Desiccation tolerance as a function of age, sex, humidity and temperature in adults of the African malaria vectorsAnopheles arabiensisPatton andAnopheles funestusGiles

Abstract

Adult mosquito survival is strongly temperature and moisture dependent. Few studies have investigated the interacting effects of these variables on adult survival and how this differs among the sexes and with age, despite the importance of such information for population dynamic models. For these reasons, the desiccation tolerance of Anopheles arabiensis Patton and Anopheles funestus Giles males and females of three different ages was assessed under three combinations of temperature and humidity. Females were more desiccation tolerant than males, surviving for longer periods than males under all experimental conditions. In addition, younger adults were more tolerant of desiccation than older groups. Both species showed reduced water loss rate (WLR) as the primary mechanism by which they tolerate desiccation. Although A. arabiensis is often considered to be the more arid-adapted of the two species, it showed lower survival times and higher WLR than A. funestus. The current information could improve population dynamic models of these vectors, given that adult survival information for such models is relatively sparse.

Temperature and humidity acclimation increase desiccation resistance in the butterfly Bicyclus anynana

“…Temperature induces, for instance, plastic responses in growth and development, reproduction, and survival in this species (Fischer et al, 2010(Fischer et al, , 2014Klockmann et al, 2017). We further explore sex differences in desiccation resistance, predicting that females are the more desiccation-resistant sex as has been found in some other insects (Sassi & Hasson, 2013;Lyons et al, 2014). We further explore sex differences in desiccation resistance, predicting that females are the more desiccation-resistant sex as has been found in some other insects (Sassi & Hasson, 2013;Lyons et al, 2014).…”

“…Against this background, we here investigate plastic responses in the loss of body mass, used as a proxy for desiccation resistance, to variation in temperature and relative humidity, comprising two key extrinsic factors influencing survival (Lyons et al, 2014). We use the tropical butterfly Bicyclus anynana (Butler) (Lepidoptera: Nymphalidae), a species inhabiting a highly seasonal environment with alternating wet-warm and dry-cool seasons, such that it relies heavily on phenotypic plasticity to master associated challenges (Brakefield, 1997;Lyytinen et al, 2004).…”

Aquatic insects in a multistress environment: cross-tolerance to salinity and desiccation

“…The tubes were covered with Parafilm to maintain a low RH (10±5%) (e.g. Bazinet et al, 2010;Lyons et al, 2014). In the control, the open glass tubes were introduced into a 7 l plastic aquarium with deionized water in the base (approximately 2 cm) enclosed with plastic film, reaching RH levels close to saturation (i.e.…”

Time series analysis of malaria in Afghanistan: using ARIMA models to predict future trends in incidence

“…It has been proposed that variables like air temperature [14], rainfall [15], altitude [16], humidity [17], vegetation index [18], and even surface water fraction [19] increase predictive power of malaria models [20], not only for short periods, but also over longer timescales [21]. Tools used to measure the association between these factors and malaria patterns have included linear regression [22], Poisson regression [23], Spearman’s correlation [24], non-linear methods [25], and autoregressive time series methods [26].…”