scholarly journals Oviposition of Culicoides insignis (Diptera: Ceratopogonidae) under laboratory conditions with notes on the developmental life history traits of its immature stages

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Dinesh Erram ◽  
Nathan Burkett-Cadena
Keyword(s):  
Abiotic Factors ◽  
Sex Ratios ◽  
Survival Rates ◽  
Oviposition Preference ◽  
Larval Survival ◽  
Larval Habitat ◽  
Hemorrhagic Disease ◽  
Immature Stages ◽  
Laboratory Conditions ◽  
Fundamental Information

Abstract Background Culicoides insignis is a confirmed vector of bluetongue virus (BTV) throughout the American tropics and a possible vector of epizootic hemorrhagic disease virus (EHDV) in Florida. Despite its importance, fundamental information on the biology and ecology of this vector species is lacking. In this study, we examined the oviposition of C. insignis under laboratory conditions, monitored the development of immature stages and attempted colonization of this species. Methods Live C. insignis females were collected from the field using CDC-UV-LED traps, allowed to blood-feed on live chicken and given various natural substrates for oviposition in two-choice assays. The eggs deposited were transferred to 0.3% agar slants, and the hatched larvae were provided a diet of Panagrellus redivivus Linnaeus nematodes and the development of all immature stages was monitored. Results Culicoides insignis females exhibited an overall oviposition preference for dishes containing mud from their larval habitat as gravid females deposited a significantly higher number of eggs on these dishes (35.3 eggs/female) than on controls (17.7 eggs/female). The ovipositing females also deposited a higher percentage of eggs on substrates with habitat mud and other organically enriched muds (≥ 75.2%) compared to controls (31.0%). The larvae developed successfully to adulthood on the nematode diet, exhibiting high overall larval survival rates (85.0%). Sex ratios of the F1 generation were male biased, approximately 3:1 (male:female). Captive mating could not be induced in the F1 adults. Conclusions Mud from the larval habitat and other organically enriched muds provide strong oviposition cues to C. insignis under laboratory conditions. Further studies will be needed to identify the key biotic/abiotic factors influencing midge oviposition in the field. The agar/nematode method is effective for the rearing of C. insignis larvae. However, further studies will be needed to address the issue of male-biased sex ratios in the progeny and to examine the mating habits/cues of C. insignis in nature, which may provide clues towards inducing captive mating in the F1 adults. Graphical abstract

Oviposition and Larval Development of Culicoides Insignis Lutz (Diptera: Ceratopogonidae) under Laboratory Conditions

2021 ◽  
Author(s):  
Dinesh Erram ◽  
Nathan Burkett-Cadena
Keyword(s):  
Larval Development ◽  
Abiotic Factors ◽  
Sex Ratios ◽  
Survival Rates ◽  
Oviposition Preference ◽  
Larval Survival ◽  
Larval Habitat ◽  
Hemorrhagic Disease ◽  
Laboratory Conditions ◽  
Fundamental Information

Abstract BackgroundCulicoides insignis Lutz (Diptera: Ceratopogonidae) is a confirmed vector of bluetongue virus (BTV) throughout the American tropics and a possible vector of epizootic hemorrhagic disease virus (EHDV) in Florida. Despite its importance, fundamental information on the biology and ecology of this species is lacking. In this study, we examined the oviposition and larval development of C. insignis under laboratory conditions and attempted colonization of this species. MethodsLive C. insignis females were collected from the field using CDC-UV-LED traps, allowed to blood-feed on live chicken, and given various natural substrates for oviposition in two-choice assays. The eggs deposited were transferred to 0.3% agar slants and the hatched larvae were provided a diet of Panagrellus redivivus Linnaeus nematodes. ResultsCulicoides insignis females exhibited an overall oviposition preference for dishes containing mud from their larval habitat as gravid females deposited a significantly higher number of eggs on these dishes (35.3 eggs/female) than on deionized water (DI) substrates (17.7eggs/female). The ovipositing females also deposited a higher percentage of eggs on substrates with habitat mud and other organically enriched muds (≥ 75.2%) compared to DI substrates (31.0%). The larvae developed successfully to adulthood on the nematode diet, exhibiting high overall larval survival rates (85.0%). Sex-ratios of the F1 generation were male biased ~3:1 (M:F). Captive mating could not be induced in the F1 adults. ConclusionsMud from the larval habitat and other organically enriched muds provide strong oviposition cues to C. insignis. Further studies will be needed to examine whether these cues are olfactory/tactile in nature. Further studies will also be needed to characterize the larval habitat of C. insignis and identify the key biotic/abiotic factors influencing midge oviposition in the field. This information, in the long term, can be potentially exploited to discourage the oviposition of C. insignis in local habitats. The agar/nematode method is effective for the rearing of C. insignis larvae. However, further studies will be needed to address the issue of male-biased sex-ratios in the progeny. Further studies will also be needed to examine the mating habits/cues of C. insignis in nature, which may provide clues towards inducing captive mating in the F1 adults.

