No association between habitat, autogeny and genetics in Moroccan Culex pipiens populations

Abstract

Background Mosquitoes of the Culex pipiens complex are found across the globe and are the focus of many research studies. Among the temperate species C. pipiens sensu stricto (s.s.), two forms are usually described: molestus and pipiens. These two forms are indistinguishable in terms of morphology but show behavioral and physiological differences that may have consequences for their associated epidemiology. The two forms are well defined in the northern part of the species distribution, where autogeny is strictly associated with the molestus form. However, whether the two remain distinct and show the characteristic differences in behavior is less clear in North Africa, at the southern edge of their range. Methods The association between autogeny, as determined by ovarian dissection, and molecular forms, based on the CQ11 microsatellite marker, was studied in six Moroccan populations of C. pipiens. Results An overall low prevalence of autogeny was found at three of the Moroccan regions studied, although it reached 17.5% in the Agadir population. The prevalence of form-specific CQ11 alleles was quite similar across all populations, with the molestus allele being rarer (approx. 15%), except in the Agadir population where it reached 43.3%. We found significant deficits in heterozygotes at the diagnostic CQ11 locus in three populations, but the three other populations showed no significant departure from panmixia, which is in line with the results of a retrospective analysis of the published data. More importantly, we found no association between the autogeny status and CQ11 genotypes, despite the many females analyzed. Conclusions There was limited evidence for two discrete forms in Morocco, where individuals carrying pipiens and molestus alleles breed and mate in the same sites and are equally likely to be capable of autogeny. These observations are discussed in the epidemiological context of Morocco, where C. pipiens is the main vector of several arboviruses. Graphical Abstract

Autogenous reproduction by Ornithodoros turicata (Ixodida: Argasidae) females and vertical transmission of the tick-borne pathogen Borrelia turicatae (Spirochaetales: Borreliaceae )

“…Facultative autogeny in the first gonotrophic cycle has been reported at variable rates in species currently classified in the genera Ornithodoros , Argas , and Carios ( 8 , 10 , 12 , 14 ). Interestingly, in other arthropods like mosquitoes, autogeny varies extensively between conspecific populations across distribution ranges ( 15 ). While studies suggest that genetic and environmental factors (e.g., temperature) modulate autogeny in soft ticks ( 11 ), additional work is needed in O. turicata to identify its frequency between geographically distinct populations.…”

Vertical transmission ofBorrelia turicatae(Spirochaetales:Borreliaceae) by autogenously reproducingOrnithodoros turicata(Ixodida: Argasidae) female naturally infected with the spirochetes

“…Facultative autogeny in the first gonotrophic cycle has been reported at variable rates in species currently classified in the genera Ornithodoros, Argas, and Carios (8,10,12,14). Interestingly, in other arthropods like mosquitoes autogeny varies extensively between conspecific populations across distribution ranges (15). While studies suggest that genetic and environmental factors (e.g.…”