Designing Aedes (Diptera: Culicidae) Mosquito Traps: The Evolution of the Male Aedes Sound Trap by Iterative Evaluation

Abstract

Effective surveillance of Aedes aegypti (Linnaeus, Diptera: Culicidae) is critical to monitoring the impact of vector control measures when mitigating disease transmission by this species. There are benefits to deploying male-specific traps, particularly when a high level of catch-specificity is desired. Here, the rationale behind the developmental process of an entirely new trap which uses a sound lure to capture male Ae. aegypti, the male Aedes sound trap (MAST), is presented as a target product profile with findings from developmental trials of key trap components and performance. Trial results suggest that the presence of a black base associated with the trap influenced male catches as did variations in size of this base, to a degree. Trap entrance shape didn't influence catch rates, but entrance size did. No significant differences in catch rates were found when sound lures were set to intermittent or continuous playbacks, at volumes between 63-74 dB or frequencies of 450 Hz compared to 500 Hz. Additionally, adult males aged 3 days post-eclosion, were less responsive to sound lures set to 500 Hz than those 4 or 6 days old. Lastly, almost no males were caught when the MAST directly faced continual winds of 1.5 ms^-1, but males were captured at low rates during intermittent winds, or if the trap faced away from the wind. The developmental process to optimising this trap is applicable to the development of alternate mosquito traps beyond Aedes sound traps and provides useful information towards the improved surveillance of these disease vectors.

Keywords: Aedes aegypti; dengue; male; mosquito trap; sound lure; sound trap.

Figure 1

Basic general design of the main prototype MAST (MAST 1) used in developmental trials.

Figure 2

The influence of different base heights on male Ae. aegypti (mean ± S.E.) catch rates in the MAST. Trials investigated catches of male Ae. aegypti caught either (A) within the semi-field flight cage, (B) at a single field premises, (C) within multiple field premises (including the outlier) or (D) within multiple field premises (excluding the outlier). Different letters above points indicate significantly different groups (Tukey HSD, p ≤ 0.05, n = 12).

Figure 3

The influence of different entrance types on male Ae. aegypti (mean ± S.E.) catch rates in the MAST. Trials investigated catches of male Ae. aegypti (per 5 min) in semi-field trials investigating influences from different entrance (A) types and (B) sizes. Square entrances are referred to by “sq” and the triangular entrance is referred to by “tri”. The length of the sides of the entrance type is also noted in treatment labels. Different letters indicate significantly different groups (Tukey HSD, p ≤ 0.05, n = 12).

Figure 4

The influence of different sound lure configurations on male Ae. aegypti (mean ± S.E.) catch rates in the MAST. Trials investigated catches of male Ae. aegypti per (A) five-minute semi-field trials comparing male catches in MASTs (n = 12) with sound lures that either played continuously or intermittently (30 s on and off), (B) five-minute semi-field trials comparing male catches in MASTs (n = 12) with sound lures set to different volumes, (C) thirty-minute tent trials comparing male catches in MASTs (n = 23) with sound lures set to different frequencies, (D) thirty-minute tent trials comparing catch rates of males of various post-eclosion ages in MASTs (n = 10–12) set to 500 Hz and 60 dB, and (E) thirty-minute tent trials comparing male catches in MASTs (n = 4) with sound lures set to different frequencies or turned off. Different letters indicate significantly different groups (Tukey HSD, p ≤ 0.05).

Figure 5

The influence of different wind conditions on male Ae. aegypti (mean ± S.E.) catch rates in the MAST. Different letters indicate significantly different groups (Tukey HSD, p ≤ 0.05, n = 7–8).