An assessment of adult mosquito collection techniques for studying species abundance and diversity in Maferinyah, Guinea

Abstract

24Background: Guinea is a West African country with a high prevalence of vector-borne 25 diseases where few entomological studies have been undertaken. Although several 26 mosquito collection methods are routinely used for surveillance in vector control 27 programmes, they target different behaviours causing bias in species diversity and 28 abundance. Given the paucity of mosquito trap data in West Africa, we compared the 29 performance of five trap-lure combinations and Human Landing Catches (HLCs) in Guinea. 30 Methods: Five mosquito traps were compared in a 5x5 Latin Square design for 15 days in 31 three villages in Guinea between June and July 2018. CDC light traps, BG sentinel 2 traps 32 (with BG and MB5 lures), gravid traps and Stealth traps were deployed for 24-hour intervals 33 with mosquitoes collected every 12 hours (day and night collections). HLCs were also 34 performed for 15 nights. A Generalised Linear Mixed Model was applied to compare the 35 effect of the traps, sites and collection times on the mosquito abundance. Species 36 identification was confirmed using PCR-based analysis and Sanger sequencing. 37Results: In total, 10,610 mosquitoes were captured across all five traps. Significantly more 38 mosquitoes (P<0.005) were collected by Stealth traps (7,096) compared to the rest of the 39 traps. Stealth traps and BG sentinel 2 traps were the best at capturing An. gambiae and Ae. 40 aegypti mosquitoes respectively. HLCs captured predominantly An. coluzzii (41%) and 41 hybrids of An. gambiae s.s. / An. coluzzii (36%) in contrast to the five adult traps, which 42 captured predominantly An. melas (83%). Senguelen (rural) presented the highest 43 abundance of mosquitoes and overall diversity in comparison with Fandie (semi-rural) and 44 Maferinyah Centre One (semi-urban). To our knowledge, four species are reported for the 45 first time in Guinea. 46Conclusions: Stealth traps presented the best performance overall, suggesting that this trap 47 has helped to reveal, together with morphological identification, the presence of 25 mosquito 50 species in this area. 51 BACKGROUND 53Control programmes which target malaria and other vector-borne diseases need to be 54 specific to the country or region in which they are implemented. In order to choose the best 55 intervention(s), it is essential to know which mosquito species are both present, and 56 transmitting human pathogens in a given area. For example, the primary vectors of malaria 57in Africa display primarily endophagic and endophilic behaviour and therefore can be 58 targeted by interventions such as Indoor Residual Spraying (IRS) or through the use of 59Long-Lasting Insecticidal Nets (LLINs). Despite primary vectors contributing to the majority 60 of the transmission of mosquito-borne diseases, secondary vector species can play an 61 essential role in maintaining residual transmission (1). However, secondary malaria vectors 62 that display exophagic and/or exophilic behaviour may not be affected by interventions 63 foused on the primary vectors. ...

Evidence for natural hybridisation and novel Wolbachia strain superinfections in the Anopheles gambiae complex from Guinea

“…Human landing catches (HLCs) and larval dipping were conducted in three villages in the Faranah Prefecture; Balayani (10.1325, −10.7443), Foulaya (10.144633, −10.749717), and Tindo (9.9612230, −10.7016560) [33]. Three districts were selected for mosquito collections in the Maferinyah sub-prefecture using a variety of traps [34]. BG sentinel 2 traps (BG2) (Biogents), CDC light traps (John W. Hock), gravid traps (BioQuip) and stealth traps (John W. Hock) were used to sample adult mosquitoes in Maferinyah Centre (09.54650, −013.28160), Senguelen (09.41150, −013.37564) and Fandie ( 09.53047, −013.24000).…”

“…BG sentinel 2 traps (BG2) (Biogents), CDC light traps (John W. Hock), gravid traps (BioQuip) and stealth traps (John W. Hock) were used to sample adult mosquitoes in Maferinyah Centre (09.54650, −013.28160), Senguelen (09.41150, −013.37564) and Fandie ( 09.53047, −013.24000). Mosquitoes collected from traps and HLCs were morphologically identified using keys and stored in RNAlater® (Invitrogen) at −80°C [33,34].…”

“…gambiae complex was initially undertaken using diagnostic species-specific PCR assays to distinguish between the morphologically indistinguishable sibling species [35,36]. To determine species identification for samples of interest and samples that could not be identified by species-specific PCR, sequences were generated by Sanger sequencing of ITS2 PCR products [34,37].…”

Considerations for mosquito microbiome research from the Mosquito Microbiome Consortium

“…Collection method The type of collection method or tool used for sample collection can influence the type and characteristics of mosquitoes collected [73,74]. Thus, methods that are appropriate for the target species, life stage, and physiological characteristics should be employed and recorded.…”

Morphology and mini‐barcodes: The inclusion of larval sampling and NGS‐based barcoding improves robustness of ecological analyses of mosquito communities

“…These traps are relatively easy to set up and are efficient in collecting many species which use carbon dioxide as host cues. However, as host‐seeking behaviours differ across mosquito species, the sole use of these traps may skew diversity and abundance estimation (Burkett et al., 2001; Cansado‐Utrilla et al., 2020; Gorsich et al., 2019). CO 2 ‐baited traps also preferentially attract female mosquitoes as only females require blood meals for oogenesis.…”