Regulation of damseifly populations: the effects of larval density on larval urvival, development rate and size in the field

Abstract Most sand flies and mosquitoes require a bloodmeal for egg production, but when blood-sources are scarce, some of them can reproduce without it, so called facultative autogeny. The evolution of autogenous reproduction is thought to involve a trade-off between the benefit of reproducing in the absence of bloodmeal hosts versus the quantitative cost of reduced fecundity and/or or qualitative effect on reduced offspring development and survivorship. We blood-fed (BF) some Phlebotomous papatasi (Scopoli) sand fly females on mice while keeping others (from the same cohort) not BF. We then compared the fecundity of BF and non-blood-fed (NBF) females and also evaluated their egg mass and hatching rate, larval development rate and survivorship, pupa mass and eclosion rates, and progeny fecundity. Among NBF females, only 55% became gravid and produced three times less mature oocytes than BF ones. Autogenous females laid 3.5 and 5.7 times fewer eggs in individual and multi-female bioassays, respectively. Egg mass and hatching rate were not affected by blood-feeding. Individual-larvae bioassays suggested reduced survival during larval stages in the autogenous group. In multi-larvae bioassays, overall and especially pupae survival was significantly reduced in the autogenous group. Development rate was slower and pupal mass was reduced in progeny from autogenous mothers. These effects were particularly apparent at high larval density. Mothers’ blood-feeding history did not affect daughter’s fecundity. Studies on the costs of autogeny provides insights on the evolution of blood feeding. Moreover, it also provides insights regarding potential implications of autogeny to the emergence of vector-borne diseases.

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The influence of algal ration and larval density on growth and survival of blacklip pearl oyster Pinctada margaritifera (L.) larvae

Aquaculture Research ◽

10.1046/j.1365-2109.2000.00483.x ◽

2000 ◽

Vol 31 (8-9) ◽

pp. 621-626 ◽

Cited By ~ 21

Author(s):

M S Doroudi ◽

P C Southgate

Keyword(s):

Larval Density ◽

Pearl Oyster ◽

Pinctada Margaritifera ◽

Growth And Survival

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A method for rearing Arhopalus ferus (Mulsant) (Coleoptera Cerambycidae) larvae on a modified artificial diet

New Zealand Plant Protection ◽

10.30843/nzpp.2015.68.5812 ◽

2015 ◽

Vol 68 ◽

pp. 353-359 ◽

Cited By ~ 2

Author(s):

A.M. Barrington ◽

D.P. Logan ◽

P.G. Connolly

Keyword(s):

Introduced Species ◽

Artificial Diet ◽

Larval Density ◽

Pine Bark ◽

Pine Wood ◽

Rearing Method ◽

Sawn Timber

Burnt pine longhorn (BPL) Arhopalus ferus (Mulsant) (Coleoptera Cerambycidae) is an introduced species sometimes found in association with export logs and sawn timber A rearing method was developed to produce larvae of a known age number and quality for control trials Growth of larvae from newly hatched to 5 weeks was measured on a standard cerambycid artificial diet and on modified diets Replacing pine wood with pine bark sawdust increased survival at 5 weeks from 23 to 76 and mean weight from 9 to 21 mg There were significant interactions between the influences of three factors (diet period of rearing initial larval density) on the weight of surviving larvae Individual rearing was preferred for convenience and a standardised method was used to rear 8740 larvae for disinfestation trials Establishment and survival to 6 weeks for these larvae was 97

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The Effect of Water Shortage on Potted Peach Trees in Relation to Ecophysiological Parameters and Infra-red Thermometry

HortScience ◽

10.21273/hortsci.33.3.541b ◽

1998 ◽

Vol 33 (3) ◽

pp. 541b-541

Author(s):

Rita Giuliani ◽

James A. Flore

Keyword(s):

