Laboratory Colony Research Articles

Food as a factor of fertility, development duration, and changes in morphometric parameters in Henosepilachna vigintioctomaculata (Motschulsky)

Relevance.The physiology of insects nutrition and digestion reflects the diversity of their food specialization, aimed at the most effective use of feed. The choice of the object of nutrition is provided byattractants in it, as well as the presence of substances necessary for the insect to pass the stages ofdevelopment and general nutrition. On the other hand, the “plant-phytophage” system has well-developed barriers that limit the choice of plants by insects for settling, feeding, and eggs laying. In themodern literature, there is very little information on the effect of food plants on fertility, developmentduration, and changes in morphometric parameters in 28-spotted potato ladybird Henosepilachnavigintioctomaculata (Motschulsky). However, they are important for understanding the ecology of thepest and developing effective control measures.Research methodology.The laboratory colony of Henosepilachna vigintioctomaculata(Motschulsky) was established in 2019. Adults were collected in various locations throughoutPrimorsky Territory, Russia. For an introduction into the culture of the insectarium, imagos,clutches, and larvae were collected in natural habitats. Standard methods of keeping andbreeding insect cultures were used, aimed at optimizing the parameters of the environment, thedensity of the content, and the feed supply.Results.The uneven influence of crops on different aspects of the ontogenesis of the potato ladybirdwas revealed. The potato was the most favorable food in most experiments. When feeding with thiscrop, the smallest incubation period of eggs, the largest sizes of larvae of initial ages, the largest sizesof pupae, fertility, low mortality was observed, and as a result, the largest growth coefficient(3.22±0.22) and the shortest period of development from eggs to imago (21.3±0.81) were revealed.The remaining forage plants used in the study showed a less unambiguous result. The different influence of crops on both individual indicators and the ontogenetic periods of the phytophage was found.When eating tomato, cucumber, pumpkin, lime, high overall mortality was noted. At the same time, linden stimulated the development of eggs and the growth of young larvae but provoked low fertility anda general prolongation of the development period. According to the set of characteristics, pumpkin,cucumber, and linden were the least favorable for nutrition.

Induction of insecticide tolerance in German cockroach (Dictyoptera: Blattellidae) due to sublethal doses of imidacloprid, indoxacarb, and lambda-cyhalothrin

The German cockroach is a global urban pest that causes serious public health problems. The induced levels of insecticide tolerance in the first-generation strains of German cockroach from previous topical treatment of laboratory colonies with LD10 or LD25 doses of imidacloprid, indoxacarb, or lambda-cyhalothrin four times with seven-day interval between each were investigated. Our results showed that the resistant ratios (RR50) at LD50, cytochrome P450 content, and glutathione S-transferase (GSTs) activity in adult cockroaches increased in the first generation when compared to the parental (field) and susceptible strains (SS). Therefore, cockroaches treated with insecticidal sublethal dose are likely to have more insecticide resistance in comparison to untreated ones.

Transovarial Transmission of Borrelia hermsii by Its Tick Vector and Reservoir Host Ornithodoros hermsi.

Transovarial passage of relapsing fever spirochetes (Borrelia species) by infected female argasid ticks to their progeny is a widespread phenomenon. Yet this form of vertical inheritance has been considered rare for the North American tick Ornithodoros hermsi infected with Borrelia hermsii. A laboratory colony of O. hermsi was established from a single infected female and two infected males that produced a population of ticks with a high prevalence of transovarial transmission based on infection assays of single and pooled ticks feeding on mice and immunofluorescence microscopy of eggs and larvae. Thirty-eight of forty-five (84.4%) larval cohorts (groups of larvae originating from the same egg clutch) transmitted B. hermsii to mice over four and a half years, and one hundred and three single and one hundred and fifty-three pooled nymphal and adult ticks transmitted spirochetes during two hundred and fourteen of two hundred and fifty-six (83.6%) feedings on mice over seven and a half years. The perpetuation of B. hermsii for many years by infected ticks only (without acquisition of spirochetes from vertebrate hosts) demonstrates the reservoir competence of O. hermsi. B. hermsii produced the variable tick protein in eggs and unfed larvae infected by transovarial transmission, leading to speculation of the possible steps in the evolution of borreliae from a tick-borne symbiont to a tick-transmitted parasite of vertebrates.

