Biology of tree-hole mosquitoes: photoperiodic control of development in northern Toxorhynchites rutilus (Coq.)

1975 ◽  
Vol 53 (7) ◽  
pp. 889-893 ◽  
Author(s):  
William E. Bradshaw ◽  
Christina M. Holzapfel
Keyword(s):  
Rapid Growth ◽  
Fourth Instar ◽  
Photoperiodic Control ◽  
The Third ◽  
Winter Conditions ◽  
Tree Hole ◽  
Critical Photoperiod ◽  
Northern Portion ◽  
Toxorhynchites Rutilus ◽  
Short Days

Carnivorous larvae of the tree-hole mosquito, Toxorhynchites rutilus, were collected from the northern portion of their range. Long days were found to promote rapid growth and metamorphosis from egg to adult; short days retard development during the second and third instars and evoke diapause in the fourth. All larvae exposed continuously to long days from embryos to the third or fourth instar developed without entering diapause. Diapause-averting long days experienced earlier in development could be reversed in at least some individuals by subsequent short days. Among laboratory-reared larvae or those caught early in the fall, the critical photoperiod for the maintenance of diapause is around 13 h of light per day. Among larvae caught in midwinter, diapause is not maintained in all larvae at any photoperiod and in 50% or less of the larvae at photophases shorter than 12.5 h. Winter conditions in the northern part of the range of T. rutilus appear to play a prominent role in the maintenance and termination of diapause.

A second diapause in Wyeomyia smithii: seasonal incidence and maintenance by photoperiod

1975 ◽  
Vol 53 (2) ◽  
pp. 215-221 ◽  
Author(s):  
L. P. Lounibos ◽  
W. E. Bradshaw
Keyword(s):  
Larval Instar ◽  
Fourth Instar ◽  
Continuous Exposure ◽  
Seasonal Incidence ◽  
Wyeomyia Smithii ◽  
The Third ◽  
Critical Photoperiod ◽  
Plant Habitat ◽  
Short Days

Wyeomyia smithii ordinarily diapauses in the third larval instar, but a second, photoperiodically maintained developmental arrest may occur in the fourth instar. Two years of sampling from a Massachusetts bog revealed that the fourth-instar diapause phenotype is most abundant in the spring after the termination of third-instar diapause, and in the fall when a new overwintering generation of third instars accumulates in the pitcher-plant habitat. Fourth-instar larvae from this population cannot, however, survive the winter. This mortality during winter is apparently balanced by advantages that a second diapause confers upon the mosquito population in the spring.Fourth-instar diapause may be induced from diapausing third-instar larvae in the laboratory by a brief exposure to long days followed by short days, or by a long-term exposure to short days at 25 °C. Continuous exposure to long days readily terminates fourth-instar diapause. The critical photoperiod and number of long days required for the termination of diapause is similar for larvae which diapause in either the third or fourth instar.

Photoperiodic control of development in the pitcher-plant mosquito, Wyeomyia smithii

1972 ◽  
Vol 50 (6) ◽  
pp. 713-719 ◽  
Author(s):  
William E. Bradshaw ◽  
L. Philip Lounibos
Keyword(s):  
Larval Instar ◽  
Pitcher Plant ◽  
Photoperiodic Control ◽  
Wyeomyia Smithii ◽  
Diapause Termination ◽  
Environmental Consequences ◽  
The Third ◽  
Short Day ◽  
Critical Daylength ◽  
Short Days

Wyeomyia smithii diapause in the third larval instar. Long days avert or terminate and short days promote or maintain diapause. Diapause occurs early in the third instar and may be terminated by photoperiodic stimuli without the intervention of chilling or other factors. Fifty percent termination of diapause requires about 3 long days and another [Formula: see text] days are consumed in the third instar for postdiapause development. The critical daylength is identical for both the initiation and termination of diapause, 14.75 h of light per day. But, the photoperiodic clock monitoring diapause decisions is several times as accurate during initiation as in termination, reflecting the more drastic environmental consequences of development misdirection in the fall than in the spring. This accuracy is further enhanced by a prolongation of the second instar under short-day conditions. The doubling in the duration of the second instar exhibits the same critical daylength properties as diapause determination.The third instar is divisible into four distinct developmental periods: prediapause, diapause, termination of diapause, and postdiapause. Methods for quantifying these periods are presented. Similar manipulations could be employed for other diapausing arthropods, regardless of the stage at which dormancy occurs or the cues used in its regulation.