Chlorophyll Fluorescence ◽

Gas Exchange ◽

Early Detection ◽

Water Potential ◽

Canopy Temperature ◽

Water Shortage ◽

Development Rate ◽

Plant Water ◽

Infra Red ◽

Peach Trees

Potted peach trees grown outdoors during the 1997 season were subjected to drought and subsequent rewatering to evaluate their dynamic response to soil water content. The investigation was primarily focused on the early detection of plant water stress to prevent negative effects on the growth. Leaf chlorophyll fluorescence and canopy temperature estimates (by infra-red thermometry) were conducted. Drought effect on physiological processes were detected through by estimates of canopy development rate, leaf gas-exchange measurements; while leaf water potential was measured to characterize plant water status. A decrease in the canopy's development rate was found 1 week after irrigation was stopped, which also coincided with a more-negative leaf water potential, whereas a decrease of the gas-exchange activities occurred several days later. No significant differences between the stressed and control plants were recorded by the chlorophyll fluorescence parameters (Fo, Fm, Fv and the ratio Fv/Fm), whereas the infra-red estimates of canopy temperature detected a slight increase of the canopy surface temperature (connected to the change of leaf energy balance and in relation to partial stomatal closure) on the non-irrigated plants 1 week after the beginning of the trial. The use of infra-red thermometry for early detection of water shortage is discussed.

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Improvement of water quality for mass anopheline rearing: evaluation of the impact of ammonia-capturing zeolite on larval development and adult phenotypic quality

Parasites & Vectors ◽

10.1186/s13071-021-04763-w ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Nwamaka Oluchukwu Akpodiete ◽

Frédéric Tripet

Keyword(s):

Water Quality ◽

Larval Development ◽

Larval Density ◽

Malaria Vector Control ◽

Larval Rearing ◽

Emergence Success ◽

Phenotypic Quality ◽

Rearing Density ◽

Daily Water ◽

The Impact

Abstract Background Malaria vector control approaches that rely on mosquito releases such as the sterile insect technique (SIT) and suppression or replacement strategies relying on genetically modified mosquitoes (GMM) depend on effective mass production of Anopheles mosquitoes. Anophelines typically require relatively clean larval rearing water, and water management techniques that minimise toxic ammonia are key to achieving optimal rearing conditions in small and large rearing facilities. Zeolites are extensively used in closed-system fish aquaculture to improve water quality and reduce water consumption, thanks to their selective adsorption of ammonia and toxic heavy metals. The many advantages of zeolites include low cost, abundance in many parts of the world and environmental friendliness. However, so far, their potential benefit for mosquito rearing has not been evaluated. Methods This study evaluated the independent effects of zeolite and daily water changes (to simulate a continuous flow system) on the rearing of An. coluzzii under two feed regimes (powder and slurry feed) and larval densities (200 and 400 larvae per tray). The duration of larval development, adult emergence success and phenotypic quality (body size) were recorded to assess the impact of water treatments on mosquito numbers, phenotypic quality and identification of optimal feeding regimes and larval density for the use of zeolite. Results Overall, mosquito emergence, duration of development and adult phenotypic quality were significantly better in treatments with daily water changes. In treatments without daily water changes, zeolite significantly improved water quality at the lower larval rearing density, resulting in higher mosquito emergence and shorter development time. At the lower larval rearing density, the adult phenotypic quality did not significantly differ between zeolite treatment without water changes and those with daily changes. Conclusions These results suggest that treating rearing water with zeolite can improve mosquito production in smaller facilities. Zeolite could also offer cost-effective and environmentally friendly solutions for water recycling management systems in larger production facilities. Further studies are needed to optimise and assess the costs and benefits of such applications to Anopheles gambiae (s.l.) mosquito-rearing programmes. Graphic abstract

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Effect of Processed Beverage By-Product-Based Diets on Biological Parameters, Conversion Efficiency and Body Composition of Hermetia illucens (L) (Diptera: Stratiomyidae)

Insects ◽

10.3390/insects12050475 ◽

2021 ◽

Vol 12 (5) ◽

pp. 475

Author(s):

Vassilios Sideris ◽

Maria Georgiadou ◽

Georgios Papadoulis ◽

Konstantinos Mountzouris ◽

Antonios Tsagkarakis

Keyword(s):

