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

BACKGROUND: Several mosquito collection methods are routinely used in vector control programmes. However, they target different behaviours causing bias in estimation of species diversity and abundance. Given the paucity of mosquito trap data in West Africa, we compared the performance of five trap-lure combinations and Human Landing Catches (HLCs) in Guinea. METHODS: CDC light traps (LT), BG sentinel 2 traps (BG2T), gravid traps (GT) and Stealth traps (ST) were compared in a 5 × 5 Latin Square design in three villages in Guinea between June and July 2018. The ST, a portable trap which performs similarly to a LT but incorporates LEDs and incandescent light, was included since it has not been widely tested. BG2T were used with BG and MB5 lures instead of CO2 to test the efficacy of these attractants. HLCs were performed for 5 nights, but not as part of the Latin Square. A Generalised Linear Mixed Model was applied to compare the effect of the traps, sites and collection times on mosquito abundance. Species identification was confirmed using PCR-based analysis and Sanger sequencing. RESULTS: A total of 10,610 mosquitoes were captured across five traps. ST collected significantly more mosquitoes (7096) than the rest of the traps, but resulted in a higher number of damaged specimens. ST and BG2T collected the highest numbers of Anopheles gambiae (s.l.) and Aedes aegypti mosquitoes, respectively. HLCs captured predominantly An. coluzzii (41%) and hybrids of An. gambiae and An. coluzzii (36%) in contrast to the five traps, which captured predominantly An. melas (83%). The rural site (Senguelen) presented the highest abundance of mosquitoes and overall diversity in comparison with Fandie (semi-rural) and Maferinyah Centre I (semi-urban). Our results confirm the presence of four species for the first time in Guinea. CONCLUSIONS: ST collected the highest number of mosquitoes suggesting this trap may play an important role for mosquito surveillance in Guinea and similar sites in West Africa. We recommend the incorporation of molecular tools in entomological studies since they have helped to identify 25 mosquito species in this area.

Assessment of color response and activity rhythms of the invasive black planthopper Ricania speculum (Walker, 1851) using sticky traps.

To be effective, management strategies of invasive alien species cannot ignore their spatiotemporal behavior particularly those exerting serious damages to human activities. The black planthopper Ricania speculum is an Asian insect that has been reported as an alien invasive species in Italy, where it threatens local plant diversity, including important crops. In our work, we analyzed the activity rhythms of this species through circular statistics and the efficiency of chromotropic traps to capture adult individuals. Captures were carried out in central Italy, where the black planthopper is showing a remarkable range expansion, after its first discovery in 2009. We observed that the species was mainly crepuscular, with a high intersexual activity overlap. Activity rhythms changed between July-August and September-October, with changing heliophany, but peaked at sunset and were the lowest in the second half of the night and early morning. The insects were mostly caught by green traps, particularly in September, which is the period of egg-laying inside the leaves; conversely, orange ones were avoided, and yellow ones captured proportionally to their local availability. Strategies for controlling this species should consider concentrating trapping effort during the activity peak, using green sticky traps to enhance the capture success of each trap, with the lowest impact over non-target species.

Expedited assessment of terrestrial arthropod diversity by coupling Malaise traps with DNA barcoding 1.

Monitoring changes in terrestrial arthropod communities over space and time requires a dramatic increase in the speed and accuracy of processing samples that cannot be achieved with morphological approaches. The combination of DNA barcoding and Malaise traps allows expedited, comprehensive inventories of species abundance whose cost will rapidly decline as high-throughput sequencing technologies advance. Aside from detailing protocols from specimen sorting to data release, this paper describes their use in a survey of arthropod diversity in a national park that examined 21 194 specimens representing 2255 species. These protocols can support arthropod monitoring programs at regional, national, and continental scales.

An assessment of mosquito collection techniques for xenomonitoring of anopheline-transmitted Lymphatic Filariasis in Ghana.

Monitoring vectors is relevant to ascertain transmission of lymphatic filariasis (LF). This may require the best sampling method that can capture high numbers of specific species to give indication of transmission. Gravid anophelines are good indicators for assessing transmission due to close contact with humans through blood meals. This study compared the efficiency of an Anopheles gravid trap (AGT) with other mosquito collection methods including the box and the Centres for Disease Control and Prevention gravid, light, exit and BioGent-sentinel traps, indoor resting collection (IRC) and pyrethrum spray catches across two endemic regions of Ghana. The AGT showed high trapping efficiency by collecting the highest mean number of anophelines per night in the Western (4.6) and Northern (7.3) regions compared with the outdoor collection methods. Additionally, IRC was similarly efficient in the Northern region (8.9) where vectors exhibit a high degree of endophily. AGT also showed good trapping potential for collecting Anopheles melas which is usually difficult to catch with existing methods. Screening of mosquitoes for infection showed a 0.80-3.01% Wuchereria bancrofti and 2.15-3.27% Plasmodium spp. in Anopheles gambiae. The AGT has shown to be appropriate for surveying Anopheles populations and can be useful for xenomonitoring for both LF and malaria.

