具有Beddington-DeAngelis功能性反应的生态流行病模型

研究了捕食者具有Beddington-DeAngelis功能性反应且食饵具有流行病的捕食模型,此模型考虑的是脉冲释放染病害虫和自然天敌.利用Floquet秉子理论、小振幅扰动技巧和比较定理证明了易感害虫根除周期解的全局稳定性以及系统持续生存的充分条件.结论表明当染病害虫的脉冲释放量p＞p*时,易感害虫灭绝;反之,系统持续生存.因此可以选择合适的参数p、q、T对害虫进行控制,为现实的害虫管理提供了理论依据与数据依据.     

一类具有阶段结构病毒感染害虫治理模型的研究

建立了病毒与害虫相互作用的害虫管理模型,利用脉冲泛函微分方程的比较原理得到了害虫灭绝周期解的全局吸引性和系统.     

具有脉冲的综合治理害虫的捕食食饵模型

建立了综合治理害虫的捕食者食饵模型,得到了易感害虫灭绝周期解局部稳定的充分条件,进而得到了系统持续生存的充分条件.     

具有生物控制和化学控制的SEI害虫管理模型

考虑一个在固定时刻分别投放染病者害虫和喷洒杀虫剂的SEI害虫管理模型.通过频闪映射,得到了易感者和潜伏者根除的害虫根除周期解,并且证明当投放的染病者害虫的数量大于某个临界值时,害虫根除周期解是全局吸引的;当投放的染病者的数量小于该临界值时,系统是持续生存的.     

一类具有脉冲效应和第Ⅱ类功能反应的捕食系统分析

本文通过生物控制和化学控制提出了具有周期脉冲效应与害虫控制的捕食系统.利用脉冲微分方程的Floquent理论,比较定理和分析的方法研究了具有脉冲效应和第二类功能性反应的捕食-食饵系统的动力学性质,给出了害虫根除平衡点全局渐进稳定的条件.     

具有阶段结构及脉冲控制的害虫管理模型

研究一类具有阶段结构、时滞及脉冲控制的害虫管理模型,利用时滞微分方程和脉冲微分方程中相关的理论与方法,得到系统害虫灭绝周期解全局吸引及系统一致持续的充分条件,并通过数值模拟验证了结论.     

具有脉冲效应的综合害虫控制SI模型的持久性分析

基于综合害虫管理(IPM)策略,考虑一个具有脉冲干扰和Holling II功能反应的害虫管理SI模型,建立了系统持续生存的充分条件,并通过脉冲微分方程的比较定理给出证明.     

一类具有脉冲的捕食与被捕食系统的动态行为

研究具有周期脉冲的捕食与被捕食模型的动态行为.通过喷洒杀虫剂和投放天敌的周期不同,得到了捕食系统害虫灭绝周期解的全局稳定性的临界值,分析喷洒杀虫剂和投放天敌的周期如何影响生物控制,为害虫治理提供了策略基础.     

具有生物和化学两类脉冲控制的捕食-食饵系统分析

基于害虫的生物和化学脉冲控制策略,研究具有阶段结构和脉冲控制的捕食-食饵系统,利用Floquet理论及比较定理分别得到系统害虫灭绝周期解全局渐进稳定和系统持续生存的充分条件.以数值模拟验证所得理论结果的可靠性.     

具有脉冲效应和HollingⅡ功能反应的治理害虫的Gompertz病毒病模型系统分析

针对一类具有脉冲效应和HollingⅡ功能反应的治理害虫的Gompertz病毒病模型,进行了理论和数值分析,以脉冲投放量p以及周期T作为分岔参数得到系统的分岔图.分析结果表明,治理害虫的病毒病模型具有复杂的动力学行为.     

Effect of acoustic clutter on prey detection by bats.

Bats that capture animal prey from substrates often emit characteristic echolocation calls that are short-duration, frequency-modulated (FM) and broadband. Such calls seem to be suited to locating prey in uncluttered habitats, including flying prey, but may be less effective for finding prey among cluttered backgrounds because echoes reflecting from the substrate mask the acoustic signature of prey. Perhaps these call designs serve primarily for spatial orientation. Furthermore, it has been unclear whether the acoustic image conveyed by FM echoes enables fine texture discrimination, or whether gleaning bats that forage in echo-cluttering environments must locate prey by using other cues, such as prey-generated sounds. Here we show that two species of insectivorous gleaning bats perform badly when compelled to detect silent and immobile prey in clutter, but are very efficient at capturing noisy prey items among highly cluttered backgrounds, and both dead or live prey in uncluttered habitats. These findings suggest that the short, broadband FM echolocation calls associated with gleaning bats are not adapted to detecting prey in clutter.     

