红火蚁入侵和未入侵生境中蚂蚁的觅食强度

采用诱饵诱集法,对华南地区3种典型的红火蚁入侵和未入侵生境中蚂蚁对4种诱饵（蜂蜜、花生油、火腿肠和黄粉虫幼虫）的搜寻时间、召集时间及召集数量进行研究,并分析了红火蚁入侵对蚂蚁觅食强度的影响.结果表明：草坪红火蚁入侵区,蚂蚁对黄粉虫幼虫和花生油的搜寻时间极显著或显著短于对照区（红火蚁非入侵区）;荒草地红火蚁入侵区,蚂蚁对4种诱饵的搜寻时间与对照区的差异均不显著,在花生油上的召集时间显著长于对照区;荔枝园红火蚁入侵区,蚂蚁对4种诱饵的搜寻时间及召集时间与对照区均无显著差异.诱饵设置30 min时,草坪红火蚁入侵区,花生油、黄粉虫幼虫、火腿肠上的红火蚁工蚁数量均显著多于本地蚂蚁工蚁数量;荒草地红火蚁入侵区,花生油上的红火蚁工蚁数量明显多于本地蚂蚁工蚁数量,其余诱饵上红火蚁工蚁数量与本地蚂蚁工蚁数量的差异不显著;荔枝园红火蚁入侵区,4种诱饵上红火蚁工蚁数量与本地蚂蚁工蚁数量的差异均不显著.     

红火蚁与黑头酸臭蚁对不同食物资源的竞争

红火蚁Solenopsis invicta Buren与黑头酸臭蚁Tapinoma melanocephalum(F.)在不同食物资源上的竞争的实验结果表明:红火蚁与黑头酸臭蚁对鸡蛋诱饵的竞争最为激烈,当二者同时出现在鸡蛋诱饵时,红火蚁取胜并占有食物诱饵的比例为53%,略高于黑头酸臭蚁(47%),但二者的占有率没有显著的差异(P＞0.05).两种蚂蚁对蜂蜜和花生油诱饵表现出不同的喜好性.红火蚁喜好花生油食物诱饵,而黑头酸臭蚁喜好糖类食物诱饵.红火蚁在鸡蛋和花生油诱饵上的工蚁召集量平均分别为269头和219头,显著高于在蜂蜜诱饵上的平均工蚁数量,仅为16头;且对鸡蛋和花生油诱饵诱饵的占有率显著高于蜂蜜诱饵.黑头酸臭蚁在鸡蛋和蜂蜜诱饵上的工蚁召集量平均分别为240头和219头,显著高于在花生油诱饵的工蚁数量,为10头以下;且对鸡蛋和蜂蜜诱饵诱饵的占有率显著高于花生油诱饵.     

华南地区桑园和荒地两种生境中红火蚁觅食工蚁的食物组成

【目的】红火蚁Solenopsis invicta Buren是世界最危险的有害入侵生物之一,2004年入侵我国华南地区,并给农林业安全、生态安全带来极大危害。调查并明确田间红火蚁觅食工蚁的食物种类及数量,不仅为评估红火蚁猎食对生态环境中节肢动物群落的影响,而且为红火蚁防治饵剂的改进提供科学依据。【方法】本研究采用蚁道剖析法,对华南地区桑园和荒地两种生境中红火蚁觅食工蚁搬运的固体残片取样和鉴定;依搬运工蚁及其固体残片尺寸进行测量分级并称重,以分析工蚁多态性与固体食物大小的关系;采用薄层色谱法和氨基酸分析法测定嗉囊液体样品的营养成分及含量。【结果】在华南地区桑园和荒地中,红火蚁觅食工蚁搬运回巢的固体食物包括固体的动物残片和植物种子,其中动物残片属于3门7纲21个类群(包括14个昆虫目),昆虫纲动物所占比例为总固体食物的45.53%~46.10%。工蚁偏好搬运长1.400±0.043 mm~2.306±0.063 mm和宽0.723±0.028 mm~1.261±0.051 mm的固体残片,其重量在0.203~0.413 mg之间。红火蚁觅食工蚁嗉囊液体由多种氨基酸、果糖和葡萄糖组成,在桑园和荒地采集到的红火蚁嗉囊液体样本中的氨基酸总含量分别为1 544.31 mg/L和861.48 mg/L,氨基酸种类分别为33种和32种,其中31种氨基酸为共有的。【结论】华南地区桑园和荒地中,红火蚁固体食物组成均以昆虫纲动物为主;参与固体残片搬运觅食蚁的80%属于中型工蚁,搬运较大型固体残片的大型工蚁仅占5%;红火蚁工蚁嗉囊液体含有丰富的氨基酸和单糖。     

