Influence of 6-methoxybenzoxazolinone and green vegetation on reproduction of the multimammate rat Mastomys coucha

Abstract

The cyclic carbamate 6-methoxybenzoxazolinone (6-MBOA), which occurs naturally in fresh green vegetation, has been shown to initiate reproductive activity in a number of rodent species, mainly American. This phenomenon is of ecological interest, since reproductive triggers are important in ensuring that breeding effort coincides with an adequate food supply, to ensure good offspring survival. 6-MBOA in green vegetation offers an alternative reproductive trigger when other cues, such as changes in day length, are either absent or correlate poorly with vegetation flushes. This paper reports the results of attempts to demonstrate in the laboratory the presence of a reproductive response to dietary supplements of 6-MBOA or green vegetation in an Old World tropical rodent, the multimammate rat Mastomys coucha. A close relative of M. coucha, M. natalensis, has been observed to be capable of rapid colonization of habitats recovering from the effects of fire and drought, which suggests that these species might be likely to show a reproductive response to 6-MBOA or fresh vegetation. Male rodents showed no response, but both 6-MBOA and fresh green vegetation had a marked stimulatory effect on the ovaries of female animals. Daar is al bewys dat die sikliese karbamaat 6-metoksibensoksasolinoon (6-MBOA), wat natuurlik in vars groen plante voorkom, voortplantingsaktiwiteit in verskeie (hoofsaaklik Amerikaanse) knaagdiere stimuleer. Hierdie verskynsel is van ekologiese belang omdat voortplantingskatalisators met die beskikbaarheid van 'n voldoende voedselbron moet ooreenstem om maksimum oorlewing van kleintjies te verseker. 6-MBOA in groen plante bied 'n alternatiewe voortplantingskatalisator wanneer ander stimulante, bv. verandering in daglengte, of afwesig is of nie met die aanvang van die groei van nuwe groen plantvoedsel ooreenstem nie. Proewe is op die Ouwereldse tropiese knaagdier, Mastomys coucha, gedoen om voortplantingsreaksie op die byvoeging van 6-MBOA in die dieet, of op die voorsiening van groen plantvoedsel, te demonstreer. Daar is bevind dat M. natalensis, wat taksonomies nou verwant is aan M. coucha, habitatte wat van brande of droogte herstel, vinnig herkoloniseer, wat daarop dui dat die aanvang van voortplanting in hierdie twee spesies wel deur of 6-MBOA of groen plante gestimuleer word. Manlike M. coucha het glad nie op die proewe gereageer nie. Beide 6-MBOA en vars groen plante het egter 'n merkbare stimulerende effek op die eierstokke van wyfies gehad.