Landscape and Environmental Factors Influencing Stage Persistence and Abundance of the Bamboo Mosquito, Tripteroides bambusa (Diptera: Culicidae), across an Altitudinal Gradient

The bamboo mosquito, Tripteroides bambusa (Yamada) (Diptera: Culicidae), is a common insect across East Asia. Several studies have looked at the ecology of Tr. bambusa developmental stages separately, but little is known about the factors associated with the persistence (how often) and abundance (how many individuals) of Tr. bambusa stages simultaneously studied across a heterogeneous landscape. Here, we ask what environmental and landscape factors are associated with the persistence and abundance of Tr. bambusa stages across the altitudinal gradient of Mt. Konpira, Nagasaki City, Japan. During a season-long study we counted 8065 (7297 4th instar larvae, 670 pupae and 98 adults) Tr. bambusa mosquitoes. We found that persistence and abundance patterns were not associated among stages, with the exception of large (4th instar) and small (1st to 3rd instars) larvae persistence, which were positively correlated. We also found that relative humidity was associated with the persistence of Tr. bambusa aquatic stages, being positively associated with large and small larvae, but negatively with pupae. Similarly, landscape aspect changed from positive to negative the sign of its association with Tr. bambusa pupae and adults, highlighting that environmental associations change with life stage. Meanwhile, Tr. bambusa abundance patterns were negatively impacted by more variable microenvironments, as measured by the negative impacts of kurtosis and standard deviation (SD) of environmental variables, indicating Tr. bambusa thrives in stable environments, suggesting this mosquito species has a finely grained response to environmental changes.

Density dependence in a seasonal time series of the bamboo mosquito,Tripteroides bambusa(Diptera: Culicidae)

The bamboo mosquito,Tripteroides bambusa(Yamada) (Diptera: Culicidae), is a mosquito species ubiquitous across forested landscapes in Japan. During 2014 we sampled adult mosquitoes from May to November using a sweep net in Nagasaki, Japan. We recorded and managed our field data using Open Data Kit, which eased the overall process of data management before performing their statistical analysis. Here, we analyse the resulting biweekly time series of the bamboo mosquito abundance using time-series statistical techniques. Specifically, we test for density dependence in the population dynamics fitting the Ricker model. Parameter estimates for the Ricker model suggest that the bamboo mosquito is under density dependence regulation and that its population dynamics is stable. Our data also suggest the bamboo mosquito increased its abundance when temperature was more variable at our study site. Further work is warranted to better understand the linkage between the observed density dependence in the adults and the larvae of this mosquito species.

Coelomomyces stegomyiae var. chapmani var.nov. with new host and locality records for Coelomomyces from mosquitoes of Taiwan

Coelomomyces stegomyiae var. chapmani var.nov. is described from Tripteroides bambusa, Topomyia yanbarensis, Aedes albopictus, and Armigeres subalbatus. Aedes malikuli may also be infected by C. stegomyiae; however, the fungal material could not be identified with certainty beyond the generic level. Coelomomyces quadrangulatus was present in Uranotaenia sp. (near recondita); Coelomomyces macleayae in T. bambusa, Aedes japonicus ssp. shintienensis, and Aedes alcasidi; and Coelomomyces omorii in Culex annulus. The C. omorii sporangia from Taiwan show intermediate characteristics in comparison with sporangia of the typical variety from Japan and "Coelomomyces dubitskii" from Kazakhstan, USSR. All host species records, except for A. albopictus, two host genera records (Tripteroides, Topomyia), and all locality records are new.