Supplemental risk evaluations of Puccinia jaceae var. solstitialis for biological control of yellow starthistle

Additional tests of native North American Cirsium species, Saussurea americana, and modern safflower cultivars (Carthamus tinctorius) were requested by regulators and specific interest groups during the risk assessment of foreign isolates of Puccinia jaceae var. solstitialis for biological control of yellow starthistle (YST, Centaurea solstitialis) in the United States. These tests supplement an earlier, extensive host range determination that established P. jaceae from YST as generally host specific and potentially useful for biological control. The additional research was in response to potential hazards identified in an earlier study, changes in safflower cultivars, and concern that P. jaceae might cause a safflower seedling disease similar to hypocotyl infections from infestation by Puccinia carthami teliospores. S. americana, a close relative of yellow starthistle, had not been tested previously. All tests were conducted in a containment greenhouse. Foliage of 19 Cirsium species, 11 safflower cultivars, and S. americana was inoculated with urediniospores and subjected to a 16-h dew period at 18–20 °C. Neither the Cirsium species nor S. americana became infected after foliar inoculations. Compared to foliar infections by P. carthami from safflower in California, only minor infections developed from inoculations with P. jaceae. These were similar to infections observed in earlier studies, and it was not possible to maintain P. jaceae under optimal greenhouse conditions on safflower foliage. Quantitative teliospore inoculations with P. jaceae did not cause infection on safflower hypocotyls, even though large cankers occurred on plants inoculated with P. carthami teliospores. Clear microscopic evidence of infection also was observed in hypocotyls inoculated with P. carthami. These data suggest that native (including rare, threatened, or endangered) Cirsium spp., modern safflower cultivars, and S. americana are not likely to be adversely affected by the use of P. jaceae for biological control of YST. Results from these studies substantiate previous findings and were incorporated in a proposal for permission to use P. jaceae for YST control in California.     

Host finding and recognition by Altica carduorum, a defoliator of Cirsium arvense

Altica carduorum Guer. (Coleoptera: Chrysomelidae) populations aggregate on vigorously growing stands of its host, the thistle Cirsium arvense (L.) Scop. (Asteraceae). The beetle needs contact to recognize a Cirsium species and biting to distinguish its host C. arvense. Feeding or mechanical damage on C. arvense, but not other Cirsium species, aggregates the beetles. Also feces from feeding on C. arvense, but not other Cirsium species, aggregates the opposite sex. Adults also aggregate on larval feces. We suggest that initial host location in the spring depends on random encounter by beetles overwintering in a stand of C. arvense. The beetles commonly make short flights after feeding and either land on another C. arvense plant, which establishes a secondary aggregation centre, or return to the original one. In this manner beetles released on a stand of C. arvense in China spread a radius of 600 m in a year, but those released 35 m away from their host failed to find it. Altica carduorum will develop on any Cirsium species to which it is confined, but is monophagous in the field because host finding is dependent on aggregation to wound and feces substances that are specific to C. arvense.     

AreAltica carduorumandAltica cirsicola(Coleoptera: Chrysomelidae) Different Species? Implications for the Release ofA. cirsicolafor the Biocontrol of Canada Thistle in Canada

Altica carduorumandAltica cirsicolaare two species of leaf-feeding beetle (Coleoptera: Chrysomelidae) which appear to be morphologically indistinguishable and reportedly hybridize in the laboratory. A European population ofA. carduorumwas previously screened for host-plant specificity and released in North America for the control of Canada thistle,Cirsium arvense.A population ofA. cirsicolafrom China is currently being considered as a biocontrol agent forC. arvenseand, as a different beetle species, must be screened using host-specificity tests similar to those used forA. carduorum.IfA. carduorumandA. cirsicolaare, in fact, one species, the screening requirements forA. cirsicolacould be significantly reduced. Hence, we investigated the taxonomic relationship betweenA. carduorumandA. cirsicolausing morphometric analyses, hybridization experiments, and DNA fingerprinting using random amplified polymorphic DNA (RAPD) analysis. Discriminant function analyses indicate thatA. carduorumandA. cirsicolacannot be reliably distinguished by their morphologies, and interspecific matings produce fertile F₁offspring. However, because interspecific matings produce significantly fewer offspring than intraspecific matings, and because of clear differences in their DNA profiles, we conclude thatA. carduorumandA. cirsicolaare separate species. This study serves to highlight the value of genetic analyses in taxonomic studies and their role in biological control programs.     

Classical Biological Control of Nodding and Plumeless Thistles

Nodding (musk) thistle (Carduus thoermeri Weinmann in the Carduus nutans L. group) and plumeless thistle (Carduus acanthoides L.) are introduced noxious weeds of Eurasian origin. Both weeds are problematic in pastures, rangelands, and croplands and along state highways in many parts of the United States. The success of both species of thistles is largely due to their prolific seed production, seed longevity, competitive ability, and lack of natural enemies. Classical biological control of nodding thistle in Virginia has been achieved with three exotic thistle herbivores, Rhinocyllus conicus Froelich (Coleoptera: Curculionidae), Trichosirocalus horridus (Panzer) (Coleoptera: Curculionidae), and Cassida rubiginosa Müller (Coleoptera: Chrysomelidae). T. horridus also effectively controls plumeless thistle. These insect herbivores complement each other. Nodding thistle biological control is achieved in about 5–6 years in Virginia, Missouri, and Montana. In addition, a rust fungus (Puccinia carduorum Jacky) (Uredinales: Pucciniaceae) has been introduced and established for control of nodding thistle in Virginia. Development and reproduction of the three thistle herbivores are not adversely affected by the rust. The rust hastens plant senescence and reduces seed production. Control of plumeless thistle with R. conicus and T. horridus takes approximately twice as long as control of nodding thistle.     

