Vectorial drivers of malaria transmission in Jabi Tehnan district, Amhara Regional State, Ethiopia.

Among the factors affecting the effectiveness of malaria control is poor knowledge of the entomologic drivers of the disease. We investigated anopheline populations as part of a baseline study to implement house screening of windows and doors as a supplementary malaria control tool towards elimination in Jabi Tehnan district, Amhara Regional State of Ethiopia. The samples were surveyed monthly using CDC light traps between June 2020 and May 2021. Mosquito trap density (< 3 mosquitoes/trap) was low, however, with a high overall Plasmodium sporozoite rate (9%; indoor = 4.3%, outdoor = 13.1%) comprising P. falciparum (88.9%) and P. vivax (11.1%). Anopheles gambiae s.l., mostly An. arabiensis, comprised > 80% of total anopheline captures and contributed ~ 42% of Plasmodium-infected mosquitoes. On the other hand, morphologically scored Anopheles funestus s.l., constituting about 6% of anopheline collections, accounted for 50% of sporozoite-infected mosquitoes. Most of the infected An. funestus s.l. specimens (86.7%) were grouped with previously unknown or undescribed Anopheles species previously implicated as a cryptic malaria vector in the western Kenyan highlands, confirming its wider geographic distribution in eastern Africa. Other species with Plasmodium infection included An. longipalpis C, An. theileri, An. demillioni, and An. nili. Cumulatively, 77.8% of the infected mosquitoes occurred outdoors. These results suggest efficient malaria parasite transmission despite the low vector densities, which has implications for effective endpoint indicators to monitor malaria control progress. Additionally, the largely outdoor infection and discovery of previously unknown and cryptic vectors suggest an increased risk of residual malaria transmission and, thus, a constraint on effective malaria prevention and control.

Spatial distribution of Glossina morsitans (Diptera: Glossinidae) in Zambia: A vehicle-mounted sticky trap survey and Maxent species distribution model.

BACKGROUND: Tsetse-transmitted African trypanosomiasis is a debilitating and fatal disease of humans and livestock if left untreated. While knowledge of the spatial distribution patterns of tsetse is essential for the development of risk-based vector control strategies, existing distribution maps in Zambia are more than 40 years old and were based on coarse spatial resolution data. The recently developed vehicle-mounted sticky trap (VST) provides an alternative sampling device to aid in updating existing distribution maps but has not been applied outside an experimental setting and is limited to motorable tracks. Therefore, the objective of the present study was to demonstrate the effectiveness of utilizing the VST for area-wide surveys of Glossina morsitans and to use the occurrence records to predict its spatial distribution in Zambia under current environmental conditions using Maxent. METHODOLOGY/PRINCIPAL FINDINGS: Two-sided all-blue VST baited with butanone and 1-octen-3-ol was used to survey 692 and 1020 km of transect routes in G. m. centralis Machado and G. m. morsitans Westwood previously published distribution in Zambia. Maxent species distribution technique was used to predict the potential distribution of the two subspecies using current climatic and environmental data which was then compared to the historical distribution. A total of 15,602 tsetse were captured with G. m. morsitans (58%) being the most abundant. G. m. centralis and G. pallidipes Austin represented 39 and 2% of the catch respectively, and G. brevipalpis Newstead was also detected. The predicted potential distribution for G. m. centralis was 80,863 km2 while that of G. m. morsitans was 70,490 km2 representing a 47 and 29% reduction compared to their historical distributions, respectively. CONCLUSION/SIGNIFICANCE: The VST is effective for sampling G. morsitans outside experimental settings and is recommended for use as an additional tsetse survey tool. The spatial distribution of G. morsitans in Zambia has reduced by 101,051 km2 due to temperature and land cover changes.

A new genus and species in the diverse dung beetle tribe Onthophagini Streubel, 1846 (Scarabaeidae: Scarabaeinae) from South Africa.

A new dung beetle genus and species is described and pictured following its recent discovery on a farm in South Africa. Hathor spinosa Deschodt, new species belongs to the subfamily Scarabaeinae, tribe Onthophagini Streubel, 1846, it shows a unique set of characters. A map is provided to show the type locality of the new genus and species that has a putative association with ants.

Efficiencies of stationary sampling tools for the tsetse fly Glossina fuscipes fuscipes in western Kenya.

