The effect of sex and time of year on the suite of semiochemicals secreted by the sternal gland of the tammar wallaby (Macropus eugenii: Marsupialia)

Thirty-two different compounds were detected in the sternal gland secretion of M. eugenii using GC and GC-MS following thermal desorption with cryofocusing. There were no major qualitative differences between the secretions collected from males and females. Compounds commonly present in the secretion included long-chain alkanes, C6-C10 aldehydes, the monoterpene ether 1,8-cineole (eucalyptol), fatty acids and acetic acid. There were no significant differences in the relative proportions of compounds in males related to time of year, unlike the situation in females where long-chain alkanes were major components of the secretion in the early part of the year while C6-C10 aldehydes dominated in the second half of the year. There was some evidence that the female secretion is affected by reproductive condition, as treatment of females with follicle stimulating hormone (FSH) then luteinising hormone (LH) in June altered the sternal secretion towards that found earlier in the year.