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Research Square Aug 2023The imosquito is an important vector of arboviral diseases including dengue and yellow fever. Despite the wide distribution of the mosquito, there is limited data on...
BACKGROUND
The imosquito is an important vector of arboviral diseases including dengue and yellow fever. Despite the wide distribution of the mosquito, there is limited data on the ecology of mosquitoes in Ghana. In this study, we report on the oviposition preference and the larval life table of mosquitoes in Accra, Ghana.
METHODS
The oviposition preference of mosquitoes to three habitat types (tyres, drums and bowls) was measured by setting up ovitraps. Ovitraps were checked for the presence of larvae every 3 days. The presence and number of larvae were recorded for each habitat type. Two-hour-old larvae were introduced into and raised in these three habitat types to undertake larval life tables. The number of surviving larvae at each developmental stage was recorded daily until they emerge as adults.
RESULTS
Car tyres showed a high abundance of larvae (52.33%) than drums (32.49%) and bowls (15.18%) (ANOVA, _ 18.79, _ 2, 159, < 0.001). The mean development time of larvae was significantly lower in car tyres (7 ± 1 days) compared to that of bowls (9 ± 0.0 days) and drums (12.6 ± 1.5 days) (H (2) = 7.448, = 0.024). The differences in pupation rates and emergence rates were not significant across the habitat types, however, the highest pupation rate was observed in bowls (0.92) and the emergence rate was highest in tyres (0.84). The proportion of first-instar larvae that survived to adults was significantly higher in tyres with a shorter survival time (0.84; 9 days) compared to that of bowls (0.72; 10 days) and drums (0.62 ± 0.2; 13 days) (H (2) = 2.822, = 0.009).
CONCLUSION
The results confirm that discarded car tyres were the preferred habitat choice for the oviposition of gravid female mosquitoes and provide the best habitat condition for larval development and survival. These findings are necessary for understanding the ecology of mosquitoes to develop appropriate strategies for their control in Ghana.
PubMed: 37693506
DOI: 10.21203/rs.3.rs-3286696/v1 -
Plants (Basel, Switzerland) Dec 2023is responsible for significant economic losses in the fruit production industry, and the market lacks biopesticides that are effective but also cheaper and less...
is responsible for significant economic losses in the fruit production industry, and the market lacks biopesticides that are effective but also cheaper and less contaminating, with fewer negative impacts on the environment. In this regard, the present study suggests as potential options ethanolic extracts from several Macaronesian plants, which inhibit the oviposition and are toxic to , and whose preparation involve a non-toxic solvent (i.e., ethanol), low energy expenditure and cheap apparatus (i.e., maceration at room temperature). Among the evaluated species, the extracts of , and are the most active (50 mg/mL), revealing an increase in adults' mortality from 21.15% to 27.41% after 72 h, a value statistically identical to azadirachtin (25.93%) at the recommended concentration (0.88 mg/mL). Considering the quantity and biomass available to prepare a biopesticide in the future, and the level of activity, the ethanolic extract of was fractionated and each fraction tested. The water fraction at 50 mg/mL proved to be more effective than the original extract, both in terms of mortality (57.69%), with LT = 72.5 h, and oviposition deterrence (83.43%), values statistically higher than those obtained by azadirachtin at 0.88 mg/mL. Analysis of this fraction by HPLC-MS/MS showed that it is mainly composed of glycosylated derivatives of quercetin and myricetin in addition to some triterpenes. These findings highlight some Macaronesian species, and in particular, the more polar fraction of ethanolic extract, as promising and ecological alternatives to conventional insecticides, for use in the integrated management of the pest.
PubMed: 38140449
DOI: 10.3390/plants12244122 -
Journal of Evolutionary Biology Nov 2023The ecological and life history drivers of the diversification of reproductive modes in early vertebrates are not fully understood. Sharks, rays and chimaeras (group...