Monitoring the effectiveness of tsetse fly control interventions that aim to reduce transmission of African trypanosomiasis requires highly efficient sampling tools that can catch flies at low densities. The sticky small target (StS-target) has previously been shown to be more effective in sampling Glossina fuscipes fuscipes compared to the biconical trap. However, its efficiency in terms of the proportion of flies it catches out of those that visit it has not been reported. Furthermore, there are no reports on whether tsetse samples caught using the StS-target can be used for subsequent processes such as molecular tests. In this study, we evaluated the efficiency of the biconical trap and targets for sampling G. f. fuscipes. All targets were tiny (0.25 × 0.50 m) but varied in their capture system. We used targets with sticky surface (StS-targets) and those with an electrified surface (ES-targets). We also assessed the suitability of flies caught on the StS-target for molecular tests by amplifying DNA of bacterial communities. Randomized block design experiments were undertaken in Mbita area and Manga Island on Lake Victoria of western Kenya. Fly catches of each sampling tool were compared to those of the sampling tool flanked by electric (E) nets and analyzed using a negative binomial regression. The total catch for each sampling tool alone was divided by the total catch of the sampling tool flanked by two E-nets to obtain its efficiency expressed as a percentage. A proportion of flies caught on the StS-target was preserved for molecular tests. Overall, the efficiencies of the biconical trap, ES-target and StS-target were 7.7%, 13.3% and 27.0%, respectively. A higher proportion of females (69 to 79%) than males approached all the sampling tools, but the trap efficiency was greater for male G. f. fuscipes than females. Furthermore, sequencing the 16S rRNA gene from fly samples caught on the StS-target revealed the presence of Spiroplasma. Our results indicate that the SS-target is the most efficient trap to monitor G. f. fuscipes population during interventions, with the biconical trap being the least efficient, and samples collected from StS-targets are suitable for molecular studies.

A novel vehicle-mounted sticky trap; an effective sampling tool for savannah tsetse flies Glossina morsitans morsitans Westwood and Glossina morsitans centralis Machado.

BACKGROUND: Black screen fly round (BFR) is a mobile sampling method for Glossina morsitans. This technique relies on the ability of operator(s) to capture flies landing on the screen with hand nets. In this study, we aimed to evaluate a vehicle-mounted sticky panel trap (VST) that is independent of the operator's ability to capture flies against BFR, for effective and rapid sampling of G. m. morsitans Westwood and G. m. centralis Machado. We also determined the influence of the VST colour (all-blue, all-black or 1:1 blue-black), orientation and presence of odour attractants on tsetse catch. METHODOLOGY/PRINCIPAL FINDINGS: Using randomised block design experiments conducted in Zambia, we compared and modelled the number of tsetse flies caught in the treatment arms using negative binomial regression. There were no significant differences in the catch indices of the three colour designs and for in-line or transversely oriented panels for both subspecies (P > 0.05). When baited with butanone and 1-octen-3-ol, VST caught 1.38 (1.11-1.72; P < 0.01) times more G. m. centralis flies than the un-baited trap. Attractants did not significantly increase the VST catch index for G. m. morsitans (P > 0.05). Overall, the VST caught 2.42 (1.91-3.10; P < 0.001) and 2.60 (1.50-3.21; P < 0.001) times more G. m. centralis and G. m. morsitans respectively, than the BFR. The VST and BFR took 10 and 35 min respectively to cover a 1 km transect. CONCLUSION/SIGNIFICANCE: The VST is several times more effective for sampling G. m. morsitans and G. m. centralis than the BFR and we recommend its use as an alternative sampling tool.

Afrotropical sand fly-host plant relationships in a leishmaniasis endemic area, Kenya.

The bioecology of phlebotomine sand flies is intimately linked to the utilization of environmental resources including plant feeding. However, plant feeding behavior of sand flies remains largely understudied for Afrotropical species. Here, using a combination of biochemical, molecular, and chemical approaches, we decipher specific plant-feeding associations in field-collected sand flies from a dry ecology endemic for leishmaniasis in Kenya. Cold-anthrone test indicative of recent plant feeding showed that fructose positivity rates were similar in both sand fly sexes and between those sampled indoors and outdoors. Analysis of derived sequences of the ribulose-1,5-bisphosphate carboxylase large subunit gene (rbcL) from fructose-positive specimens implicated mainly Acacia plants in the family Fabaceae (73%) as those readily foraged on by both sexes of Phlebotomus and Sergentomyia. Chemical analysis by high performance liquid chromatography detected fructose as the most common sugar in sand flies and leaves of selected plant species in the Fabaceae family. Analysis of similarities (ANOSIM) of the headspace volatile profiles of selected Fabaceae plants identified benzyl alcohol, (Z)-linalool oxide, (E)-ß-ocimene, p-cymene, p-cresol, and m-cresol, as discriminating compounds between the plant volatiles. These results indicate selective sand fly plant feeding and suggest that the discriminating volatile organic compounds could be exploited in attractive toxic sugar- and odor- bait technologies control strategies.

