蚂蚁光顾云南紫胶虫对其天敌紫胶黑虫种群的影响

为了弄清蚂蚁光顾云南紫胶虫Kerria yunnanensis Ouet Hong对其天敌紫胶黑虫Holcocera pulverea Meyr种群的影响,于云南紫胶虫成虫期,对有无蚂蚁光顾的胶被抽样,调查胶被上紫胶黑虫的为害率及种群数量变化。结果显示,紫胶黑虫对有无蚂蚁光顾的胶被的为害率均很高,并逐月增加;其中有蚂蚁光顾的胶被紫胶黑虫的为害率略小于无蚂蚁光顾的胶被。蚂蚁光顾能明显减少紫胶黑虫的种群数量(︱t︱=2.764,df=356,P<0.01),其原因可能是蚂蚁光顾能干扰紫胶黑虫的产卵行为、破坏卵、取食卵和幼虫并且这种保护主要发生在云南紫胶虫幼虫期;云南紫胶虫进入成虫期后,由于紫胶黑虫生活于胶被内,并且产卵于胶被的凹陷处或雄虫胶壳内或雌虫肛突孔处,蚂蚁很少与紫胶黑虫相遇,故蚂蚁光顾对紫胶黑虫每月增长量没有显著影响(︱t︱=0.970,df=161,P>0.05)。紫胶黑虫和蚂蚁相遇的行为反应存在显著差异(χ2=4.781,df=1,P<0.05),蚂蚁对紫胶黑虫有捕食作用。蚂蚁与云南紫胶虫之间存在互利关系。蚂蚁取食云南紫胶虫的蜜露,能降低紫胶黑虫的为害率,并减少紫胶黑虫的种群数量,从而保护云南紫胶虫。     

云南紫胶虫与粗纹举腹蚁之间的互利关系

为了明确云南紫胶虫Kerria yunnanensis和粗纹举腹蚁Crematogaster macaoensis之间的相互作用关系, 于2009年4月至2010年10月, 在云南省墨江县雅邑乡紫胶种植园, 结合野外调查和室内试验对比研究了粗纹举腹蚁取食人工食物、 云南紫胶虫排泄的蜜露和无食物的3种处理下粗纹举腹蚁个体体重和存活率的变化, 以及在粗纹举腹蚁垄断蜜露、 自然条件下和无蚂蚁照顾的3种处理下云南紫胶虫个体怀卵量、 虫体大小、 死亡率和生活史周期的变化。结果显示： 云南紫胶虫排泄的蜜露是一种高质量的食物资源, 能够稳定增加粗纹举腹蚁工蚁的体重百分比［人工食物（44.55%）>蜜露（25.81%）>无食物（-4.13%）］ （F_（2,54）=18.81; P＜0.01）, 并提高其存活率［人工食物（85.78%）>蜜露（82.48%）>无食物（78.74%）］ （F_（2,55）=7.31; P＜0.01）。粗纹举腹蚁取食蜜露的同时, 有利于增加单位面积上云南紫胶虫的雌虫数量［蚂蚁垄断蜜露（80.81%）>自然状态（75.55%）>无蚂蚁照顾（75.33%）］ （F_（2,143）=54.08; P＜0.01）, 提高云南紫胶虫的个体怀卵量［蚂蚁垄断蜜露（401.85粒）>自然状态（395.73粒）>无蚂蚁照顾（353.34粒）］ （F_（2,144）=4.82; P＜0.01）, 降低云南紫胶虫的死亡率［蚂蚁垄断蜜露（89.42%）<自然状态（89.78%）<无蚂蚁照顾（90.82%）］ （F_（2,146）=3.45; P＜0.05）; 云南紫胶虫虫体有变小的趋势［蚂蚁垄断蜜露（12.92 mm²）<自然状态（13.04 mm²）<无蚂蚁照顾（14.90 mm²）］ （F_（2,147）=10.88; P＜0.01）, 生活史周期变长［蚂蚁垄断蜜露（203.96 d）>无蚂蚁照顾（202.85 d）>自然状态（200.00 d）］ （F_（2,71）=19.77; P＜0.01）, 提示粗纹举腹蚁取食蜜露增加了云南紫胶虫的代谢压力。结果说明, 以蜜露为纽带的粗纹举腹蚁和云南紫胶虫之间的相互作用关系是兼性互利的。     

紫胶虫蜜露对地表蚂蚁多样性的影响

2009年12月至2010年5月,采用陷阱法在云南省墨江县雅邑乡调查了紫胶林地表蚂蚁群落多样性,分析了紫胶虫蜜露对地表蚂蚁多样性的影响.结果表明:紫胶虫蜜露资源的有无及变动对地表蚂蚁群落物种组成、多度及多样性均产生影响.在紫胶林样地共采集蚂蚁标本4953头,隶属5亚科23属34种,在对照样地共采集蚂蚁标本2416头,隶属5亚科20属30种;紫胶林地表蚂蚁相对多度、物种丰富度(S)及ACE估计值均高于对照样地,地表蚂蚁常见种和指示种均与对照样地不同,表明放养紫胶虫改变了地表蚂蚁群落结构;紫胶虫成虫期蜜露分泌量高于幼虫期,其地表蚂蚁相对多度、S及ACE估计值也高于幼虫期,且两阶段的蚂蚁常见种和指示种显著不同.     

