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.     

几种饵料对红火蚁觅食的引诱作用

在荒地类型生境中测定花生酱、猫饲料、狗饲料、花生油、面包及蜂蜜等几种常见饵料对红火蚁的引诱作用。结果表明:面包、狗饲料、猫饲料和花生酱对红火蚁引诱力较强,花生油次之,蜂蜜最低;选择性试验结果表明红火蚁对供试的几种饵料无明显选择性。     

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。     

3种生境蚂蚁群落组成和觅食动态调查

蚂蚁是地球上最常见、数量最多的一类昆虫,是指示生物多样性和环境变化的重要物种。大多数蚂蚁由于其社会性而具有群体觅食的特点,然而不同蚂蚁种类由于食性的差异以及种间竞争等原因会产生觅食节律的分化。为研究相同生境中不同种类蚂蚁觅食规律的差异,本研究分别用20%蔗糖水和鸡肉火腿肠以诱饵法诱集湖边、树林、荔枝园3种生境中的蚂蚁,以此确定不同生境中的优势蚂蚁种类及其觅食行为随时间的动态变化。研究结果表明,虽然不同生境诱集到的蚂蚁种类数无显著差异,但诱集到的蚂蚁数量则差异显著。不同生境的优势种也不一样,湖边的最大优树林势种群为小大头蚁(44.21%);树林的优势种群为白跗节狡臭蚁(67.36%)、小大头蚁、宽结大头蚁;荔枝园的最大优势种群为小大头蚁(63.46%)。结果发现,大多数情况下不同调查时间点上觅食工蚁数或同一时间点上不同蚂蚁的数量之间的差异并无统计学意义。研究结果将为不同生境蚂蚁群落多样性的研究提供理论基础。     

两种红火蚁监测方法应用效果的比较

红火蚁Solenopsis invicta是全国农业、林业和进境植物检疫性有害生物,是世界自然保护联盟收录的最具有破坏力的入侵生物之一。高效精准监测红火蚁在其防控中尤为重要,而诱饵诱集是监测红火蚁的有力措施,相对诱饵的筛选和改进,诱集器方面研究则较为滞后。本文对“透明塑料瓶+火腿肠”（PS）和“新型诱集器+火腿肠”（TS）这两类诱集器的红火蚁诱集效果进行比较分析。结果表明,下午1∶30至3∶30时段,PS处理透明塑料瓶在放置5 min之后存在明显的升温效应,伴随着诱集到的红火蚁数量明显减少,诱集到红火蚁的诱饵比例也下降明显,较TS处理下降了43.6%。而且,TS的投放时间和回收耗时均明显比PS的短;在复杂的荒地生境中,投放的诱集器数量越多,PS的诱集器回收率则越低;当投放的诱集器达到90个时,PS处理回收率为92.34%,而TS处理为98.67%。综合上述分析,诱集方法TS由于诱饵开放、诱集和标示一体、稳定性好等特点在应用效果上较PS有优势,适用面更广,今后还需对其进一步完善和改进并应用于红火蚁的调查监测。     

小火蚁的形态特征、分布危害及监测与防控

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,已从其原产地南美洲扩散到除南极洲以外的每个大陆,近期被报道成功入侵中国。本文对小火蚁的分类学与形态特征进行了描述;简要探讨了小火蚁的原产地范围和在全球的扩散历史,进一步阐述其对农业生产、人类健康、生态系统等方面的影响;同时,介绍了小火蚁的监测与调查方法;最后就小火蚁的检疫、化学防治与生物防治等防控技术进行了归纳,以期提升大众对小火蚁的认识并为积极应对小火蚁的入侵提供参考。     

