Development time and fitness: is there an adaptive development delay in the Rhodnius prolixus fifth nymphal stage?
2017
Aldana, Elis | Medone, Paula | Pineda, Daniela | Menu, Frédéric | Rabinovich, Jorge
Triatomines (Hemiptera: Reduviidae) are vectors of Trypanosoma cruzi Chagas, the etiological agent of Chagas's disease. They display pre‐adult development delay – that is, a development time much longer than on average – which usually has been considered as a maladaptive trait. However, this hypothesis has not been tested. We carried out an experiment under controlled laboratory conditions to (1) test whether a development delay exists in the fifth nymphal stage of Rhodnius prolixus Stål (Hemiptera: Reduviidae, Rhodniini), and (2) measure any fitness cost related to such delay by estimating the relationship between individual development time and other life‐history traits. We analyzed the development time with various continuous statistical distributions (normal, log‐normal, Weibull, gamma, Pareto, Burr, and log‐logistic). Using goodness‐of‐fit tests, the best fit was obtained with asymmetrical distributions, with the Burr distribution showing the best fit to the data. We concluded that a development delay exists in stage five of R. prolixus without fitness cost. The combination of our results and previous work suggests that such a delay could be viewed as an adaptive response to environmental stochasticity and/or density‐dependence rather than as a maladaptive trait. We propose further investigations to provide a conclusive test of adaptive delay in triatomines.
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