Gyretes Brullé (Coleoptera: Gyrinidae) from Brazil: Morphology of eggs and early instars

Zootaxa ◽  
2018 ◽  
Vol 4526 (3) ◽  
pp. 331 ◽  
Author(s):  
DANIARA COLPANI ◽  
CÉSAR JOÃO BENETTI ◽  
NEUSA HAMADA ◽  
VANDERLY ANDRADE-SOUZA ◽  
MARIANO C. MICHAT
Keyword(s):  
Related Species ◽  
Sequence Data ◽  
Larval Survival ◽  
Molecular Techniques ◽  
Coi Gene ◽  
Immature Stages ◽  
Closely Related Species ◽  
Species Association ◽  
Dna Sequence Data ◽  
Laboratory Conditions

Taxonomic information regarding Gyrinidae is mostly based on adults, especially due to the difficulty in collecting immatures and assigning them to a particular species. Association between immatures and adults is sometimes difficult because closely related species can be found in the same habitat. To solve this problem a feasible technique is rearing under laboratory conditions. However, this method is challenging because larval survival rate is usually low, and emulation of natural conditions is difficult. Molecular techniques, especially the use of the COI gene, have been applied to identify species and to associate different life stages. However, in some species groups this marker has not been successful in distinguishing closely related species. The objectives of this study are to describe the egg and the first two instars of Gyretes nubilus Ochs, 1965 and the egg of G. minax Ochs, 1967 and to evaluate the utility of COI to associate immatures and adults. The association of these immature stages with adults was done either rearing adults under laboratory conditions or by using DNA sequence data (COI), corroborating the utility of this molecular marker to associate immature and adults in Gyretes. These immature stages are described, including chaetotaxic analysis of larvae for the first time for the genus Gyretes Brullé, 1835. The eggs are described based on scanning electron microscopy. The eggs are similar to those of other Gyrinidae genera in having a micropylar region in the anterior pole and a longitudinal fissure, and by the absence of an aeropyle, but they differ mainly in characters related to chorionic structure and reticulation. Larvae of Gyretes can be distinguished from those of the other Neotropical Gyrinidae genera by a combination of several characters, including the frontoclypeal seta FR3 short, presence of three conspicuous additional setae on lateral region of parietal (contiguous to stemmata), and posterior margin of lacinia smooth, with apex not indented. 

Status of the Hawaiian monk seal (Monachus schauinslandi) population

1995 ◽  
Vol 73 (6) ◽  
pp. 1185-1190 ◽  
Author(s):  
W. G. Gilmartin ◽  
L. L. Eberhardt
Keyword(s):  
Complex System ◽  
Sex Ratios ◽  
Current Trend ◽  
Survival Rates ◽  
Hawaiian Monk Seal ◽  
Monachus Schauinslandi ◽  
Young Females ◽  
Adult Females ◽  
Unknown Factor ◽  
Adult Sex Ratio

Restoration of the Hawaiian monk seal (Monachus schauinslandi) population to its former abundance poses a number of problems in managing a complex system. Sharp differences in history and current trend exist among the six major pupping sites. A severely unbalanced adult sex ratio has resulted in deaths from "mobbing" of estrus females at two sites. Some unknown factor apparently severely reduced the numbers of females at three of the sites and thus produced the observed excess of males. Sex ratios subsequently decreased, but losses of adult females continue at two sites. A simple model indicates that sex ratios at the two sites where mobbing is a problem would require more than 10 years to approach an equilibrium value. Data on trends from counts are compared with estimates from reproduction and survival rates and agree closely except at one site (Kure Atoll), where introductions of young females have been made.

