Ecology and Evolution of the Pitcher‐plant Mosquito: 1. Population Dynamics and Laboratory Responses to Food and Population Density

Abstract

It is commonplace to emphasize that ecological and evolutionary processes are related and ought to be studied together, but analyses of natural populations which unravel the interrelations of historical evolutionary factors, current population processes, and the prevailing effects of natural selection are not common. This is the direction of our studies of the pitcher-plant mosquito, Wyeomyia smithii. In this paper we present: the natural history and population dynamics of this species in a single bog; an experiment to determine if the larval part of the population saturates its resources at a critical time preceding metamorphosis; and studies of laboratory responses of the species to food and population density.The field data show that larval abundance is more tightly regulated (i.e., steadier) than the abundance of other parts of the life cycle. Our laboratory data show how the components of fitness are influenced by different food levels and larval density. Central in these studies is completion of the life cycle. We are trying to understand the factors which encourage or discourage completion of the life cycle and influence the average fitness of individuals under different ecological circumstances.Study of W. smithii was undertaken for a variety of conceptual and practical reasons. The ecological and evolutionary consequences of a complex life cycle (two or more distinct ecological stages) are of some interest (Istock, 1967(Istock, , 1970. The species

Inter- and Intra-Specific Density-Dependent Effects on Life History and Development Strategies of Larval Mosquitoes

“…Furthermore, this response was sex-specific, consistent with other studies [9], [16], [19], [44], [56]–[58]. In both species of this study, male and female emergence overlapped considerably, with males generally preceding females by 1–2 days.…”

Abundance of Pitcher-Plant Mosquitoes, Wyeomyia smithii (Coq.) (Diptera: Culicidae) and Midges, Metriocnemus knabi Coq. (Diptera: Chironomidae), in Relation to Pitcher Characteristics of Sarracenia purpurea L.

“…(Istock et al, 1975;Fish and Hall, 1978;Mogi and Mokry, 1980;Bradshaw, 1983). Younger, larger pitchers with little organic matter had more mosquitoes.…”

“…and a midge (Metriocnemus knabi Coq.) Mosquitoes prefer younger pitchers; however, midges do not appear to distinguish among pitchers of different ages (Istock et al, 1975;Fish and Hall, 1978;Mogi and Mokry, 1980;Bradshaw, 1983). The female of both insect species oviposits on the surface of the water in the pitcher (Price, 1958;Wiens, 1972) or on the inner side of a newly opened pitcher (Fish and Hall, 1978;Mogi and Mokry, 1980).…”

“…commonly inhabit the aquatic environment in pitchers of the northern pitcher plant (Sarracenia purpurea L. ). Larval development and pupation may be greatly affected by environmental conditions in the pitcher (e.g., Istock et al, 1975;Lounibos et al, 1982;Paterson and Cameron, 1982;Farkas andBrust, 1985, 1986), which are determined partially by pitcher characteristics. Why a female chooses a particular pitcher for oviposition is not well understood.…”

Eryngium (Apiaceae) phytotelmata and their macro-invertebrate communities, including a review and bibliography

“…Habitat selection has been observed in phytotelminhabiting mosquitoes (e.g., Istock et al, 1975;Lounibos, 1978), but the mechanism of host-plant specificity for most of the phytotelmata is little known. However, it is known that the fauna inhabiting phytotelmata with high turnover rate exhibit greater habitat specificity than those inhabiting phytotelmata with low turnover rate (Fish, 1983).…”