Standardization of the FAO/IAEA Flight Test for Quality Control of Sterile Mosquitoes

[EN] Successful implementation of the sterile insect technique (SIT) against Aedes aegypti and Aedes albopictus relies on maintaining a consistent release of high-quality sterile males. Affordable, rapid, practical quality control tools based on the male's flight ability (ability to escape from a flight device) may contribute to meeting this requirement. Therefore, this study aims to standardize the use of the original FAO/IAEA rapid quality control flight test device (FTD) (version 1.0), while improving handling conditions and reducing the device's overall cost by assessing factors that could impact the subsequent flight ability of Aedes mosquitoes. The new FTD (version 1.1) is easier to use. The most important factors affecting escape rates were found to be tube color (or "shade"), the combined use of a lure and fan, mosquito species, and mosquito age and density (25; 50; 75; 100 males). Other factors measured but found to be less important were the duration of the test (30, 60, 90, 120 min), fan speed (normal 3000 rpm vs. high 6000 rpm), and mosquito strain origin. In addition, a cheaper version of the FTD (version 2.0) that holds eight individual tubes instead of 40 was designed and successfully validated against the new FTD (version 1.1). It was sensitive enough to distinguish between the effects of cold stress and high irradiation dose. Therefore, the eight-tube FTD may be used to assess Aedes' flight ability. This study demonstrated that the new designs (versions 1.1 and 2.0) of the FTD could be used for standard routine quality assessments of Aedes mosquitoes required for an SIT and other male release-based programs.The authors are grateful to Empresa de Transformación Agraria S.A., S.M.E, M.P. (TRAGSA), Spain, and to Wolbaki, China, for donating their strain for testing. They are grateful to the two reviewers for their useful comments/suggestions that improved our manuscript. This research was funded by the United States of America under the grant to the IAEA entitled ¿Surge expansion for the sterile insect technique to control mosquito populations that transmit the Zika virus.¿ The funders and the agency had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.Maïga, H.; Lu, D.; Mamai, W.; Somda, NSB.; Wallner, T.; Bakhoum, MT.; Masso, OB.... (2022). Standardization of the FAO/IAEA Flight Test for Quality Control of Sterile Mosquitoes. Frontiers in Bioengineering and Biotechnology. 10:1-14. https://doi.org/10.3389/fbioe.2022.8766751141

The first darter (Aves: Anhingidae) fossils from India (late Pliocene).

New fossils from the latest Pliocene portion of the Tatrot Formation exposed in the Siwalik Hills of northern India represent the first fossil record of a darter (Anhingidae) from India. The darter fossils possibly represent a new species, but the limited information on the fossil record of this group restricts their taxonomic allocation. The Pliocene darter has a deep pit on the distal face of metatarsal trochlea IV not reported in other anhingids, it has an open groove for the m. flexor perforatus et perforans digiti II tendon on the hypotarsus unlike New World anhingid taxa, and these darter specimens are the youngest of the handful of Neogene records of the group from Asia. These fossil specimens begin to fill in a significant geographic and temporal gap in the fossil record of this group that is largely known from other continents and other time periods. The presence of a darter and pelican (along with crabs, fish, turtles, and crocodilians) in the same fossil-bearing horizon strongly indicates the past presence of a substantial water body (large pond, lake, or river) in the interior of northern India in the foothills of the Himalayan Mountains

The <i>Anhinga</i> tarsometatarsus shaft (KP/KK/BS/102) from the Khetpurali section, India.

<p>(A) Dorsal view. (B) Plantar view. Scale bar equals 1 cm. Abbreviations: abIV–m. abductor digiti IV groove; dif–dorsal infracotylar fossa; ehl–broad notch for the m. extensor hallucis longus; mhc–medial hypotarsal crest; and mtI–metatarsal I facet.</p

The proximal tarsometatarsus of fossil and extant Anhingidae with a focus on the hypotarsus.