紫胶生产系统对节肢动物不同功能群的影响路径和强度研究

土地利用方式的转换对农业生态系统中节肢动物不同功能群之间的相互作用关系有显著的影响.本研究通过调查不同经营方式的紫胶林中蚂蚁Formicidae和紫胶虫寄生蜂的多样性情况,探究紫胶生产系统对这两种功能群之间相互关系的影响路径和强度.于2018年4-9月,在临沧市云县两块不同的紫胶林样地中放置了树栖陷阱和地表陷阱用于收集蚂蚁,并用套笼法收集紫胶虫Kerria spp.的寄生蜂.结果表明:有地表覆盖的紫胶林样地(X2)中地表蚂蚁的多度显著高于无地表覆盖样地(X1)(F=7.256,P=0.011),而X2样地紫胶虫寄生蜂的物种丰富度(F=20.250,P=0.003)和多度(F=17.108,P=0.003)却显著低于X1样地.地表覆盖对树栖蚂蚁(β=0.787,P<0.001)和地表蚂蚁(β=0.652,P=0.004)均有显著的积极影响,而地表覆盖(β=-0.932,P<0.001)及地表蚂蚁(β=-0.362,P=0.039)对寄生蜂多度有显著的负面影响.本研究揭示了紫胶生产系统中,地表覆盖有利于维系蚂蚁-紫胶虫互利关系,抑制紫胶虫寄生蜂,从而对紫胶生产产生积极作用.     

An episodic model of honeydew production in scale insects

Honeydew produced by sooty beech scale insects (Ultracoelostoma spp., Homoptera: Coelostomidiidae) is a keystone ecological process in New Zealand beech (Nothofagus spp., Nothofagaceae) forest. This work puts forward a model of honeydew production based on individual insects that presumes feeding and excretion are episodic processes driven by the insect rather than the passive processes that were previously assumed. The model is parameterized using existing data and then compared to an independent pre‐existing dataset. The model suggests that over a 12‐h period, on average the insects suck sap for 2 h, and excrete waste sap for 12 min. Resource uptake by the insects appears to be limited by the time required to process the sap, consistent with the observed relationship between honeydew production rates and ambient temperature. This implies that insect feeding rates may be ultimately limited by the low nitrogen content of phloem sap.     

Ant tending impairs performance of Aenasius bambawalei by manipulating the honeydew composition produced by Phenacoccus solenopsis

Honeydew produced by hemipterans is known as a possible kairomonal resource for parasitoids. The application of artificial honeydew effectively improves the performance of natural enemies. Aenasius bambawalei is a particularly dominant and aggressive endoparasitoid of the invasive mealybug Phenacoccus solenopsis. Our previous study showed that tending by the ghost ant Tapinoma melanocephalum significantly reduced the parasitism of A. bambawalei. We hypothesize that ghost ant tending influences host location of parasitoids by manipulating the composition of the honeydew produced by mealybugs. In this study, we tested whether the honeydew composition differs between treatments with and without ant attendance and whether changes in the honeydew influence the performance of A. bambawalei. Our results show that the sucrose concentration increased significantly in the ant‐attendance treatment but decreased when ant attendance was switched to an ant‐exclusion treatment; the inverse was true for the glucose concentration. Compared with the plastic honeydew treatment (mealybug with ant attendance), parasitoids spent much more time searching, had longer lifespans and showed higher parasitism on filter papers treated with natural honeydew (mealybug without any pre‐treatment) and those treated with convalescent honeydew (mealybug having experienced ant attendance and then switched to ant exclusion). These results support the hypothesis that ant tending influences the performance of parasitoids by manipulating honeydew composition.     

