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Conservation biological control could be an alternative to insecticides for the management of the aphid Myzus persicae (Sulzer). To develop sustainable strategies for M. persicae control in peach orchards in the Mediterranean, a 2-yr field experiment was conducted to identify the key predators of the aphid; to determine whether the proximity of insectary plants boost natural enemies of M. persicae in comparison to the resident vegetation; and whether selected insectary plants enhance natural enemy populations in the margins of peach orchards. Aphidoletes aphidimyza Rondani (Diptera: Cecidomyiidae) and Episyrphus balteatus De Geer (Diptera: Syrphidae) were the most abundant predators found among sentinel aphid colonies, accounting for 57% and 26%, respectively. Samplings during 2015 yielded twice as many hoverflies in M. persicae sentinel plants close to the insectary plants as those close to the resident vegetation. The abundance of other natural enemies in sentinel plants, depending on their proximity to the insectary plants, was not significantly different in either of the 2 yr. Hoverflies hovered more often over the insectary plants than over the resident vegetation and landed significantly more often on Lobularia maritima (L.) Desv., Moricandia arvensis (L.) DC., and Sinapis alba L. (Brassicales: Brassicaceae) than on Achillea millefollium L. (Asterales: Compositae). Parasitoids were significantly more abundant in L. maritima and A. millefollium. The vicinity of selected insectary plants to peach orchards could improve the presence of hoverflies, which might benefit the biological control of M. persicae.

Background Aedes aegypti and Ae. albopictus are important vectors of infectious diseases, especially those caused by arboviruses such as dengue, chikungunya and Zika. Aedes aegypti is very well adapted to urban environments, whereas Ae. albopictus inhabits more rural settings. Pyrethroid resistance is widespread in these vectors, but limited data exist from the Southwest Pacific Region, especially from Melanesia. While Aedes vector ecology is well documented in Australia, where incursion of Ae. albopictus and pyrethroid resistance have so far been prevented, almost nothing is known about Aedes populations in neighbouring Papua New Guinea (PNG). With pyrethroid resistance documented in parts of Indonesia but not in Australia, it is important to determine the distribution of susceptible and resistant Aedes populations in this region. Methods The present study was aimed at assessing Aedes populations for insecticide resistance in Madang and Port Moresby, located on the north and south coasts of PNG, respectively. Mosquitoes were collected using ovitraps and reared in an insectary. Standard WHO bioassays using insecticide-treated filter papers were conducted on a total of 253 Ae. aegypti and 768 Ae. albopictus adult mosquitoes. Subsets of samples from both species (55 Ae. aegypti and 48 Ae. albopictus ) were screened for knockdown resistance mutations in the voltage-sensitive sodium channel ( Vssc ) gene, the target site of pyrethroid insecticides. Results High levels of resistance against pyrethroids were identified in Ae . aegypti from Madang and Port Moresby. Aedes albopictus exhibited susceptibility to pyrethroids, but moderate levels of resistance to DDT. Mutations associated with pyrethroid resistance were detected in all Ae . aegypti samples screened. Some genotypes found in the present study had been observed previously in Indonesia. No Vssc mutations associated with pyrethroid resistance were found in the Ae. albopictus samples. Conclusions To our knowledge, this is the first report of pyrethroid resistance in Ae . aegypti mosquitoes in PNG. Interestingly, usage of insecticides in PNG is low, apart from long-lasting insecticidal nets distributed for malaria control. Further investigations on how these resistant Ae . aegypti mosquito populations arose in PNG and how they are being sustained are warranted.