The ecological and life history drivers of the diversification of reproductive modes in early vertebrates are not fully understood. Sharks, rays and chimaeras (group Chondrichthyes) have an unusually diverse variety of reproductive modes and are thus an ideal group to test the factors driving the evolution of reproductive complexity. Here, using 960 species representing all major Chondrichthyes taxa, we reconstruct the evolution of their reproduction modes and investigate the ecological and life history predictors of reproduction. We show that the ancestral Chondrichthyes state was egg-laying and find multiple independent transitions between egg-laying and live-bearing via an intermediate state of yolk-only live-bearing. Using phylogenetically informed analysis, we also show that live-bearing species have larger body size and larger offspring than egg-laying species. In addition, live-bearing species are distributed over shallow to intermediate depths, while egg-layers are typically found in deeper waters. This suggests that live-bearing is more closely associated with pelagic, rather than demersal habitats. Taken together, using a basal vertebrate group as a model, we demonstrat how reproductive mode co-evolves with environmental conditions and life-history traits.
Topics: Animals; Sharks; Reproduction; Oviposition; Fishes; Ecosystem; Biological Evolution; Phylogeny
PubMed: 37885147
DOI: 10.1111/jeb.14231 -
Heliyon Sep 2023The whiteflies of complex, composed of >44 cryptic species, are economically important pests of tomatoes for their direct feeding and virus transmission. The present...
The whiteflies of complex, composed of >44 cryptic species, are economically important pests of tomatoes for their direct feeding and virus transmission. The present study aimed to evaluate the impact of leaf trichomes on the host selection and development of whitefly; comparative invasiveness between Q and A cryptic species; and the ability of weeds as hosts of the population of insect whitefly. We carried out our investigation through adult host selection and oviposition in multi-choice conditions, immature development and survival, and adult survival and oviposition in no-choice conditions. We investigated leaf trichomes type and densities on the leaves of four tomato varieties and two weed species. Results showed that the leaf trichomes of tomatoes and weeds impact the host selection and immature development differently on the cryptic species Q and A. In the multi-choice case, Q adults preferred tomato varieties Ao-Ni-Er and He-Fen for both settling and oviposition whereas A preferred Ao-Ni-Er, He-Fen, and Billy-Goat-Weed for settling but oviposited more eggs on both weed species Billy-Goat-Weed and False-Mallow. Both Q and A adults refused Ye-Sheng either settling or oviposition. In the case of immature development, Q developed faster than A. Concerning plant, Q developed faster on Ao-Ni-Er, He-Fen and Billy-Goat-Weed but A on Billy-Goat-Weed, False-Mallow and Ao-Ni-Er. The immature survival of Q was higher than that of A. Immature of Q survived well (68.6-86.8%) on all plants except Ye-Sheng (49.3%) but A survived very less (0-17.6%) on any tomatoes where 70.4% on Billy-Goat-Weed and 60.5% on False-Mallow. After seven days of adult infestation, both Q and A died on Ye-Sheng where 52.5-78.1% survivorships were observed on other plants. In seven days, Q laid more eggs compared to A. Considering the plants, both species laid more eggs on Ao-Ni-Er, He-Fen and False-Mallow, whereas the lowest number was laid on Ye-Sheng. The highest number of glandular trichome Type IV was observed on Ye-Sheng which showed resistance against both Q and A cryptic species. The cryptic species Q showed a wider range adaptation ability on plants than that of A. Weeds can play a significant role as an infestation source of whiteflies to tomatoes and other crops. These findings suggest that glandular trichomes may be used in plant breeding programmes for the development of whitefly-resistant crop cultivars.
PubMed: 37809545
DOI: 10.1016/j.heliyon.2023.e20077 -
BioRxiv : the Preprint Server For... Mar 2024Tympanal organs as "insect ears" have evolved repeatedly. Dinidorid stinkbugs were reported to possess a conspicuous tympanal organ on female's hindlegs. Here we report...
