The Effect of Temperature on the Immature Stages of Culiseta inornata (Diptera: Culicidae) in the Laboratory

1967 ◽  
Vol 99 (1) ◽  
pp. 59-64 ◽  
Author(s):  
W. Hanec ◽  
R. A. Brust

AbstractA study was initiated to determine the effects of various constant and alternating temperatures on the survival and development of the immature stages of Culiseta inornata (Williston). Eggs did not hatch at 2° and 5 °C. but at 10°, 15°, 21° and 26 °C. between 83 and 96% hatched. Larvae required up to 239 days to reach the pupal stage at 5 °C. but no adults emerged at this temperature. The optimum temperature for rearing C. inornata was near 21 °C. Temperatures below 21 °C. caused an extended period of development; above 21 °C. high mortality occurred among late instar larvae and pupae.

1991 ◽  
Vol 39 (2) ◽  
pp. 191 ◽  
Author(s):  
JG Hamilton ◽  
MP Zalucki

C. plebejana were reared from egg to adult at a range of constant temperatures. At 10-degrees-C no immature stages survived. Development rates increased over the temperature range 14-34-degrees-C; these were simulated with a non-linear model. Females emerged before males. Fecundity decreased with increased rearing temperature as a direct result of reduced adult female weight. At 34-degrees-C development rate and survival were reduced and all eggs laid were infertile. Optimum temperature for population increase was 28-degrees-C. Validation of a non-linear model for development rate shows that the species of host-plant affects mean development rates of tipworm. Although 5.3 tipworm generations are possible on cotton annually, only one occurs; reasons for this are suggested.


1981 ◽  
Vol 29 (1) ◽  
pp. 25 ◽  
Author(s):  
PL Walker

Age-specific life and fecundity studies on the weevil Phlyctinus callosus (Boh.) (a polyphagous pest in gardens in parts of southern Australia, especially Victoria) revealed that mortality was greatest in the immature stages and that high temperatures were lethal to eggs (>30 deg C) and larvae (>25 deg C). The intrinsic rate of natural increase was greatest at 20 deg C, and the greater proportion of its value was accounted for early in the egg-laying period. Larvae could be reared on carrot roots in the laboratory; 76% of larvae reared in this manner to the pupal stage passed through 7 instars, 12% through 6, and 12% through 8. Head-capsule width was a suitable criterion for identifying the instars. Eggs could be stored for as long as 12 weeks at 5 deg C with no loss of viability. These results are discussed in relation to control measures against the weevil.


1958 ◽  
Vol 49 (1) ◽  
pp. 157-163 ◽  
Author(s):  
Micha Bar-Zeev

The effect of temperature on the growth rate and survival of the immature stages of Aëdes aegypti (L.) was studied by rearing them at each of a series of constant temperatures from 14–38°C. in water to which adequate food (bakers' yeast) was added. Larvae were hatched, by immersing eggs in water, in four successive groups with an interval of six hours between each, and six hours after the last group hatched, and every 24 hours thereafter, those surviving in each group were recorded and transferred to fresh water and food, the exuviae remaining being recorded. The average time at which any given stage was reached was taken as the mid-point of the 6-hr. period within which the number of individuals that had completed the previous stage reached 50 per cent, of the total that finally did so.The curve relating temperature and time of development from newly hatched larva to adult is hyperbolic, except at the extremes. The later the instar, the lower is the temperature at which growth is most rapid. The threshold of development was between 9° and 10°C., the developmental zero 13.3°C., and the average thermal constant (between 16° and 32°C.) 2,741 degree-hours. The highest and lowest temperatures permitting development from newly hatched larva to adult were 36° and 14°C., respectively. The average durations of the four successive larval stages and the pupal stage, expressed as percentages of the time taken for newly hatched larvae to reach the adult stage, were 14.6, 13.9, 17.5, 33.3 and 20.6, respectively.