Active optical sensor assessment of spider mite damage on greenhouse beans and cotton.

The two-spotted spider mite, Tetranychus urticae Koch, is an important pest of cotton in mid-southern USA and causes yield reduction and deprivation in fiber fitness. Cotton and pinto beans grown in the greenhouse were infested with spider mites at the three-leaf and trifoliate stages, respectively. Spider mite damage on cotton and bean canopies expressed as normalized difference vegetation index indicative of changes in plant health was measured for 27 consecutive days. Plant health decreased incrementally for cotton until day 21 when complete destruction occurred. Thereafter, regrowth reversed decline in plant health. On spider mite treated beans, plant vigor plateaued until day 11 when plant health declined incrementally. Results indicate that pinto beans were better suited as a host plant than cotton for rearing T. urticae in the laboratory.

Assessment of Sampling Methods for Sarcosaprophagous Species and Other Guilds of Calyptratae (Diptera) in Temperate Forests of Southern South America.

The aim of the present study was to compare three different collecting methods, namely, baited traps, active capture with hand net, and Malaise traps, to establish which method is more appropriate for sampling different Calyptratae guilds inhabiting temperate forests of South America. Specifically, it was analyzed which technique or combination of techniques is more adequate for obtaining sarcosaprophagous Calyptratae, which are of great interest from a veterinary and medical viewpoint. Taxa were classified into guilds according to their biology. Active capture was the technique that registered the highest diversity of guilds. When analyzing sarcosaprophagous species, it was observed that their percentage of captures, diversity, and abundance showed clear differences in guild composition between the trapping techniques studied. From these analyses it can be concluded that baited traps and active trapping are complementary methods for capturing sarcosaprophagous Calyptratae species. From the perspective of the biodiversity of this group, the combination of both methodologies allows obtaining a more complete inventory of sarcosaprophagous species of austral temperate forests of South America.

The Technical and Performance Characteristics of a Low-Cost, Simply Constructed, Black Light Moth Trap.

The universal mercury vapor black light trap is an effective device used for collecting moth specimens in a wide variety of habitats; yet, they can present challenges for researchers. The mercury vapor trap is often powered by a heavy automotive battery making it difficult to conduct extensive surveys in remote regions. The mercury vapor trap also carries a considerable financial cost per trap unit, making trapping challenging with low research budgets. Here, we describe the development and trapping properties of a lighter, simply constructed, and less expensive trap. The LED funnel trap consists of a funnel, soda bottles with plastic vanes, and is powered by rechargeable 9-V batteries. Two strips of low-wavelength LEDs are used as attractants. We tested the trapping parameters of this trap design compared to a standard mercury vapor trap over 10 trap nights in a suburban woodlot in the summer of 2015. The mercury vapor trap caught significantly more moth individuals than the LED trap (average of 78 vs 40 moths per trap night; P < 0.05), and significantly more species than the LED trap (23 vs 15 per trap night; P < 0.05); the mercury vapor trap caught a total of 104 macromoth species over the duration of the study, compared to a total of 87 by the LED trap. Despite the lower yields, the low cost of the LED trap (<$30 ea.) makes it superior to the mercury vapor trap in cost-acquisition per moth species and per moth individual trapped. The LED trap may be a viable alternative to the standard mercury vapor trap, facilitating insect trapping in more diverse settings.

Inexpensive trap for monitoring the green June beetle.

Green June beetle, Cotinis nitida (L.), is an important pest of grapes, peaches, blackberries, blueberries, apples, and pears. Currently, there is no inexpensive, commercially available lure or trap that could serve monitoring green June beetle adults. The objective of this study was to develop and optimize an inexpensive bottle trap baited with isopropanol to attract and capture green June beetle adults. Bottle traps baited with 8 mm diameter cotton wicked dispensers emitted from 9 to 43 ml isopropanol in 48 h and maintained that alcohol at a fairly constant concentration compared with the prototypical bottle trap with large surface evaporation of isopropanol poured into the bottom of the trap. Over 5 d, the isopropanol in the wicked dispensers remained at the same stable concentration of 45-44.5%, whereas isopropanol concentration in the bottom of prototypical traps dropped from 45% to approximately 11% after 24 h and to 0.2% by 48 h. Bottle traps with isopropanol dispensers and cotton wicks of 4, 6, or 8 mm in diameter caught significantly more green June beetles than did prototypical bottle traps with no dispensers. Isopropanol concentrations of 45.5, 66, and 91% attracted more green June beetle adults than the lower concentrations. Significantly more green June beetle adults were attracted to traps with dispensers set at 1.3 m height than those at lower heights, and traps topped with a blue, orange, or white band captured more green June beetle adults than those with bands of other colors. The optimized bottle trap is made from recycled transparent polyethylene terephthalate beverage bottle (710-ml; 24 oz.) with a blue, orange, or white band, baited with an 8 mm cotton wick dispenser of 45.5% isopropanol and hung at a height of 1.3 m. Cost and uses for this trap are discussed.

