiples of the fundamental frequency. "

" Taken together, these results suggest that the spectral content of fish agonistic sounds may signal male features that are key in fight outcome."

"Within this family, Lusitanian toadfish (Halobatrachus didactylus) males mainly defend their nests with agonistic boatwhistles (BW) that are similar to mating advertisement BW except for presenting lower dominant frequencies and weaker amplitude modulation [16]. "

"Type I males nest under rocks or in crevices, are territorial, vocalize to attract mates and provide parental care to the eggs in the nest. In contrast, Type II males are not territorial and sneak fertilizations [20]."

"For resident fish we tallied the frequency of agonistic escalated behaviours (escalated fight, EF) such as chasing, bite attempts, bites and mouth–mouth fight."

"The Lusitanian toadfish used BW as the primary response to intruders, both during approaches and while facing actual intrusions in the nest (Fig. 1). Nest-holders typically only resorted to escalated fight when opponents did not flee after first receiving BW, and only after the intruder entered the nest. These results are consistent with BW signalling territorial ownership and serving as a warning of a possible attack."

Sound Name Quotes

"Lusitanian toadfish males (Halobatrachus didactylus) are highly territorial during the breeding season and use sounds (boatwhistles, BW) to defend nests from intruders. BW present most energy in either the fundamental frequency, set by the contraction rate of the sonic muscles attached to the swimbladder, or in the harmonics, which are multiples of the fundamental frequency. "

"We measured BW duration (Dur, ms), from the start of the first pulse to the end of the last pulse, and pulse period (PP) of the BW tonal phase [cf. 28] (ms, average peak-to-peak interval of six consecutive pulses in the middle of this segment — Fig. 1a)."