红火蚁工蚁受侵扰的行为反应强度与蚁巢大小和侵扰强度之间的关系研究

红火蚁Solenopsis invicta Buren的防御行为是其被认定为社会性昆虫的关键特征之一。红火蚁蚁巢受到侵扰时,工蚁会快速涌出搜寻侵扰物并展开攻击。然而,蚁巢受侵扰后工蚁的行为反应与蚁巢大小和侵扰强度之间的关系有待进一步明确。为此,本研究通过野外视频记录并结合室内统计分析的方法来明确不同大小的红火蚁蚁巢受侵扰后工蚁反侵扰行为的动态过程。结果表明,蚁巢大小和受侵扰强度对蚁巢受侵扰后工蚁的反应速度具有显著影响。同等侵扰强度下,与中、大型蚁巢相比,小型蚁巢的工蚁往往表现出更慢的行为反应。尤其在低侵扰强度时,小蚁巢工蚁的反应时间平均0.8 s,而中蚁巢和大蚁巢均仅为0.34 s。当侵扰强度相同时,蚁巢越大,受侵扰后召集工蚁的数量越多;当蚁巢大小相同时,侵扰强度越高,召集工蚁的数量越多。但无论是蚁巢大小还是侵扰强度的不同,红火蚁蚁巢受侵扰后,召集工蚁的数量到达峰值的时间均为30 s左右。研究结果为进一步了解红火蚁的防御行为,科学预防红火蚁的攻击,以及有效开展红火蚁的防治提供了重要的实验依据。     

扶桑绵粉蚧及其蜜露对红火蚁的召集作用

为了明确扶桑绵粉蚧Phenacoccus solenopsis Tinsley及其蜜露对红火蚁Solenopsis invicta Buren的召集作用,利用双向选择诱集装置测定了扶桑绵粉蚧雌成虫及其分泌蜜露对红火蚁工蚁的诱集数量动态。结果表明：（1）蜜露对红火蚁工蚁具有强烈的召集作用,不管扶桑绵粉蚧存在与否,均可在10~20 min出现觅食工蚁的数量高峰,之后随着蜜露量减少,觅食工蚁诱集数量也逐渐降低,明显高于对照;（2）仅有扶桑绵粉蚧雌成虫存在时,红火蚁觅食工蚁数量呈现逐渐增加的趋势,50 min才达到数量高峰,之后无明显下降趋势;（3）对比蜜露和雌成虫对红火蚁工蚁的诱集结果发现,蜜露对红火蚁工蚁的召集作用明显较强,10 min即可出现91.50头的觅食工蚁数量高峰,而雌成虫对红火蚁的诱集量较低,诱集高峰出现在42 min,诱集量仅为39.17头。因此,扶桑绵粉蚧及其蜜露均对红火蚁工蚁具有一定的召集作用,蜜露的召集作用明显较强,而雌成虫的召集作用较为稳定,未随着时间延长出现明显下降。     

荒草地和荔枝园生境短期入侵的红火蚁与黑头酸臭蚁种间的干扰竞争

【背景】红火蚁入侵后对新发生地区生物多样性的影响及与土著物种的关系是入侵生物学研究的重点之一,解释红火蚁与类似生态位的土著蚂蚁的关系对全面了解该蚁入侵的生态学效应具有重要意义。【方法】通过野外模拟设置蚁巢,观察、记录距离红火蚁和黑头酸臭蚁蚁巢30 cm处诱集到的黑头酸臭蚁工蚁在红火蚁入侵前、入侵中及移除后的数量变化,研究短期入侵红火蚁实验种群与荒草地和荔枝园黑头酸臭蚁间的干扰竞争。【结果】红火蚁实验种群短期入侵对荒草地生境黑头酸臭蚁的干扰较明显,而对荔枝园生境黑头酸臭蚁的干扰较小;红火蚁未入侵荒草地生境黑头酸臭蚁受干扰最明显,移除红火蚁20 min后,处理诱饵上召集的黑头酸臭蚁数量才与入侵前差异不显著;红火蚁未入侵荔枝园生境黑头酸臭蚁受干扰最小,移除红火蚁仅5 min后,处理诱饵上黑头酸臭蚁数量就恢复到入侵前,甚至超过入侵前数量。【结论与意义】红火蚁入侵对黑头酸臭蚁的觅食行为存在较大的干扰抑制作用,其影响程度与生境的复杂性有着密切关系。研究结果可为了解红火蚁入侵的生态学效应提供证据。     