Exploring the influence of different habitats and their volatile chemistry in modulating sand fly population structure in a leishmaniasis endemic foci, Kenya.

Phlebotomine sand flies transmit many viral protozoan and bacterial pathogens of public health importance. Knowledge of the ecologic factors influencing their distribution at local scale can provide insights into disease epidemiology and avenues for targeted control. Animal sheds, termite mounds and houses are important peri-domestic and domestic habitats utilized by different sand flies as resting or breeding habitats. However, our knowledge for selection of these habitats by sand flies remains poor. Here, we tested the hypothesis that these habitat types harbor different composition of sand fly species and differ in their volatile chemistry that could influence sand fly selection. To achieve this, we employed CDC light traps following a cross-sectional survey to investigate the distribution of sand flies in the three habitats in an endemic site for leishmaniasis in Kenya. The study was carried out during the dry season, when sand flies are optimally abundant in 2018 and 2020. Sand fly abundance did not vary between the habitats, but species-specific differences in abundance was evident. Measures of sand fly community structure (Shannon diversity and richness) were highest in animal shed, followed by termite mound and lowest inside human dwelling (house). This finding indicates broader attraction of both sexes of sand flies and females of varying physiological states to animal sheds potentially used as breeding or resting sites, but also as a signal for host presence for a blood meal. Furthermore, gas chromatography-mass spectrometric analysis of volatiles collected from represented substrates associated with these habitats viz: human foot odor on worn socks (houses indoors), cow dung (animal sheds) and termite mounds (enclosed vent), revealed a total of 47 volatile organic compounds. Of these, 26, 35 and 16 were detected in human socks, cow dung and enclosed termite vent, respectively. Of these volatiles, 1-octen-3-ol, 6-methyl-5-hepten-2-one, α-pinene, benzyl alcohol, m-cresol, p-cresol and decanal, previously known as attractants for sandflies and other blood-feeding insects, were common to the habitats. Our results suggest that habitat volatiles may contribute to the composition of sand flies and highlight their potential for use in monitoring sand fly populations.

Plant nutrient quality impacts survival and reproductive fitness of the dengue vector Aedes aegypti.

BACKGROUND: In a recent study using DNA barcoding, we identified the plants fed upon by four Afro-tropical mosquito species that vector dengue, malaria, and Rift Valley fever. Herein, we have expanded on this study by investigating the role of three of the plants, Pithecellobium dulce (Fabaceae), Leonotis nepetifolia (Lamiaceae), and Opuntia ficus-indica (Cactaceae), on the survival, fecundity, and egg viability of the dengue vector Aedes aegypti. METHODS: We tested these effects using females that received (i) an initial three rations of blood meals and (ii) no blood meal at all. Two controls were included: age-matched females fed on glucose solution with or without an initial blood meal and those fed exclusively on blood meals. Data were collected daily over a 30-day period. The amino acid contents of Ae. aegypti guts and their respective diets were detected by coupled liquid chromatography-mass spectrometry. RESULTS: Females fed on P. dulce and an exclusively blood meal diet had a shorter survival than those fed on glucose. On the other hand, females fed on L. nepetifolia survived longer than those fed exclusively on blood meals, whereas those fed on O. ficus-indica had the shortest survival time. With an initial blood meal, females fed on L. nepetifolia laid 1.6-fold more eggs while those fed on the other diets laid fewer eggs compared to those fed exclusively on blood meals. Hatching rates of the eggs laid varied with the diet. Mass spectroscopic analysis of gut contents of mosquitoes exposed to the different diets showed qualitative and quantitative differences in their amino acid levels. CONCLUSION: Our findings highlight the central role of plant nutrients in the reproductive fitness of dengue vectors, which may impact their disease transmission potential.

Biological traits of wild-caught populations of Aedes aegypti in dengue endemic and non-endemic regions of Kenya.

Variation in vector traits can modulate local scale differences in pathogen transmission. Here, we compared seasonal variation in the wing length (proxy for body size) and energy reserves of adult wild-caught Aedes aegypti populations from a dengue endemic (Kilifi) and non-endemic (Isiolo) area of Kenya. Vector sampling in the dengue endemic site was conducted during the dry and wet seasons. In the non-endemic area, it was limited to the dry season which characterizes this ecology where sporadic or no rainfall is commonplace during the year. We found variation by site in the body size of both sexes, with an overall smaller size of Ae. aegypti populations collected from Isiolo than those from Kilifi. Our results show that although total carbohydrates and lipids levels were highest in both sexes during the dry season, they were two-fold higher in males than females. However, we found weak correlations between body size and energy reserves for both sexes, with body size being more sensitive in identifying differences at a population level. These results provide insights into the determinants of the vectoring potential of Ae. aegypti populations in dengue endemic and non-endemic ecologies in Kenya.

