A model for the development of Aedes (Stegomyia) aegypti as a function of the available food.

ROMEO AZNAR, V; M S DE MAJO; S FISCHER; D FRANCISCO; M A NATIELLO; H G SOLARI

JOURNAL OF THEORETICAL BIOLOGY

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2015 vol. 365 p. 311 - 324

0022-5193

We discuss the preimaginal development of the mosquito Aedes aegypti from the point of view of thestatistics of developmental times and the final body-size of the pupae and adults. We begin thediscussion studying existing models in relation to published data for the mosquito. The data suggest adevelopmental process that is described by exponentially distributed random times. The existing datashow as well that the idea of cohorts emerging synchronously is verified only in optimal situationscreated at the laboratory but it is not verified in field experiments. We propose a model in whichimmature individuals progress in successive stages, all of them with exponentially distributed times,according to two different rates (one food-dependent and the other food-independent). This phenom-enological model, coupled with a general model for growing, can explain the existing observations andnew results produced in this work. The emerging picture is that the development of the larvae proceedsthrough a sequence of steps. Some of the steps depend on the available food. While food is in abundance,all steps can be thought as having equal duration, but when food is scarce, those steps that depend onfood take considerably longer times. For insufficient levels of food, increase in larval mortality sets in.As a consequence of the smaller rates, the average pupation time increases and the cohort disperses intime. Dispersion, as measured by standard deviation, becomes a quadratic function of the average timeindicating that cohort dispersion responds to the same causes than delays in pupation and adultemergence. During the whole developmental process the larva grows monotonically, initially at anexponential rate but later at decreasing rates, approaching a final body-size. Growth is stopped bymaturation when it is already slow. As a consequence of this process, there is a slight bias favoring smallindividuals: Small individuals are born before larger individuals, although the tendency is very weak.