Tympanal organs as "insect ears" have evolved repeatedly. Dinidorid stinkbugs were reported to possess a conspicuous tympanal organ on female's hindlegs. Here we report an unexpected discovery that the stinkbug's "tympanal organ" is actually a novel symbiotic organ. The stinkbug's "tympanum" is not membranous but a porous cuticle, where each pore connects to glandular secretory cells. In reproductive females, the hindleg organ is covered with fungal hyphae growing out of the pores. Upon oviposition, the females skillfully transfer the fungi from the organ to the eggs. The eggs are quickly covered with hyphae and physically protected against wasp parasitism. The fungi are mostly benign Cordycipitaceae entomopathogens and show considerable diversity among insect individuals and populations, indicating environmental acquisition of specific fungal associates. These results uncover a novel external fungal symbiosis in which host's elaborate morphological, physiological and behavioral specializations underpin the selective recruitment of benign entomopathogens for a defensive purpose.
PubMed: 38585921
DOI: 10.1101/2024.03.25.586038 -
Ecology and Evolution Apr 2024is a salt-tolerant euryhaline mosquito that lays its eggs in rock pools. Although it is a pest that can transmit flaviviruses and filarial worms to humans, ecological...
is a salt-tolerant euryhaline mosquito that lays its eggs in rock pools. Although it is a pest that can transmit flaviviruses and filarial worms to humans, ecological studies have not been previously conducted because of its limited habitat. However, rising sea levels have created a more favorable environment for , increasing the risk of -borne diseases. We examined the oviposition and growth rates of at 0-35 psu to obtain ecological data. It exhibited the highest oviposition preference at 0 psu; however, the hatching rate was highest at 10 psu, the pupation rate was highest at 25 psu, and the emergence rate was highest at 5 psu. showed the highest rate of growth into adults at 25 psu. The results were assessed using Mann-Whitney and Kruskal-Wallis tests (post hoc test: Bonferroni), and a regression equation was generated for the incidence of adult based on the change in salinity ( = -14.318 + 9.821; = adult incidence rate; = salinity). The oviposition habits and developmental conditions of were confirmed, and the incidence of based on changes in sea level and ocean salinity was predicted. The results of this study will be useful for controlling salt-tolerant vectors and responding to vector-borne diseases.
PubMed: 38660469
DOI: 10.1002/ece3.11289 -
Insects Jul 2023L. is a destructive pest affecting cruciferous vegetables, causing massive economic losses worldwide. Plant-based insecticides are considered promising insect control...
L. is a destructive pest affecting cruciferous vegetables, causing massive economic losses worldwide. Plant-based insecticides are considered promising insect control agents. The extract inhibited female oviposition, with an oviposition deterrence index (ODI) of 61.65% at 12.5 mg/mL. We aimed to identify the bioactive compounds in extract. The compounds from extract were analyzed using LC-MS techniques. The toxicity and behavioral responses of larvae and adults of to ten compounds were investigated. We found that the caryophyllene oxide and 3,4-dimethoxycinnamic acid inhibited female oviposition; the ODIs were 98.31% and 97.59% at 1.25 mg/mL, respectively. The extract, caryophyllene oxide, and 3,4-dimethoxycinnamic acid caused larval mortality, with LC values of 21.31, 4.56, and 5.52 mg/mL, respectively. The EAG response of females was higher than that of males under extract conditions, while the EAG response of males was higher than that of females in caryophyllene oxide and 3,4-dimethoxycinnamic acid conditions. The extract and caryophyllene oxide showed repellent activity against both female and male adults, while the 3,4-dimethoxycinnamic acid did not elicit any notable behavioral responses from adults. extract and caryophyllene oxide are potential insecticides, oviposition deterrents, and behavioral regulators against , and they could be potential candidates for the development of biological insecticides to control .
PubMed: 37504619
DOI: 10.3390/insects14070613 -
PeerJ 2023The odor of various fermented organic materials acts as an attractant for oviposition by gravid females of the black soldier fly (BSF) to find larval food sources....
BACKGROUND
The odor of various fermented organic materials acts as an attractant for oviposition by gravid females of the black soldier fly (BSF) to find larval food sources. Females display oviposition site selection on various organic materials, but little work has been done on the response to substrate attractants under caged conditions similar to those in a BSF farm production system.