The evolution of müllerian mimicry in multispecies communities

Prey species that are unprofitable to attack often share conspicuous colours and patterns with other coexisting defended species. This phenomenon, termed müllerian mimicry, has long been explained as a consequence of selection on defended prey to adopt a common way of advertising their unprofitability. However, studies using two unpalatable prey types have not always supported this theory. Here we show, using a system of humans hunting for computer-generated prey, that predators do not always generate strong selection for mimicry when there are two unprofitable prey types. By contrast, we demonstrate that when predators are faced with a range of different prey species, selection on unprofitable prey to resemble one another can be intense. Here the primary selective force is not one in which predators evaluate the profitabilities of distinct prey types independently, but one in which predators learn better to avoid unprofitable phenotypes that share traits distinguishing them from profitable prey. This need to simplify decision making readily facilitates the spread of imperfect mimetic forms from rarity, and suggests that müllerian mimicry is more likely to arise in multispecies communities.     

具有避难所的非自治差分修正Leslie-Gower捕食-食饵系统的动力学行为研究

研究一类具有避难所的非自治差分修正Leslie-Gower捕食-食饵系统,通过对系统动力学行为的详细分析,得到保证系统持久和全局渐近稳定的充分性条件,发现只要避难所足够大就可以保证食饵种群持久生存.借助差分不等式获得一组保证食饵种群绝灭而捕食者种群持久的充分性条件,发现当避难所较小时,食饵种群会由于捕食者的捕食而最终绝灭,但此时捕食者由于拥有其他的食物来源仍可持久生存.     

依赖比率的捕食被捕食系统的全局分析:捕食与被捕食者均有密度制约的情况

近年来依赖比率的捕食与被捕食模型已引起了生态学者和生物数学研究者的密切注意，这是因为它们比传统的模型更加接近实际情形．本文研究了依赖比率的捕食与被捕食系统的全局定性性态，这里捕食与被捕食者均为密度制约的．     

猛禽视觉研究新进展

 鸟类高度依赖其对视觉环境的评估结果。概述了以猛禽为代表的鸟类视觉生理系统和视觉信息感知系统特性的研究现状，对比了不同种类猛禽视觉系统的特性与优缺点。首先描述了包括眼外周结构、眼球壁和眼内的折光系统在内的解剖学结构，分析了猛禽眼和其他动物的眼之间的区别；然后介绍了猛禽视觉信息的传导通路和中枢；最后阐明了猛禽与其他动物不同的颜色感知特性、双中央凹特性以及猛禽视觉敏锐度特性，并概述了当前模拟猛禽视觉特性的研究方法以及关键问题，探讨了其未来的发展趋势。     

具有两性的捕食者-食饵模型的渐近性态

研究具有Holling Ⅱ功能反应的捕食者食饵模型. 得到了食饵两性具有不同的出生率和死亡率时, 边界平衡点全局稳定的条件及食饵和捕食者一致持续生存的条件. 数值模拟表明, 捕食者的存在最终不会改变食饵的性别比例.     

Patterns of predation in a diverse predator-prey system

There are many cases where animal populations are affected by predators and resources in terrestrial ecosystems, but the factors that determine when one or the other predominates remain poorly understood. Here we show, using 40 years of data from the highly diverse mammal community of the Serengeti ecosystem, East Africa, that the primary cause of mortality for adults of a particular species is determined by two factors--the species diversity of both the predators and prey and the body size of that prey species relative to other prey and predators. Small ungulates in Serengeti are exposed to more predators, owing to opportunistic predation, than are larger ungulates; they also suffer greater predation rates, and experience strong predation pressure. A threshold occurs at prey body sizes of approximately 150 kg, above which ungulate species have few natural predators and exhibit food limitation. Thus, biodiversity allows both predation (top-down) and resource limitation (bottom-up) to act simultaneously to affect herbivore populations. This result may apply generally in systems where there is a diversity of predators and prey.     

具有时滞的非自治捕食系统的动力学行为分析

研究一个具有时滞和HollingⅡ型功能反应的非自治的捕食者一食饵模型,该系统是两个具有竞争关系的捕食种群捕食一个食饵,研究其动力学行为,包括持久性、全局渐近稳定性、周期解的存在唯一性。     

具有简化Holling-IV类功能性反应且包含食饵避难所的捕食-食饵模型的定性分析

研究了一类具有简化Holling-IV类功能性反应且包含食饵避难所的捕食-食饵模型.分析了该系统的平衡点性态,通过对正平衡点焦点量的计算,得到正平衡点外围至少可以存在2个极限环,并得到在食饵避难所作用下的Hopf分支和异宿轨分支.此外还分析了食饵避难所对系统的影响.     

贵州疣螈捕食和反捕行为的初步观察

采用野外调查与室内饲养观察相结合的方法,对我国云贵高原特有种贵州疣螈（Ｔｙ ｌｏｔｏｔｒｉｔｏｎｋｗｅｉｃｈｏｗｅｎｓｉｓ）的捕食行为和反捕行为进行了初步观察。记录了贵州疣螈常见的捕食行为和反捕行为。贵州疣螈的捕食行为基本上是一种被动式的捕食方式,捕食过程中嗅觉起了主要作用,捕食动作迅猛而准确;幼体时期存在相互残食现象。反捕行为基本上是一种防御行为,利用其自身良好的保护色和逃逸作为反捕手段,在其被捕捉后,又利用嘴、尾等攻击敌人,同时还利用体表分泌的一种有特殊臭味的粘液来作为御敌手段。