华南地区典型生境中红火蚁觅食行为及工蚁召集规律

观察研究了华南地区几种典型生境中红火蚁对不同类型食物的觅食行为和工蚁召集动态规律。研究结果表明红火蚁觅食行为存在搜寻、召集及搬运等主要过程。不同生境中红火蚁对食物的搜寻时间存在一定差异,荔枝园中搜寻时间明显长于其它生境;荔枝园、荒地、路边生境中红火蚁对蜂蜜的搜寻时间明显长于其它几种食物;同一生境中红火蚁对不同重量的同种食物搜寻时间无明显变化。发现食物后召集的工蚁数量随着时间延长呈现不断增加的趋势,对于较大的食物一般30min左右召集的工蚁数量达到最大,之后趋于稳定并逐渐减少,而对于可以直接搬动的食物发现后15min左右群体召集数量达到最大并很快将其搬走。召集工蚁数量与发现后时间的关系符合二次非线性方程,建立了火腿肠、花生油和蜂蜜等食物上红火蚁工蚁召集数量与发现时间的关系模型,分别为Na=4183.91e^-0.0327T-4231.48e^-0.0346T,Na=3253.78e^-0.0233T-3314.59e^-0.0271T,Na=117.97e^-0.0131T-163.93e^-0.0808T。对于不同食物红火蚁发现后召集的最大工蚁数量间有明显差异,其中花生油上最大,平均为176．3头,火腿肠上次之,为90．4头,蜂蜜上最少,为68．0头。对于不同重量的同种食物,工蚁的召集动态规律较为一致,发现食物后25-30min左右工蚁的召集数量均达到最大值,之后缓慢减少,发现食物后时间长度和食物上工蚁数量也符合房室模型函数Na=c1×exp（-c2T）-c3×exp（-c4T）。同种食物不同重量之间同一时间召集的工蚁数量存在较大差异,呈随食物重量增大而增大趋势。不同生境中对相同质量同种食物工蚁召集数量动态总体变化规律相近,但在发现食物后工蚁数量增长的速度和最大召集工蚁的数量存在明显差异,以路边工蚁数量增长最快、工蚁总数最多,苗圃次之,荔枝园、荒地中工蚁增长速度均较低。红火蚁对不同食物种类切割、搬运耗时存在很大差异,搬运完0．5g的火腿肠需要26．23h,而黄粉虫幼虫（重量约为0．1g）仅为15．6min。不同生境中红火蚁对相同重量同一种食物的搬运耗时也不同,荔枝园要长于其它生境。     

西双版纳入侵长足捷蚁与土著黄猄蚁的种间竞争

【目的】入侵物种能够通过竞争影响本地物种的种群,从而影响入侵地的生物多样性。长足光捷蚁Anoplolepis gracilipes是全球最具破坏力的入侵蚂蚁之一。本研究旨在明确西双版纳地区入侵长足捷蚁与土著优势种蚂蚁黄猄蚁Oecophylla smaragdina之间的竞争关系。【方法】通过野外调查和室内控制试验相结合的方法,观察和对比分析长足捷蚁和黄猄蚁的体型大小,雾凉季和雨季的巢穴外觅食活动规律,觅食能力(搜寻食物的时间、在觅食时间内召集的最大工蚁数),打斗行为(不同打斗组合的攻击强度和死亡率)以及对饥渴的耐受性(无食物和水分供应时平均存活时间和存活率随时间的变化)。【结果】长足捷蚁工蚁体长(3.66±0.06 mm)显著小于黄猄蚁工蚁(8.27±0.16 mm)。在雾凉季时,长足捷蚁具有比黄猄蚁更长的觅食活动时间;而在雨季时,两种蚂蚁均在下午温度较高时段觅食活动的个体数量减少。苹果、蜂蜜和火腿肠3种食物作为诱饵时,长足捷蚁具有更快搜寻食物的能力,4~8 min便能找寻到食物,而黄猄蚁需要8~21 min才能找寻到食物,此外在寻找到食物后,长足捷蚁也有更快召集同伴的能力。在人工控制试验中,1头长足捷蚁和1头黄猄蚁同时存在时主要以不攻击和低强度攻击为主,而当两种蚂蚁中的任意其中一种的个体数量增加到5头时,攻击强度会显著增加,两种蚂蚁均存在种间协作行为。在饥渴状态下,两种蚂蚁工蚁的平均存活时间差异不显著,但长足捷蚁最长存活120 h,黄猄蚁最长存活96 h。【结论】在西双版纳地区,长足捷蚁相较于土著黄猄蚁具有更强的觅食的能力,雾凉季觅食活动时间更长,暗示长足捷蚁可能具有较强的温度适应能力。有必要加强对这一入侵蚂蚁的研究,并密切关注其种群在该地区的发展。     

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.     

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。     

Immediate impacts of invasion by Wasmannia auropunctata (Hymenoptera: Formicidae) on native litter ant fauna in a New Caledonian rainforest

Abstract For the last 30 years, Wasmannia auropunctata (the little fire ant) has spread throughout the Pacific and represents a severe threat to fragile island habitats. This invader has often been described as a disturbance specialist. Here we present data on its spread in a dense native rainforest in New Caledonia. We monitored by pitfall trapping the litter ant fauna along an invasive gradient from the edge to the inner forest in July 1999 and March 2000. When W. auropunctata was present, the abundance and richness of native ants drops dramatically. In invaded plots, W. auropunctata represented more than 92% of all trapped ant fauna. Among the 23 native species described, only four cryptic species survived. Wasmannia auropunctata appears to be a highly competitive ant that dominates the litter by eliminating native ants. Mechanisms involved in this invasive success may include predation as well as competitive interactions (exploitation and interference). The invasive success of W. auropunctata is similar to that of other tramp ants and reinforces the idea of common evolutionary traits leading to higher competitiveness in a new environment.     

