Differentiation of Multiple Fluorescent Powders, Powder Transfer, and Effect on Mating in Aedes aegypti (Diptera: Culicidae)

Abstract

Five different fluorescent powders (orange, yellow, green, blue, and violet) were tested on Aedes aegypti adults to evaluate the differentiation of multiple fluorescent powder colors applied externally in the same female mosquito, their effect on coupling time, copulation time, insemination success, mate choice, and the extent of transference of powders between marked and unmarked individuals, either during copulation or same-sex interactions. Marking with multiple powders was evaluated after applying different powders in the same female at different times and combinations. The comparative effect of powders on mating was explored using different cross-combinations of marked/unmarked couples. Transference of powders between marked/unmarked individuals after copulation was checked in mated individuals, and between same-sex interactions by allowing them to interact under crowded and uncrowded conditions. Identification of the colors included in multiple markings in the same individual was possible when exploring almost all combinations (exception: green–yellow). No important effect of powder marking between cross-combinations was found on coupling time (overall 95% CI (Confidence Interval) 37.6–49.6 min), copulation time (overall 95% CI 17–20 s), insemination success, nor their mate choice. Transferred powder after copulation activity, concentrated in genitalia, legs, and the tip of wings, occurred in >80% of females and 100% of males. Powder transference in legs and genitalia, between same-sex individuals, occurred only in males (ranged between 23–35%) under both density conditions. The lack of important effects of these powders on the studied aspects of Ae. aegypti provides information about their usefulness and limitations, which should be recognized for future applications and to avoid bias.

A bacterium against the tiger: further evidence of the potential of noninundative releases of males with manipulated Wolbachia infection in reducing fertility of Aedes albopictus field populations in Italy

“…28,36 This represents an asset of IIT in comparison to SIT trials in the field, as the latter requires marking of irradiated male releases with fluorescent dusts, which progressively lose detectability over time and can be passed to other males during fights. 37 In order to evaluate the potential efficacy and sustainability of ARwP male release as a potential control strategy, we estimated the per-male efficiency associated to the incompatible strain, by taking into account not only the incompatible:wild male ratio, but also male survival. 32 A male competitiveness value (C 1 ) of 0.36 was estimated based on the overall viability rate of eggs in ovitraps in 2019.…”

“…Notably, the estimate of the incompatible:sterile wild male ratio was very straightforward thanks to an effective male marking system stable throughout the whole male life: the w Pip Wolbachia ‐specific PCR‐assay 28,36 . This represents an asset of IIT in comparison to SIT trials in the field, as the latter requires marking of irradiated male releases with fluorescent dusts, which progressively lose detectability over time and can be passed to other males during fights 37 …”

From the Lab to the Field: Long-Distance Transport of Sterile Aedes Mosquitoes

“…Sterile males are marked before release in the field for most of the SIT pilot programs [ 17 ]. Marking using fluorescent powders is a common technique for externally marking adult mosquitoes [ 18 , 19 , 20 , 21 ]. This is to help assess multiple biological parameters, including population size, dispersal, mating and survival [ 22 , 23 , 24 , 25 , 26 ].…”