scholarly journals Population Density of Soybean Piercing Sucking Pests in Relation to Varieties, Chlorophyll and some Weather Factors

2020 ◽  
Vol 11 (2) ◽  
pp. 115-119
Author(s):  
E. El-khayat ◽  
Safaa Halawa ◽  
H. Saleh ◽  
Esmat Zaghlol
Keyword(s):  
Population Density ◽  
Weather Factors

PARASITISM OF OVERWINTERING PUPARIA OF THE CABBAGE MAGGOT, DELIA RADICUM (L.) (DIPTERA: ANTHOMYIIDAE), IN RELATION TO HOST DENSITY AND WEATHER FACTORS

1995 ◽  
Vol 127 (4) ◽  
pp. 535-542 ◽  
Author(s):  
W.J. Turnock ◽  
G. Boivin ◽  
J.W. Whistlecraft
Keyword(s):  
Population Density ◽  
Host Density ◽  
Host Population ◽  
Delia Radicum ◽  
Degree Days ◽  
Parasitoid Species ◽  
Weather Factors ◽  
Aleochara Bilineata ◽  
Trybliographa Rapae ◽  
Cabbage Maggot

AbstractPuparia of Delia radicum collected in late autumn at Winnipeg and Portage la Prairie (Manitoba), St-Jean-sur-Richelieu (Quebec), London (Ontario), and St. John’s (Newfoundland) were parasitized mainly by Aleochara bilineata (Gyllenhal) (Coleoptera: Staphylinidae) and Trybliographa rapae (Westwood) (Hymenoptera: Cynipidae). At Winnipeg, St-Jean, and St. John’s parasitism by A. bilineata was high (<94%) and by T. rapae was low (<3%). At London, both parasitoids attacked less than 14% of the host puparia. At Winnipeg, host population density was related to parasitism by A. bilineata and to the temperature and rainfall during June and July. Parasitism by A. bilineata may be related to cumulative degree-days over 5°C during June and July at Winnipeg and during June and September at London. In Canada, the parasitoid complex is not effectively stabilizing host population density. The introduction of additional parasitoid species should be considered.

Convergence of regional population density in Russia over 120 years

2020 ◽  
pp. 133-158
Author(s):  
K. A. Kholodilin ◽  
Y. I. Yanzhimaeva
Keyword(s):  
Population Density ◽  
Spatial Dependence ◽  
Population Distribution ◽  
Regional Level ◽  
Capital City ◽  
County Level ◽  
Spatial Effects ◽  
Russian Regions ◽  
Regional Population ◽  
Regional Population Density

A relative uniformity of population distribution on the territory of the country is of importance from socio-economic and strategic perspectives. It is especially important in the case of Russia with its densely populated West and underpopulated East. This paper considers changes in population density in Russian regions, which occurred between 1897 and 2017. It explores whether there was convergence in population density and what factors influenced it. For this purpose, it uses the data both at county and regional levels, which are brought to common borders for comparability purposes. Further, the models of unconditional and conditional β-convergence are estimated, taking into account the spatial dependence. The paper concludes that the population density equalization took place in 1897-2017 at the county level and in 1926—1970 at the regional level. In addition, the population density increase is shown to be influenced not only by spatial effects, but also by political and geographical factors such as climate, number of GULAG camps, and the distance from the capital city.

Sign in / Sign up

Export Citation Format

Share Document