The enigmatic dung beetle genus Stiptopodius Harold, 1871 (Coleoptera: Scarabaeidae: Scarabaeinae) revisited: new species descriptions from southern Africa.

It is proposed that the genus Stiptopodius Harold, 1871 should be subdivided into two species groups based on the shape of the lateral edge of the pronotum. Three new species are described from southern Africa: Stiptopodius peringueyi Daniel Deschodt, new species, Stiptopodius savuti Daniel Deschodt, new species, and Stiptopodius muellerae Daniel Deschodt, new species. Stiptopodius savuti new species is the first record of the genus from Botswana. A distribution map for the new taxa is provided. The identification key to the known species of Stiptopodius is updated.

Upsa centennial, a new genus and species (Coleoptera: Scarabaeidae: Scarabaeinae: Endroedyolini) from the Southern Mistbelt forest in South Africa: celebrating 100 years of entomology at the University of Pretoria.

Upsa centennial Deschodt, Sole Scholtz, new genus and species is described, celebrating a century of entomology at the University of Pretoria. This new genus in the dung beetle tribe Endroedyolini (Scarabaeidae: Scarabaeinae) occurs in the Albany Coastal Mistbelt forest in the Eastern Cape Province in South Africa. A distribution map and key for all genera and species in the tribe are provided.[Genus Zoobank url: urn:lsid:zoobank.org:act:92A64613-A8CE-48DF-84D9-7450EA1D40AA].

Revision of the southern African genera Nemopterella Banks and Nemia Navás (Neuroptera: Nemopteridae: Nemopterinae), with descriptions of new genera and species.

The southern African genera Nemopterella Banks, 1910 and Nemia Navás, 1915 (Neuroptera: Nemopteridae: Nemopterinae) are revised. Nemopterella is split into three genera: Nemopterella sensu stricto with type species Nemopteryx africana Leach, 1815 (= Nemopterella africana), Afroptera gen. nov., with type species Nemopterella munroi Tjeder, 1967, and the monotypic genus Siccanda gen. nov., with type species Nemopterella arenaria Tjeder, 1967. Eight new species are described in Afroptera gen. nov.: A. acuta Abdalla Mansell sp. nov., A. alba Mansell Abdalla sp. nov., A. brinkmani Abdalla Mansell sp. nov., A. balli Abdalla Mansell sp. nov., A. cylindrata Abdalla Mansell sp. nov., A. folia Abdalla Mansell sp. nov., A. koranna Mansell Abdalla sp. nov., A. maraisi Abdalla Mansell sp. nov., as well as two new species in the genus Nemopterella: N. kabas Mansell Abdalla sp. nov., and N.cedrus Mansell Abdalla sp. nov.

A new species of Versicorpus Deschodt, Davis amp; Scholtz, 2011 (Scarabaeidae: Scarabaeinae: Byrrhidiini) from the Brandberg Mountain, Namibia.

The recently described dung beetle tribe Byrrhidiini currently comprises seven genera and nineteen species (Davis et al. 2019). During a recent collecting expedition to the Brandberg Mountain [S21.11° E14.69°] in Namibia, a single male specimen, together with various disarticulated body parts of a new species belonging to this tribe were collected. It was found amongst dried hyrax (Procavia capensis) dung pellets between large granite boulders. This new species clearly fits the current definition of the genus Versicorpus Deschodt, Davis Scholtz, 2011. This raises the number of the constituent species of Versicorpus to three and that for Byrrhidiini to twenty.

A beautiful new species of Hyalonthophagus Palestrini amp; Giacone, 1988 (Coleoptera: Scarabaeidae: Scarabaeinae), from the Northern Cape Province, South Africa.

Hyalonthophagus Palestrini Giacone, 1988, from Afrotropical savanna, is raised to generic status having been originally described as a subgenus within the genus Onthophagus Latreille, 1802. Hyalonthophagus pulcher Deschodt Davis, new species is described from the Northern Cape, South Africa. Maps are provided to show (1) the locally-restricted distribution pattern of the new species isolated from adjoining savanna in warm, dry Karoo climate to the south of the Orange River, and, (2) the disjunct distribution pattern in relation to those of three other southern African species centred in savanna to the northeast beyond areas with unsuitable climatic or ecological conditions. An assessment of the conservation status for Hyalonthophagus pulcher Deschodt Davis, new species is also provided.