Review and Meta-Analysis of the Evidence for Choosing between Specific Pyrethroids for Programmatic Purposes.

Simple SummaryA group of insecticides, called pyrethroids, are the main strategy for controlling the mosquito vectors of malaria. Pyrethroids are used in all insecticide-treated bednets, and many indoor residual spray programmes (in which insecticides are sprayed on the interior walls of houses). There are different types of pyrethroids within the class (e.g., deltamethrin and permethrin). Across the world, mosquitoes are showing signs of resistance to the pyrethroids, such as reduced mortality following contact. However, it is unclear if this resistance is uniform across the pyrethroid class (i.e., if a mosquito is resistant to deltamethrin, whether it is resistant to permethrin at the same level). In addition, it is not known if switching between different pyrethroids can be used to effectively maintain mosquito control when resistance to a single pyrethroid has been detected. This review examined the evidence from molecular studies, resistance testing from laboratory and field data, and mosquito behavioural assays to answer these questions. The evidence suggested that in areas where pyrethroid resistance exists, different mortality seen between the pyrethroids is not necessarily indicative of an operationally relevant difference in control performance, and there is no reason to rotate between common pyrethroids (i.e., deltamethrin, permethrin, and alpha-cypermethrin) as an insecticide resistance management strategy.Pyrethroid resistance is widespread in malaria vectors. However, differential mortality in discriminating dose assays to different pyrethroids is often observed in wild populations. When this occurs, it is unclear if this differential mortality should be interpreted as an indication of differential levels of susceptibility within the pyrethroid class, and if so, if countries should consider selecting one specific pyrethroid for programmatic use over another. A review of evidence from molecular studies, resistance testing with laboratory colonies and wild populations, and mosquito behavioural assays were conducted to answer these questions. Evidence suggested that in areas where pyrethroid resistance exists, different results in insecticide susceptibility assays with specific pyrethroids currently in common use (deltamethrin, permethrin, α-cypermethrin, and λ-cyhalothrin) are not necessarily indicative of an operationally relevant difference in potential performance. Consequently, it is not advisable to use rotation between these pyrethroids as an insecticide-resistance management strategy. Less commonly used pyrethroids (bifenthrin and etofenprox) may have sufficiently different modes of action, though further work is needed to examine how this may apply to insecticide resistance management.

Virulence of entomopathogenic fungi against Culex pipiens: Impact on biomolecules availability and life table parameters.

Culex pipiens mosquitoes considered as vectors for many arboviruses such as the West Nile virus and encephalitis virus showing a global impact on human health. The natural management of the aquatic stages of this pest is crucial for maintaining an insecticide-free and sustained environment. The present work focused on studying the biological and biochemical effects of the entomopathogenic fungi: Metarhizium anisopliae, Beauveria bassiana, and Paecilomyces lilicanus, against 3rd instar larvae of Culex pipiens laboratory colony. The results revealed that M. anisopliae showed maximum larval mortality (88%) with the lowest lethal time (LT50) (22.6 hrs) at 108 spores/ml followed by B. bassiana (73.33%) with LT50 (38.35 hrs), while P. lilicanus showed minimum percent mortality (65%) with highest LT50 (51.5 hrs). The median lethal concentration (LC50) values were found to be 1.027 × 105 spores/ml for M. anisopliae, 1.24 × 106 spores/ml for B. bassiana, while it was 8.453 × 106 spores/ml for P. lilicanus. A reduction in female fecundity, number of hatched eggs, pupation and adult emergence percentage were recorded. The biochemical analysis of the treated larvae revealed different quantitative decrease in total soluble proteins, lipids, and carbohydrate hydrolyzing enzymes compared to control. Histopathological effects of fungal infection upon insect cuticles, muscles, and midgut were investigated. Based on the obtained results, M. anisopliae proved its superior virulent effect as a bio-control agent against Cx. pipiens.

