Population Ecology (2014) 56, 185-194

Babak Zahiri, Yaghoub Fathipour, Mohammad Khanjani, Saeid Moharramipour and Zalucki Myron Philip (2014)
Alternatives to key factor analyses for assessing the population dynamics of Hypera postica (Coleoptera: Curculionidae)
Population Ecology 56 (1), 185-194
Abstract: Key factors are those causes that are most responsible for the observed changes in population density between generations. Stage-frequency of alfalfa weevil was modeled using Manly-1997 model. Multiple decrement life table parameters from an 8 year-field study were analyzed using traditional and λ contribution methods. In traditional method, the key factor was determined as k_LII, the death of period-two larvae from all mortality factors, whereas in λ contribution method, the key factor was determined as b_2and3, oviposition rate of females per square meter. These differences result directly from the sensitivity of the population growth rate, λ, to variation of both k and b in various stages of the weevil. Among all mortality factors, only k_LI-Z, the death of period-one larvae from the entomopathogenic fungus, Zoophthora phytonomi (Arthur) Batko (Zygomycetes: Entomophthoraceae), k_LII and k_LII-Z, the death of period-two larvae from Z. phytonomi, acted in a density dependent fashion. Remaining factors were independent of population densities affected. Using λ contribution method, life table approach still remains a major way of studying the dynamics of field populations for applied ecologists and population managers.
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Link to article at publishers website
Database assignments for author(s): Yaghoub Fathipour, Saeid Moharramipour, Mohammad Khanjani

Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
population dynamics/epizootiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Hypera postica		Iran
Zoophthora phytonomi (entomopathogen)	Hypera postica		Iran