Spatial and temporal distribution, environmental drivers and community structure of mosquitoes in the Kaipara Harbour, New Zealand.

Mosquito communities across the globe frequently comprise a mix of native and cosmopolitan species. New Zealand's mosquito communities are no exception. Here we describe the abundance, distribution and phenological patterns for a community of six mosquito taxa resident across the Kaipara Harbour region of northern New Zealand. Adult mosquitoes were sampled using baited light traps, serviced biweekly for 3½ years. Seasonal fluctuations in abundance of adults were examined for correlations with temperature and rainfall over the preceding weeks. Four endemic species comprised over 98% of the total catch, with Coquillettidia iracunda being the most abundant. Two introduced species, Aedes notoscriptus and Culex quinquefasciatus were widely distributed, but each comprised <1% of the total catch. Culiseta tonnoiri was the only species that appeared geographically restricted, occurring at one-third of the sites. Distinct temporal peaks in adult abundance were evident: Aedes antipodeus was most abundant in spring, Ae. notoscriptus and Cq. iracunda were most abundant in summer and Cx. quinquefasciatus was most abundant in autumn. Culiseta tonnoiri and Culex pervigilans were of variable abundance throughout the year. For all species examined, temporal variations in abundance were more strongly associated with temperature in the preceding weeks than with preceding rainfall. A better knowledge of the factors driving patterns of spatial and temporal abundance will allow an improved understanding of how non-native species may integrate themselves into resident mosquito communities.

A serological survey of cattle in the Thames - Coromandel district of New Zealand for antibodies to Ross River virus.

AIM: To determine if cattle exposed to the southern saltmarsh mosquito (SSM), Aedes camptorhynchus, in the Thames-Coromandel district of New Zealand had been exposed to Ross River virus (RRV). METHODS: A purposive sampling design was used to test cattle from seven farms located in close proximity to four sites infested with A. camptorhynchus in the Thames-Coromandel district. Sera from 207 cattle were tested for antibodies to RRV, using an ELISA and confirmatory virus neutralisation test (VNT) as the gold standard. RESULTS: All 207 cattle tested negative for antibodies to RRV using the ELISA and VNT. CONCLUSIONS: This study found no evidence of exposure to RRV in cattle in locations in the Thames-Coromandel district of New Zealand where populations of SSM were present.