Life cycle, population parameters, and predation rate of the hover fly Eupeodes corollae fed on the aphid Myzus persicae

AbstractTo improve the effectiveness of biological control procedures, it is necessary to quantify the survival rate of a natural enemy through the various stages of the life cycle, the fecundity rate, and the predation rate from birth to death. It is not only important to obtain all the parameters associated with a life table, but also to quantify the predation rate in the life table framework. For this purpose, the life history, population parameters, and predation rate of Eupeodes corollae (Fabricius) (Diptera: Syrphidae) were determined using Myzus persicae (Sulzer) (Hemiptera: Aphididae) as prey and the age‐stage, two‐sex life table methods. As predators released in biocontrol programs are mass‐produced from small populations with a consequent loss of genetic variability, we used specimens from a laboratory colony with similar characteristics. The highest mortality was found in the egg stage (54%). The mean developmental time of the pre‐adult stage was 13.70 ± 0.08 days. In the adult stage, the mean longevity was 23.81 ± 1.14 days, with the males living longer than the females. The total pre‐oviposition period was 17.62 ± 0.45 days and the mean female fecundity was 169.81 ± 29.65 eggs per female. The population parameters indicated that the population grew with a net reproduction rate of 32.87 ± 7.25 offspring per individual and an average generation time of 23.05 ± 0.65 days. The values related to the number of aphid nymphs consumed by the larvae were: a mean predation rate (cxj) of 485.20 ± 11.61 nymphs, a net predation rate (C0) of 216.68 ± 16.89, and a finite predation rate (ω) of 28.03 ± 1.18. The obtained results support the use of E. corollae as valuable resource in the biological control of aphids, specifically M. persicae. Moreover, the technique implemented in this paper allows the objective comparison of E. corollae capacity as control agent with that of other aphidophagous hover fly species and other aphid natural enemies.

Spinosad resistance in field populations of melon fly, Zeugodacus cucurbitae (Coquillett), in Hawaii.

BACKGROUNDControl of Zeugodacus cucurbitae, a serious agricultural pest worldwide, often includes or is dependent on the use of spinosad‐based insecticides. This is especially the case in Hawaii, where GF‐120, a protein bait containing spinosad as the active ingredient, has been in use as a key integrated pest management (IPM) tool against this Tephritid for the last two decades. Here, we report on resistance to spinosad [resistance ratios (RRs) and median lethal concentration (LC50)] in Hawaii's populations of Z. cucurbitae.RESULTSHigh resistance was found in populations from three farms on Oahu (RR = 102–303; LC50 = 191–567 mg L–1) and in a population from Maui (RR = 8.50; LC50 = 15.9 mg L–1). These will be problematic for control given that the most concentrated dilution ratio on the GF‐120 label is 96 mg L–1 of spinosad (1 part GF‐120 to 1.5 parts water). Background resistance in a naïve wild population from the Island of Hawaii (RR = 2.73; LC50 = 5.1 mg L–1) was relatively low compared with a spinosad‐susceptible laboratory colony (LC50 = 1.87 mg L–1). Resistance in the three Oahu and one Maui populations declined over generations in the absence of spinosad but remained elevated in some cases. Moreover, melon flies collected from one of the Oahu farms 1 year after the cessation of spinosad use revealed high persistence of resistance.CONCLUSIONCompared with a 2008 survey of spinosad resistance, our findings indicate a 34‐fold increase in resistance on one of the Oahu farms over 9 years. The evolution and persistence of high levels of resistance to spinosad in Z. cucurbitae in Hawaii highlights the need for alternative control tactics, particularly rotation of active ingredients. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Parasites rather than phoronts: Teratorhabditis synpapillata nematodes reduce lifespan of their Rhynchophorus ferrugineus host in a life stage-dependent manner.

Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) red palm weevils are often reported in association with different organisms including nematodes. The significance of this interaction and whether nematodes can influence their life‐history traits is unclear. We collected Rhynchophorus ferrugineus red palm weevils at different developmental stages and locations in Tunisia, observed and dissected them in search for nematodes and other interacting organisms, established laboratory colonies and identified the nematodes associated with them, and conducted nematode–insect interaction assays to determine the capacity of the nematodes to influence their life‐history traits. We observed Beauveria bassiana fungi in larvae, nymph, and adults; Centrouropoda and Uroobovella acari associated with the adults, and Teratorhabditis synpapillata nematodes associated with larvae and adults. Nematode–insect interaction bioassays revealed that T. synpapillata nematodes reduce the lifespan of the insect larvae in a population‐dependent manner, but do not influence the lifespan of adults. Our study uncovers an important factor that may determine population dynamics of this important palm pests and provides evidence to conclude that these organisms establish a parasitic relationship, rather than a phoretic relationship.

