Mosquitoes were collected from parks using various traps and/or aspirated from culverts in Franklin County, Ohio, from October to mid-May from 2019 to 2022.
By early October 2021, roughly 95% of
We collected blood-fed and gravid
- Award ID(s):
- 1944214
- PAR ID:
- 10525547
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Insect Molecular Biology
- ISSN:
- 0962-1075
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Background Culex mosquitoes are the primary vectors of West Nile virus (WNV) across the USA. Understanding when these vectors are active indicates times when WNV transmission can occur. This study determined the proportion of femaleCulex mosquitoes that were in diapause during the fall and winter and when they terminated diapause and began blood feeding in the spring.Methods Culex mosquitoes were morphologically identified to species, and the ovaries of females were dissected to determine their diapause and parity statuses.Results Culex pipiens collected in culverts were in diapause and 98% ofCx. erraticus were in diapause. Furthermore, gravid and blood-fedCulex salinarius ,Cx. pipiens , andCx. restuans were collected in late November in 2019 and 2021 in standard mosquito traps. In the winter of 2021, the proportions of non-diapausingCulex decreased within culverts. The last non-diapausingCx. erraticus was collected in late December 2021 while the final non-diapausingCx. pipiens was collected in mid-January 2022, both in culverts. Roughly 50% ofCx. pipiens terminated diapause by mid-March 2022, further supported by our collections of gravid females in late March in all 3 years of mosquito collection. In fact, male mosquitoes ofCx. pipiens ,Cx. restuans , andCx. territans were collected by the 1st week of May in 2022, indicating that multiple species ofCulex produced a second generation that reached adulthood by this time.Conclusions Culex females into late November in 2 of the 3 years of our collections, indicating that it might be possible for WNV transmission to occur in late fall in temperate climates like Ohio. The persistence of non-diapausingCx. pipiens andCx. erraticus throughout December has important implications for the winter survival of WNV vectors and our overall understanding of diapause. Finally, determining whenCulex terminate diapause in the spring may allow us to optimize mosquito management programs and reduce the spread of WNV before it is transmitted to humans.Graphical Abstract -
Females of the Northern house mosquito, Culex pipiens, enter an overwintering dormancy, or diapause, in response to short day lengths and low environmental temperatures. Diapausing female mosquitoes feed exclusively on sugar-rich products rather than human or animal blood, thereby reducing disease transmission. During diapause, Major Royal Jelly Protein 1 (MRJP1) is upregulated in females of Cx. pipiens. This protein is highly abundant in royal jelly, a substance produced by honey bees (Apis mellifera), that is fed to future queens throughout larval development and stimulates longevity and fecundity. However, the role of MRJP1 in Cx. pipiens is unknown. We investigated how supplementing the diets of both diapausing and nondiapausing females of Cx. pipiens with royal jelly affects gene expression, egg follicle length, fat content, protein content, longevity, and metabolic profile. We found that feeding royal jelly to long day-reared females significantly reduced the egg follicle lengths of females and switched their metabolic profiles to be similar to diapausing females. In contrast, feeding royal jelly to short day-reared females significantly reduced lifespan and switched their metabolic profile to be similar nondiapausing mosquitoes. Moreover, RNAi directed against MRJPI significantly increased egg follicle length of short day-reared females, suggesting that these females averted diapause, although RNAi against MRJP1 also extended the lifespan of short day-reared females. Taken together, our data show that consuming royal jelly reverses the seasonal responses of Cx. pipiens and that these responses are likely mediated in part by MRJP1.more » « less
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Consuming royal jelly alters several phenotypes associated with overwintering dormancy in mosquitoesmore » « less
Introduction Females of the Northern house mosquito,
Culex pipiens , enter an overwintering dormancy, or diapause, in response to short day lengths and low environmental temperatures that is characterized by small egg follicles and high starvation resistance. During diapause,Culex pipiens Major Royal Jelly Protein 1 ortholog (CpMRJP1) is upregulated in females ofCx. pipiens . This protein is highly abundant in royal jelly, a substance produced by honey bees (Apis mellifera ), that is fed to future queens throughout larval development and induces the queen phenotype (e.g., high reproductive activity and longer lifespan). However, the role of CpMRJP1 inCx. pipiens is unknown.Methods We first conducted a phylogenetic analysis to determine how the sequence of CpMRJP1 compares with other species. We then investigated how supplementing the diets of both diapausing and nondiapausing females of
Cx. pipiens with royal jelly affects egg follicle length, fat content, protein content, starvation resistance, and metabolic profile.Results We found that feeding royal jelly to females reared in long-day, diapause-averting conditions significantly reduced the egg follicle lengths and switched their metabolic profiles to be similar to diapausing females. In contrast, feeding royal jelly to females reared in short-day, diapause-inducing conditions significantly reduced lifespan and switched their metabolic profile to be similar nondiapausing mosquitoes. Moreover, RNAi directed against
CpMRJPI significantly increased egg follicle length of short-day reared females, suggesting that these females averted diapause.Discussion Taken together, our data show that consuming royal jelly reverses several key seasonal phenotypes of
Cx. pipiens and that these responses are likely mediated in part by CpMRJP1. -
The Northern house mosquito (Culex pipiens) is a major vector of West Nile virus. To survive harsh conditions in winter adult females of Cx. pipiens enter a state of arrested reproductive development called diapause. Diapause is triggered by the short daylengths of late summer and early fall. The methods by which Cx. pipiens measures daylength are still unknown. However, it is suspected that clock genes, which provide information on daylength, may also regulate diapause. The proteins produced by these genes often cycle in abundance throughout the day in diapausing and nondiapausing insects. Two clock genes suspected to control diapause are cycle (cyc) and Par domain protein1 (Pdp1) as they encode circadian transcription factors that may regulate genes that are involved in diapause. Using Western blotting we measured the relative protein abundance of CYC and PDP1 throughout the day in the whole bodies and the heads of Cx. pipiens reared under either long-day, diapause-averting conditions or short-day, diapause-inducing conditions. We found that in whole bodies there was no significant oscillation of CYC or PDP1 abundance in both long day and short day-reared mosquitoes. In the heads of long day-reared mosquitoes both CYC and PDP1 cycled. In contrast, only PDP1 abundance showed diel differences in abundance in the heads of short day-reared mosquitoes. These data bring us one step closer to understanding the role that CYC and PDP1 may play in regulating diapause and other biological processes.more » « less
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Abstract In diapausing mosquitoes, cold tolerance and prolonged lifespan are important features that are crucial for overwintering success. In the mosquito Culex pipiens, we suggest that PDZ domain-containing protein (PDZ) (post synaptic density protein [PSD95], drosophila disc large tumor suppressor [Dlg1], and zonula occludens-1 protein [zo-1]) domain-containing protein is involved with these diapause features for overwintering survival in Culex mosquitoes. The expression level of pdz was significantly higher in diapausing adult females in the early stage in comparison to their nondiapausing counterparts. Suppression of the gene that encodes PDZ by RNA interference significantly decreased actin accumulation in the midgut of early-stage adult diapausing females. Inhibition of pdz also significantly reduced the survivability of diapausing females which indicates that this protein could play a key role in preserving the midgut tissues during early diapause.
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1111/imb.12871
