Photoperiodic diapause in a subtropical population of Aedes albopictus in Guangzhou, China: optimized field-laboratory-based study and statistical models for comprehensive characterization

Abstract

BackgroundAedes albopictus is among the 100 most invasive species worldwide and poses a major risk to public health. Photoperiodic diapause provides a crucial ecological basis for the adaptation of this species to adverse environments. Ae. albopictus is the vital vector transmitting dengue virus in Guangzhou, but its diapause activities herein remain obscure.MethodsIn the laboratory, yeast powder and food slurry were compared for a proper diapause determination method, and the critical photoperiod (CPP) was tested at illumination times of 11, 11.5, 12, 12.5, 13, and 13.5 h. A 4-parameter logistic (4PL) regression model was selected to estimate the CPP. In the field, the seasonal dynamics of the Ae. albopictus population, egg diapause, and hatching of overwintering eggs were investigated monthly, weekly, and daily, respectively. A distributed lag non-linear model (DLNM) was used to assess the associations of diapause with meteorological factors.ResultsIn the laboratory, both the wild population and the Foshan strain of Ae. albopictus were induced to diapause at an incidence greater than 80%, and no significant difference (P > 0.1) was observed between the two methods for identifying diapause. The CPP of this population was estimated to be 12.312 h of light. In the field, all of the indexes of the wild population were at the lowest levels from December to February, and the Route Index was the first to increase in March. Diapause incidence displayed pronounced seasonal dynamics. It was estimated that the day lengths of 12.111 h at week2016, 43 and 12.373 h at week2017, 41 contributed to diapause in 50% of the eggs. Day length was estimated to be the main meteorological factor related to diapause.ConclusionsPhotoperiodic diapause of Ae. albopictus in Guangzhou of China was confirmed and comprehensively elucidated in both the laboratory and the field. Diapause eggs are the main form for overwintering and begin to hatch in large quantities in March in Guangzhou. Furthermore, this study also established an optimized investigation system and statistical models for the study of Ae. albopictus diapause. These findings will contribute to the prevention and control of Ae. albopictus and mosquito-borne diseases.Electronic supplementary materialThe online version of this article (10.1186/s40249-018-0466-8) contains supplementary material, which is available to authorized users.

Altitudinal variations in wing morphology of Aedes albopictus (Diptera, Culicidae) in Albania, the region where it was first recorded in Europe

“…albopictus uses diapause at the egg stage to survive the low temperatures in winter and delay reproduction until favorable climatic conditions arrive. As a key environmental signal, the shortening of days will cause females to lay diapause-programmed eggs (halted development, reduced metabolism, and increased resistance) [46]. It is therefore likely that climatic conditions, at the end and beginning of diapause, might also have played a role in the phenotypic differentiation observed in adults in our study.…”

Semi-field life-table studies of Aedes albopictus (Diptera: Culicidae) in Guangzhou, China

“…The low egg-hatching rate in the winter might be attributable to the overwintering of Ae. albopictus eggs or potential diapause [45,46]. Xia et al found that eggs collected from the field in Guangzhou may enter diapause when the photoperiod was about 12 h [45].…”

Population genomics of two invasive mosquitoes (Aedes aegypti and Aedes albopictus) from the Indo-Pacific

“…The most common source of Ae. albopictus incursions was southern China, where diapause has been observed in field populations [72]. Many other factors may also influence long-distance dispersal outcomes, such as differences in behaviour when boarding and travelling on vessels and the relative abundance of each species around airports and seaports.…”