<p>The Siwalik Hills specimen (KP/KK/BS/101) in: (A) Medial view; (B) Dorsal view; (C) Lateral view; (D) Plantar view; and (E) Proximal view (the missing medial hypotarsal crest is marked by a dashed line). Outline of the tarsometatarsus of <i>Anhinga melanogaster</i> in: (F) Proximal view. Outline of the tarsometatarsus of <i>Anhinga anhinga</i> in: (G) Proximal view. Outline drawings redrawn from Harrison’s [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0177129#pone.0177129.ref037" target="_blank">37</a>] type A and B morphologies. Scale bar equals 1 cm. Abbreviations: fdl–canal for the m. flexor digitorum longus tendon; fhl–canal for the m. flexor hallucis longus tendon; fp–groove for the m. flexor perforatus digiti II tendon; fpp–groove/canal for the m. flexor perforans et preforatus digiti II tendon; ie–intercotylar eminence; lc–lateral cotyle; lcl–impression for the lateral collateral ligament; lhr–lateral hypotarsal ridge (ridge bounding the groove for the m. fibularis longus tendon); mc–medial cotyle; mf–groove for the m. fibularis tendon; mhc–medial hypotarsal crest; pf–proximal vascular foramen; rr- retinacular ridges; and tc–attachment for the m. tibialis cranialis.</p

The geology, location, stratigraphy, and magnetostratigraphy of the Ketpurali section and region, northern India.

<p>The correlation of the lithostratigraphy with the magnetostratigraphy (and geochronological boundaries) is provided on the right side. The vertebrate fossil bone horizon is marked with a red star (map and stratigraphic section). The figure is modified from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0177129#pone.0177129.ref004" target="_blank">4</a>].</p

Fossil and recent anhingid distal tarsometatarsi.

<p><i>Anhinga</i> sp. (VPL/RP-KPB1) from India in: (A) Medial view; (B) Dorsal View; (C) Lateral View; (D) Plantar view; and (E) Distal view. <i>Anhinga melanogaster</i> (MVZ 149268) in: (F) Distal view; (G) Dorsal view; and (H) Plantar view. Scale bars equal 1 cm. The specimens are presented at the same size, but the <i>Anhinga melanogaster</i> specimen is larger (bottom scale bar) as compared to the fossil (top scale bar). Abbreviations: abIV–groove for m. abductor digiti IV; df–distal vascular foramen; dp–deep pit on the distal face of metatarsal trochlea IV; lp–collateral ligament pit; mtI–facet for metatarsal I; tIII–metatarsal trochlea III; and tIV–metatarsal trochlea IV.</p

Distal tarsometatarsus measurements (mediolateral width) of fossil and extant anhingids (in mm).

<p>Distal tarsometatarsus measurements (mediolateral width) of fossil and extant anhingids (in mm).</p

From the Lab to the Field: Long-Distance Transport of Sterile <i>Aedes</i> Mosquitoes

Pilot programs of the sterile insect technique (SIT) against Aedes aegypti may rely on importing significant and consistent numbers of high-quality sterile males from a distant mass rearing factory. As such, long-distance mass transport of sterile males may contribute to meet this requirement if their survival and quality are not compromised. This study therefore aimed to develop and assess a novel method for long-distance shipments of sterile male mosquitoes from the laboratory to the field. Different types of mosquito compaction boxes in addition to a simulation of the transport of marked and unmarked sterile males were assessed in terms of survival rates/recovery rates, flight ability and morphological damage to the mosquitoes. The novel mass transport protocol allowed long-distance shipments of sterile male mosquitoes for up to four days with a nonsignificant impact on survival (>90% for 48 h of transport and between 50 and 70% for 96 h depending on the type of mosquito compaction box), flight ability, and damage. In addition, a one-day recovery period for transported mosquitoes post-transport increased the escaping ability of sterile males by more than 20%. This novel system for the long-distance mass transport of mosquitoes may therefore be used to ship sterile males worldwide for journeys of two to four days. This study demonstrated that the protocol can be used for the standard mass transport of marked or unmarked chilled Aedes mosquitoes required for the SIT or other related genetic control programs

Mating harassment may boost the effectiveness of the sterile insect technique for Aedes mosquitoes

Abstract The sterile insect technique is based on the overflooding of a target population with released sterile males inducing sterility in the wild female population. It has proven to be effective against several insect pest species of agricultural and veterinary importance and is under development for Aedes mosquitoes. Here, we show that the release of sterile males at high sterile male to wild female ratios may also impact the target female population through mating harassment. Under laboratory conditions, male to female ratios above 50 to 1 reduce the longevity of female Aedes mosquitoes by reducing their feeding success. Under controlled conditions, blood uptake of females from an artificial host or from a mouse and biting rates on humans are also reduced. Finally, in a field trial conducted in a 1.17 ha area in China, the female biting rate is reduced by 80%, concurrent to a reduction of female mosquito density of 40% due to the swarming of males around humans attempting to mate with the female mosquitoes. This suggests that the sterile insect technique does not only suppress mosquito vector populations through the induction of sterility, but may also reduce disease transmission due to increased female mortality and lower host contact