Improving estimations of life history parameters of small animals in mesocosm experiments: A case study on mosquitoes

We used an experimental setup with 48 aquatic mesocosms, each with twenty first instar mosquito (Culex pipiens) larvae and under one of twelve treatments with varying temperatures and nutrient concentrations. We took daily subsamples of the aquatic life stages as well as counting the emerging adults. We developed a method to estimate the survival and development probabilities at each life stage, based on optimising a matrix population model. We used two different approaches, one calculating the difference between predictions and observations based on a normal distribution, and the other using a combination of a normal and a multinomial distribution. For each approach, the resulting optimisation problem had around 100 parameters, making conventional gradient descent ineffective with our limited number of data points. We solved this by computing the formal derivatives of our matrix model.