The performance of the Napoleon weaver, the Orange weaver, and the Paradise Whydah in the weaver finch test for luteinizing hormones

Abstract

The performance of three species of African weaver birds in the weaver finch test for hypophysial and nonhypophysial luteinizing hormones (LH and HCG) has been studied. The determinants and modifiers of the sensitivity of these birds for luteinizing hormones are poorly understood, but may include genetic, dietary, and environmental factors, as well as the biologic factor and the commercial source of the hormone being investigated. Accordingly, it would seem to indicate that levels of sensitivity should be formulated with reference to the shipment of birds studied and the totality of experimental conditions under which the tests were made. Available evidence suggests that the threshold (a minimum response shown by 50% of test animals) of the Napoleon weaver is between 0.04 and 0.10 mg of bovine LH and slightly less than 0.04 mg of ovine LH, whereas between 0.1 and 0.2 mg bovine LH and between 0.2 and 1.0 mg of ovine LH is required in the Orange weaver. The approximate threshold for HCG is 25 IU in the Napoleon whereas between 125 and 250 IU are required in the Orange weaver. Present experience has been with Paradise Whydah birds collected in Senegal; these birds gave 5% positive responses in 40 trials with doses of LH or HCG at or above the reported threshold values. A positive response was obtained with 0.2 mg of bovine LH in a female bird. No positive responses were elicited with HCG. At no time have we approached the sensitivity level of 0.005 mg of LH reported to exist for the Napoleon weaver and the Paradise Whydah. However, we have confirmed that the Napoleon weaver can detect 30 IU of HCG.