Experimental evidence that the introduced fire ant, Solenopsis invicta, does not competitively suppress co-occurring ants in a disturbed habitat

1. The fire ant, Solenopsis invicta, is a globally distributed invasive ant that is largely restricted to disturbed habitats in its introduced range. For more than half a century, biologists have believed its success results from superior competitive abilities relative to native ant species, as well as an escape from their natural enemies. 2. We used large volumes of hot water to kill fire ant colonies, and only fire ant colonies, on experimental plots in pastures, and found that populations and diversity of co-occurring ants did not subsequently increase. 3. These results are contrary to classical predictions and indicate that S. invicta is not a superior competitor that suppresses native ants, and that the low diversity and abundance of native ants in degraded ecosystems does not result from interaction with fire ants. Instead, other factors such as prior disturbance and recruitment limitation may be the primary limiting factors for native species in these habitats.     

Sampling efficacy for the red imported fire ant Solenopsis invicta (Hymenoptera: Formicidae)

Cost-effective detection of invasive ant colonies before establishment in new ranges is imperative for the protection of national borders and reducing their global impact. We examined the sampling efficiency of food-baits and pitfall traps (baited and nonbaited) in detecting isolated red imported fire ant (Solenopsis invicta Buren) nests in multiple environments in Gainesville, FL. Fire ants demonstrated a significantly higher preference for a mixed protein food type (hotdog or ground meat combined with sweet peanut butter) than for the sugar or water baits offered. Foraging distance success was a function of colony size, detection trap used, and surveillance duration. Colony gyne number did not influence detection success. Workers from small nests (0- to 15-cm mound diameter) traveled no >3 m to a food source, whereas large colonies (>30-cm mound diameter) traveled up to 17 m. Baited pitfall traps performed best at detecting incipient ant colonies followed by nonbaited pitfall traps then food baits, whereas food baits performed well when trying to detect large colonies. These results were used to create an interactive model in Microsoft Excel, whereby surveillance managers can alter trap type, density, and duration parameters to estimate the probability of detecting specified or unknown S. invicta colony sizes. This model will support decision makers who need to balance the sampling cost and risk of failure to detect fire ant colonies.     

Patterns of abundance of fire ants and native ants in a native ecosystem

Abstract 1. This correlational study examines the relationship between the red imported fire ant (Solenopsis invicta) and native ants in a longleaf pine savanna. Fire ants are frequently associated with a decline in native ants throughout the invaded range, but fire ant invasion is often coupled with habitat disturbance. Invasion of fire ants into the longleaf pine savanna provides an opportunity to examine the structure of the ant community in the absence of habitat disturbance. 2. Pitfall trapping was conducted within the longleaf pine savanna as well as across a naturally occurring soil moisture gradient, in plots that had been artificially watered. 3. Species richness did not vary as a function of fire ant density. There was an inverse relationship between native ant density and fire ant density, but this abundance pattern does not necessarily imply a causal link between fire ant invasion and native ant decline. For individual species, fire ant densities were negatively correlated with the densities of only two native ant species, including Solenopsis carolinensis, a native species that potentially limits the invasion of fire ants. Additionally, fire ants and native ants respond differently to soil moisture, with native ants favouring drier conditions than fire ants. 4. The possible exclusion of fire ants by some native ants, as well as differences in habitat preferences, provide alternative explanations for the frequently observed negative correlation between fire ants and native ants.     

Effectiveness of protein-rich pea flour for the control of stored-product beetles

Abstract The association between visiting ants and the extrafloral nectaries (EFN)‐bearing shrub Hibiscus pernambucensis Arruda (Malvaceae) was investigated in two different coastal habitats – a permanently dry sandy forest and a regularly inundated mangrove forest. In both habitats the frequency of plants with ants and the mean number of ants per plant were much higher on H. pernambucensis than on non‐nectariferous neighbouring plants. In the sandy forest the proportion of live termite baits attacked by ants on H. pernambucensis was much higher than on plants lacking EFNs. In the mangrove, however, ants attacked equal numbers of termites on either plant class. Ant attendance to tuna/honey baits revealed that overall ant activity in the sandy forest is higher than in the mangrove area. The vertical distribution (ground vs. foliage) of ant activity also differed between habitats. While in the mangrove foraging ants were more frequent at baits placed on foliage, in the sandy forest ant attendance was higher at ground baits. Plants housing ant colonies were more common in the mangrove than in the sandy forest. Frequent flooding in the mangrove may have resulted in increased numbers of ant nests on vegetation and scattered ant activity across plant foliage, irrespective of possession of EFNs. Thus plants with EFNs in the mangrove may not experience increased ant aggression towards potential herbivores relative to plants lacking EFNs. The study suggests that the vertical distribution of ant activity, as related to different nest site distribution (ground vs. foliage) through a spatial scale, can mediate ant foraging patterns on plant foliage and probably affect the ants’ potential for herbivore deterrence on an EFN‐bearing plant species.     

