Female grasshoppers can affect the fitness of their offspring through their selection of oviposition site. Knowledge of soil type on oviposition, and its effects on subsequent development can provide guidelines for ha...Female grasshoppers can affect the fitness of their offspring through their selection of oviposition site. Knowledge of soil type on oviposition, and its effects on subsequent development can provide guidelines for habitat manipulations that reduce the harmful effects of these pests on farmers fields. The influence of soil types on the oviposition site preference of variegated grasshopper (Zonocerus variegatus L.) reared some cassava (Manihot esculenta Crantz) varieties, was investigated in a cage trial carried out at the Bio factory laboratory, School of Agriculture and Food Sciences, Njala University, Sierra Leone during 2022/2023. The treatments comprised three soil types (Sandy, Loamy and Clay), each with three replications laid out in a randomized complete block design (RCBD) in wooden cages. Data were collected on the following development parameters including, Net reproductive growth ratio (R0), Generation time (Tc), Intrinsic rate of increase (rm), Finite rate of increase (), Doubling time (Dt), and overall survivorship. Findings revealed that, Z. variegatus L. preferred sandy soil in which, on average, most eggs were deposited (338, 6.62 4.40), followed by loamy soil, 286 (5.53 3.96), and then, clayey soil, 200 (3.91 3.85);though, the differences were not significant. This study established that Z. variegatus deposited more eggs in sandy soil > loamy soil > clayey soil, respectively;and subsequent survivorship of the immature unto mature adult insect, revealed a similar order. This indicates that the sandy soil is the most preferred substrate for oviposition and subsequent development into adult insects.展开更多
ISD即教学系统设计模型(Instructional System Design Model),它是以传播理论、学习理论、教学理论为基础,运用系统理论的观点和方法分析学习中的问题和需求,并从中找出最佳答案的一种课程开发模型,注重对培训活动的有效分析、设计、规...ISD即教学系统设计模型(Instructional System Design Model),它是以传播理论、学习理论、教学理论为基础,运用系统理论的观点和方法分析学习中的问题和需求,并从中找出最佳答案的一种课程开发模型,注重对培训活动的有效分析、设计、规划和安排。ISD模型在高校非学历继续教育培训项目中的运用,通过问卷调查法、文献资料法、观察法和访谈法,对培训对象、培训需求、培训内容、培训效果等进行分析,及时了解培训对象的学习动机与需求,可开发出更符合培训对象需求的培训课程,从而提高培训对象的学习积极性和培训质量与效果,有利于促进高校非学历教育培训管理理念与管理模式的创新。展开更多
文摘Female grasshoppers can affect the fitness of their offspring through their selection of oviposition site. Knowledge of soil type on oviposition, and its effects on subsequent development can provide guidelines for habitat manipulations that reduce the harmful effects of these pests on farmers fields. The influence of soil types on the oviposition site preference of variegated grasshopper (Zonocerus variegatus L.) reared some cassava (Manihot esculenta Crantz) varieties, was investigated in a cage trial carried out at the Bio factory laboratory, School of Agriculture and Food Sciences, Njala University, Sierra Leone during 2022/2023. The treatments comprised three soil types (Sandy, Loamy and Clay), each with three replications laid out in a randomized complete block design (RCBD) in wooden cages. Data were collected on the following development parameters including, Net reproductive growth ratio (R0), Generation time (Tc), Intrinsic rate of increase (rm), Finite rate of increase (), Doubling time (Dt), and overall survivorship. Findings revealed that, Z. variegatus L. preferred sandy soil in which, on average, most eggs were deposited (338, 6.62 4.40), followed by loamy soil, 286 (5.53 3.96), and then, clayey soil, 200 (3.91 3.85);though, the differences were not significant. This study established that Z. variegatus deposited more eggs in sandy soil > loamy soil > clayey soil, respectively;and subsequent survivorship of the immature unto mature adult insect, revealed a similar order. This indicates that the sandy soil is the most preferred substrate for oviposition and subsequent development into adult insects.
文摘ISD即教学系统设计模型(Instructional System Design Model),它是以传播理论、学习理论、教学理论为基础,运用系统理论的观点和方法分析学习中的问题和需求,并从中找出最佳答案的一种课程开发模型,注重对培训活动的有效分析、设计、规划和安排。ISD模型在高校非学历继续教育培训项目中的运用,通过问卷调查法、文献资料法、观察法和访谈法,对培训对象、培训需求、培训内容、培训效果等进行分析,及时了解培训对象的学习动机与需求,可开发出更符合培训对象需求的培训课程,从而提高培训对象的学习积极性和培训质量与效果,有利于促进高校非学历教育培训管理理念与管理模式的创新。