Photoperiodism in Orthopodomyia signifera

1973 ◽  
Vol 51 (3) ◽  
pp. 355-357 ◽  
Author(s):  
William E. Bradshaw
Keyword(s):  
North Carolina ◽  
Rapid Development ◽  
Larval Instar ◽  
Developmental Rate ◽  
Photoperiodic Response ◽  
The Third ◽  
Tree Hole ◽  
Fourth Larval Instar ◽  
Lower Temperature ◽  
Short Days

Larvae of the tree-hole mosquito, Orthopodomyia signifera, were collected from North Carolina and subjected to long- and short-day photoperiods. Long days at 25 °C permit rapid molting of fourth instar larvae to pupae. Lower temperature (15 °C) modifies developmental rate but does not appear to block photoperiodic response to long days. Short days at 25 °C may halt development, may retard development, or may permit rapid development in either the third or fourth larval instar. O. signifera is probably polymorphic for both the stage at which diapause may occur and for the depth or firmness with which it is established.

Comparison of egg size and related life-history characteristics for two predaceous tree-hole mosquitoes (Toxorhynchites)

1980 ◽  
Vol 58 (11) ◽  
pp. 2065-2070 ◽  
Author(s):  
R. J. Lamb ◽  
S. M. Smith
Keyword(s):  
Life History ◽  
Egg Size ◽  
Prey Size ◽  
Prey Availability ◽  
Fourth Instar ◽  
Natural Environments ◽  
First Instar ◽  
Life History Characteristics ◽  
Tree Hole ◽  
Toxorhynchites Rutilus

Certain life-history characteristics of Toxorhynchites brevipalpis and Tx. rutilus septentrionalis were compared in the laboratory with the aim of accounting for a more than twofold difference in the weight of their eggs. First- and second-instar larvae of Tx. rutilus were longer and third-instar larvae shorter than corresponding stages of Tx. brevipalpis. The sizes of the two species did not differ appreciably in the later stages. Toxorhynchites rutilus first-instar larvae consumed more prey but total prey consumption was much greater for Tx. brevipalpis due to differences in consumption during the fourth instar. Developmental times from egg to adult did not differ at 25 °C. Toxorhynchites brevipalpis produced twice as many eggs per day during the first 14 days of oviposition but, due to size differences, the weight of the eggs produced per day was equal for the two species. Female Tx. brevipalpis laid an average of 5.9 eggs per oviposition flight. A corresponding value for Tx. rutilus was not determined. Newly hatched Tx. brevipalpis larvae withstood starvation for a longer period of time than Tx. rutilus larvae. Larval Tx. rutilus captured and consumed larger prey.It is hypothesized that egg size and fecundity are adapted to prey size and heterogeneity in prey availability in the natural environments of the two species.

scholarly journals Biologi Stenocranus pacificus Kirkaldy (Hemiptera: Delphacidae) pada tanaman jagung (Zea mays L.) di rumah kasa

2020 ◽  
Vol 17 (2) ◽  
pp. 104
Author(s):  
Dosma Ulina Simbolon ◽  
Maryani Cyccu Tobing ◽  
Darma Bakti
Keyword(s):  
Zea Mays ◽  
Life Cycle ◽  
Sex Ratio ◽  
Zea Mays L ◽  
Instar Nymph ◽  
Fourth Instar ◽  
The Third ◽  
First Instar ◽  
Corn Plants ◽  
North Sumatra