Efficacy of Anystis baccarum against Foxglove Aphids, Aulacorthum solani, in Laboratory and Small-Scale Greenhouse Trials.

Simple SummaryThe foxglove aphid (FGA), Aulacorthum solani (Keltenbach), feeds on many important greenhouse crops in Canada. Currently, biological control of this pest is difficult as existing biocontrol agents are only moderately effective. Access to a generalist predator would strengthen biocontrol programs for this and other similarly challenging pests. Anystis baccarum (L.) is a globally distributed generalist predatory mite. We assessed the predatory efficacy of A. baccarum against FGA in a series of laboratory and small-scale greenhouse trials. The laboratory trials showed that A. baccarum readily consumed all FGA life stages and was particularly effective against first instars. In a greenhouse trial on sweet peppers, working together with Aphidius ervi Haliday, an aphid-specific parasitoid wasp, A. baccarum successfully eradicated the aphids and higher fruit yields were obtained compared to plants protected by the parasitoids only. Pepper plants also became naturally infested with western flower thrips during the trial, which caused feeding damage to the fruits. The fruits were likely to have less thrips’ feeding damage on plants carrying A. baccarum as the predator also fed on these pests. The results demonstrate that A. baccarum could be a useful addition to greenhouse IPM programs for hard-to-control pests like FGA, especially when they occur together with other pest species.A generalist predatory mite, Anystis baccarum (L.), has been identified as a key predator of small, soft-bodied pest species in various agroecosystems around the world. The foxglove aphid Aulacorthum solani (Keltenbach) is a new problematic pest in Canadian greenhouses. Laboratory colonies of A. baccarum were established and its predatory efficacy against A. solani was assessed. In laboratory trials, A. baccarum ate approximately one adult aphid or seven first instar aphids in 24 h. In a greenhouse bench trial on sweet peppers with the free-flying aphid parasitoid, Aphidius ervi Haliday, the population dynamics of A. solani in the presence or absence of A. baccarum was evaluated. Although the parasitoid alone successfully eradicated A. solani, when A. baccarum were present on the plants, the aphid population was eradicated more rapidly. Fruit yield was also 15% higher from plants where A. baccarum was released than the control (without A. baccarum). Furthermore, plants were naturally infested by Frankliniella occidentalis (Pergande) during the trial, which caused visible feeding damage to the fruits. Anystis baccarum also predates on thrips and thrips’ feeding damage to the fruits was reduced on plants where A. baccarum was released. Anystis baccarum was able to establish in sweet peppers and was determined to be complementary to the current practice of using A. ervi for the biological control of A. solani.

Interactions of the Insect-Specific Palm Creek Virus with Zika and Chikungunya Viruses in Aedes Mosquitoes.

Palm Creek virus (PCV) is an insect-specific flavivirus that can interfere with the replication of mosquito-borne flaviviruses in Culex mosquitoes, thereby potentially reducing disease transmission. We examined whether PCV could interfere with arbovirus replication in Aedes (Ae.) aegypti and Ae. albopictus mosquitoes, major vectors for many prominent mosquito-borne viral diseases. We infected laboratory colonies of Ae. aegypti and Ae. albopictus with PCV to evaluate infection dynamics. PCV infection was found to persist to at least 21 days post-infection and could be detected in the midguts and ovaries. We then assayed for PCV–arbovirus interference by orally challenging PCV-infected mosquitoes with Zika and chikungunya viruses. For both arboviruses, PCV infection had no effect on infection and transmission rates, indicating limited potential as a method of intervention for Aedes-transmitted arboviruses. We also explored the hypothesis that PCV–arbovirus interference is mediated by the small interfering RNA pathway in silico. Our findings indicate that RNA interference is unlikely to underlie the mechanism of arbovirus inhibition and emphasise the need for empirical examination of individual pairs of insect-specific viruses and arboviruses to fully understand their impact on arbovirus transmission.

