Pest Management Science (2012) 68, 378-385

Jens Jacob, Stefan Endepols, Hans-Joachim Pelz, Engelbert Kampling, Trevor G. Cooper, Ching Hei Yeung, Klaus Redmann and Stefan Schlatt (2012)
Vitamin K requirement and reproduction in bromadiolone-resistant Norway rats
Pest Management Science 68 (3), 378-385
Abstract: BACKGROUND:
Nucleotide polymorphisms in the VKORC1 gene can be linked to anticoagulant rodenticide resistance in Norway rats (Rattus norvegicus Berkenhout). This provides a fitness advantage to rats exposed to anticoagulant actives, but may also cause fitness costs. The vitamin K requirement and reproductive parameters of bromadiolone-resistant rats (Westphalian resistant strain; VKOR variant Tyr139Cys) and bromadiolone-susceptible Norway rats were compared.
RESULTS:
At vitamin K deficiency, blood clotting times increased in all homozygous resistant males within 8 days and in 80% of homozygous resistant females within 15 days. There was little effect on blood clotting in heterozygous males and no effect in heterozygous females and VKOR wild-type individuals. Litter size was about 20% higher in sensitive pairs compared with resistant pairs. Testes growth, male gonad weight, sperm motility and testis cell concentration were unaffected by the mutation.
CONCLUSIONS:
The VKOR variant Tyr139Cys causes considerable physiological cost in Norway rats in terms of vitamin K requirement and reproduction. This may affect the distribution and spread of resistant individuals in the wild. Decreased litter size of resistant parents seems to be due to lowered female reproductive performance, as there was no significant effect of the mutation on any aspects of male reproduction considered, but this requires further study.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Jens Jacob, Hans-Joachim Pelz

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Rattus norvegicus