Booms,busts and population collapses in invasive ants

The abundance of many invasive species can vary substantially over time, with dramatic population declines and local extinctions frequently observed in a wide range of taxa. We highlight population crashes of invasive ants, which are some of the most widespread and damaging invasive animals. Population collapse or substantial declines have been observed in nearly all of the major invasive ant species including the yellow crazy ant (Anoplolepis gracilipes), Argentine ants (Linepithema humile), big-headed or coastal brown ant (Pheidole megacephala), the tropical fire ant (Solenopsis geminata), red imported fire ants (Solenopsis invicta), and the little fire ant or electric ant (Wasmannia auropunctata). These declines frequently attract little attention, especially compared with their initial invasion phase. Suggested mechanisms for population collapse include pathogens or parasites, changes in the food availability, or even long-term effects of the reproductive biology of invasive ants. A critical component of the collapses may be a reduction in the densities of the invasive ant species, which are often competitively weak in low abundance. We propose that mechanisms causing a reduction in invasive ant abundance may initiate a local extinction vortex. Declines in abundance likely reduce the invasive ant’s competitive ability, resource acquisition and defense capability. These reductions could further reduce the abundance of an invasive ant species, and so on. Management of invasive ants through the use of pesticides is expensive, potentially ecologically harmful, and can be ineffective. We argue that pesticide use may even have the potential to forestall natural population declines and collapses. We propose that in order to better manage these invasive ants, we need to understand and capitalize on features of their population dynamics that promote population collapse.     

The Effects of Invasive Ants on Prospective Ant Mutualists

Ants are recognized for their abilities both to engage in mutualistic interactions with diverse taxa, and to invade and dominate habitats outside their native geographic range. Here, we review the effects of invasive ants on three guilds of mutualists: ant-dispersed plants, ant-tended arthropods, and ant-tended plants. We contrast how those three guilds are affected by invasions, how invasive ants differ from native ants in their interactions with those guilds, and how the seven most invasive ant species differ amongst themselves in those interactions. Ant-dispersed plants typically suffer from interactions with invasive ants, a result we attribute to the small size of those ants relative to native seed-dispersing ants. Effects on the ant-tended arthropods and plants were more frequently positive or non-significant, although it is unclear how often these interactions are reciprocally beneficial. For example, invasive ants frequently attack the natural enemies of these prospective mutualists even in the absence of rewards, and may attack those prospective mutualists. Many studies address whether invasive ants provide some benefit to the partner, but few have asked how invasives rank within a hierarchy of prospective mutualists that includes other ant species. Because ant invasions typically result in the extirpation of native ants, this distinction is highly relevant to predicting and managing the effects of such invasions. Interspecific comparisons suggest that invasive ants are poorer partners of ant-dispersed plants than are most other ants, equally effective partners of ant-tended arthropods, and perhaps better partners of ant-tended plants. Last, we note that the invasive ant taxa differ amongst themselves in how they affect these three mutualist guilds, and in how frequently their interactions with prospective mutualists have been studied. The red imported fire ant, Solenopsis invicta, appears particularly likely to disrupt all three mutualistic interactions, relative to the other six invasive species included in this review.     

The urban fire ant paradox: native fire ants persist in an urban refuge while invasive fire ants dominate natural habitats

In contrast to the widespread extirpation of native fire ants (Solenopsis geminata) across southern US following the invasion by imported red fire ants (S. invicta), some residential areas of Austin form unexpected refuges for native fire ants. Ironically, these urban environments provide refuges for the native fire ants while adjacent natural habitats have been overrun by invasive fire ants. Resistance to invasive fire ants in these urban areas occurs mainly in older residential properties constructed prior to the S. invicta invasion, while more recent construction has allowed establishment by S. invicta. The invasive ability of S. invicta is often attributed to escape from parasitoids and efficient dispersal of polygyne multiple queen colonies. Here we also show the importance of landscape parameters in the invasion process, where low levels of disturbance and continuous plant cover in older residential areas form possible barriers to colonization. Dense leaf cover (high NDVI) was also found to be associated with native ant refuges. Long term residential land ownership may have resulted in lower recent disturbance levels and increased plant cover that support refuges of native fire ants.