Reproductive success and progeny sex ratio of a laboratory colony of Anagyrus fusciventris (Hymenoptera: Encyrtidae)

ABSTRACT Anagyrus fusciventris (Girault) is a parasitoid of both Pseudococcus calceolariae (Maskell) and P. longispinus (Targioni Tozzetti), two economically important mealybug pests in New Zealand. A male-biased sex ratio was often observed in a laboratory colony of A. fusciventris. We investigated the effect of mating status on female A. fusciventris longevity, fecundity, progeny sex ratio and the rate of parasitism achieved under controlled laboratory conditions. In addition, the impact of host body size on progeny sex ratio was investigated. The progeny sex ratio of unmated (virgin) females (VF) and two types of mated females (24hM: opportunities for mating limited to 24 h or LtM – lifetime opportunities for mating) was tested under similar conditions. Results indicated that females can be reproductively active within 24 h. On average, 24hM females produced 23% female offspring while LtM females produced 45% females, suggesting that multiple mating is required for a balanced sex ratio. VF produced only male offspring through arrhenotokous parthenogenesis. When reared at 23°C and 16 h photoperiod, VF, 24hM and LtM females lived for 25, 44, 51 days, and parasitised 46, 67 and 87 mealybugs respectively. The average lifetime reproductive output (total number of offspring emerged) of VF, 24hM and LtM females was 41, 58 and 75 offspring, respectively. Female-biased progeny emerged from larger hosts while male-biased progeny often emerged from smaller hosts. Implications of these results are discussed in relation to opportunities to improve the quality of a laboratory colony with a balanced progeny sex ratio.

Efficacy of buprofezin, pyriproxyfen and spirotetramat against Bemisia tabaci MEAM1 nymphal field populations in Florida

The whitefly, Bemisia tabaci MEAM1 (Gennadius) (Hemiptera: Aleyrodidae) is a major pest of vegetable crops in the USA, causing yield losses through transmission of plant viruses and induction of plant disorders. Irregular ripening of tomato and silvering of squash leaves are whitefly-induced plant disorders associated with B. tabaci nymphal feeding. Insecticides applied to manage B. tabaci nymphs and these plant disorders include insect growth regulators (IGRs) and lipid biosynthesis inhibitors. Eleven B. tabaci MEAM1 field populations were collected from vegetables and weeds in south Florida in 2019–2020 to assess the efficacy of nymphal insecticides using a maximum dose bioassay. A susceptible laboratory colony of B. tabaci MEAM1 and a colony of B. tabaci MED were also tested. Among the field populations, spirotetramat was the least efficient product for reducing adult emergence and pyriproxyfen and buprofezin were both highly effective. In contrast to the field populations, the lab MED colony was highly susceptible to spirotetramat while pyriproxyfen and buprofezin demonstrated low efficacy for reducing adult emergence. The results indicate that tolerance to spirotetramat may be present in field populations of B. tabaci.

Assessing of reproductive performance of commercial Bombus terrestris dalmatinus colonies in different conditions and some practical ways to mitigation of its invasive risk

To better understand the potential establishment and spread of B. t. dalmatinus, we compared reproductive outputs of 45 commercially produced B. t. dalmatinus colonies, containing one queen and 50 workers in their natural habitat, greenhouse, and laboratory conditions. The total number of adult gynes and gyne pupae produced per colony was significantly higher in the laboratory colonies (100.90 ± 46.20) than in the field colonies (63.70 ± 44.70) and greenhouse colonies (28.47 ± 12.39), respectively. Although laboratory colonies significantly produced more gynes, reproductive abilities of greenhouse and field colonies show that commercial movement of bumblebee colonies for pollination could have serious impacts on natural ecosystems notably for pollination of open field crops. The nest entrance of all colonies was restricted by fitting with a queen excluder. All vents of the greenhouses were suitably covered with nets. Colonies were removed from the greenhouses about 6 weeks after initial placement. Following these measures, we prevented 266 gynes from escaping from 15 hives in 2.3 ha area of tomato greenhouse. To be 100% effective, we strongly recommend that these measures should be implemented together.

