Predation risk effects on larval development and adult life of Aedes aegypti mosquito

Abstract

Biological control is one of the methods available for control of Aedes aegypti populations. We used experimental microcosms to evaluate the effects of actual predation and predation risk by dragonfly larvae (Odonata) on larval development, adult longevity, and adult size of Ae. aegypti. We used six treatments: control, removal, variable density cues (Cues VD), fixed density cues (Cues FD), variable density predator (Predator VD), and fixed density predator (Predator FD) (n = 5 each). Predator treatments received one dragonfly larva. Cue treatments were composed of crushed Ae. aegypti larvae released into the microcosm. For the FD treatments, we maintained a larval density of 200 individuals. The average mortality of Ae. aegypti larvae in the Predator VD treatment was used as the standard mortality for the other treatments. Mosquitoes from the Predator VD and Cues VD treatments developed faster, and adults were larger and had greater longevity compared to all other treatments, likely due to the higher food availability from larval density reduction. High larval density negatively affected larval developmental time, adult size, and longevity. Males were less sensitive to density-dependent effects. Results from this study suggest that the presence of predators may lead to the emergence of adult mosquitoes with greater fitness, causing an overall positive effect on Ae. aegypti population growth rates.

Predators’ size influences life history traits of Aedes aegypti

“…For food solution preparation, Spirulina was weighted using an analytical balance (Bel Engenharia SKU M -0.0001g) and then mixed in distilled water for 3 min. The amount of larval food was based on Cozzer et al (2022). Each microcosm had a plastic cage of 3.5 cm diameter positioned in the upper area.…”

“…In this way, special attention has been given to the lethal effects of prey capture and consumption by predators (Preisser et al 2005; Bellamy and Alto 2018). In this densitymediated interaction (DMI) model, the predator releases the negative pressure from prey density by killing and consuming individuals (Bellamy and Alto 2018; Cozzer et al 2022).…”

“…On the other hand, only the predator's presence or its cues, such as feces, urine, slaughtered prey, and kairomones (Pessarrodona et al 2019), can lead to non-lethal effects on prey once it may adopt strategies to avoid predation (Preisser and Bolnick 2008;Preisser et al 2009;Cozzer et al 2022). In this trait-mediated interaction (TMI), the predator presence may cause negative effects on prey populations, such as: i) decrease on foraging activity (Wood et al 2018); ii) changes in reproductive physiology (Creel et al 2007); iii) increase on the starvation risk (Preisser and Bolnick 2008;Preisser et al 2009), and iv) alter the asymmetry of the wings, through stress exerted during the developmental phase (Gutiérrez-…”

“…Also, injured conspeci cs and exudates (e.g., feces and exuvia) released by a large-bodied predator may increase the basis for bacterial development by enriching the microcosms and with food sources for Ae. aegypti larvae (Albeny-Simões et al 2014;Cozzer et al 2022). Therefore, the enriched environment increases the food resource availability and decreases the predation risk by reducing the need for foraging travels in presence of large-bodied predators(Lane et al 2002).The predator presence resulted in an average decrease in Ae.…”

Predatory efficiency of dragonfly nymphs, Crocothemis servilia and Rhyothemis variegata against the mosquito, Culex quinquefasciatus Say

“…Despite this, the presence of other prey does not negatively affect the role of predators in controlling the population of mosquito larvae (Stav et al, 2005). Some aquatic bugs (Saha et al, 2007;Valbon et al, 2018Valbon et al, , 2019, larvivorous fishes (Das et al, 2018;Riaz et al, 2018), diving beetles (Choo et al, 2021;Lundkvist et al, 2003), and odonate nymphs (Córdoba-Aguilar et al, 2021;Cozzer et al, 2022;Samanmali et al, 2018) are among the natural predators that can help control the population of mosquito larvae. Odonate nymphs are voracious predators that use unique protractible labium to grab their prey, which includes mosquito larvae, various smaller aquatic invertebrates, and even larvae of fish and amphibians (Zia et al, 2011).…”