亚致死浓度赤藓糖醇对红火蚁工蚁觅食和弃尸行为的影响

红火蚁是国际上最具危险性外来害虫之一,已入侵华南地区并造成严重危害。为弄清潜在杀虫剂赤藓糖醇在亚致死浓度下对红火蚁的影响,本研究使用0.05 g/mL赤藓糖醇水溶液喂食室内蚁群24 h,观察了工蚁的觅食行为和弃尸行为的变化。结果显示,取食赤藓糖醇后工蚁发现食物时间约为5 min,而取食10%蔗糖水后发现食物时间缩短到2 min以内;取食赤藓糖醇后工蚁招募速度和食物搬运效率也显著低于对照。取食赤藓糖醇后工蚁发现尸体时间和弃尸速度变化显著,发现尸体时间由对照的3.45 min延长至8.13 min,开始丢弃尸体时间由20 min延长至37.5 min,丢弃完所有尸体耗时由3.08 h增大至5.37 h。亚致死浓度赤藓糖醇显著降低了红火蚁工蚁觅食和弃尸能力。     

红火蚁工蚁对颜色信号的选择与利用

为探明红火蚁Solenopsis invicta工蚁对颜色信号的选择与利用,本研究测定了不同颜色色卡对工蚁的趋向行为以及不同颜色饵料对工蚁觅食行为的影响,以期为红火蚁的高效监测与防控提供重要基础。结果表明颜色显著影响了红火蚁工蚁的趋向行为,黑色对工蚁的引诱率最高,可达32%;黄色对工蚁的引诱率最低,仅为7%。研究也发现不同颜色的饵料显著影响了红火蚁工蚁的觅食。在5 min时间内,工蚁在黄色、绿色以及蓝色饵料上觅食的数量最多,显著高于在紫色和黑色上饵料的觅食工蚁数;工蚁对红色、橙色、黄色、绿色、蓝色饵料的搬运量最大,显著高于紫色与黑色的饵料。综上,红火蚁工蚁可以识别与利用颜色信号,在制备红火蚁监测与防控饵剂时,可以考虑将饵剂染色红、橙、黄、绿、蓝等反射波长较长的颜色,以便工蚁能快速定位到饵剂并搬运更多的饵剂到蚁巢中。     

诱饵诱集时间与红火蚁工蚁诱集量的关系研究

为了明确诱饵诱集时间与红火蚁工蚁诱集量之间的关系,确定最佳的诱饵放置时间,本研究采用火腿肠诱饵诱集法,观察不同季节、不同时间段红火蚁诱集的个体数量,利用房室模型分析诱饵诱集时间与红火蚁工蚁诱集量之间的关系。结果表明,随着诱饵放置时间的增加,红火蚁工蚁的诱集数量会出现一个高峰,春季诱集高峰出现在诱饵放置后38-44 min,秋季出现在诱饵放置后24-29 min,并建立了不同季节、不同时间段红火蚁诱集量与时间的关系模型,分别为Y=12764.8807×e(-0.029102 X)"12820.4625×e(-0.030064 X)(春季上午)、Y=16166.6800×e(-0.023994 X)"16217.0808×e(-0.024866 X)(春季下午)、Y=12211.9095×e(-0.040576 X)"12275.2496×e(-0.041620 X)(秋季上午)、Y=12306.4111×e(-0.049724 X)"12383.6907×e(-0.051217 X)(秋季下午)。因此,在利用火腿肠诱饵监测红火蚁时,春季诱饵放置的最适时间约为40 min,秋季的最适时间约为30 min。     

4种饵料对小火蚁工蚁的诱集效果比较

小火蚁Wasmannia auropunctata Roger被世界自然保护联盟（IUCN）列为最具危害性的100种入侵物种之一。2022年1月份,小火蚁首次被发现入侵中国大陆,开发小火蚁的监测技术对于摸清该种入侵蚂蚁的发生程度与分布范围有重要意义。本文测定了火腿肠、花生酱、花生油和蜂蜜等4种饵料对小火蚁的诱集效果,并对不同生境小火蚁数量进行了调查。室内试验中火腿肠诱集效果最好,花生酱和花生油次之,蜂蜜最差。在野外试验中,花生酱和火腿肠的诱集效果最佳,放置30 min的诱集数量与60 min时无显著差异,并且饵料摆放瓶口处能诱集到更多工蚁,上午和下午更适宜进行诱集试验。利用花生酱进行野外调查发现小火蚁在山腰、山脚、屋内、田埂和路边等生境中均有分布。以上结果为进一步开展小火蚁疫情的调查提供了参考。     