Redescription of the holotype of Bostrichoclerus bicornus Van Dyke, 1938, a rare species of the New World Tillinae Fauna (Coleoptera: Cleridae), with some taxonomic notes.

Bostrichoclerus bicornus Van Dyke is known from southwest United States and northwest Mexico. To date, only two specimens have been captured: the holotype, collected on Isla Angel de la Guarda, in the Gulf of California, Mexico, and a second individual collected in San Bernardino County, California, United States. The original description of B. bicornus is brief and lacks any images. Considering its rarity, we present the redescription of this species based on the examination of the holotype and compare this taxon to similar genera of New World Tillinae. Images of the holotype and the Bostrichoclerus specimen collected in southern California are given. We conclude that B. bicornus is undoubtedly a member of the subfamily Tillinae with unclear intergeneric relations in the group.

An update to the taxonomy of the genus Macroderes Westwood 1842 (Coleoptera: Scarabaeidae: Scarabaeinae) with descriptions of new species from South Africa.

The genus Macroderes Westwood, 1842 (Scarabaeidae: Scarabaeinae, tribe incertae sedis) is practically endemic to South Africa with only one species that is found little north in southern Namibia. The ranges of the species are limited to the winter-fall and bimodal biomes of South Africa comprising the regions of Richtersveld as extreme points of its northerly distribution, and extending to the south through Namaqualand to Cape Agulhas. The taxonomy of the genus is revised. Fourteen valid species are recognised and three others are of doubtful validity. Seven new species are described, these are: M. cederbergensis Abdalla Deschodt, new species, M. tortuosus Abdalla Scholtz, new species, M. gifboomi Abdalla Scholtz, new species, M. leipoldti Abdalla Deschodt, new species, M. oreatus Abdalla Deschodt, new species, M. porselinus Abdalla, new species, and M. soleiana Abdalla Deschodt, new species. Macroderes nitidus Harold, 1877 is redescribed and its lectotype is designated. The diagnostic characters as well as an updated geographic distribution of each species are summarised. An updated key of the genus, photographs of habitus, sclerites of internal sac, pronotum, pronotal punctures and elytra also are provided.

A revision of and keys to the genera of the Mantispinae of the Oriental and Palearctic regions (Neuroptera: Mantispidae).

The Mantispinae (Neuroptera: Mantispidae) genera of the Oriental and Palearctic regions are revised. A morphological key to the genera is generated. Austroclimaciella, Campancella, Mantispa, Mantispilla, Necyla, Stenomantispa and Tuberonotha are redescribed. The Ohl (2004) catalogue is updated for the relevant genera. Sagittalata (= Perlamantispa) is assigned as a synonym of Mantispilla which is restored as a valid genus. Orientispa is assigned as a synonym of Necyla.

Host plant forensics and olfactory-based detection in Afro-tropical mosquito disease vectors.

The global spread of vector-borne diseases remains a worrying public health threat, raising the need for development of new combat strategies for vector control. Knowledge of vector ecology can be exploited in this regard, including plant feeding; a critical resource that mosquitoes of both sexes rely on for survival and other metabolic processes. However, the identity of plant species mosquitoes feed on in nature remains largely unknown. By testing the hypothesis about selectivity in plant feeding, we employed a DNA-based approach targeting trnH-psbA and matK genes and identified host plants of field-collected Afro-tropical mosquito vectors of dengue, Rift Valley fever and malaria being among the most important mosquito-borne diseases in East Africa. These included three plant species for Aedes aegypti (dengue), two for both Aedes mcintoshi and Aedes ochraceus (Rift Valley fever) and five for Anopheles gambiae (malaria). Since plant feeding is mediated by olfactory cues, we further sought to identify specific odor signatures that may modulate host plant location. Using coupled gas chromatography (GC)-electroantennographic detection, GC/mass spectrometry and electroantennogram analyses, we identified a total of 21 antennally-active components variably detected by Ae. aegypti, Ae. mcintoshi and An. gambiae from their respective host plants. Whereas Ae. aegypti predominantly detected benzenoids, Ae. mcintoshi detected mainly aldehydes while An. gambiae detected sesquiterpenes and alkenes. Interestingly, the monoterpenes ß-myrcene and (E)-ß-ocimene were consistently detected by all the mosquito species and present in all the identified host plants, suggesting that they may serve as signature cues in plant location. This study highlights the utility of molecular approaches in identifying specific vector-plant associations, which can be exploited in maximizing control strategies such as such as attractive toxic sugar bait and odor-bait technology.