Pro-social effects of oxytocin and its homologues are well-documented in birds and mammals. However, in fishes, the effect of isotocin, the homologue of oxytocin, on social behaviour is less clear. Studies in fishes have generally shown no effect of isotocin on social behaviours or even an anti-social effect. In our study, we measured association preference for conspecifics in 92 adult guppies (46 females and 46 males), half of which were injected with isotocin and the other half with an isotocin antagonist. We found that individuals injected with isotocin spent 29% more time associating with conspecifics than individuals injected with an isotocin antagonist. The effect of isotocin on association time did not differ between males and females. Our study provides some of the first evidence of a pro-social effects of isotocin in a fish and suggests that in fishes, isotocin may have a homologous role to oxytocin, at least in promoting shoaling behaviour.

中文翻译：

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同位素对孔雀鱼（Poecilia reticulata）暗沙行为的影响。

催产素及其同系物的亲社会作用在鸟类和哺乳动物中有充分的文献记载。但是，在鱼类中，催产素同系物-同位素对社交行为的影响尚不清楚。对鱼类的研究通常显示，异氰酸酯对社会行为没有影响，甚至没有反社会影响。在我们的研究中，我们在92位成年孔雀鱼（46位女性和46位男性）中测量了同种异体的关联偏好，其中一半注射了异霉素，另一半注射了异拮抗剂。我们发现，注射同素素的个体与同种异体相关的时间要比注射同素素拮抗剂的个体多29％。雌激素对缔合时间的影响在男性和女性之间没有差异。