Calling-song function in male haglids (Orthoptera: Haglidae,Cyphoderris)

Abstract

We studied the response of males to the singing of nearby male conspecifics in two species of the orthopteran genus Cyphoderris, primitive relatives of crickets and katydids. Lone male Cyphoderris buckelli stridulating in a large cage made a phonotactic approach to a nearby speaker broadcasting conspecific calling song. But in field experiments no phonotaxis to song broadcasts occurred; rather, a significant number of male C. buckelli increased their chirp duty cycle and pulse rate. There was no change in their carrier frequency. Calling male Cyphoderris monstrosa were exposed in the field to (i) playback of a synthetic calling song at a typical conspecific pulse rate, (ii) relayed broadcast of their own call, and (iii) low-frequency audio noise. Call duty cycle decreased significantly in response to the noise, while the pooled song models fell just short of significance. Singing C. buckelli were marked individually and their perches flagged over successive nights. We observed low site fidelity and extensive male displacement. Such behaviour is inconsistent with defense of topographically fixed singing territories and concurs with the absence of fighting in this species. Chirp duty cycle was increased significantly in C. buckelli in response to the singing of nearby conspecifics, but unlike in C. monstrosa, this change in duty cycle plays no role in overt aggression, though it may maintain a male's relative attractiveness to females.

Functional morphology of tegmina-based stridulation in the relict speciesCyphoderris monstrosa(Orthoptera: Ensifera: Prophalangopsidae)

“…Furthermore, Cyphoderris spp. sing at ∼12-15 kHz (Morris and Gwynne, 1978;Morris et al, 2002), a range higher than that in field crickets (3-8 kHz; Hoy et al, 1982;Otte, 1992) but lower than that in most bush crickets (>20 kHz; Montealegre-Z, 2009). In summary, Cyphoderris spp.…”

“…2) (Morris and Gwynne, 1978;Spooner, 1973;Morris et al, 2002). Mean peak frequency of the call is 13.08±0.1 kHz (N=5).…”

“…However, similar to field crickets, tegminal stridulation in Cyphoderris spp. occurs from largely symmetrical forewings (Morris et al, 2002). In addition, unlike both field and bush crickets, stridulation in Cyphoderris spp.…”

Mechanical phase shifters for coherent acoustic radiation in the stridulating wings of crickets: the plectrum mechanism

“…In some species, however, individuals with either tegminal overlapping can be found in equal proportions (Kavanagh and Young, 1989;Masaki et al, 1987). In any case, it is not clear whether crickets voluntarily switch tegminal overlapping during stridulation (the sound produced with either overlapping is not statistically different) as observed in hump-back crickets (Morris et al, 2002;Morris and Gwynne, 1978).…”

“…As crickets, haglids have bilaterally symmetrical tegmina (subtle symmetry might be present) and males produce puretone signals for intraspecific communication (Mason, 1996;Morris et al, 2002;Spooner, 1973), therefore, the production of pure-tone signals using bilaterally symmetrical tegmina is probably a plesiomorphic trait of the ancestors of extant Ensifera.…”