Body Composition ◽

Crude Protein ◽

Larval Density ◽

Mass Reduction ◽

Spent Coffee Grounds ◽

Hermetia Illucens ◽

Protein Levels ◽

Spent Grains ◽

Coffee Grounds ◽

By Products

The effect of spent coffee grounds (SCG), brewer’s spent grains (BSG) and their mixtures with the addition of brewer’s yeast (BY) were tested in two rearing densities of the Black Soldier Fly, Hermetia illucens (L.). Different treatments were investigated on larval development, survival, yield, protein conversion (PrCR) and bioconversion rate (BCR), substrate mass reduction and body composition of the insect. BSF larvae were able to develop sufficiently in all diets, except on sole SCG. The addition of BY enhanced the performance properties of diets, especially in the case of SCG, where larvae underperformed. Substrate mass reduction, PrCR and BCR were affected only by feed and exhibited higher values on reference feed, followed by BSG and SCG+BSG enriched with BY. Density did not have a significant effect on various larval nutrients, except for fat, which was higher on larvae fed enriched feeds with BY and in the 300 larval density. The interaction between feed and density strongly affected the nitrogen and protein levels, larval yield and ash. Generally, diets which contained SCG exhibited high larval crude protein levels. Our results illustrate that low value beverage by-products can be successfully utilized as constituents of a successful BSF diet.

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The effects of host plant species and larval density on immune function in the polyphagous moth Spodoptera littoralis

Ecology and Evolution ◽

10.1002/ece3.7802 ◽

2021 ◽

Author(s):

Kristina Karlsson Green

Keyword(s):

Immune Function ◽

Host Plant ◽

Plant Species ◽

Spodoptera Littoralis ◽

Larval Density ◽

Host Plant Species

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Effect of Temperature on the Development and Survival of Feltiella Acarisuga (Vallot) (Diptera: Cecidomyiidae) Preying on Tetranychus Urticae (Koch) (Acari: Tetranychidae)

Insects ◽

10.3390/insects12060508 ◽

2021 ◽

Vol 12 (6) ◽

pp. 508

Author(s):

Yong-Seok Choi ◽

Sung-Hoon Baek ◽

Min-Jung Kim

Keyword(s):

Developmental Stages ◽

Gall Midge ◽

Mass Rearing ◽

Immature Stage ◽

Development Rate ◽

Effect Of Temperature ◽

Thermal Constant ◽

Fundamental Information ◽

Threshold Temperatures ◽

Response To Temperature

The predatory gall midge, Feltiella acarisuga (Vallot) (Diptera: Cecidomyiidae), is an acarivorous species that mainly feeds on spider mites (Acarina: Tetranychidae). Because of its cosmopolitan distribution and predation efficacy, it is considered an important natural enemy available as a biological agent for augmentative biocontrol. However, despite its practical use, the thermal development and survival response to temperature have not yet been fully studied. In this study, we investigated the stage-specific development and survival of F. acarisuga at seven temperatures (11.5, 15.7, 19.8, 23.4, 27.7, 31.9, and 35.4 °C) to examine the effect of temperature on its lifecycle. All developmental stages could develop at 11.5–31.9 °C, but the performance was different according to the temperature. From the linear development rate models, the lower development threshold and thermal constant of the total immature stage were estimated at 8.2 °C and 200 DD, respectively. The potential optimal and upper threshold temperatures for the total immature stage were estimated as 29.3 and 35.1 °C using a non-linear development model. The operative thermal ranges for development and survival at 80% of the maximum rate were 24.5–32.3 and 14.7–28.7 °C, respectively. Thus, it was suggested that 24.5–28.7 °C was suitable for the total immature stage. In contrast, conditions around 8 °C and 35 °C should be avoided due to the lower development rate and high mortality. Our findings provide fundamental information for an effective mass-rearing and releasing program of F. acarisuga in an augmentative biocontrol program and help to predict phenology.

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