Mosquito responses to trait- and density-mediated interactions of predation
Mosquito and predatory larvae often share the same habitat. Predators may influence mosquito prey populations through both lethal effect and non-lethal pathways. A series of experimental manipulations were used to distinguish between lethal (density-mediated interaction) and non-lethal (trait-mediated interaction) effects in a model system comprised of invasive prey mosquito, Aedes aegypti, and a predatory mosquito Toxorhynchites rutilus. Treatments with predators present or manipulations mimicking daily mortality (density reduction) reduced developmental time and recruitment to the adult stage. Daily records of adult survival of A. aegypti showed that exposure to predators during the juvenile stage shortened the lifespan of adults. This was also observed in treatments, where A. aegypti were replaced at the rate of consumption by T. rutilus. In contrast, numerical reductions in A. aegypti that mimicked daily rate of predation led to adults with the longest lifespan. These observations suggest strong effects of density and trait-mediated interactions in the influence of predators on mosquito biology relevant to their ability to transmit pathogens. These results have potentially important implications for disease control strategies. The primary approach to reduce risk of mosquito-borne diseases is through population reduction of the vectors. We show an unanticipated benefit of biological control by predation for the control of juvenile stages of mosquitoes. Specifically, mosquitoes that are exposed to predators but survive to adulthood will have compromised life expectancy, a key parameter in determining risk of disease transmission.
KeywordsPredator–prey Disease vector ecology Life histories Aedes aegypti Toxorhynchites rutilus
We thank Sheila O’Connell for assistance in establishing a colony of Toxorhynchites rutilus at the Florida Medical Entomology Laboratory and Steven Juliano for useful communications about the experimental protocols used in the treatment manipulations.
Author contribution statement
BWA conceived and designed the experiments. SB performed the experiments. SB and BWA analyzed the data. SB and BWA wrote the manuscript.
- Benard MF (2004) Predator-induced phenotypic plasticity in organisms with complex life histories. Annu Rev Ecol Evol Syst 35:651–673. https://doi.org/10.1146/annurev.ecolsys.35.021004.112426 CrossRefGoogle Scholar
- Briegel H, Knüsel I, Timmermann SE (2000) Aedes aegypti: size, reserves, survival, and flight potential. J Vector Ecol 26(1):21–31Google Scholar
- Caltagirone LE (1981) Landmark examples in classical biological control. Annu Rev Entomol 26(1):213–232. https://doi.org/10.1146/annurev.en.26.010181.001241 CrossRefGoogle Scholar
- Corbet PS, Griffiths A (1963) Observations on the aquatic stages of two species of Toxorhynchites in Uganda. Proc R Entomol Soc A 38:125–135. https://doi.org/10.1111/j.1365-3032.1963.tb00767.x Google Scholar
- Fox LR (1975) Cannibalism in natural populations. Ann Rev Ecol Syst 6(1):87–106. https://doi.org/10.1146/annurev.es.06.110175.000511 CrossRefGoogle Scholar
- Lounibos LP (1985) Interactions influencing production of treehole mosquitoes in south Florida. In: Lounibos LP, Rey J, Frank JH (eds) Ecology of mosquitoes: Proceedings of a workshop Florida Medical Entomology Laboratory, Vero Beach, Florida, USA, pp 65–77Google Scholar
- Relyea RA (2000) Trait-mediated indirect effects in larval anurans: reversing competition with the threat of predation. Ecology 81(8):2278–2289. https://doi.org/10.1890/0012-9658(2000)081[2278:TMIEIL]2.0.CO;2 CrossRefGoogle Scholar
- Sailer RI (1971) Invertebrate predators. USDA Forest Service, Res. Paper NE-195:32-44Google Scholar
- Scheiner SM (2001) MANOVA: multiple response variables and multispecies interactions. In: Scheiner SM, Gurevitch J (eds) Design and analysis of ecological experiments, 2nd edn. Oxford University Press, Oxford, pp 99–115Google Scholar
- Stoks R, De Block M, Slos S, Doorslaer WV, Rolff J (2006) Time constraints mediate predator-induced plasticity in immune function, condition, and life history. Ecology 87:809–815. https://doi.org/10.1890/0012-9658(2006)87[809:TCMPPI]2.0.CO;2 CrossRefPubMedGoogle Scholar