Selemani Mwajabu, Makundi Rhodes H, Massawe Apia W, Mhamphi Ginethon, Mulungu Loth S, Belmain Steven R
Department of Wildlife Management, Sokoine University of Agriculture, Morogoro, Tanzania.
Pest Management Centre, Sokoine University of Agriculture, Morogoro, Tanzania.
Integr Zool. 2022 Nov;17(6):991-1001. doi: 10.1111/1749-4877.12563. Epub 2021 Jun 12.
The black rat is considered one of the world's top pests. With increased restrictions on rodenticides, new alternatives to manage rats are urgently needed. Research on the use of contraceptive hormones, levonorgestrel (LE), and quinestrol (QU), have been evaluated against some rodent species, and this research is the first study to assess these on black rats. Hormones were incorporated into rodent bait at 10 and 50 ppm concentrations singly and in combination (EP-1). Groups of 10 animals of each sex were fed the baits over 7 days. Lower bait consumption was observed with slight body mass reductions. On dissection, it was observed that the uterus was in a state of edema and male reproductive organs weighed less with reduced sperm counts/motility. The 2 most promising baits, 50 ppm QU and EP-1, were used to assess impact on pregnancy and litter size. Pregnancy was reduced from 70% success when both males and females consumed untreated bait, down to 30% when males had consumed contraceptive bait but females had not, and down to 0% when females had consumed contraceptive bait, regardless of whether they had paired with a treated or untreated male. Litter size in the untreated pairs was 8 pups, but only 4 pups in those cases where the male only had consumed the contraceptive. Further studies should investigate how long the effect lasts and its reversibility. Field studies at the population level may also shed light on the practicality of using contraceptive baits for black rats in different habitats.
黑家鼠被认为是世界上最主要的害虫之一。随着对灭鼠剂的限制增多，迫切需要管理老鼠的新方法。关于使用避孕激素左炔诺孕酮（LE）和炔雌醚（QU）对一些啮齿动物物种进行的研究已经得到评估，而本研究是首次对黑家鼠进行此类评估。将激素以10 ppm和50 ppm的浓度单独及混合（EP - 1）掺入啮齿动物诱饵中。每组10只雌雄动物，连续7天投喂这些诱饵。观察到诱饵消耗量较低，体重略有减轻。解剖时发现，子宫处于水肿状态，雄性生殖器官重量减轻，精子数量/活力降低。两种最有前景的诱饵，即50 ppm的QU和EP - 1，被用于评估对怀孕和产仔数的影响。当雌雄都食用未处理的诱饵时，怀孕成功率为70%；当雄性食用了避孕诱饵而雌性未食用时，怀孕率降至30%；当雌性食用了避孕诱饵时，无论其与处理过或未处理过的雄性配对，怀孕率都降至0%。未处理组的产仔数为8只幼崽，但在雄性仅食用了避孕药的情况下，产仔数仅为4只幼崽。进一步的研究应调查这种影响持续多长时间及其可逆性。在种群水平上的实地研究也可能有助于了解在不同栖息地对黑家鼠使用避孕诱饵的实用性。