Foraging behavior and recruitment of red imported fire ant Solenopsis invicta Buren in typical habitats of South China

The foraging behavior consisted of three steps: searching, recruitment and transportation. Searching time was different for different foods; searching time for honey was longer than that for any other food tested. It was also affected by habitats with the searching time of fire ants in a litchi orchard being significantly longer than that for other habitats (p<0.01). However, the weight of the food had no obvious effect on the searching time. The recruitment of fire ant workers during foraging was regular, and there was a strong relationship between the number of recruited workers and the transportation time. When the food was too heavy to transport immediately into the nest, the number of recruited workers was maximum at 30 min after the food was initially found. For smaller sized food sources maximum recruitment of workers was possible at a shorter time and the food was more rapidly transported back to the nest. For different foods, the dynamics of recruitment were similar although the number of recruits was different. The weight of the food and the habitats also deeply affected the time spent on transportation.     

Foraging behavior and recruitment of red imported fire ant Solenopsis invicta Buren in typical habitats of South China

The foraging behavior consisted of three steps: searching, recruitment and transportation. Searching time was different for different foods; searching time for honey was longer than that for any other food tested. It was also affected by habitats with the searching time of fire ants in a litchi orchard being significantly longer than that for other habitats (p<0.01). However, the weight of the food had no obvious effect on the searching time. The recruitment of fire ant workers during foraging was regular, and there was a strong relationship between the number of recruited workers and the transportation time. When the food was too heavy to transport immediately into the nest, the number of recruited workers was maximum at 30 min after the food was initially found. For smaller sized food sources maximum recruitment of workers was possible at a shorter time and the food was more rapidly transported back to the nest. For different foods, the dynamics of recruitment were similar although the number of recruits was different. The weight of the food and the habitats also deeply affected the time spent on transportation.     

Does Mutualism Drive the Invasion of Two Alien Species? The Case of Solenopsis invicta and Phenacoccus solenopsis

Although mutualism between ants and honeydew-producing hemipterans has been extensively recognized in ecosystem biology, however few attempts to test the hypothesis that mutualism between two alien species leads to the facilitation of the invasion process. To address this problem, we focus on the conditional mutualism between S. invicta and P. solenopsis by field investigations and indoor experiments. In the laboratory, ant colony growth increased significantly when ants had access to P. solenopsis and animal-based food. Honeydew produced by P. solenopsis also improved the survival of ant workers. In the field, colony density of P. solenopsis was significantly greater on plots with ants than on plots without ants. The number of mealybug mummies on plants without fire ants was almost three times that of plants with fire ants, indicating a strong effect of fire ants on mealybug survival. In addition, the presence of S. invicta successfully contributed to the spread of P. solenopsis. The quantity of honeydew consumption by S. invicta was significantly greater than that of a presumptive native ant, Tapinoma melanocephalum. When compared with the case without ant tending, mealybugs tended by ants matured earlier and their lifespan and reproduction increased. T. melanocephalum workers arrived at honeydew more quickly than S. invicta workers, while the number of foraging S. invicta workers on plants steadily increased, eventually exceeding that number of T. melanocephalum foragers. Overall, these results suggest that the conditional mutualism between S. invicta and P. solenopsis facilitates population growth and fitness of both species. S. invicta tends to acquire much more honeydew and drive away native ants, promoting their predominance. These results suggest that the higher foraging tempo of S. invicta may provide more effective protection of P. solenopsis than native ants. Thus mutualism between these two alien species may facilitate the invasion success of both species.     

Distance effects on resource profitability and recruitment in the giant tropical ant,Paraponera clavata

Summary We examine how cost and benefit components of resource profitability affect recruitment in the giant tropical ant, Paraponera clavata. To vary resource profitability, we changed the quantity of artificial nectar baits presented to foragers and the distance of nectar baits from the nest. Both distance to and amount of resource affected quantitative aspects of recruitment. At increased distances foragers were less likely to recruit, and fewer workers were recruited to the resource area. The amount of nectar affected the tendency of foragers to recruit, but had no effect on the number of ants recruited. Variation in resource distance was also associated with qualitative changes in recruitment strategy. Foragers at distant sites recruited from the canopy rather than from the nest, and often transferred nectar to other workers for transport to the nest. Nectar transfer and extra-nidal recruitment significantly reduced the time required for resource collection. It may also have increased the ability of workers to specialize in specific foraging tasks. A portion of the colony's foraging force specialized spatially by remaining in distant foraging areas without returning to the nest. The flexible recruitment system of P. clavata increases colonial net energetic gain rates by concentrating foraging effort on resources yielding the highest net energetic rewards, and increases the competitive abilities of individual colonies at resource sites by decreasing collection times.     