An inexpensive, versatile mosquito rearing chamber for field, laboratory, and classroom investigations.

An inexpensive mosquito rearing chamber for field, laboratory, and classroom investigations is described. The rearing chamber is made from plastics recycled from peanut butter jars and room deodorizers. The top of the chamber requires mesh material and gluing. The cost for the rearing chamber is negligible. The design of the chamber allows for direct field collecting of larvae and for easy knock down/cold storage of emerged adults. In addition to its use in field and laboratory investigations, the chamber is an excellent device for classroom study of insect metamorphosis.

Multiple orifice distribution system for placing green lacewing eggs into verticel larval rearing units.

Green lacewings are widely used biological control agents for various insect pests. To meet the needs of growers, green lacewings are being mass-reared commercially around the world. A common salt shaker has been used regularly to distribute eggs into Verticel lacewing larval rearing units. This technique is time consuming and inefficient because the number of eggs distributed in each cell is inconsistent. The multiple orifice distribution (MOD) system described here greatly improved egg distribution efficiency by increasing the percentage of Verticel cells containing the desired one to four eggs per cell (i.e., 40.8 and 52.1% by using salt shaker method versus 61.9% by using the MOD system). This mechanical system significantly reduced the labor and time involved in the process and would cost under $3500. In addition, this new system could be modified for distribution of other insect eggs.

Field trials of an improved cost-effective device for detecting peridomestic populations of Triatoma infestans (Hemiptera: Reduviidae) in rural Argentina.

An improved device for detecting peridomestic Triatoma infestans consisting of one-liter recycled Tetra Brik milk boxes with a central structure was tested using a matched-pair study design in two rural areas in Argentina. In Olta (La Rioja), the boxes were installed beneath the thatched roofs and on the vertical wooden posts of each peridomestic structure. After a 5-month exposure, at least one of the recovered boxes detected 88% of the 24 T. infestans-positive sites, and 86% of the 7 negative sites by timed manual collections at baseline. In Amamá (Santiago del Estero), the boxes were paired with the best performing prototype tested before (shelter unit). After 3 months, some evidence of infestation was detected in 89% (boxes) and 79% (shelters) of 18-19 sites positive by timed collections, whereas 19% and 16% of 32 negative sites were positive, respectively. Neither device differed significantly in the qualitative or quantitative collection of every sign of infestation. The installation site did not modify significantly the boxes' sampling efficiency in both study areas. As the total cost of each box was half as expensive as each shelter unit, the boxes are thus the most cost-effective and easy-to-use tool for detecting peridomestic T. infestans currently available.

A comparison of three types of "M" traps for sampling tsetse fly (Diptera: Glossinidae) populations at south Luangwa game management area, Zambia.

A field trial was conducted between 27th July and 1st August, 1992 in Mfuwe, south Luangwa, Zambia to assess the effectiveness of locally developed "M" traps for suppressing and sampling the tsetse flies Glossina pallidipes Austen and Glossina morsitans morsitans Westwood. The tsetse catches in the "M" traps and the standard F3 traps were collected at 24 hour intervals. The highest catches of both tsetse species in the series of "M" traps were in the M3 trap. The numbers of female flies caught for both species in all the trap types were significantly higher than those for male flies (p < 0.001). Trap catches for G. pallidipes were uniformly distributed among the M2, M3 and F3 traps. In contrast, there was a significant drop in the M1 catches. For G. m. morsitans, the results were not significantly different between the M1 and the M3 catches. Based on the results of this trial, it is been recommended adopting the M1 trap, a more cost effective trap for suppression and the M3 trap for sampling of G. m. morsitans which is the only species in Kampumbu (our trial suppression area) in the Isoka district of Zambia.

Development of a low-cost tsetse trap and odour baits for Glossina pallidipes and G. longipennis in Kenya.

Experiments were carried out to improve the NG2B tsetse trap (Brightwell et al., 1987), baited with acetone and cow urine, for use by rural communities to control G.pallidipes Austen and G.longipennis Corti. Modifications included a lower dose rate of acetone, a new cage design and raising the trap about 15-20 cm. Research on different trap cone materials showed that the degree of light transmission of the netting, rather than its colour, was the crucial factor affecting the catch of G.pallidipes. Adding an additional metre of blue cloth to one side of the trap increased catches of females of both species by about 60%. Traps baited with synthetic phenols yielded similar numbers of G.pallidipes and significantly more G.longipennis than those baited with natural cow urine. The latter difference was not apparent when octenol was also used, so cow urine was retained as one of the odour baits in preference to the imported phenols. Although octenol increased catches of G.pallidipes by only about 30%, catches of G.longipennis were increased 2-4-fold, making it a very useful attractant for the latter species. The cost of the trap/odour-bait system was estimated to be US$8.5 per unit per annum. The economics of this method of tsetse control are discussed.