scholarly journals Effects of Noncatastrophic Control Technologies that Alter Life History Parameters on Insect Population Growth: A Simulation Study

1989 ◽  
Vol 18 (6) ◽  
pp. 1050-1055 ◽  
Author(s):  
James E. Throne
1985 ◽  
Vol 42 (5) ◽  
pp. 873-879 ◽  
Author(s):  
J. M. Berkson ◽  
D. P. DeMaster

A series of population simulations were used to test the accuracy of estimating the discrete rates of population change (RPC) from annual pup counts. The simulations indicate that pup counts can give a biased estimate of RPC, and that the magnitude and direction of bias depends on which life history parameters are density dependent and on the maximum rate of population change. In general, if pre-census pup survival is density dependent the estimated RPC using pup counts is too low. If post-census pup survival is density dependent, the estimated RPC is too high. If adult survival is density dependent, there is very little bias in the estimate. The results indicate that pup counts can be reliable indicators of population growth, but caution should be used in interpreting the results unless density feedback mechanisms have been identified.


1995 ◽  
Vol 43 (4) ◽  
pp. 381 ◽  
Author(s):  
W Danthanarayana ◽  
H Gu ◽  
S Ashley

Life-history parameters and developmental rates of Epiphyas postvittana were determined for four natural food plants and Shorey's diet at each of six temperatures. The rate of development of larvae and the life-history parameters were influenced by both temperature and diet. The highest r(m) value was given by populations feeding on Plantago lanceolata, followed by those on Shorey's diet and Rumex crispus, all at 25 . 2 degrees C, then by Malus pumila at 19 . 9 degrees C and Trifolium repense at 25 . 2 degrees C. Zero population growth occurred at 7 . 1 and 30 . 7 degrees C. A life-table study of five geographical strains of the moth under non-variable conditions (constant temperature and artificial diet) showed that finite rate of increase (lambda) was significantly correlated with climatic features of habitats, viz. mean annual Values of temperature, rainfall and relative humidity. Peak values of lambda occurred at cooler temperatures, moderate levels of habitat moisture and high altitudes (500-1000 m); the Canberra population gave the highest value (lambda = 1 . 157), followed by Armidale (lambda = 1 . 152), Melbourne (lambda = 1 . 141), Mildura (lambda = 1 . 135) and Auckland (lambda = 1 . 118). Higher performance of E. postvittana on herbaceous plants than on woody plants suggests that it primarily evolved as a feeder on herbaceous plants.


2012 ◽  
Vol 125-126 ◽  
pp. 69-76 ◽  
Author(s):  
Vera Sequeira ◽  
Ana Neves ◽  
Rafaela Barros Paiva ◽  
João Pereira de Lima ◽  
Ana Rita Vieira ◽  
...  

2008 ◽  
Vol 29 (2) ◽  
pp. 245-256 ◽  
Author(s):  
Carissa Jones ◽  
Isaac Rojas-González ◽  
Julio Lemos-Espinal ◽  
Jaime Zúñiga-Vega

Abstract There appears to be variation in life-history strategies even between populations of the same species. For ectothermic organisms such as lizards, it has been predicted that demographic and life-history traits should differ consistently between temperate and tropical populations. This study compares the demographic strategies of a temperate and a tropical population of the lizard Xenosaurus platyceps. Population growth rates in both types of environments indicated populations in numerical equilibrium. Of the two populations, we found that the temperate population experiences lower adult mortality. The relative importance (estimated as the relative contribution to population growth rate) of permanence and of the adult/reproductive size classes is higher in the temperate population. In contrast, the relative importance for average fitness of fecundity and growth is higher in the tropical population. These results are consistent with the theoretical frameworks about life-historical differences among tropical and temperate lizard populations.


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