Effect of rearing temperature and larval density on larval survival, age at pupation and adult size of Anopheles gambiae

1992 ◽  
Vol 63 (3) ◽  
pp. 265-271 ◽  
Author(s):  
E. O. Lyimo ◽  
W. Takken ◽  
J. C. Koella
Keyword(s):  
Anopheles Gambiae ◽  
Larval Density ◽  
Larval Survival ◽  
Adult Size ◽  
Rearing Temperature

THE EFFECT OF TEMPERATURE AND FOOD DEPRIVATION ON SURVIVAL OF FIRST-INSTAR DOUGLAS-FIR TUSSOCK MOTHS (ORGYIA PSEUDOTSUGATA) (LEPIDOPTERA: LYMANTRIIDAE)

1983 ◽  
Vol 115 (6) ◽  
pp. 663-666 ◽  
Author(s):  
Roy C. Beckwith
Keyword(s):  
Food Deprivation ◽  
Larval Survival ◽  
Douglas Fir ◽  
Effect Of Temperature ◽  
Rearing Temperature ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
First Instar ◽  
Starvation Conditions

AbstractMortality of neonatal Douglas-fir tussock moth larvae varied from 0% to 100% depending on the rearing temperature and duration of food deprivation. Lower temperatures apparently favor larval survival under starvation conditions. For each period of food deprivation, mortality occurs earlier as the temperature increases; this shift to earlier mortality was significant at P <.01. Some implications are discussed.

scholarly journals Detection and quantification of Anopheles gambiae sensu lato mosquito larvae in experimental aquatic habitats using environmental DNA (eDNA).

2018 ◽  
Vol 3 ◽  
pp. 26 ◽  
Author(s):  
Joel Odero ◽  
Bruno Gomes ◽  
Ulrike Fillinger ◽  
David Weetman
Keyword(s):  
Anopheles Gambiae ◽  
Limit Of Detection ◽  
Larval Density ◽  
Indoor Residual Spraying ◽  
Environmental Dna ◽  
Malaria Vectors ◽  
Mosquito Larvae ◽  
Cyt B ◽  
Aquatic Habitats ◽  
Detection And Quantification

Background: Growing insecticide resistance and changes in biting and resting behavior of malaria vectors threaten efficacy of insecticide treated nets and indoor residual spraying. Larval source management (LSM) is a promising approach that can target mosquitoes irrespective of their behavior as adults. However, the use of traditional monitoring methods for immature stages of Anopheles mosquitoes is a major challenge to LSM due to the variability in their breeding habitats.  We evaluate the use of an environmental DNA (eDNA) analysis technique in monitoring Anopheles gambiae sensu lato larvae in experimental aquatic habitats. Methods: eDNA was simultaneously sampled and extracted from different volumes of water, number of larvae, and occupation time. Larval presence was detected using PCR and eDNA concentration in samples from 1 L habitats quantified using an IGS and cyt b TaqMan assays. The limit of detection of the two assays was tested and larval density correlated with eDNA positivity. Results: 74% of replicates in the 50 mL habitats were PCR positive with at least 6h required to get a signal from a single larva (0.02 larvae/mL). All 12 replicates where 1 L of water was used were positive with stronger PCR bands than replicates with the same larval density in 50 mL for 24 h. There was a correlation between larval densities and eDNA detection in both assays: IGS, r = 0.503, p = 0.047; and cyt b, r = 0.558, p = 0.025. There was stochasticity in eDNA detection rates, using both PCR and qPCR across all the dilutions. Conclusion: This study has demonstrated the potential use of eDNA analysis for detection and quantification of An. gambiae s.s. mosquito larvae in aquatic habitats. The stochasticity observed in eDNA detection suggest that this technique is best for monitoring aquatic habitats with many larvae at low densities.