2015 ◽  
Vol 112 (4) ◽  
pp. 664-675 ◽  
Author(s):  
Ismael SANCHEZ-RAMOS ◽  
Susana PASCUAL ◽  
Cristina E. FERNANDEZ ◽  
Aranzazu MARCOTEGUI ◽  
Manuel GONZALEZ-NUNEZ

1958 ◽  
Vol 36 (4) ◽  
pp. 623-628 ◽  
Author(s):  
Premvati

The optimum temperature for the complete development of the free-living and the infective larvae of Strongyloides fülleborni is 25 °C. Morphological changes are seen at higher or lower temperatures.


Author(s):  
P.E. Gibbs ◽  
J.C. Green ◽  
P.L. Pascoe

In the summer of 1995 a massive kill of the dog-whelk, Nucella lapillus, occurred in Bude Bay on the north Cornish coast. High mortality was detectable along 12 km of shoreline. The only other intertidal species affected appeared to be another neogastropod, Ocenebra erinacea. The cause of the kill is unknown but the evidence suggests that it occurred in early July following an extended period of warm, calm weather in June. Possible causes of this event are discussed: algal toxicity may have been responsible since an algal bloom was detected offshore in July in the area. Laboratory experiments exposing gastropods to different species and concentrations of microalgae, designed to test whether N. lapillus is more sensitive than Monodonta lineata and Littorina littorea, gave inconclusive results. No comparable kill has occurred in the Bude area for at least 20 y, but it is suggested that nutrients from a newly-constructed, offshore sewage outfall may now stimulate local algal bloom development during calm weather periods.


2011 ◽  
Vol 8 (4) ◽  
pp. 870-876 ◽  
Author(s):  
Baghdad Science Journal

The study aimes to investigate the effects of leaves & fruits ethanolic extract of Duranta repens L. on biological performance for all stages of life cycle of the mosquito Culex pipiens piepiens L., For this purpose the mosquitoes were reared in the laboratory till the fourth generation .Different concentrations of leaves (800,1000,1200,1400ppm) and fruits (800,1000,1200ppm) were tested on (eggs,larval stages,pupal stages and the adult stages). The results revealed that the extracts gave highest mortality rate for the eggs at(100%) compared with control,fruits extract shown highest mortality rate of the four larval instars (100%)at 1200ppm compared with leave extract at(80,50,33.33,20%).Also the extract caused a high mortality rate for pupal stage compared with fruits extract at(76.66,53.33%)respectively.Also ethanolic extract caused a 83.33,76.66% for male &femail. Developmental deformation was observed.. In conclusion, the findings of the present study indicate that the leaves &fruits extracts of Duranta repens L., , can be widely and effectively used in the control of mosquito.


2009 ◽  
Vol 99 (9) ◽  
pp. 1045-1052 ◽  
Author(s):  
Paul W. Tooley ◽  
Marsha Browning ◽  
Kerrie L. Kyde ◽  
Dana Berner

We investigated the temperature and moisture conditions that allow Phytophthora ramorum to infect Rhododendron ‘Cunningham's White’. Most experiments were performed with a single P. ramorum isolate from the NA1 clonal lineage. For whole plants incubated in dew chambers at 10 to 31°C, the greatest proportion of diseased leaves, 77.5%, occurred at the optimum temperature of 20.5°C. Disease occurred over the entire range of temperatures tested, although amounts of disease were minor at the temperature extremes. For whole plants exposed to varying dew periods at 20°C and then incubated at 20°C for 7 days, a dew period as short as 1 h resulted in a small amount of disease; however, at least 4 h of dew were required for >10% of the leaves to become diseased. Moisture periods of 24 and 48 h resulted in the greatest number of diseased leaves. In detached-leaf, temperature-gradient-plate experiments, incubation at 22°C resulted in the greatest disease severity, followed by 18°C and then 14°C. In detached-leaf, moisture-tent experiments, a 1-h moisture period was sufficient to cause disease on 67 to 73% of leaves incubated for 7 days at 20°C. A statistical model for disease development that combined the effects of temperature and moisture period was generated using nonlinear regression. Our results define temperature and moisture conditions which allow infection by P. ramorum on Cunningham's White rhododendron, and show that P. ramorum is able to infect this host over a wide range of temperatures and moisture levels. The results indicate that P. ramorum has the potential to become established in parts of the United States that are outside its current range.


