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A Contribution to the Biology and Phenology of Agrotis ypsilon Rott. in Israel
Year:
1963
Source of publication :
Journal of Applied Entomology
Authors :
Rivnay, Ezekiel
;
.
Volume :
53
Co-Authors:
Facilitators :
From page:
295
To page:
309
(
Total pages:
15
)
Abstract:

The phenology of this insect in Israel is described, and some of the underlying causes of that situation are discussed.

The three immature stages were studied at various degrees of temperature in order to establish the length of development period and the number of generations of the moth in Israel.

Thus, this moth could raise at least seven generations during the year if it were a constant resident there. In fact only four generations develop as no moths develop in Israel during the summer.

In attempting to explain this, special attention was given to the study of the effects upon the adults of temperature and humidity during the immature stages. When both larvae or pupae were kept at temperatures of 26°C or above, the fecundity of adults was affected. The higher the temperature above this degree, the more non-laying females developed and the more non-viable eggs were laid. Similarly the preoviposition period and the length of life of the adults were affected. The highest temperature employed in the experiments was 30°C, but the temperature in the ground during the summer is above 30°C which further accentuates the ill effects. Also the percentage of relative humidity at which immature stages were kept affected the adults in this way. The most favourable relative humidity was 75%.

Because of these physiological characteristics and the climatic conditions which exist in the coastal plain of Israel, the fourth summer generation of this insect is sparse and leaves no offspring, although larvae and pupae could tolerate the existing conditions. In view of this, the population during September is reestablished by immigrating moths from elsewhere.

It was pointed out that there was a general depression everywhere in the number of moths caught during the summer; during 2–3 months no moths were caught.

At Elat, situated at the tip of the Akkaba Bay, where the moth cannot breed, no moths were caught during the summer. There were rich trappings during the spring, suggesting a northward migration of moths (which do not necessarily breed in Israel), and rich autumn catches, suggesting southward flights; some of these moths oviposit as they pass through Israel and leave behind offspring. These catches, together with observations recorded in the literature from the neighbouring countries, served as the foundation for a hypothesis regarding the line of migration of A. ypsilon in this part of the world, namely from the shores of Africa northward to the Hermon and Lebanon Mountains and back.

Note:
Related Files :
Agrotis
Agrotis ipsilon
insects
Israel
pests
plant protection
Show More
Related Content
More details
DOI :
https://doi.org/10.1111/j.1439-0418.1963.tb02897.x
Article number:
0
Affiliations:
Database:
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
57639
Last updated date:
02/03/2022 17:27
Creation date:
17/01/2022 12:07
Scientific Publication
A Contribution to the Biology and Phenology of Agrotis ypsilon Rott. in Israel
53
A Contribution to the Biology and Phenology of Agrotis ypsilon Rott. in Israel

The phenology of this insect in Israel is described, and some of the underlying causes of that situation are discussed.

The three immature stages were studied at various degrees of temperature in order to establish the length of development period and the number of generations of the moth in Israel.

Thus, this moth could raise at least seven generations during the year if it were a constant resident there. In fact only four generations develop as no moths develop in Israel during the summer.

In attempting to explain this, special attention was given to the study of the effects upon the adults of temperature and humidity during the immature stages. When both larvae or pupae were kept at temperatures of 26°C or above, the fecundity of adults was affected. The higher the temperature above this degree, the more non-laying females developed and the more non-viable eggs were laid. Similarly the preoviposition period and the length of life of the adults were affected. The highest temperature employed in the experiments was 30°C, but the temperature in the ground during the summer is above 30°C which further accentuates the ill effects. Also the percentage of relative humidity at which immature stages were kept affected the adults in this way. The most favourable relative humidity was 75%.

Because of these physiological characteristics and the climatic conditions which exist in the coastal plain of Israel, the fourth summer generation of this insect is sparse and leaves no offspring, although larvae and pupae could tolerate the existing conditions. In view of this, the population during September is reestablished by immigrating moths from elsewhere.

It was pointed out that there was a general depression everywhere in the number of moths caught during the summer; during 2–3 months no moths were caught.

At Elat, situated at the tip of the Akkaba Bay, where the moth cannot breed, no moths were caught during the summer. There were rich trappings during the spring, suggesting a northward migration of moths (which do not necessarily breed in Israel), and rich autumn catches, suggesting southward flights; some of these moths oviposit as they pass through Israel and leave behind offspring. These catches, together with observations recorded in the literature from the neighbouring countries, served as the foundation for a hypothesis regarding the line of migration of A. ypsilon in this part of the world, namely from the shores of Africa northward to the Hermon and Lebanon Mountains and back.

Scientific Publication
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