Reproductive diapause in the Argentine stem weevil, Listronotus bonariensis, (Kuschel) (Coleoptera: Curculionidae), in New Zealand

1981 ◽  
Vol 71 (2) ◽  
pp. 275-287 ◽  
Author(s):  
S. L. Goldson
Keyword(s):  
New Zealand ◽  
Juvenile Hormone ◽  
Body Fat ◽  
Seasonal Changes ◽  
Laboratory Experiments ◽  
Reproductive Activity ◽  
Reproductive Diapause ◽  
Reproductive Morphology ◽  
Critical Photoperiod ◽  
Listronotus Bonariensis

AbstractTo improve the precision of understanding of the phenology of Listronotus bonariensis (Kuschel), samples were collected at regular intervals near Canterbury, New Zealand, and the seasonal changes in their reproductive morphology monitored by regular dissection. It was demonstrated that the adult weevils enter hibernatory reproductive diapause in early March and remain in this state until late July when reproductive activity resumes. Adults emerging in February may enter diapause immediately. The existence of diapause was further supported by its associated cessation of mating, increase in body fat and apparent drop in the haemolymph titre of juvenile hormone. Laboratory experiments indicated that a critical photoperiod induces diapause and an eventual reduction in sensitivity to photoperiod allows reproductive activity to resume.

Effect of the ratios ofListronotus bonariensisandSitona discoideus(Coleoptera: Curculionidae) to their respective parasitoidsMicroctonus hyperodaeandM. aethiopoides(Hymenoptera: Braconidae), on parasitism, host oviposition and feeding in the laboratory

1996 ◽  
Vol 86 (2) ◽  
pp. 101-108 ◽  
Author(s):  
B.I.P. Barratt ◽  
A.A. Evans ◽  
P.D. Johnstone
Keyword(s):  
New Zealand ◽  
Exposure Time ◽  
Indirect Effects ◽  
Laboratory Experiments ◽  
Parasite Number ◽  
Listronotus Bonariensis ◽  
Microctonus Aethiopoides ◽  
Microctonus Hyperodae

AbstractThe parasitoidsMicroctonus hyperodaeLoan andM. aethiopoidesLoan have been introduced into New Zealand to control the forage pestsListronotus bonariensis(Kuschel) andSitona discoideusGyllenhal, respectively. Laboratory experiments were carried out to investigate the effect of host–parasitoid ratio, and exposure time on host survival, parasitism, oviposition and feeding. Cages of 20 field collected weevils were exposed to 0, 1, 3 or 6 parasitoids for 0, 1, 12 or 48 hours, maintained until parasitoid pupal emergence, and surviving weevils dissected. Over the ranges studied, increasing parasite number, and to a greater extent, period of exposure of parasitoids to their hosts increased parasitism levels.Microctonus aethiopoidesachieved higher levels of parasitism inS. discoideusat the lower parasitoid contact treatments than didM. hyperodaeinL. bonariensis. Fecundity in unparasitized weevils was progressively reduced in bothL. bonariensisandS. discoideusin relation to increasing exposure to parasitoids. Feeding was reduced by about 40% inL. bonariensisfor at least four days after parasitoids were removed, and inS. discoideusfor the duration of the experiment, averaging 15%. Results were discussed in relation to possible mechanisms of indirect effects of parasitoids on unparasitized hosts.

Listronotus bonariensis. [Distribution map].

1998 ◽  
Author(s):  
Keyword(s):  
New Zealand ◽  
South America ◽  
Geographical Distribution ◽  
New South ◽  
South Australia ◽  
Distribution Map ◽  
South Wales ◽  
Pasture Grasses ◽  
Listronotus Bonariensis ◽  
New Distribution

Abstract A new distribution map is provided for Listronotus bonariensis (Kuschel) Coleoptera: Curculionidae Attacks Lolium spp. and other pasture grasses and cereals. Information is given on the geographical distribution in SOUTH AMERICA, Argentina, Bolivia, Brazil, Chile, Uruguay, OCEANIA, Australia, New South Wales, South Australia, Tasmania, Victoria, Western Australia, New Zealand.

scholarly journals Reproductive diapause in Nysius huttoni White (Heteroptera Lygaeidae)

2002 ◽  
Vol 55 ◽  
pp. 308-311
Author(s):  
X.Z. He ◽  
Q. Wang ◽  
A. Carpenter
Keyword(s):  
Life Cycle ◽  
Immature Stages ◽  
Life Stages ◽  
Reproductive Diapause ◽  
Entire Life ◽  
Entire Life Cycle ◽  
Adult Females ◽  
Critical Photoperiod

The induction of reproductive diapause of Nysius huttoni was studied in the laboratory at 20 1C and 60 10 RH under a series of photoperiod regimes 168 h 1410 h 1212 h and 1014 h lightdark Reproductive diapause was considered to have occurred if females failed to lay eggs for 50 days after emergence The sensitivity of different life stages to diapauseinducing photoperiods varied When newly emerged females whose immature stages had been reared at 168 h were transferred to 1014 h and 1212 h 467 and 793 of them entered reproductive diapause respectively However when fifth instar nymphs were transferred from 168 h to 1014 h and 1212 h 100 of adult females entered reproductive diapause If the entire life cycle was maintained at 1014 h and 1212 h 667 and 400 of females entered reproductive diapause respectively The critical photoperiod for reproductive diapause was estimated to lie between 1311 h and 135105 h