Temperature and food sources influence subadult development and blood-feeding response of Culicoides obsoletus (sensu lato) under laboratory conditions

BackgroundCulicoides obsoletus (s.l.) is the most abundant Culicoides species in northern Europe and an important vector of bluetongue virus and Schmallenberg virus. Nevertheless, information on its subadult life stages remains scarce and no laboratory-reared colony exists.MethodsC. obsoletus (s.l.) adults were collected in Belgium and transferred to the laboratory in an attempt to establish a laboratory-reared colony. C. obsoletus (s.l.) were reared from eggs to adults at different temperatures (28 °C, 24 °C, 20/16 °C) and under different food regimes.ResultsThe most suitable temperature for rearing seemed to be 24 °C for most developmental parameters, but resulted in a biased 3:1 male/female sex ratio. The latter could be optimized to a 1:1 sex ratio when a 20/16 °C day/night temperature gradient was applied, but rearing at these low temperature conditions resulted in significantly lower egg hatching and pupation rates and a longer subadult development time. Independent of the rearing temperature, adding dung as an additional food source during larval development resulted in a significantly higher adult emergence rate and a decrease in subadult development time. Furthermore, blood-feeding rates of field-collected C. obsoletus (s.l.) were compared for different blood sources and feeding systems. The overall blood-feeding success was low and only successful with cotton pledgets (2.7% blood-fed midges) and through a membrane system with chicken skin (3.5% blood-fed midges). Higher feeding rates were obtained on cattle blood compared to sheep blood.ConclusionsThese results will help us to determine the necessary conditions to rear a viable laboratory colony of this important vector species, although further optimization is still required.Graphical abstract

First record of a new microsporidium pathogenic to Gonipterus platensis in Brazil

Microsporidia are naturally occurring fungal-related parasites that can infect nearly all animal hosts, but their biocontrol potential of insect pests is routinely overlooked in agriculture and forestry. This research brings the first report describing the natural occurrence of a microsporidium causing disease in field-collected populations of the invasive eucalyptus snout beetle, Gonipterus platensis (Coleoptera: Curculionidae), a major destructive pest of eucalyptus plantations in Brazil. Adult beetles were collected during field surveys in commercial eucalyptus plantations in southern Brazil to be examined and dissected with typical symptoms to verify presence of microsporidian spores in haemolymph. From 14 plantations in different sites, the natural infection occurrence in these populations ranged from 0 to 65%, while a lab colony exhibited an infection incidence of 70%. Spore density in haemolymph of symptomatic insects averaged 2.1 (± 0.4) × 107 spores/beetle. Symptoms in infected adults were identified by an abnormal abdomen with malformation of the second pair of wings, impairing their flight activity. Electron transmission microscopy of the pathogen showed morphological features similar to species belonging to the genus Nosema or Vairimorpha. Phylogenetic analysis of the full-length small subunit ribosomal RNA gene suggests this pathogen’s placement in the genus Vairimorpha, but with a sequence identity of ~ 94% with the nearest neighbours. The low level of sequence identity suggests this pathogen may represent a novel taxon in the genus and further requires whole genome sequencing for definitive taxonomic resolution. These findings provide insights on the natural occurrence of this novel pathogen of this invasive pest in Eucalyptus plantations in Brazil. Further studies are needed to determine potential of this microsporidium in the design of conservative or augmentative biological control programs for this invasive pest.

Larvicidal potency of Dioscorea sansibarensis leaf extract against vector mosquitoes: Anopheles gambiae s.s. and Culex quinquefasciatus

