Population regulation of a mosquito Armigeres theobaldi with description of the animal fauna in zingiberaceous inflorescences

Abstract

Summary Inflorescences of some Curcuma and Zingiber (Zingiberaceae) in tropical Asia provide an unique aquatic habitat being discrete, small, and made of numerous smaller compartments (the bracts). The aquatic community in inflorescences of Curcuma in northern Thailand was composed of immature Diptera, of which the biting midge Dasyhelea and the mosquito Armigeres theobaldi were the commonest. No important competitors, predators or pathogenic parasites for the mosquito were confirmed. Inter‐inflorescence distribution of the mosquito was contagious. Within each inflorescence, the fourth‐instar larvae or pupae usually occupied bracts singly. The k‐value analysis detected density‐dependent mortality due to contest competition in the mosquito larvae. Variations in the larval and pupal mosquito size were density‐independent and remarkably small as compared with size variations known for other mosquitoes. These population attributes (large density‐dependent mortality with density‐independent, minimally variable individual size) appear unique among mosquitoes, arising from conspecific killing, efficient foraging (inter‐bract movement by crawl and single occupation of bracts), and availability of host plant tissues as supplementary food. A simple population model suggested that a small proportion of adult females lay eggs.