Meier CJ, Martin LE, Hillyer JF. Mosquito larvae exposed to a sublethal dose of photosensitive insecticides have altered juvenile development but unaffected adult life history traits.
Parasit Vectors 2023;
16:412. [PMID:
37951916 PMCID:
PMC10638795 DOI:
10.1186/s13071-023-06004-8]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 10/06/2023] [Indexed: 11/14/2023] Open
Abstract
BACKGROUND
Larvicides are critical for the control of mosquito-borne diseases. However, even sublethal exposure to a larvicide can alter development and life history traits, which can then affect population density and disease transmission dynamics. Photosensitive insecticides (PSIs) are a promising class of larvicide that are toxic when ingested and activated by light. We investigated whether the time of day when exposure occurs, or the process of pupation, affects larval susceptibility to PSI phototoxicity in the mosquito Anopheles gambiae, and whether sublethal exposure to PSIs alters life history traits.
METHODS
Larvae were treated with lethal concentrations of the PSIs methylene blue (MB) and rose bengal (RB), and larval survival was measured at various times of day. Additionally, larvae were exposed to two concentrations of each PSI that resulted in low and medium mortality, and the life history traits of the surviving larvae were measured.
RESULTS
Pupation, which predominantly occurs in the evening, protected larvae from PSI toxicity, but the toxicity of PSIs against larvae that had yet to pupate was unaffected by time of day. Larval exposure to a sublethal concentration of MB, but not RB, shortened the time to pupation. However, larval exposure to a sublethal concentration of RB, but not MB, increased pupal mortality. Neither PSI had a meaningful effect on the time to eclosion, adult longevity, or adult melanization potential.
CONCLUSIONS
PSIs are lethal larvicides. Sublethal PSI exposure alters mosquito development, but does not affect adult life history traits.
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