Effects of juvenile hormone mimics on the codling moth Cydia Pomonella (L.) (Lep., Olethreutidae)

1973 ◽  
Vol 63 (1) ◽  
pp. 7-16 ◽  
Author(s):  
I. Gelbič ◽  
F. Sehnal
Keyword(s):  
Juvenile Hormone ◽  
Laboratory Experiments ◽  
Cydia Pomonella ◽  
Codling Moth ◽  
The Other ◽  
Wide Range ◽  
Juvenile Hormone Analogues ◽  
Juvenile Hormone Mimics

AbstractLaboratory experiments with juvenile hormone analogues on Cydia pomonella (L.) showed that Cecropia C17 juvenile hormone (methyl 10,ll-epoxy-3,7,ll-trimethyl-2,6-dodecadienoate) was the most active of the 28 compounds tested. When applied to four-hour-old eggs at 0.1 μg/egg, the hormone caused 100% failure in embryogenesis, while the other compounds were at least five times less effective. Depending on the time since ecdysis and the dose, juvenile hormone mimics applied to last-instar larvae resulted in a wide range of intermediate forms. Against three-day-old last-instar larvae, the Cecropia C17 hormone gave 100% inhibition of development at a dose of 1 μg/larva, while three other compounds (methyl 10,11-epoxy-3,7,11-trimethyl-2,6-dodecadienoate, ethyl 11-chloro-3,7,11-trimethyl-2-dodecenoate and ethyl 3,7,11-tri-methyl-2,4-dodecadienoate) gave the same effect at 2–5 μg/larva. Against newly emerged adults, the last two compounds at 10–50 μg/insect reduced fecundity and fertility to 0–81% and 0–50%, respectively, of their normal levels.

scholarly journals Characterization of the imaginal reproductive diapause of Oebalus poecilus (Dallas) (Hemiptera: Pentatomidae)

2003 ◽  
Vol 63 (4) ◽  
pp. 695-703 ◽  
Author(s):  
R. S. S. Santos ◽  
L. R. Redaelli ◽  
L. M. G. Diefenbach ◽  
H. P. Romanowski ◽  
H. F. Prando
Keyword(s):  
Body Fat ◽  
Sexual Maturation ◽  
Abdominal Cavity ◽  
Reproductive Organs ◽  
Reproductive Organ ◽  
The Body ◽  
Reproductive Diapause ◽  
Male And Female ◽  
In The Beginning

The state of development of the internal reproductive organs of male and female Oebalus poecilus (Dallas) as well as the body fat amount in the abdominal cavity during hibernation, of individuals sampled in bamboo litter in Eldorado do Sul (30º02'S and 51°23'W), RS, Brazil was investigated. Females and males showed the abdominal cavity filled with body fat in the beginning of the hibernation phase. The decrease in fat reserve level occurred from August on for males and from October on for females. Ovaries and testis doubled in length and tripled in width from immature to the reproductive phase. Male sexual maturation occurred in the hibernation sites while for females it occurred later on outside of the sites. Reproductive organ immaturity and abdominal body fat hypertrophy characterized the diapause of O. poecilus.

Oestrous activity in three subtropical sheep breeds in Upper Egypt and response to long-day light treatment

1991 ◽  
Vol 116 (1) ◽  
pp. 139-143 ◽  
Author(s):  
A. M. Aboul-Naga ◽  
H. Mansour ◽  
M. B. Aboul-Ela ◽  
M. T. Mousa ◽  
Ferial Hassan ◽  
...  
Keyword(s):  
Breeding Season ◽  
Seasonal Changes ◽  
Nile Delta ◽  
Reproductive Activity ◽  
Light Treatment ◽  
Continuous Exposure ◽  
Upper Egypt ◽  
Sheep Breeds ◽  
Awassi Sheep ◽  
Long Day

SUMMARYOestrous activity in local Rahmani and Ossimi sheep and imported subtropical Awassi sheep at different times of the year in Upper Egypt and the effect of continuous exposure to long-day conditions from July till December on this activity was studied in 1986. The three breeds differed substantially in oestrous activity but differences did not seem to be directly related to latitude of origin. Rahmani ewes from the Nile Delta were mostly cyclic all year round; the percentage coming to oestrus each month never fell below 70%. Ossimi ewes originating from mid-Egypt had a very long breeding season; 74% had an anoestrous period of 68·8 days (v. 27% for Rahmani ewes). All Awassi ewes, except one, had an anoestrous period of 96·5 days on average.Awassi ewes also showed more response to continuous exposure to long days (14 h) than Ossimi ewes, seen in a shorter reaction interval and a greater decrease in the percentage of ewes coming into oestrus (27 and 90% in control and treated Awassi ewes, respectively). The results indicated that changes in daylength, although small in subtropical regions, may be a major factor controlling seasonal changes in reproductive activity in subtropical sheep breeds, the more seasonal breed being more responsive to changes in daylength. The possibility of selection within these breeds for continuous reproductive activity is also indicated.

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