Mosquitoes are responsible for transmission of illnesses of public health importance including malaria, lymphatic filariasis, dengue, chikungunya, and many other diseases caused by viruses. Vector control using synthetic insecticides has been the cornerstone for management of vector-borne diseases. However, the chemical based interventions have not been sustainable due to emergency of resistance against insecticides among disease vectors. Plant based mosquitocidal products can be potential alternative tools in vector control. Therefore, the present study aimed at exploring the larvicidal properties of Dioscorea sansibarensis leaf extract against malaria and lymphatic filariasis vectors; Anopheles gambiae s.s. and Culex quinquefasciatus. The larvicidal activities of Dioscorea sansibarensis were assessed following WHO test procedures. Ethanol leaf extract of Dioscorea sansibarensis was evaluated against all the four instar larvae stages of An. gambiae s.s and Cx. quinquefasciatus susceptible laboratory colonies. The highest larvicidal potency was shown against the 4th instar stages of both species with the LC50 values of 60.915 ppm and 80.700 ppm for Cx. quinquefasciatus and An. gambiae s.s., respectively. The respective LC95 values for Cx. quinquefasciatus and An. gambiae s.s. were 168.898 ppm and 249.295 ppm. This implies that the extract can be applied as mosquito larvicide should its impact on non-targeted species be established.
 Keywords: Dioscorea sansibarensis; vectors, mosquitoes, Zanzibar yams, Dar es Salaam, Tanzania

Identification of Abnormal States in Videos of Ants Undergoing Social Phase Change

Biology is both an important application area and a source of motivation for development of advanced machine learning techniques. Although much attention has been paid to large and complex data sets resulting from high-throughput sequencing, advances in high-quality video recording technology have begun to generate similarly rich data sets requiring sophisticated techniques from both computer vision and time-series analysis. Moreover, just as studying gene expression patterns in one organism can reveal general principles that apply to other organisms, the study of complex social interactions in an experimentally tractable model system, such as a laboratory ant colony, can provide general principles about the dynamics of other social groups. Here, we focus on one such example from the study of reproductive regulation in small laboratory colonies of more than 50 Harpegnathos ants. These ants can be artificially induced to begin a ~20 day process of hierarchy reformation. Although the conclusion of this process is conspicuous to a human observer, it remains unclear which behaviors during the transient period are contributing to the process. To address this issue, we explore the potential application of One-class Classification (OC) to the detection of abnormal states in ant colonies for which behavioral data is only available for the normal societal conditions during training. Specifically, we build upon the Deep Support Vector Data Description (DSVDD) and introduce the Inner-Outlier Generator (IO-GEN) that synthesizes fake “inner outlier” observations during training that are near the center of the DSVDD data description.We show that IO-GEN increases the reliability of the final OC classifier relative to other DSVDD baselines. This method can be used to screen video frames for which additional human observation is needed. Although we focus on an application with laboratory colonies of social insects, this approach may be applied to video data from other social systems to either better understand the causal factors behind social phase transitions or even to predict the onset of future transitions.

Comprehensive Ecological and Geographic Characterization of Eukaryotic and Prokaryotic Microbiomes in African Anopheles.

Exposure of mosquitoes to numerous eukaryotic and prokaryotic microbes in their associated microbiomes has probably helped drive the evolution of the innate immune system. To our knowledge, a metagenomic catalog of the eukaryotic microbiome has not been reported from any insect. Here we employ a novel approach to preferentially deplete host 18S ribosomal RNA gene amplicons to reveal the composition of the eukaryotic microbial communities of Anopheles larvae sampled in Kenya, Burkina Faso and Republic of Guinea (Conakry). We identified 453 eukaryotic operational taxonomic units (OTUs) associated with Anopheles larvae in nature, but an average of 45% of the 18S rRNA sequences clustered into OTUs that lacked a taxonomic assignment in the Silva database. Thus, the Anopheles microbiome contains a striking proportion of novel eukaryotic taxa. Using sequence similarity matching and de novo phylogenetic placement, the fraction of unassigned sequences was reduced to an average of 4%, and many unclassified OTUs were assigned as relatives of known taxa. A novel taxon of the genus Ophryocystis in the phylum Apicomplexa (which also includes Plasmodium) is widespread in Anopheles larvae from East and West Africa. Notably, Ophryocystis is present at fluctuating abundance among larval breeding sites, consistent with the expected pattern of an epidemic pathogen. Species richness of the eukaryotic microbiome was not significantly different across sites from East to West Africa, while species richness of the prokaryotic microbiome was significantly lower in West Africa. Laboratory colonies of Anopheles coluzzii harbor 26 eukaryotic OTUs, of which 38% (n = 10) are shared with wild populations, while 16 OTUs are unique to the laboratory colonies. Genetically distinct An. coluzzii colonies co-housed in the same facility maintain different prokaryotic microbiome profiles, suggesting a persistent host genetic influence on microbiome composition. These results provide a foundation to understand the role of the Anopheles eukaryotic microbiome in vector immunity and pathogen transmission. We hypothesize that prevalent apicomplexans such as Ophryocystis associated with Anopheles could induce interference or competition against Plasmodium within the vector. This and other members of the eukaryotic microbiome may offer candidates for new vector control tools.

