Arginine vasotocin induces calling behavior with a female social stimulus and interacts with gonadotropins to affect sexual behaviors in male Xenopus tropicalis

Abstract

Arginine vasotocin (AVT) and the mammalian homologue, arginine vasopressin (AVP), modulate vertebrate social behaviors, including vocalizations in male anurans. To study the impact of AVT and social stimuli on calling in male Xenopus tropicalis, we injected males with vehicle, 1 μg, or 10 μg AVT and recorded vocalizations under four social contexts (no stimulus, with male call playback, with a female, and with call playback and a female). More males called when injected with 10 μg AVT. Furthermore, calling males called only when paired with a female. We identified four call types: long fast trill; short fast trill; slow trill; or click. Next, we injected males with vehicle, 10 μg, or 20 μg AVT and recorded vocalizations with or without a female. AVT treatment did not affect calling in this experiment, but we confirmed that more males, regardless of AVT treatment, called when a female was present. Then we evaluated the effect of human chorionic gonadotropin (hCG) on male sexual behavior. 20 IU hCG elevated behavior compared to controls while the 10 IU hCG treatment group was not different from either treatment. Last, we examined the effect of AVT on hCG-induced reproductive behavior. Males were injected with 10 IU hCG or with 10 IU hCG and 20 μg AVT. Males receiving hCG and AVT clasped and called significantly more than males receiving hCG only. Our results suggest that AVT and a female stimulus induce vocalizations in a male pipid anuran, X. tropicalis, and the interaction between gonadotropins and neurohormones influences reproductive behaviors in this anuran amphibian.

Petroleum-derived naphthenic acids disrupt hormone-dependent sexual behaviours in male Western clawed frogs

“…The four types of S. tropicalis calls were observed ( Fig. 1 ) and consistent with previous descriptions ( Miranda et al, 2015 ). However, in our animals, slow trills were very rare and not observed in most frogs.…”

“…The four types of male S. tropicalis calls previously reported ( Miranda et al , 2015 ) were all observed and further characterized ( Fig. 1 ).…”

The Influence of Behavioral, Social, and Environmental Factors on Reproducibility and Replicability in Aquatic Animal Models

“…The presence or absence of female X. tropicalis affects male vocalizations and is further influenced by the administration of hormones such as HCG or arginine vasotocin. For example, a social stimulus is necessary to illicit male vocalization, but hormonal manipulation influences both male vocalization and behavior [192]. Therefore, sensory and social stimuli, including odor, sound, the presence/absence of other animals, and colony hierarchy, should be considered when evaluating neuroendocrine system responses in this species.…”

Arginine Vasotocin, the Social Neuropeptide of Amphibians and Reptiles

“…Overall, studies have mainly addressed the influence of AVT on male frogs’ signaling, revealing that AVT favors the display of reproductive behaviors by promoting the emission of advertisement calls (Figure 3 ). Systemic AVT treatment induces three main changes in the vocal activity of male frogs, relative to control saline injections: (1) increased number of calls emitted per time unit (i.e., call rate), (2) increased likelihood to resume calling after experimental treatment (measured as the proportion of males that resumes calling after AVT injection), and (3) reduced latency to resume calling after disturbance or experimental manipulation ( 63 – 71 ). All three effects suggest that AVT increases the motivation to call.…”

“…Despite the behavioral similarities between frog and T. granulosa amplexus, differences have been found in AVT’s modulation of clasping behavior among these amphibians. While AVT strongly induces amplectic behavior in T. granulosa ( 45 ), experiments conducted with western clawed frogs ( Xenopus tropicalis ) and great plain toads [ Bufo (= Anaxyrus ) cognatus ] have failed to elicit amplexus through systemic AVT treatment ( 66 , 71 ). Still, the influence of AVT on frog amplectic behavior cannot be dismissed, as male X. tropicalis attempt to clasp females more often after being injected with a combination of human chorionic gonadotropin (hCG) plus AVT relative to frogs receiving hCG only ( 71 ).…”