Foraging activity of leaf-cutter ants is affected by barometric pressure

Among all activities displayed by ant colonies, searching for food is essential for all individuals survival. However, many external activities are hazardous or restrictive for the entire society. Even though leaf-cutter ants are highly successful insects, they are subject to extreme aspects of foraging, as raindrops and wind. Although recruitment and food exploitation are known to change with temperature and humidity, barometric pressure changes and how they affect ant behavior remain unknown. We aimed to determine how an increase or decrease in barometric pressure might modify foraging strategies of the leaf-cutter ant Atta sexdens compared to steady pressure. The first modification observed in the workers behavior was the scouts greater promptness in leaving the nest when the barometric pressure decreased. Regard to the foragers, there was no difference in the number of individuals recruited for collecting leaves. However, it was cut and brought into the nest 1.5 and 2 times more leaves during the pressure drop, respectively. The reason for this foraging efficiency as a whole was ultimately the sum of the efficiency of each forager. The shifts in behavior, therefore, could be related to the indirect consequences of a pressure decrease, such as rainfall and strong winds, both strong constraints on ants on a trail. This is the first report of barometric pressure affecting the behavior of a social insect under controlled conditions.     

红火蚁觅食活动的气象因子相关性及其等级划分

[背景]气象因子是制约害虫种群动态的重要因素,也是昆虫觅食活动的影响因子。【方法】通过系统的田间调查分析了红火蚁在华南地区的觅食活动年变动规律及其与气象因子的关系。[结果]红火蚁在12和1月份时觅食活动最弱,3—6月出现一个觅食高峰,在下半年的9—11月出现另一个高峰,7、8月份受高温的影响觅食活动有一定程度的回落现象。红火蚁工蚁觅食活动的年变化规律又因不同生境类型呈现一定的差异。相关分析结果表明,红火蚁觅食工蚁数与降水量、月平均气温、月最低气温、月最高气温、月最小相对湿度呈正相关,而与月平均气压呈负相关,且各相关性均达显著水平。逐步回归分析表明,月平均气温、日照时数、月最低气温综合影响红火蚁觅食活动的变化。其中,月平均气温可以作为一个非常重要的直接影响红火蚁觅食活动的参数。对荔枝园内全年红火蚁觅食活动进行分级,对方程进行求导得到红火蚁在荔枝园中觅食活动的5个活动级别所对应的月平均温度、日照时数和月平均最低气温实际临界值。[结论与意义]气象因子与红火蚁的觅食活动存在密切的相关性,研究结果可为红火蚁的监测与控制提供依据。     

Behavioral and developmental homeostasis in the fire ant, Solenopsis invicta

The von Bertalanffy rule (1960) predicts that low incubation temperature during larval development will result in larger adult body size. If larval development in social insects followed this rule, then low incubation temperature would induce the development of larger workers and possibly even sexuals. To test this prediction, the effect of incubation temperature on larval development, larval meal size, larval tending and worker recruitment to food in the fire ant, Solenopsis invicta was investigated. Temperatures tested where within the range at which brood remains viable.Contrary to the predictions of the von Bertalanffy rule, worker size was unaffected by incubation temperature, and sexuals were reared at the high rather than the low incubation temperature. Moreover, larval meal size, the rate of larval tending by workers and the total number of workers recruited to food were unaffected by temperature.Mechanisms regulating developmental and behavioral homeostasis were as follows: the duration of larval development and the rate of larval growth changed proportionately with temperature such that the mean and variation of pupal size was unaffected by incubation temperature. Larvae solicited at the same rate, swallowed at the same rate and swallowed for the same duration such that meal size was unaffected by incubation temperature. On the brood pile, fewer workers tended brood at higher incubation temperatures, but worker tempo increased; as a result, brood tending was not adversely affected by incubation temperature. The rate of worker recruitment to food sites outside the nest increased with temperature, but the duration of the recruitment effort decreased such that, over time, the same total number of workers was employed to retrieve food.Incubation humidity was also investigated. When brood chambers were less than 100% humid, workers recruited to food and tended larvae (retrieved, sorted and groomed them), but did not feed larvae. Eventually, larvae died of starvation and were cannibalized.