Narrow Results

In this paper, we extend the famous Ross's model to establish a new model for malaria to incorporate the impact of blood meal resources for mosquitoes and temperature on the transmission of malaria. A dynamical analysis for the new model is provided and it is shown that with the new growth rate for mosquitoes, the transmission dynamics of malaria becomes more complex and the Hopf bifurcation may occur which induces sustained oscillations not only in the mosquito population but also in the infected human population. Our results suggest that the abundance of blood meal resource for mosquitoes can be a factor which is important to characterize the transmission dynamics of malaria in a region. The impact of maturation time delay related to temperature changes is also analyzed which suggests that increasing the temperature exacerbates the transmission of malaria.

The sterile insect technique (SIT) is a biological control technique that can be used either to eliminate or decay a wild mosquito population under a given threshold to reduce the nuisance or the epidemiological risk. In this work, we propose a model using a differential system that takes into account the variations of rainfall and temperature over time and study their impacts on sterile males’ releases strategies. Our model is as simple as possible to avoid complexity while being able to capture the temporal variations of an Aedes albopictus mosquito population in a domain treated by SIT, located in Réunion island. The main objective is to determine what period of the year is the most suitable to start a SIT control to minimize the duration of massive releases and the number of sterile males to release, either to reduce the mosquito nuisance, or to reduce the epidemiological risk. Since sterilization is not $100\%$ efficient, we also study the impact of different levels of residual fertility within the released sterile males population. Our study shows that rainfall plays a major role in the dynamics of the mosquito and the SIT control, that the best period to start a massive SIT treatment lasts from July to December, that residual fertility has to be as small as possible, at least for nuisance reduction. Indeed, when the main objective is to reduce the epidemiological risk, we show that residual fertility is not necessarily an issue. Increasing the size of the releases is not always interesting. We also highlight the importance of combining SIT with mechanical control, i.e., the removal of breeding sites, in particular when the initial mosquito population is large. Last but not least our study shows the usefulness of the modeling approach to derive various simulations to anticipate issues and demand in terms of sterile insects’ production.

Growth of birds is described by a variety of mathematical equations. These equations generally lack a biological motivation. As a result, it remains unclear why growth in different species should be described by different equations. In this article, we argue that the gradual development of endothermy affects the growth of birds. Hence, differences in the growth curve may result from differences in the thermal ontogeny. We assume that birds would grow according to the von Bertalanffy growth equation, if their temperature were constant. Using the deviations from this growth curve, we reconstruct the time course of the temperature of growing birds. This reconstruction well describes data on the ontogeny of the body temperature in birds.