The ecology of Sminthurus viridis (Collembola) II. Diapause in the aestivating egg

1968 ◽  
Vol 16 (5) ◽  
pp. 871 ◽  
Author(s):  
MMH Wallace
Keyword(s):  
Adaptive Significance ◽  
Field Conditions ◽  
Food Plants ◽  
Egg Diapause

The existence of an aestivating diapause in the egg batches of S. viridis is established. The production of diapause eggs is influenced in females by the increasing maturity of food plants in the spring. Morphogenesis is resumed in diapause eggs following physical removal of the soil covering in the laboratory or exposure to summer field conditions for a period of 2-3 months. The mechanisms of the egg diapause in S. viridis are studied experimentally, and their adaptive significance for the species is discussed.

Observations on the Reproductive Potential of Melanoplus bilituratus (Wlk.) (Orthoptera: Acrididae) Reared on Different Food Plants in the Laboratory

1958 ◽  
Vol 90 (8) ◽  
pp. 483-485 ◽  
Author(s):  
R. Pickford
Keyword(s):  
Reproductive Potential ◽  
Field Conditions ◽  
Food Plants ◽  
Mixed Diet ◽  
Average Production ◽  
Number Of Authors

The fecundity of the migratory grasshopper, Melanoplus bilituratus (Wlk.), when reared under a variety of conditions, has been reported by a number of authors. In the laboratory, Barnes (1955), rearing cultures of the subspecies found in Arizona on five separate foods, obtained an average production of 8.8 egg-pods per female from those fed the most favourable diet; Parker (1930) reported an average production of 8.8 egg-pods per female from Montana specimens reared on a mixed diet; one of these females laid 15 egg-pods. Under field conditions, Pfadt (1949) in Wyoming and Smith et al. (1952) in Manitoba reared this species on a variety of food plants and reported that the greatest numbers of egg-pods per female resulting from use of the most favourable food plants were 9.8 and about 6 egg-pods, respectively.

Role of natural day-length and temperature in determination of summer and winter diapause in Pieris melete (Lepidoptera: Pieridae)

2011 ◽  
Vol 102 (3) ◽  
pp. 267-273 ◽  
Author(s):  
H.J. Xiao ◽  
S.H. Wu ◽  
H.M. He ◽  
C. Chen ◽  
F.S. Xue
Keyword(s):  
Adaptive Significance ◽  
Field Conditions ◽  
Day Length ◽  
Effect Of Temperature ◽  
Path Coefficient ◽  
Path Coefficient Analysis ◽  
Summer Diapause ◽  
Increasing Temperature

AbstractUnder field conditions, the cabbage butterfly, Pieris melete, displays a pupal summer diapause in response to relatively low daily temperatures and gradually increasing day-length during spring and a pupal winter diapause in response to the progressively shorter day-length. To determine whether photoperiod is ‘more’ important than temperature in the determination of summer and winter diapause, or vice versa, the effects of naturally changing day-length and temperature on the initiation of summer and winter diapause were systematically investigated under field conditions for five successive years. Field results showed that the incidence of summer diapause significantly declined with the naturally increasing temperature in spring and summer generations. Path coefficient analysis showed that the effect of temperature was much greater than photoperiod in the determination of summer diapause. In autumn, the incidence of diapause was extremely low when larvae developed under gradually shortening day-length and high temperatures. The incidence of winter diapause increased to 60–90% or higher with gradually shortening day-length combined with temperatures between 20.0°C and 22.0°C. Decreasing day-length played a more important role in the determination of winter diapause induction than temperature. The eco-adaptive significance of changing day-length and temperature in the determination of summer and winter diapause was discussed.

The Large Narcissus Fly, Merodon equestris, Fab. (Syrphidae)

1932 ◽  
Vol 23 (4) ◽  
pp. 429-448 ◽  
Author(s):  
W. E. H. Hodson
Keyword(s):  
Control Measures ◽  
Field Conditions ◽  
Food Plants ◽  
Immature Stages ◽  
Additional Information ◽  
History Of ◽  
Combination Of Methods

1. The history of the occurrence of Merodon equestris in various countries is related and a list of known food-plants given.2. The immature stages of the fly are described in detail.3. The biology of the fly is fully discussed and additions made to our knowledge regarding it.4. Control measures are reviewed and additional information is given, particularly with reference to the use of a poison-bait spray against the adult flies.5. Recommendations are made as to the most satisfactory combination of methods to use for the purpose of obtaining control of the fly under field conditions.6. A list of literature cited is given.