Establishing Babesia bovis-Free Tick Colony Following Treatment of the Host with Diminazene Aceturate (Berenil).

Babesia bovis is a widely-spread tick-borne hemoparasite of cattle with major economic and animal welfare consequences. Rhipicephalus (Boophilus) annulatus is a one-host tick which transmits bovine babesiosis in the Middle East and Africa. Laboratory rearing of ixodid ticks is essential for the investigation on ticks or tick-borne diseases. Establishing a tick colony in the laboratory usually originates from ticks harvested in the field, which may be naturally infected with various pathogens. This especially applies to carriage of B. bovis as it is highly prevalent in endemic areas and is transmitted transovarially in ticks. Here, we describe the use of diminazene aceturate (Berenil) in order to establish laboratory colonies of Babesia-free R. annulatus, from ticks collected in the field. Ticks collected in the field were kept until oviposition and hatched larvae were introduced to naïve calves, which led to infection of the calves with B. bovis. Calves were then treated with diminazene aceturate several times until the engorged ticks dropped. The eggs and larvae collected from these ticks were parasite-free, as demonstrated both by infection of splenectomized calves and by PCR. This suggested protocol is a useful tool to create parasite-free tick colony and may, theoretically, also be beneficial to reduce parasite circulation in the field, although not recommended, as resistance to diamenizene aceturate might develop.

Cultivation and Genome Sequencing of Bacteria Isolated From the Coffee Berry Borer (Hypothenemus hampei), With Emphasis on the Role of Caffeine Degradation.

The coffee berry borer, the most economically important insect pest of coffee worldwide, is the only insect capable of feeding and reproducing solely on the coffee seed, a food source containing the purine alkaloid caffeine. Twenty-one bacterial species associated with coffee berry borers from Hawai’i, Mexico, or a laboratory colony in Maryland (Acinetobacter sp. S40, S54, S55, Bacillus aryabhattai, Delftia lacustris, Erwinia sp. S38, S43, S63, Klebsiella oxytoca, Ochrobactrum sp. S45, S46, Pantoea sp. S61, Pseudomonas aeruginosa, P. parafulva, and Pseudomonas sp. S30, S31, S32, S37, S44, S60, S75) were found to have at least one of five caffeine N-demethylation genes (ndmA, ndmB, ndmC, ndmD, ndmE), with Pseudomonas spp. S31, S32, S37, S60 and P. parafulva having the full complement of these genes. Some of the bacteria carrying the ndm genes were detected in eggs, suggesting possible vertical transmission, while presence of caffeine-degrading bacteria in frass, e.g., P. parafulva (ndmABCDE) and Bacillus aryabhattai (ndmA) could result in horizontal transmission to all insect life stages. Thirty-five bacterial species associated with the insect (Acinetobacter sp. S40, S54, S55, B. aryabhattai, B. cereus group, Bacillus sp. S29, S70, S71, S72, S73, D. lacustris, Erwinia sp. S38, S43, S59, S63, K. oxytoca, Kosakonia cowanii, Ochrobactrum sp. S45, S46, Paenibacillus sp. S28, Pantoea sp. S61, S62, P. aeruginosa, P. parafulva, Pseudomonas sp. S30, S31, S32, S37, S44, S60, S75, Stenotrophomonas sp. S39, S41, S48, S49) might contribute to caffeine breakdown using the C-8 oxidation pathway, based on presence of genes required for this pathway. It is possible that caffeine-degrading bacteria associated with the coffee berry borer originated as epiphytes and endophytes in the coffee plant microbiota.