<p><em>Stenocranus pacificus </em>Kirkaldy (Hemiptera: Delphacidae) is destructive pest on corn plants in South Lampung and it has been reported to cause corn damages in North Sumatra. The  objective of this research was to study some aspects biology of <em>S. pacificus</em> on corn plants in screenhouse. The research was conducted by observing the biology of <em>S. pacificus</em> that was reared on corn plants in screenhouse.<em> </em>The results showed that life cycle of <em>S. pacificus </em>was 38–47 (41,60 ± 3,19) days: egg was 9–11 (10,20 ± 0,79) days, the first instar nymph was 3–4 (3,70 ± 0,48) days, the second instar nymph was 3–4 (3,90 ± 0,32) days, the third instar nymph was 3–4 (3,70 ± 0,48) days, the fourth instar nymph was 3–4 (3,80 ± 0,42) days, and the fifth instar nymph was 3–4 (3,60 ± 0,52) days. Age of female was 13–17 (15,30 ± 1,34) days. It was longer than age of male which was 8–12 (10,10 ± 1,20) days. Female could produce 181–214 (197,60 ± 11,64) eggs during its life. The sex ratio was 1:1,98.</p>

PHOTOPERIODIC MODULATION OF GONADOTROPHIN SECRETION IN CASTRATED JAPANESE QUAIL

1982 ◽  
Vol 92 (1) ◽  
pp. 73-83 ◽  
Author(s):  
H. F. URBANSKI ◽  
B. K. FOLLETT
Keyword(s):  
Japanese Quail ◽  
Plasma Levels ◽  
Time Course ◽  
Neural Mechanisms ◽  
Gonadal Steroids ◽  
Photoperiodic Control ◽  
Gonadotrophin Secretion ◽  
Lh Secretion ◽  
Sexually Mature ◽  
Short Days

Male Japanese quail were castrated when sexually immature and immediately exposed to one of the following stimulatory lighting regimes for 52 days: 11 h light: 13 h darkness/day (11L : 13D), 12L : 12D, 13L : 11D, 14L : 10D, 15L : 9D, 16L : 8D, 20L : 4D or 23L : 1D. One group was retained on short days (8L : 16D). Clearcut differences in the plasma levels of LH and FSH emerged between the various groups. Levels remained very low in castrated quail on 8L : 16D but were much greater in those on 14L : 10D, 15L : 9D, 16L : 8D, 20L : 4D and 23L : 1D, eventually becoming 15 to 20 times higher. Less pronounced castration responses developed on 13L : 11D, 12L : 12D or 11L : 13D. Alterations in photoperiod after day 52 caused an appropriate rise or fall in LH secretion. Photoperiodically induced suppressions were rapid, being highly significant within 4 days, but increases usually had a slower time course. When sexually mature quail (on 16L : 8D) were castrated and transferred to 8L : 16D they also exhibited a rapid suppression in LH secretion. Thus in quail, unlike some mammals, the photoperiodic control over gonadotrophin secretion is independent of the reproductive status of the animal at the time of castration. The results confirm the view that changes in sensitivity of the hypothalamo-pituitary axis to gonadal steroids are not a primary factor in the neural mechanisms underlying photoperiodism in quail.

Tagesperiodische antagonistische Schwankungen der Blauviolett- und Gelbrot-Empfindlichkeit als Grundlage der photoperiodischen Diapause-Induktion bei Pieris brassicae

1960 ◽  
Vol 15 (4) ◽  
pp. 205-213 ◽  
Author(s):  
Erwin Bünning ◽  
Gabriele Joerrens
Keyword(s):  
Dark Period ◽  
Red Light ◽  
Pieris Brassicae ◽  
Light Period ◽  
Measuring Process ◽  
The Third ◽  
Long Day ◽  
Critical Daylength ◽  
Qualitative Responses ◽  
Short Days