Yellow Fever

2021 ◽  
Author(s):  
Melvin Sanicas ◽  
Merlin Sanicas
Keyword(s):  
South America ◽  
Yellow Fever ◽  
Survival Rates ◽  
Antiviral Drug ◽  
Specific Treatment ◽  
Preventive Measure ◽  
Hemorrhagic Disease ◽  
Supportive Treatment ◽  
Tropical Areas ◽  
At Risk Populations

Yellow fever is an acute viral hemorrhagic disease transmitted by infected mosquitoes. The "yellow" in the name refers to the jaundice from direct liver damage. The virus is endemic in tropical areas of Africa and Central and South America. There is no specific treatment or antiviral drug for yellow fever but appropriate supportive treatment in hospitals improves survival rates. Vaccination is the single most important preventive measure. Several yellow fever vaccines are manufactured by different developers. All of them are safe, affordable, and appear to provide protection for >30–35 years. Some are WHO-prequalified. The Eliminate Yellow Fever Epidemics (EYE) Strategy launched in 2017 aims at protecting at-risk populations, preventing international spread, and containing outbreaks rapidly. By 2026, it is expected that more than 1 billion people will be protected against the disease.

scholarly journals Long-term trends and drought: spatiotemporal variation in juvenile sex ratios of North American ducks

2021 ◽  
Author(s):  
Sage Ellis ◽  
Madeleine Lohman ◽  
James Sedinger ◽  
Perry Williams ◽  
Thomas Riecke
Keyword(s):  
United States ◽  
North American ◽  
Sex Ratios ◽  
Survival Rates ◽  
The United States ◽  
Avian Communities ◽  
Eastern United States ◽  
Bird Populations ◽  
Long Term Trends

Sex ratios affect population dynamics and individual fitness, and changing sex ratios can be indicative of shifts in sex-specific survival at different life stages. While climate- and landscape-change alter sex ratios of wild bird populations, long-term, landscape scale assessments of sex ratios are rare. Further, little work has been done to understand changes in sex ratios in avian communities. In this manuscript, we analyse long-term (1961-2015) data on five species of ducks across five broad climatic regions of the United States to estimate the effects of drought and long-term trends on the proportion of juvenile females captured at banding. As waterfowl have a 1:1 sex ratio at hatch, we interpret changes in sex ratios of captured juveniles as changes in sex-specific survival rates during early life. Seven of twelve species-region pairs exhibited evidence for long-term trends in the proportion of juvenile females at banding. The proportion of juvenile females at banding increased for duck populations in the western United States and typically declined for duck populations in the eastern United States. We only observed evidence for an effect of drought in two of the twelve species-region pairs, where the proportion of females declined during drought. As changes to North American landscapes and climate continue and intensify, we expect continued changes in sex-specific juvenile survival rates. More broadly, we encourage further research examining the mechanisms underlying long-term trends in juvenile sex ratios in avian communities.

Biology and immature stages of a lonchaeid fly, Earomyia crystallophila (Becker, 1895) (Diptera, Lochaeidae), developing in stems of Veratrum album L.

Zootaxa ◽  
2017 ◽  
Vol 4291 (2) ◽  
pp. 396
Author(s):  
A.L. OZEROV ◽  
M.G. KRIVOSHEINA
Keyword(s):  
Immature Stages ◽  
Laboratory Conditions ◽  
Veratrum Album ◽  
First Time

The development of lonchaeid flies of the genus Earomyia Zetterstedt, 1842 (Diptera: Lochaeidae) in Veratrum album L. stems is reported for the first time. Larvae were collected in July 2015 in Serbia (Crni Vrh) in mountains at 988 m a.s.l. from inside a blackened decaying part of the stem at a point 1/3 from the apex. No other insects were discovered in the same part of stem. Emergence of adult E. crystallophila (Becker, 1895) occurred under laboratory conditions in January 2016. The larva and puparia are described for the first time. 

scholarly journals Effects of Temperature on the Survival and Larval Development of Deiratonotus Japonicus (Brachyura, Camptandriidae) as a Biological Indicator

2020 ◽  
Vol 8 (3) ◽  
pp. 213 ◽  
Author(s):  
Il-Kweun Oh ◽  
Seung-Woo Lee
Keyword(s):  
Larval Development ◽  
Brachionus Plicatilis ◽  
Survival Rates ◽  
Biological Indicator ◽  
Larval Survival ◽  
Effect Of Temperature ◽  
Larval Stages ◽  
Kanagawa Prefecture ◽  
Survival And Growth ◽  
Increasing Temperature

