Hostname: page-component-74656f9884-npj9w Total loading time: 0 Render date: 2026-11-07T00:48:15.692Z Has data issue: false hasContentIssue false

Less is more: partial larvicidal efficacy of plant leachate leads to larger Aedes aegypti mosquitoes

Published online by Cambridge University Press:  07 August 2023

Isabella Bodanese Marsaro
Affiliation:
Communitarian University of Chapecó Region – UNOCHAPECÓ, Servidão Anjo da Guarda, 295-D, Efapi, 89809-000 Chapecó, Santa Catarina, Brazil
Gilberto Dinis Cozzer
Affiliation:
Communitarian University of Chapecó Region – UNOCHAPECÓ, Servidão Anjo da Guarda, 295-D, Efapi, 89809-000 Chapecó, Santa Catarina, Brazil
Emanuel Rampanelli Cararo
Affiliation:
Communitarian University of Chapecó Region – UNOCHAPECÓ, Servidão Anjo da Guarda, 295-D, Efapi, 89809-000 Chapecó, Santa Catarina, Brazil
Raquel De Brito
Affiliation:
Communitarian University of Chapecó Region – UNOCHAPECÓ, Servidão Anjo da Guarda, 295-D, Efapi, 89809-000 Chapecó, Santa Catarina, Brazil
William Gabriel Borges
Affiliation:
Communitarian University of Chapecó Region – UNOCHAPECÓ, Servidão Anjo da Guarda, 295-D, Efapi, 89809-000 Chapecó, Santa Catarina, Brazil
Jacir Dal Magro
Affiliation:
Communitarian University of Chapecó Region – UNOCHAPECÓ, Servidão Anjo da Guarda, 295-D, Efapi, 89809-000 Chapecó, Santa Catarina, Brazil
Cássia Alves Lima-Rezende
Affiliation:
Communitarian University of Chapecó Region – UNOCHAPECÓ, Servidão Anjo da Guarda, 295-D, Efapi, 89809-000 Chapecó, Santa Catarina, Brazil
Renan de Souza Rezende*
Affiliation:
Communitarian University of Chapecó Region – UNOCHAPECÓ, Servidão Anjo da Guarda, 295-D, Efapi, 89809-000 Chapecó, Santa Catarina, Brazil
*
Corresponding author: Renan de Souza Rezende; Email: renanrezende30@gmail.com
Rights & Permissions [Opens in a new window]

Abstract

Major efforts to control the population of Aedes aegypti mosquitoes involve the use of synthetic insecticides, which can be harmful to the environment. Most plant compounds are eco-friendly and some of them have biocontrol potential, whereas a fraction of these compounds is released into the environment through the leaf-leaching process. We evaluated the effects of secondary compounds from Ateleia glazioviana and Eucalyptus grandis senescent leaf leachates on Ae. aegypti larval mortality, adult emergence time, and wing size using a microcosm approach. The microcosms consisted of 10 larvae kept in water (control) and under four treatments with leachates from a combination of plant species and leaching time (7 or 14 days). Chemical analyses of the leachates showed the presence of carboxaldehyde and Heptatriocotanol, which have antimicrobial properties, potentially reducing the food available for larvae. β-Sitosterol, Stigmasterol, α-Amyrin, and Lupeol are compounds with inhibitory, neurotoxic, and larvicidal effects. Both plant species’ leachates increased larval mortality and decreased emergence time due to the presence of compounds toxic to the larvae. Larger organisms emerged in treatments with 7-days leachates, likely due to the high concentration of dissolved organic matter in the leachates. The higher mortality in 7-days leachates may also increase the organic matter from co-specific decomposition, improving adult size. Therefore, if the mosquito population is not locally extinct, compounds present in leaf leachates may act as a resource enhancing larvae growth, potentially increasing survivors’ fitness. In conclusion, biocontrol attempts using urban green spaces may have unexpected outcomes, such as resulting in larger pest organisms.

Information

Type
Research Paper
Copyright
Copyright © The Author(s), 2023. Published by Cambridge University Press
Figure 0

Figure 1. Experimental design to test the effects of Ateleia glazioviana and Eucalyptus grandis leaf leachates on A. aegypti survival.

Figure 1

Table 1. Chemical compounds of Eucalyptus grandis and Ateleia glazioviana leaf leachates

Figure 2

Figure 2. Responses in larval mortality (a), emergence time (b) and adult size (female – c – and male – d, separately) to different treatments (control, Ateleia glazioviana 7 days and 14 days leachates and Eucalyptus grandis 7 days and 14 days leachates). The boxes represent the quartiles, the average is indicated by a horizontal black bar, the vertical lines represent the upper and lower limits, open circles represent the sampling units, and closed circles represent the extreme values (outliers).

Figure 3

Table 2. We employed Generalized Linear Models (GLMs) to investigate the impact of plant species and leaching time (A. glazioviana 7 days leachate ‘Ag7’, A. glazioviana 14 days leachate ‘Ag14’, E. grandis 7 days leachate ‘Eg7’, E. grandis 14 days leachate ‘Eg14’, and control) on larval mortality (a), emergence time (b), and adult size (separately for females - c - and males - d -)

Figure 4

Figure 3. Size and direction of the effect of plant species and leaching time on larval mortality (a) and adult size (b) expressed by the logarithmic relationships between the different treatments (Ateleia glazioviana 7 days and 14 days leachates and Eucalyptus grandis 7 days and 14 days leachates) and their respective controls. Circles represent the means, and the lines depict the 95% confidence intervals. Black circles indicate statistically significant results, with intervals that reject the null hypothesis (indicated by not touching the dashed line at the 0 effect size). Open circles represent statistically non-significant results, with intervals that do not reject the null hypothesis (indicated by touching the dashed line at the 0 effect size).