In Pieris brassicae, diapause is inhibited if long-day conditions are imposed during and immediately after the third molting. The critical daylength is approximately 14 hours. Under short-day conditions with a main light period of 6 or 12 hours’ duration, supplementary light given in the period from 14 to 16 hours after the beginning of the main light period will inhibit diapause. In contrast to this effect of late exposures to light, light given from 1 to 12 hours after the beginning of the main light period promotes diapause. Experiments with extremely long light periods (10—35 hours), but always with a dark period of 10 hours, show that these diurnal fluctuations in quantitative and qualitative responses to light can continue endogenously for several days. Thus, this time-measuring process operates through the mechanism of endogenous diurnal oscillations in just the same way as do photoperiodic reactions in plants.The inhibition of diapause by light in the second half of the diurnal oscillation (under long days or by light interruptions in the dark period) and the promotion by light in the first half (under short days) occur only with light of short wavelengths: ultraviolet, violet, and blue up to about 550 mμ. Yellow and red light act in the opposite fashion, giving diapause inhibition in the first half of the cycle and promotion in the second half. In white light the violet reaction predominates, so that diapause is promoted by short days and inhibited by long days.

scholarly journals Day-Length Control of Inflorescence Initiation in the Grass Rottboellia Exaltata L.F.

1962 ◽  
Vol 15 (2) ◽  
pp. 291 ◽  
Author(s):  
LT Evans
Keyword(s):  
Day Length ◽  
Inflorescence Development ◽  
Short Day ◽  
Critical Photoperiod ◽  
The One ◽  
Short Days

R. exaltata is a strict short�day plant with a critical photoperiod of about 13 hr. The number of short days required for inflorescence initiation varies with age, being 6 with plants 5 weeks old. Exposure to additional short days increases the rate of inflorescence development. The expanding leaf is the one most sensitive to short.day induction and removal of the leaves below it accelerates inflorescence development.

GEOGRAPHIC DIFFERENTIATION IN THE DEVELOPMENT OF AEDES SIERRENSIS (DIPTERA: CULICIDAE) IN NATURE

1980 ◽  
Vol 112 (2) ◽  
pp. 205-210 ◽  
Author(s):  
Robert G. Jordan
Keyword(s):  
Laboratory Data ◽  
Fourth Instar ◽  
Geographic Differentiation ◽  
Critical Photoperiod ◽  
Geographic Populations ◽  
Treehole Mosquito ◽  
Aedes Sierrensis

AbstractThe critical photoperiod for fourth instar diapause of the western treehole mosquito, Aedes sierrensis, varies among geographic populations. When reared together in the field at different latitudes, larvae from northern (ca. 45°N), central (ca. 39°N), and southern (ca. 33°N) populations all develop more rapidly through the early instars at more southerly latitudes. The order of pupation dates among the populations, however, depends on their critical photoperiods, and can be predicted from laboratory data on photoperiodism.

Growth and development of larvae and adults of Tipula sacra Alexander (Insecta: Diptera) in a series of abandoned beaver ponds

1976 ◽  
Vol 54 (2) ◽  
pp. 266-284 ◽  
Author(s):  
G. Pritchard
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Growth And Development ◽  
Adult Emergence ◽  
Head Capsule ◽  
Fourth Instar ◽  
Beaver Ponds ◽  
The Third ◽  
First Instar ◽  
Two Peaks

Collections of all stages of the crane fly, Tipula sacra have been made over a period of years from a series of abandoned beaver ponds in the Kananaskis Valley, Alberta. The growth of larvae was followed by head-capsule measurements and weights. Eggs hatch within a month; first-instar larvae grow rapidly and enter the second instar after a few weeks. The second instar may last for 3 months and the third instar usually lasts for 6 months, including the first winter. Most larvae spend almost a full year in the fourth instar and overwinter for a second time. However, there was much variation in growth rate within the population. Adult emergence curves were consistent in form in 4 years. Each spanned a period of just over 2 months, although individual adults lived for only a few days. These curves snowed two peaks, the second of which contained 15–20% of the year's emergents. These two groups may represent different cohorts that have grown at different rates, suggesting that the life history may be semivoltine or univoltine. The sex ratio changes from about 1:1 in the third instar to 2:1 in favor of males in the late fourth instar, pupa, and adult.

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