Plankton-generated chaos in the modelled dynamics of haddock

1995 ◽  
Vol 350 (1332) ◽  
pp. 109-118 ◽  
Keyword(s):  
Food Supply ◽  
Chaotic Dynamics ◽  
Larval Density ◽  
Larval Survival ◽  
Laboratory Studies ◽  
Model Parameterization ◽  
Regions Of Stability ◽  
Underlying Mechanisms ◽  
Plankton Model ◽  
Stock And Recruitment

This study illustrates the feasibility of regimes of chaotic dynamics in gadoid populations. A previously developed plankton model related fish larval survival to larval density and their copepod food supply. This model is extended to a full-population model, incorporating age structure, fishing and a stockrecruitment relation implicit in the plankton model. Parameterization is based upon the Georges’ Bank haddock. It is shown that regions of stability, aperiodic and chaotic-like dynamics exist as both the copepod food-supply and fishing rates are varied. The deterministic aperiodic dynamics are significantly complicated by additional stochastic elements. The implications are that chaotic dynamics are plausible and that analyses of output data on stock and recruitment can reveal relatively little; field and laboratory studies are needed to elucidate the underlying mechanisms. Traditional fitting of stock and recruitment relations may give an overly optimistic interpretation for fisheries managers.

scholarly journals Root exudate chemical cues of an invasive plant modulate oviposition behavior and survivorship of a malaria mosquito vector

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Trizah K. Milugo ◽  
David P. Tchouassi ◽  
Reginald A. Kavishe ◽  
Rhoel R. Dinglasan ◽  
Baldwyn Torto
Keyword(s):  
Anopheles Gambiae ◽  
Survival Time ◽  
Root Exudate ◽  
Invasive Plant ◽  
Oviposition Behavior ◽  
Gravid Female ◽  
Larval Survival ◽  
Mosquito Vector ◽  
Treated Water ◽  
Gravid Females

AbstractGravid female Anopheles gambiae mosquitoes identify suitable oviposition sites through a repertoire of cues, but the influence of allelochemicals, especially root phytochemicals in modulating this behavior and impacting subsequent progeny bionomics remains unexplored. We addressed these questions in the malaria vector Anopheles gambiae and its invasive host plant Parthenium hysterophorus. Using chemical analysis combined with laboratory behavioral assays, we demonstrate that a blend of terpenes, namely α-pinene, α-phellandrene, β-phellandrene, 3-carene and (E)-caryophyllene emitted from P. hysterophorus root exudate treated-water attracted gravid females. However, fewer eggs (55%) hatched in this treatment than in control water (66%). The sesquiterpene lactone parthenin, identified in both the natural aquatic habitat harboring P. hysterophorus and root exudate-treated water was found to be responsible for the ovicidal effect. Moreover, larvae exposed to parthenin developed 2 to 3 days earlier but survived 4 to 5 days longer as adults (median larval survival time = 9 days (all replicates);11 to 12 days as adults) than the non-exposed control (median larval survival time = 11 days (reps 1 & 2), 12 days (rep 3); 6 to 7 days as adults). These results improve our understanding of the risk and benefits of oviposition site selection by gravid An. gambiae females and the role root exudate allelochemicals could play on anopheline bionomics, with potential implications in malaria transmission.

Long-term monitoring of potamodromous migratory fish larvae in an undammed river

2020 ◽  
Vol 71 (3) ◽  
pp. 384 ◽  
Author(s):  
Rafael Rogério Rosa ◽  
Jislaine Cristina Silva ◽  
Andréa Bialetzki
Keyword(s):  
Fish Larvae ◽  
Larval Density ◽  
Temporal Distribution ◽  
Larval Survival ◽  
Local Conditions ◽  
Key Species ◽  
Survival And Growth ◽  
Term Monitoring ◽  
Salminus Brasiliensis