Weed floral resources are often overlooked in biological control manipulations, yet common species in this group can contribute to enhanced biological control efficacy. Weed floral resources may not be examined as frequently as certain insectary species (buckwheat). Furthermore, they may require less maintenance and are adapted to grow in the planted area. Here, we investigated the effects of weed and other non-crop floral resources on Eretmocerus mundus , a parasitoid of the whitefly, Bemisia tabaci , in the laboratory. The two common weeds evaluated were shepherd’s purse ( Capsella bursa - pastoris ) and white rocket ( Diplotaxis erucoides ). These were compared with buckwheat ( Fagopyrum esculentum ) and alyssum ( Lobularia maritima ). Adults of the above parasitoid were exposed to flowers of the selected plants and survived six times longer with buckwheat than those in the control (water only) and 2.8, 3.1 and four times longer with shepherd’s purse, rocket and alyssum, respectively. All plant species significantly increased parasitoid longevity, egg load and fecundity compared to the control. Buckwheat had the greatest effect on these parameters. Parasitism rate of the pest increased by up to 72.1%. This work illustrates that the selected non-buckwheat species could have value where buckwheat germination rate and phenology may be limiting such as in arid climates, for which this work was targeted.

Background Understanding the ecology of larval malaria and lymphatic filariasis mosquitoes in a changing environment is important in developing effective control tools or programmes. This study characterized the breeding habitats of Anopheles mosquitoes in rural communities in different ecological zones in Ghana during the dry and rainy seasons. Methods The spatio-temporal distribution, species composition, and abundance of larval Anopheles mosquitoes in breeding habitats were studied in five locations in three ecological zones of Ghana. These were Anyakpor (coastal savannah area), Duase (forest area), and Libga, Pagaza, and Kpalsogu (Sahel savannah area). Larvae were collected using standard dippers and were raised in the insectary for identification. Results Out of a total of 7984 mosquito larvae collected, 2152 (27.26%) were anophelines and were more abundant in the rainy season (70.82%) than in the dry season (29.18%). The anophelines comprised 2128 (98.88%) An. gambiae s.l., 16 (0.74%) An. rufipes , and 8 (0.37%) An. pharoensis . In the coastal savannah and forest zones, dug-out wells were the most productive habitat during the dry (1.59 larvae/dip and 1.47 larvae/dip) and rainy seasons (11.28 larvae/dip and 2.05 larvae/dip). Swamps and furrows were the most productive habitats in the Sahel savannah zone during the dry (0.25 larvae/dip) and rainy (2.14 larvae/dip) seasons, respectively. Anopheles coluzzii was the most abundant sibling species in all the ecological zones. Anopheles melas and An. arabiensis were encountered only in the coastal savannah and the Sahel savannah areas, respectively. Larval habitat types influenced the presence of larvae as well as larval density ( p  < 0.001). The land-use type affected the presence of Anopheles larvae ( p  = 0.001), while vegetation cover influenced larval density ( p  < 0.05). Conclusion The most productive habitats were dug-out wells in the coastal savannah and forest zones, and furrows from irrigated canals in the Sahel savannah zone. Anopheles coluzzii was the predominant vector species in all the ecological zones. The abundance of Anopheles breeding habitats and larvae were influenced by anthropogenic activities. Encouraging people whose activities create the larval habitats to become involved in larval source management such as habitat manipulation to stop mosquito breeding will be important for malaria and lymphatic filariasis control.

Background Host-associated microbes, collectively known as the microbiota, play an important role in the biology of multicellular organisms. In mosquito vectors of human pathogens, the gut bacterial microbiota influences vectorial capacity and has become the subject of intense study. In laboratory studies of vector biology, genetic effects are often inferred from differences between geographically and genetically diverse colonies of mosquitoes that are reared in the same insectary. It is unclear, however, to what extent genetic effects can be confounded by uncontrolled differences in the microbiota composition among mosquito colonies. To address this question, we used 16S metagenomics to compare the midgut bacterial microbiome of six laboratory colonies of Aedes aegypti recently derived from wild populations representing the geographical range and genetic diversity of the species. Results We found that the diversity, abundance, and community structure of the midgut bacterial microbiome was remarkably similar among the six different colonies of Ae. aegypti , regardless of their geographical origin. We also confirmed the relatively low complexity of bacterial communities inhabiting the mosquito midgut. Conclusions Our finding that geographically diverse colonies of Ae. aegypti reared in the same insectary harbor a similar gut bacterial microbiome supports the conclusion that the gut microbiota of adult mosquitoes is environmentally determined regardless of the host genotype. Thus, uncontrolled differences in microbiota composition are unlikely to represent a significant confounding factor in genetic studies of vector biology.

