Top‐down effects on aquatic communities in subtropical lentic microhabitats

Abstract

Natural lentic microhabitats are important for aquatic invertebrate communities in subtropical aquatic systems, which are usually dominated by mosquitoes, predators and zooplankton. Subtropical lentic microhabitats might be strongly affected by top-down effects of predators. We evaluated the predator effects on aquatic macroinvertebrate and zooplankton communities by using black plastic buckets (10 L) to simulate lentic microhabitats, which were divided into four treatments: predator absence and presence, and initial (on experiment start) and final (on experiment end) community controls. Large top predators (Odonata) had a stronger effect on community structure by their sit-and-wait predatory behaviour. The richness of total macroinvertebrates, Culex genus (most abundant organism), and zooplankton was highest in predators' absence. On the other hand, the sit-and-wait behaviour increased the density of organisms by selective predation on macroinvertebrates that feed in the bottom of the system. Also, the sit-and-wait behaviour increased the density of gathering and filtering collectors (top swimmers) by differences in space preference. We observed a positive species-specific relationship between Culex and predators. We concluded that predators' presence contributes to the balance of lentic microhabitat in subtropical lentic microhabitats by top-down control.

Predators’ size influences life history traits of Aedes aegypti

“…Therefore, there is an increasing risk of improper garbage disposal (e.g., tires, cups, and bottles, and/or natural reservoirs such as tree hollows) which during the rainy season may create aquatic micro-habitats for larval development of many mosquitoes (Lopes et al 1993; Carvalho et al 2020) as the Ae. aegypti (Rezende et al 2020;Kroth et al 2022). Besides, urbanization usually leads to an increase in biodiversity loss (Priawandiputra et al 2018), which on the one hand may facilitate the establishment of exotic and invasive species such as Ae.…”

“…Direct consumption or intimidation by predators may shift prey behaviors, such as its reproductive and feeding characteristics in the food web (Preisser et al 2005;Brose et al 2019). Furthermore, changes in behavior and reproduction may modify the structure of populations (e.g., number of individuals; Brose et al 2019), communities (e.g., species relative abundance; Kroth et al (2022), and ecosystems (e.g., nutrient cycle; Rezende et al 2015). 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).…”