Freshwater fish reproduce annually in environments that provide favourable conditions for spawning and larval survival and growth. Thus, the aims of this study were to use long-term larval density data to evaluate the temporal distribution of the dourado Salminus brasiliensis, its habitat use for larval development and the effects of environmental variables on reproduction. S. brasiliensis larvae were mainly recorded in October and January in the Ivinheima River, and higher densities of larvae, primarily in the preflexion and flexion stages, were captured in the river and backwater biotopes. Water level, dissolved oxygen and temperature were the primary variables affecting the density of larvae, and this species can migrate over 200km to reproduce in the Ivinheima River and its tributaries. Therefore, S. brasiliensis is reproducing annually, indicating favourable local conditions for migration and spawning, and exhibits differential use of biotopes for reproduction, including rivers and backwaters (spawning) and lagoons (refuge and growth). Therefore, considering that the dourado is a key species for conservation, ensuring its reproductive success means maintaining a balanced ecological structure.

scholarly journals Effects of Larval Population Density and Food Type on the Life Cycle of Musca domestica (Diptera: Muscidae)

2020 ◽  
Author(s):  
Meltem Kökdener ◽  
Filiz Kiper
Keyword(s):  
Life History ◽  
Musca Domestica ◽  
Wheat Bran ◽  
Development Time ◽  
Larval Density ◽  
Larval Survival ◽  
Food Type ◽  
Adult Survival ◽  
Larval Population ◽  
Life History Parameters

Abstract Larval density is an important factor modulating larval resource-acquisition, influencing development of insects. This study aimed to evaluate the effect of larval density and substrate content on some life-history parameters of Musca domestica Linnaeus, 1758 (Diptera: Muscidae). This research was carried out from March 2019 through September 2019 at Animal Physiology Laboratory of Ondokuz Mayıs University, Samsun, Turkey. Groups of 25, 100, 200, and 400 newly hatched M. domestica larvae were transferred to a polyethylene cup filled with different substrates (i.e., wheat bran, poultry meal, soybean meal) and kept at 25°C, 62% RH with a photoperiod of 12:12 (L:D) h. A two-way analysis of variance (Two way ANOVA) was used to analyze the data on the percentage of pupal and larval survival development time, pupal, and adult weight to evaluate the effect of density and rearing substrate. In this study, increasing larval density and nutrient content of food led to changes in the larval and pupal development time of M. domestica. The results also indicated that the weight of pupae and adult survival was negatively affected by increasing larval density. The wheat bran diet was superior to the other diets for all parameters tested. Our study indicated that life history parameters of Musca domestica are affected by the rearing conditions.

scholarly journals White Grub (Coleoptera: Scarabaeidae) Population Density in Relation to Root Damage to Fraser Fir Seedlings in Transplant Beds

2004 ◽  
Vol 22 (2) ◽  
pp. 85-87
Author(s):  
R. Chris Williamson
Keyword(s):  
Larval Density ◽  
Larval Survival ◽  
Root Damage ◽  
White Grub ◽  
Plant Weight ◽  
Abies Fraseri ◽  
Fraser Fir ◽  
Christmas Trees ◽  
Plant Injury ◽  
Phyllophaga Anxia

Abstract A field experiment was conducted in 2002 to evaluate the effect of five grub densities of second instar Phyllophaga anxia (LeCont) Glasgow larvae on feeding damage to roots of young seedlings of Fraser fir, Abies fraseri (Pursh) Poir., Christmas trees in a transplant bed. Larval densities were equivalent to approximately 0, 31, 62, 93, and 124 larvae per m2 (≈ 0, 3, 6, 9, and 12 larvae per ft2). Larval survival and variations in larval and seedling weight were also evaluated. Regardless of the larval density, when P. anxia grubs were present, all Fraser fir seedlings experienced significant root damage as well as subsequent plant injury (i.e., decline or mortality). Larval density as low as one grub per 0.11 m2 (≈ 3 larvae per ft2) caused heavy to severe root damage to young, two-year-old, P2-0 Fraser fir seedlings. An inverse relationship was observed between plant weight and root damage.

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