Deiratonotus japonicus (D. japonicus) inhabits isolated locations and upstream brackish waters from Kanagawa Prefecture to Okinawa Prefecture in Japan. This species faces the threat of extinction because of changing habitat conditions. Our previous studies have shown that its complete larval development from hatching to metamorphosis consists of five zoeal stages and one megalopal stage. In this study, the effect of temperature on the survival and growth of larval development in D. japonicus under controlled laboratory conditions of 13, 18, 23, 24, 25, and 26 °C was investigated by rearing larvae (30 PSU; 12:12 h light/dark cycle; fed a diet of Brachionus plicatilis rotundiformis and Artemia sp. nauplii). The survival rates and developmental periods were measured for each larval stage. The highest survival rates were obtained at 18–24 °C. Metamorphosis to megalopa occurred at 23–25 °C. There were rapid and synchronous developments at 25–26 °C but delayed and extended developments at 13 °C. The molting period decreased with increasing temperature. With decreasing temperature, the beginning of the development and duration of molting was prolonged. In addition, there were very low survival rates at 13 °C and 26 °C in all zoeal stages. Our results indicate that the early larval stages of D. japonicus are well adapted to 18–24 °C, the range observed in the estuarine marine environment of the Kita River during the breeding season. Optimum larval survival and growth were obtained at 23 °C. Temperature significantly affected the survival rate, developmental period, and molting of the larvae. The relationship between the cumulative periods of development from hatching through individual larval stages (y) and temperatures (T) was described as a power function (y = a × Tb).

scholarly journals Amblyomma nodosum (Neumann, 1899): observations on life cycle under laboratory conditions

2015 ◽  
Vol 24 (3) ◽  
pp. 357-360 ◽  
Author(s):  
Michele da Costa Pinheiro ◽  
Elizabete Captivo Lourenço ◽  
Iwine Joyce Barbosa de Sá-Hungaro ◽  
Kátia Maria Famadas
Keyword(s):  
Life Cycle ◽  
Relative Humidity ◽  
Environmental Conditions ◽  
Oryctolagus Cuniculus ◽  
Adult Stage ◽  
Immature Stages ◽  
Experimental Conditions ◽  
Laboratory Conditions ◽  
Natural Hosts

The natural hosts of Amblyomma nodosum in the immature stages are a variety of birds and the anteater in the adult stage. However, so far no data have been published about this tick’s life cycle. To fill this gap, a record was made of its development under laboratory conditions. All the procedures were controlled in a BOD chamber set at 27±1 °C and 80±10% relative humidity and scotophase. The parasitic stages were raised on rabbits (Oryctolagus cuniculus Linnaeus, 1758), from which more than 50% of larvae and nymphs were recovered, although only a small portion performed ecdysis. The adults did not fixed on the rabbits, which suggests that the experimental conditions were unsuitable for the requirements of this species. The data obtained here indicate that A. nodosum is highly dependent on its host and environment whereas under laboratory conditions and host chosen for the study was not obtained satisfactory results and new studies with different hosts and new environmental conditions should be elaborated.

Aquaculture Revisited

1976 ◽  
Vol 33 (4) ◽  
pp. 880-887 ◽  
Author(s):  
John E. Bardach
Keyword(s):  
Social Impact ◽  
Information Dissemination ◽  
Raw Materials ◽  
Survival Rates ◽  
Larval Survival ◽  
Larval Rearing ◽  
Tropical Asia ◽  
Economy Of Scale ◽  
The Pacific ◽  
Choice Of Species

Opportunities for and constraints of animal aquaculture are considered with special reference to the Pacific basin. Choice of species for husbandry depends on biological, cultural, and marketability criteria. Seed production (spawning and larval rearing) may be centralized, with certain economy of scale advantages, even in artisanal aquaculture enterprises, provided adequate distribution facilities for postlarvae are made. Larval survival rates for several actual or potential cultivars still need enhancement through applied research. Practices for the growout phase of aquatic stock differ, depending on the intensity of fixed and variable inputs, by analogy with terrestrial systems one may distinguish feedlot, managed pasturage, and ranching modes. For much of tropical Asia best expansion opportunities exist in managed pasturage polyculture possibly combining the grow-out of crustacea for export with local, largely herbivorous and planktivorous semistaple species. Extraneously supplied feeds, when used, will differ with the species and locally available raw materials. Nonbiotechnical constraints to aquaculture expansion are found in the areas of training, credit, extension, social impact of change, and information dissemination. They may be as difficult, if not more difficult, to overcome as purely biological ones.

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