scholarly journals Bagworm decorations are an anti-predatory structure

2019 ◽  
Author(s):  
Md Kawsar Khan
Keyword(s):  
Experimental Evidence ◽  
Adaptive Significance ◽  
Field Conditions ◽  
Defence Mechanism ◽  
Oecophylla Smaragdina ◽  
Weaver Ant ◽  
Environmental Materials ◽  
Natural Predator ◽  
Bagworm Moth

AbstractMany animals decorate their exterior with environmental materials and these decorations are predicted to increase their survival. The adaptive significance of these decorations, however, has seldomly been tested experimentally under field conditions. Here, I studied the anti-predatory functions of the decoration (bag) of a bagworm moth, Eumeta crameri against their natural predator, Oecophylla smaragdina, the Asian weaver ant. I experimentally tested if bag removal from caterpillars resulted in more predation than bagged caterpillar under field conditions, which would support the hypothesis that bags are selected to protect the caterpillars against their predators. In support of that, I showed that caterpillars without a bag were attacked, killed and taken to ants’ nest significantly more than bagged caterpillars. My study provides rare experimental evidence for anti-predatory functions of the decoration. My study suggests that decorating behaviour has evolved in animals as an anti-predatory defence mechanism.

Microhabitat Variation in Egg Diapause Incidence in Summer Within a Local Population: An Adaptation to Decline in Host-Plant Suitability in Trigonotylus caelestialium (Hemiptera: Miridae)

2020 ◽  
Vol 49 (4) ◽  
pp. 912-917
Author(s):  
Yoshinori Shintani ◽  
Keisuke Nagamine
Keyword(s):  
Host Plant ◽  
Host Plants ◽  
Local Population ◽  
Triticum Aestivum L ◽  
Adaptive Significance ◽  
Factors Affecting ◽  
Egg Diapause ◽  
Host Plant Suitability ◽  
Diapause Incidence ◽  
Trigonotylus Caelestialium

Abstract Diapause induction in multivoltine insects is an ecophysiological event that is generally triggered by seasonal cues such as photoperiod and temperature. The rice leaf bug, Trigonotylus caelestialium (Kirkaldy), feeds on various Poaceae grasses and produces several generations a year. Previous studies have shown that adults produce diapause and nondiapause eggs under short-day and long-day conditions, respectively. However, there is a distinct mid-summer peak in diapause incidence before an autumnal increase in diapause incidence in the field, which cannot be explained by the laboratory results. The present study was performed to examine the environmental factors affecting the diapause incidence in mid-summer and the adaptive significance of this phenomenon. Seasonal trends in diapause incidence differed significantly among three sites located 150–400 m apart from each other and with different host plants. The suitability of host plants differs depending on species and seasonally. Therefore, the microhabitat difference in diapause trend is believed to be due to the difference in host plants. When field-collected female adults laying diapause eggs in late June were fed a seasonally deteriorating host (the orange foxtail, Alopecurus aequalis Sobol. [Poales: Poaceae]), they kept laying diapause eggs, whereas when fed a suitable host (the wheat, Triticum aestivum L. [Poales: Poaceae]) for 5 d, they changed oviposition mode to lay nondiapause eggs. These results indicate that host-plant suitability affects the oviposition mode of T. caelestialium. Diapause-egg oviposition in mid-summer in T. caelestialium has adaptive significance as a bet-hedging strategy against unpredictable dietary conditions.

Ichthyotoxicity of the microalga Pseudochattonella farcimen under laboratory and field conditions in Danish waters

2015 ◽  
Vol 116 (3) ◽  
pp. 165-172 ◽  
Author(s):  
NG Andersen ◽  
PJ Hansen ◽  
K Engell-Sørensen ◽  
LH Nørremark ◽  
P Andersen ◽  
...  
Keyword(s):  
Field Conditions

Immobilization of Radionuclides on Iron Canister Material at Simulated Near-field Conditions

2008 ◽  
Author(s):  
Daqing Cui ◽  
Ylva Ranebo ◽  
Jeanett Low ◽  
Vincenzo Rondinella ◽  
Jinshan Pan ◽  
...  
Keyword(s):  
Near Field ◽  
Field Conditions
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