The main reason for adding plants to accompany the main crop is to protect it from pests and diseases. We reviewed the effectiveness of white mustard (Sinapis alba L.), sweet alyssum (Lobularia maritima L.), and coriander (Coriandrum sativum L.) in this regard. White mustard proximity had a strong positive influence on the occurrence of Syrphidae, parasitoids, Coccinellidae, and Carabidae, as well as on the fertility of Syrphidae and the longevity of parasitoids—all of which are essential for biological pest control. It also reduced many pests and diseases. The influence of S. alba on yield depends on the spacing used and the species of protected plant. Sweet alyssum positively affected the occurrence of Syrphidae, Coccinellidae, Anthocoridae, epigeal, and soil fauna, as well as the longevity of parasitoids and Anthocoridae. Its effect on the crop yield is variable, depending on the references consulted. The sensitivity of L. maritima to Phyllotreta spp. excludes it as a companion plant for hosts of these pests. Coriander positively affected the occurrence of Chrysopidae, Coccinellidae, Staphylinidae, and Aranea, as well as the longevity of parasitoids and the egg-laying of Syrphidae. It also reduced some crop pests. Introduction of the reviewed plants can improve the biodiversity of beneficial entomofauna that can help control pests and reduce diseases, with benefits to crop and yield. The use of synthetic insecticides can thus be greatly reduced, though it is not always possible to avoid them completely.

Background The rapid and widespread evolution of insecticide resistance has emerged as one of the major challenges facing malaria control programs in sub-Saharan Africa. Understanding the insecticide resistance status of mosquito populations and the underlying mechanisms of insecticide resistance can inform the development of effective and site-specific strategies for resistance prevention and management. The aim of this study was to investigate the insecticide resistance status of Anopheles gambiae ( s.l. ) mosquitoes from coastal Kenya. Methods Anopheles gambiae ( s.l. ) larvae sampled from eight study sites were reared to adulthood in the insectary, and 3- to 5-day-old non-blood-fed females were tested for susceptibility to permethrin, deltamethrin, dichlorodiphenyltrichloroethane (DDT), fenitrothion and bendiocarb using the standard World Health Organization protocol. PCR amplification of rDNA intergenic spacers was used to identify sibling species of the An. gambiae complex. The An. gambiae ( s.l. ) females were further genotyped for the presence of the L1014S and L1014F knockdown resistance (kdr) mutations by real-time PCR. Results Anopheles arabiensis was the dominant species, accounting for 95.2% of the total collection, followed by An. gambiae ( s.s. ), accounting for 4.8%. Anopheles gambiae ( s.l. ) mosquitoes were resistant to deltamethrin, permethrin and fenitrothion but not to bendiocarb and DDT. The L1014S kdr point mutation was detected only in An. gambiae ( s.s. ), at a low allelic frequency of 3.33%, and the 1014F kdr mutation was not detected in either An. gambiae ( s.s. ) or An. arabiensis . Conclusion The findings of this study demonstrate phenotypic resistance to pyrethroids and organophosphates and a low level of the L1014S kdr point mutation that may partly be responsible for resistance to pyrethroids. This knowledge may inform the development of insecticide resistance management strategies along the Kenyan Coast. Graphical Abstract