METHODS
Fifty of each reproductive status (mated and virgin) and sex (males and females) of BSF adults were marked and then exposed to one of five different oviposition attractants in a transparent acrylic chamber: no substrate (control) plus pineapple, mixed vegetables, okara, and fermented fish to represent fruit-, vegetable-, plant protein-, and animal protein-based substrates, respectively. The frequency of the perching activity on the oviposition apparatus and flying behavior under the LED illumination, including the laid egg weight, were recorded.
RESULTS
The sexually-related activities of BSF adults were clearly observed. A majority of the females preferred to perch on the oviposition apparatus and fly around the illuminated area compared to the very low activities of the mated males. The BSF adults displayed different behavioral responses to the different tested attractants. While active flying was common when using plant protein- and animal protein-based substrates, mated females showed the greatest perching preference for plant-based substrates (fruit and vegetables) and this correlated with the laid egg weight.
DISCUSSION
Egg-laying was more likely to happen on the plant-based substrate than on the animal protein-based substrate. However, the strong smell of the animal protein-based substrate could strongly trigger lekking behavior, which is an important part of mating behavior. This knowledge can support egg trapping in nature and also improve the efficiency of egg production in mass-rearing facilities.
PubMed: 37520258
DOI: 10.7717/peerj.15701 -
Insects May 2024(Del Guercio, 1918) (Hemiptera: Triozidae) is a citrus pest which produces gall symptoms on leaves and transmits bacteria associated with the citrus disease...
(Del Guercio, 1918) (Hemiptera: Triozidae) is a citrus pest which produces gall symptoms on leaves and transmits bacteria associated with the citrus disease Huanglongbing, ' Liberibacter' spp. In the present work, the biology and behaviour of were studied in different rootstock-cultivar combinations. Six rootstocks were used, Flying dragon (FD), 'Cleopatra' mandarin (CL), Carrizo citrange (CC), Forner-Alcaide no.5 (FA5), Forner-Alcaide no.517 (FA517) and (CM), and six scion cultivars: 'Star Ruby', 'Clemenules', 'Navelina', 'Valencia Late', 'Fino 49' and 'Ortanique'. Survival and oviposition were evaluated in a no-choice trial, and preference in a choice trial, all of them under greenhouse conditions. did not show a clear settle preference for any citrus combination. However, it was able to lay more eggs in 'Fino 49' grafted on CC than on FD. In terms of survival, 'Ortanique' grafted onto FA5 was more suitable than when grafted onto FA517, and in the case of 'Valencia Late', when it was grafted onto CM rather than CC. Our results showed that behave differently depending on the citrus combination.
PubMed: 38786919
DOI: 10.3390/insects15050363 -
Current Biology : CB Oct 2023Animals generate a wide range of highly coordinated motor outputs, which allows them to execute purposeful behaviors. Individual neurons in the circuits that generate...
Animals generate a wide range of highly coordinated motor outputs, which allows them to execute purposeful behaviors. Individual neurons in the circuits that generate behaviors have a remarkable capacity for flexibility as they exhibit multiple axonal projections, transmitter systems, and modes of neural activity. How these multi-functional properties of neurons enable the generation of adaptive behaviors remains unknown. Here, we show that the HSN neuron in C. elegans evokes multiple motor programs over different timescales to enable a suite of behavioral changes during egg laying. Using HSN activity perturbations and in vivo calcium imaging, we show that HSN acutely increases egg laying and locomotion while also biasing the animals toward low-speed dwelling behavior over minutes. The acute effects of HSN on egg laying and high-speed locomotion are mediated by separate sets of HSN transmitters and different HSN axonal compartments. The long-lasting effects on dwelling are mediated in part by HSN release of serotonin, which is taken up and re-released by NSM, another serotonergic neuron class that directly evokes dwelling. Our results show how the multi-functional properties of a single neuron allow it to induce a coordinated suite of behaviors and also reveal that neurons can borrow serotonin from one another to control behavior.
Topics: Animals; Caenorhabditis elegans; Motor Neurons; Serotonin; Oviposition; Serotonergic Neurons; Caenorhabditis elegans Proteins
PubMed: 37769660
DOI: 10.1016/j.cub.2023.08.088