1947 ◽  
Vol 24 (1-2) ◽  
pp. 79-94
Author(s):  
L. E. S. EASTHAM ◽  
F. SEGROVE

1. The effects of temperature and humidity on the duration of each instar of the life cycle of Calandra granaria Linn. have been examined. The insects were reared at temperatures ranging from 15 to 30° C. and at atmospheric humidities ranging from 40 to 80% R.H. 2. A method is described for assessing the effect of temperature as an independent factor. 3. The temperatures employed fall within the ‘vital zone’. Extrapolation indicates the threshold temperature to be approximately 11° C. for the egg and larval instars though somewhat lower for the pupa. 30° C. is below the optimum temperature. 4. The durations of the egg and pupal stages are not affected by atmospheric humidity. 5. The duration of all larval instars is affected by moisture. It is suggested that this is largely due to atmospheric humidity and that food water is of little significance. 6. Shortage of moisture acts as an obstacle to development. Evidence is presented which indicates that drier atmospheres tend to desiccate the insect and that desiccation is responsible for retarded growth and development. 7. Since much earlier work on temperature and moisture has been done on fasting insects and, therefore, on insects deficient in one of the most important environmental factors, we suggest that our results, incomplete as they are, indicate the need for new approaches to be made. More complete data on feeding insects under controlled conditions of food, temperature and moisture are required, from which can be drawn up more complete balance sheets of development involving measurements of food utilization and respiratory rates.


1961 ◽  
Vol 9 (2) ◽  
pp. 173 ◽  
Author(s):  
DA Maelzer

The distribution and abundance of the univoltine species A. tasmaniae in the lower south-east of South Australia appears to be related to annual rainfall. The effects of moisture on the mortality rates of the immature stages were consequently studied and observations were made of the effects of variations in moisture in the field. Laboratory experiments and field observations suggested that variations in soil moisture have little effect on the eggs and the diapausing prepupae in the field. Eggs absorbed water and hatched normally within a pF range of 2.50-3.75 in a sand and in a clay loam. At pF 4.0 in both soils, eggs lost weight and did not hatch. The adults, however, tend to lay the eggs well within the pF range in which the eggs can develop, and soil samples suggested that eggs would develop with little mortality in the kinds of places in which they are usually laid. When prepupae enter diapause they have a water content of c. 77%. When desiccated in the laboratory, few prepupae died until their water content fell below 62%. The mortality rate then increased sharply, and it was estimated that 50% of the prepupae died when their water content dropped to 57%. Droughts of sufficient duration and intensity to kill 50% of the prepupae have never been recorded from the study area, and field observations suggested that few prepupae died of desiccation in summer. Unlike the two stages above, the first and third instar larvae may be markedly affected by variations in moisture in the field. The first instar larvae, after hatching, do not move to the surface of the soil and do not feed much until the soil is saturated with rain. As rainfall is variable at this time of the year, the larvae may be in dry soil for many weeks before they are stimulated to extend their burrows to the surface and search for food. Many larvae may die of starvation during this time, and the mortality rate of the larvae was related empirically to the length of the autumn "drought". Third instar larvae may be affected, on the other hand, by excessive water. In wet winters, vast numbers of larvae are drowned when extensive flooding occurs on the poorly-drained soils, and on well-drained soils a large proportion of larvae are killed by the entomophagous fungus Cordyceps aphodii. The above data have suggested that moisture is one of the major factors affecting the distribution and abundance of the species. Temperature has little effect on the rate of increase of the species.


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