Background Eggs of anopheline mosquitoes hatch within a few days of laying and require high levels of humidity to survive. Assessing natural variation in egg hatching and its environmental and genetic determinants in sibling species of the malaria vector Anopheles gambiae s.l. is important for understanding their adaptation to variable aquatic habitats. Crucially, it can also inform insectary rearing practices toward the optimization of mosquito production for genetic vector control strategies. Methods Hatching rates and timing of egg hatching in long-established and recently colonized strains of An. gambiae s.s, Anopheles arabiensis , and Anopheles coluzzii , were compared under still water conditions (26 ℃) and with cold (4 ℃) and (15 ℃) water agitation regimes. Next, early and late hatching strains of the recently colonized An. coluzzii VK colony were generated through bidirectional selection for 18–23 generations to detect a genetic component for this trait. Results Hatching rates differed significantly between species and treatments. The older An. arabiensis Senn and An. gambiae s.s. Kisumu strains had the highest proportion of hatching and preferred the nonagitation treatment at 26 °C. In contrast, the more recently colonized An. coluzzii VK and An. arabiensis Rufisque strains had lower overall hatching success but responded strongly to agitation at 4 °C, while the An. coluzzii Mopti strain did not significantly respond to water agitation. In all strains, eggs hatching started at day 2 and continued till day 5 in the older strains, whilst it was more staggered and extended up to day 6 in the younger strains. Bidirectional selection for early and late hatching over many generations resulted in early hatching selected strains with eggs hatching 2–3 days earlier than in late hatching ones indicating a significant heritable component for these traits. Conclusions Water agitation and temperature and age of colonization are likely important determinants of egg hatching in natural An. gambiae s.l. populations. Current rearing protocols systematically select for fast hatching and result in the progressive loss of staggered egg hatching in older laboratory strains. The selection of novel slow-hatching strains may prove instrumental to enable the mass production, shipping, and release of Anopheles mosquitoes across Africa as part of genetic vector control programs. Graphical Abstract

Parasitoid wasps are invaluable agents in pest biological control. Early detection and identification of parasitoid immatures are vital in characterizing parasitoid–host interactions and for evaluating parasitism rates accurately in the field. Trichogramma is the most widely used parasitoid wasp, and several studies have been performed for its molecular identification. However, those studies were mainly focused on Trichogramma adults and rarely on immatures. Here, we report a method to detect and identify Trichogramma larvae in their host eggs. We designed a pair of Trichogramma-specific primers that amplified Trichogramma mtCOI sequences from Corcyra cephalonica (Stainton) eggs parasitized by any of eight Trichogramma species tested but not from nonparasitized eggs of four lepidopteran hosts. This PCR method reliably detected Trichogramma immatures in parasitized eggs as early as 1 h after parasitism. We further developed an RFLP (restriction fragment length polymorphism) assay using restriction enzymes SspI and VspI to differentiate eight Trichogramma species at their immature stage. Overall, we developed a sensitive and reliable PCR–RFLP method to detect and identify immature-stage Trichogramma in their lepidopteran hosts. This method shows promise for conveniently identifying Trichogramma in insectaries and accurately evaluating parasitism rates in the field.

Background Colonizing fleas under laboratory conditions is a crucial step to studying their biology, conducting bioassays, and evaluating their ability to transmit pathogens. Starting a colony implies collecting and maintaining wild-caught specimens to obtain the next generations. Here we describe methods to collect, safely transport, and maintain adult and immature stages, and for the first time, to produce viable next generations of Pulex irritans , the human flea in the insectary. Methods Adult fleas were collected using human landing catches, while immature stages were obtained using the Berlese–Tullgren method. Blood feeding was performed using an artificial feeding device and the survival of adult fleas maintained on human or sheep blood was assessed. Results More than 200 F0 adults survived and produced eggs for approximately 6 weeks, with an average lifespan of 6 days for males and 10 days for females. Pupation occurred around 10 days after arrival in the laboratory, yielding more than 900 cocoons within 8 weeks, with an emergence rate of approximately 80%. Challenges included high mortality among F1 adults, with both sexes surviving an average of 7 days. Although blood source assay was inconclusive, fleas were maintained on human blood. Factors that may have contributed to the low survival of F1 are discussed. Conclusions This study provides a foundational framework for laboratory-based research on P. irritans and its role in vector-borne disease transmission. While further studies are needed to establish a sustainable laboratory colony, we demonstrate that a substantial F1 population can be obtained within 3 weeks of laboratory rearing, enabling experimental studies on this species. Graphical Abstract