Ontogeny of sexually dimorphic ultrasonic vocalizations in mongolian gerbils

Abstract

Sexual differentiation of emission rates (Experiment 1) and physical structure of ultrasonic vocalizations (Experiment 2) were investigated in Mongolian gerbils between 17 and 85 days of age. Animals from different litters were allowed to interact in iso- and heterosexual pairs. Vocalization rates increased in all groups, reaching a plateau at approximately day 56. Female pups had significantly higher rates of all vocalizations than male pairs before the plateau stage. Five stereotypic categories of physical structure were easily distinguished and confirmed by sound spectrographic analysis. Only mid-range frequencies of vocalizations appeared to decline throughout the juveniles' lives: this change may communicate the animal's age. Two male and one female categories were sexually dimorphic and similar in structure to those made during courtship interactions. Rates of male-type vocalizations appear to increase as testicular androgens start rising.

Classification of vocalizations in the Mongolian gerbil, Meriones unguiculatus

“…The other ten syllable types characterized here appear to be different than any previously reported types (Holman, 1980;Holman and Seale, 1991). The most notable differences are the lower frequency calls (fundamental frequency <30 kHz: AFM, DFMl, DFM, QCF, and NB) and the five composite syllables (AFM-QCF, QCF-AFM, uSFM-DFM, uSFM-DFM-QCF, NB þ QCF).…”

Ultrasonic vocalizations by infant laboratory mice: A preliminary spectrographic characterization under different conditions

“…Depending on the frequency modulation and duration of the acoustic signal, we assigned the US vocalizations produced by the pups to one of five sound categories in order to establish an association between the US call and a given experimental condition. The categories were defined on the basis of the previous descriptions by Sales and Smith (1978) and Holman and Seale (1991).…”

“…Although there is then substantial information available concerning the influence of environmental conditions on the number of ultrasounds emitted, little is known about how such conditions modulate the call structure (frequency, intensity, duration) of the US signals (Holman & Seale, 1991;Sales & Smith, 1978).…”

Automated classification of mouse pup isolation syllables: from cluster analysis to an Excel-based “mouse pup syllable classification calculator”

“…Arbitrary boundaries were set between slow FM, regular FM, and rapid FM categories. Branchi et al (1998) morphed these categories (Sales and Smith, 1978) with those used for gerbil communication (Holman and Seale, 1991) to construct five categories; only the frequency stepped category of Sales and Smith (1978) remained. New arbitrary syllable borders were introduced; the rates of FM change used by Sales and Smith (1978) were replaced by measurements of the magnitude of the FM change (Branchi et al, 1998).…”