Macrocyclops albidus(Copepoda: cyclopidae) for the Biocontrol ofAedes albopictusandCulex pipiensin Italy

Abstract

The aim of our study was to assess the potential of Macrocyclops albidus as a biological control agent against the 1st and 2nd instars of Culex pipiens and Aedes albopictus. Under laboratory conditions of prey saturation (50 1st instars/copepod), an average of 58.98% of Cx. pipiens and 54.99% of Ae. albopictus larvae were killed by 1 copepod in 24 h. Trials run in big drums containing 200 liters of water showed that the M. albidus population, inoculated in April, efficiently controlled the mosquito population for the entire season. The predator was particularly effective against Ae. albopictus, as only 2 larvae of this species were found in the treated drums, compared to 814 larvae in untreated control drums throughout the study period. No difference was observed in the control efficacy between the 2 initial densities of copepods used. The reduction in Ae. albopictus density in the drums with 100 and 500 M. albidus with respect to the control drums was 99.90 ± 0.35% and 100.0 ± 0.0%, respectively. For Cx. pipiens, the reduction in density was 88.69 ± 13.51% and 84.65% in drums inoculated with 100 and 500 copepods, respectively. Macrocyclops albidus populations survived through the winter and continued to keep the mosquito population under control during the 2008 season. The M. albidus population developed very well both in drums placed in sunny and shaded areas and proved to be tolerant to both high (summer) and low (winter) temperatures. Trials performed on M. albidus survival in catch basins showed that after a few weeks, the copepod population dramatically decreased and subsequently disappeared. The main problem for copepod survival in catch basins seemed to be the low oxygen tension and accumulation of toxic substances, rather than copepods being flushed out in heavy rainfall episodes. During the period when copepods were present, they maintained the mosquito population under control; their partial disappearance from the catch basins, however, would require more recolonization intervention to maintain mosquito control during the season.

Predation efficiency of copepods against the new invasive mosquito species Aedes koreicus (Diptera: Culicidae) in Italy

“…This is quite surprising as M. albidus has proven to be a formidable predator of Ae. albopictus worldwide, with predation rates ranging from 28.4 to 45.0 larvae per copepod in 24 hours (Marten 1990;Rey et al 2004;Veronesi et al 2015). One explanation may be, as Marten and Reid (2007) described, that different populations of the same copepod species may express differences in predation behaviour.…”

“…israelensis and insect growth regulators) as well as natural predators of mosquito larvae (Baldacchino et al 2015). Cyclopoid copepods (Copepoda: Cyclopoida; hereafter referred to as copepods) are the most effective invertebrate mosquito predators (Veronesi et al 2015). Because they survive for several months in artificial containers, they provide long-lasting control of mosquito populations (Marten & Reid 2007;Veronesi et al 2015).…”

“…Cyclopoid copepods (Copepoda: Cyclopoida; hereafter referred to as copepods) are the most effective invertebrate mosquito predators (Veronesi et al 2015). Because they survive for several months in artificial containers, they provide long-lasting control of mosquito populations (Marten & Reid 2007;Veronesi et al 2015). Copepods prey mainly on first and second instar mosquito larvae, and the largest copepod species (> 1.4 mm body length) can kill up to 30-40 Aedes larvae per day (Marten & Reid 2007).…”

“…To date, the predatory efficiency of about 50 copepod species belonging to 15 genera has been tested mostly in the laboratory, but also in the field, mainly against Aedes and Culex mosquitoes (Marten & Reid 2007;Veronesi et al 2015). Two taxa of cyclopoids have proved to be particularly effective for controlling Aedes species such as Ae.…”

“…While several laboratory and field studies have already been carried out on the use of M. albidus against Ae. albopictus in the United States, Brazil and, in one study, Italy (Marten 1990;Santos & Andrade 1997;Rey et al 2004;Veronesi et al 2015), no copepod species had been previously tested against Ae. koreicus larvae.…”