Occurrence of the white cochineal Parlatoria blanchardi in the fur of the black rat and potential risks for its spread to the date palm stands

The current study presents the first documented interaction between the date palm scale insect (Parlatoria blanchardi) and the black rats (Rattus rattus). For a year, this study investigated whether R. rattus could serve as a means of phoresy for the survival of P. blanchardi and the potential risks associated with its spread to date palm stands. Our research revealed a prevalence rate of P. blanchardi on R. rattus of 5.79% during the year, while a higher rate of 9.33% was observed during a specific five-month period. The mean infestation intensity was 3.39 parasites/rat during these five months. Statistical data revealed a highly significant difference in the distribution of the three age classes of P. blanchardi among the age categories of R. rattus (χ 2 = 62.067, df = 24, P = 3.244e-05). Furthermore, rat age classes differed significantly in their P. blanchardi infestation levels (χ 2 = 18.246, df = 3, P = < 0.001). The Negative Binomial Mixed Model showed a significant positive effect of temperature [(generalised linear mixed-effects models (GLMM): z (estimate/standard error) = 3.13, P < 0.01)] and sex (male) (GLMM: z = 2.22, P < 0.001) on insect abundance. These findings suggest that black rats may represent a previously unknown form of phoresy for the survival of the date palm scale insect, emphasising the need for further research to investigate this novel ecological interaction and its potential implications for pest management.