The influence of black bean aphid, Aphis fabae Scop., and its honeydew on leaf growth and dry matter production of sugar beet

A. fabae populations, started at the 3–4 leaf-stage of sugar beet in the glasshouse and peaking at 3000 individuals per plant, reduced leaf area by 64% at the 14 leaf-stage. The size of the heavily-infested leaves number 5 to 10 was reduced by 80% or more. The rate of leaf growth regained normal values after the aphid populations collapsed, but the infested plants did not make up for the decrease in leaf area production that had been incurred during the infestation. Total dry matter production over a period of 15 weeks was reduced by 47%. Honeydew had no effect on leaf size or dry matter production. Sugar beet plants in the field became infested with A. fabae at the 2–3, 4–5 and 6–8 leaf stages. Maximum populations of 800, 2100 and 2200 aphids per plant were recorded, respectively. The pertinent reductions in leaf area were 91%, 67% and 34% at the 10–12 leaf-stage and 79%, 65% and 14% at harvest while the total dry matter produced was reduced by 91%, 79% and 16%. Neighbouring plants of the early-infested sugar beet plants gained significantly higher weights than control plants. Honeydew had no effect on leaf area or dry matter production. The consequences of these results for our understanding of Aphis fabae injury in sugar beet and aphid control in the field are discussed.     

蚂蚁-紫胶虫兼性互利关系对蚂蚁群落多样性的影响

为了探讨蚂蚁-紫胶虫兼性互利关系对树冠上蚂蚁群落多样性的影响,作者于2009年12月至2010年5月,采用目光搜寻的方法调查了不同紫胶虫数量样地(样地Ⅰ有效枝条寄生率为60％、样地Ⅱ为30％、样地Ⅲ为10％、样地Ⅳ不放养紫胶虫)中钝叶黄檀(Dalbergia obtusifolia)树冠蚂蚁群落的多样性.结果显示,兼性互利关系能够显著提高树冠蚂蚁群落多度及物种丰富度,改变树冠上蚂蚁的群落结构;由紫胶虫数量高低导致的蜜露产量的多寡对树冠上蚂蚁的多度和群落结构均具有显著影响,但对物种丰富度无显著影响;同时紫胶虫的个体发育阶段也是影响树冠上蚂蚁多度的重要因素.本研究证明,紫胶虫对于提高树冠上蚂蚁的多样性具有显著的正面影响,紫胶林对蚂蚁多样性保护有利.     

Effect of plant water stress on honeydew production, weight gain and oviposition of brown planthopperNilaparvata lugens on rice cultivars

Glasshouse studies were made on honeydew production, adult and nymphal body weight gain, fecundity and size of egg groups of brown planthopper Nilaparvata lugens (Stål) (Homoptera: Delphacidae) (BPH) on CVS TN1, ASD7, Babawee, Mudgo, Rathu-Heenati and Ptb33 rice plants with watering regimes of 10 ml, 20 ml, 30 ml and excess water daily. Honeydew production, weight gain, fecundity and size of egg groups were greatest on TN1, followed by ASD7. BPH did less well on Babawee, Mudgo and Rathu-Heenati and they did worst on Ptb33. Watering regimes greatly affected performance, with significantly less honeydew, less weight gain, lower fecundity and smaller egg groups on plants with 10 ml water daily than on plants with excess water. The 20 ml and 30 ml watering regimes also significantly reduced honeydew production on TN1 and ASD7 and fecundity and weight gain of adults and nymphs on Mudgo. On Babawee adults gained most weight on the 20 ml and 30 ml treatments, and nymphs gained most weight on the 30 ml treatment. BPH laid most eggs on TN1, ASD7, Babawee and Rathu-Heenati when plants were given 30 ml water daily.     

Aphid honeydew and its effect on the phyllosphere microflora of Picea abies (L.) Karst

Aphids of the genus Cinara, feeding on Norway spruce, excrete copious amounts of honeydew, a carbon-rich waste product, which accumulates locally on needles and twigs. We investigated the role of honeydew as a potential source of energy which might promote the growth of micro-organisms in the phyllosphere of conifer trees. To approach this question, we followed the population dynamics of Cinara spp. in a natural forest stand over two seasons. We also studied the amounts of honeydew produced by individual aphids and identified potential parameters which might influence honeydew production. Finally, we determined the growth of micro-organisms on infested and uninfested needles of Norway spruce during the growing season. Confined to Picea abies, the investigated Cinara species only became abundant in midsummer, when needles and shoots were expanding. The populations showed only a single peak in abundance, the timing and magnitude of which may vary from year to year due to weather conditions, changes in plant quality in a yearly cycle or the impact of natural enemies. The amount of honeydew produced by individual aphids was dependent on the developmental stage of the aphid, the nutritional supply of its host plant and on the developmental state of the Norway spruce (e.g. bud burst, end of shoot extension). The presence of honeydew significantly increased the growth of bacteria, yeast and filamentous fungi on the surface of needles and there was a pronounced seasonal trend, with the highest abundance in midsummer correlating with the period of peak aphid abundance. Taken together, these findings indicate that aphids have an influence on microbial ecology in the phyllosphere of trees. The implication of our study, from interactions at the population level to effects and potential consequences for C and N fluxes at the level of forest ecosystems, is discussed.