Field assessment in land of origin of host specificity,infestation rate and impact of <Emphasis Type="Italic">Ceratapion basicorne</Emphasis> a prospective biological control agent of yellow starthistle

Yellow starthistle, Centaurea solstitialis (Asteraceae), is an important invasive alien weed in the western United States. Currently established biological control agents attack only the capitula (flowerheads), and are not effectively controlling the plant in much of its range. The geographic center of diversity for the plant appears to be in Turkey, but no agents have been introduced from this country. Ceratapion basicorne (Coleoptera: Apionidae) is common in Central Turkey, attacking 25–100% of yellow starthistle plants. In a field experiment, Ceratapion spp. attacked 90% of yellow starthistle plants and 88% of milk thistle plants (Silybum marianum) but not seven other plant species, including artichoke and safflower. We suspect that a different species of insect attacked milk thistle, but they emerged before the plants were sampled. Laboratory tests showed that C. basicorne does not oviposit in milk thistle. Ceratapion basicorne appears to be more host specific than was suggested by previous studies of a population in Italy (Clement etal. 1989. Ann. Entomol. Soc. Am. 82: 741–747). The insect is gregarious, and the number of larvae per plant was positively correlated to root diameter. The level of damage to individual plants was positively correlated to the proportion of plants attacked, indicating aggregation both among plants and within plants. Field data did not show any impact of the insect on plant size or number of capitula, but germination rate of seeds produced by infested plants was 15% lower than for uninfested plants at two of three sites studied.     

Evaluation of Puccinia carduorum for biological control of Carduus pycnocephalus in Tunisia

Puccinia carduorum, a rust fungus from Italian thistle in Tunisia, was most aggressive on young growth stages of the weed in greenhouse tests. Repeated inoculations with the fungus significantly reduced weed biomass. Host-range tests suggest the fungus may be a safe biological control agent of Italian thistle in Tunisia.     

First documentation of adult Trichosirocalus horridus on several non-target native Cirsium species in Tennessee

Releases of Trichosirocalus horridus (Panzer) (Coleoptera: Curculionidae), native to Europe, began in Tennessee in 1989 as part of a biological control program against musk thistle (Carduus nutans L.). In surveys conducted to investigate non-target feeding of T. horridus on native Cirsium thistle species from 2005 to 2008, adults of T. horridus were observed on all five native Cirsium thistles. These adult occurrences are the first documentation of T. horridus occurring on three of these native species [C. carolinianum (Walt.) Fern & Schub., C. horridulum Michx. and C. muticum Michx.], and the first record of T. horridus occurring in the Great Smoky Mountains National Park. While C. carolinianum and C. horridulum did not show symptoms of larval feeding in the meristematic tissues, C. altissimum, C. discolor, and C. muticum all had damaged meristems and possible oviposition scars on the midribs of the leaves. However, the impact of feeding by larvae of T. horridus on the reproductive potential of native plants is uncertain, because even in the target species (musk thistle and other introduced Cirsium species) plant death only sometimes occurs, and seed production continues.     

The potential of Ulocladium botrytis for biological control of Orobanche spp.

A strain of Ulocladium botrytis isolated from diseased Orobanche crenata shoots caused disease on the parasitic weed in pathogenicity tests. The potential of the fungus to be developed as a mycoherbicide for Orobanche spp. was further investigated. Although the fungus significantly decreased O. crenata germination in vitro by 80%, it did not generally lead to a decreased number of O. crenata shoots or tubercles in inoculated root chambers or pots. However, the number of diseased or dead tubercles and underground shoots was significantly increased compared to the noninoculated treatments. Postemergence inoculation of O. crenata shoots with a conidial suspension resulted in the death of almost all inoculated plants 14 days after application under greenhouse conditions. In preliminary host-range studies, the pathogen caused disease on Orobanche cumana on sunflower whereas on Orobanche aegyptiaca shoots parasitizing tomato only minimal disease symptoms could be detected after postemergence inoculation. Based on the results of our investigations, we conclude that Ulocladium botrytis has only a limited potential to be used as a biocontrol agent against Orobanche spp.     

Variable correspondence of female host preference and larval performance in a phytophagous ladybird beetle Epilachna pustulosa (Coleoptera: Coccinellidae)

Genetic and environmental factors causing intraspecific variation of the thistle Cirsium kamtschaticum Ledeb. as a host plant of the phytophagous ladybird Epilachna pustulosa Kôno were investigated through simple food-choice tests and rearing of larvae. Two thistle clones (T1U₁ and T4H₂) were used, originally growing approximately 12 km apart. A previous study showed that adult female ladybirds preferred T1U₁ to T4H₂, and that larval performance was better on T1U₁, when leaves from the clones in situ were examined. The two clones retained their characteristics with respect to beetle preference after transplantation into a common garden. However, the difference between T1U₁ and T4H₂ with respect to larval performance was reduced after the transplantation. When leaves from shoots of T1U₁ exposed to different sunlight intensities were offered, adult female ladybirds did not show obvious preferences. Larval eclosion rates increased significantly with the increase in leaf sunlight intensity exposure. These results suggest strongly that both genetic and environmental factors are involved in interclonal variation of thistle quality in beetle preference and/or performance. It is suggested that the quality of thistle leaves for larval performance is largely affected by environmental factors, while leaf quality for beetle preference may be determined strictly by genetic factors. Under certain conditions, E. pustulosa females may behave maladaptively, preferring plants not appropriate for larval growth, or not choosing plants appropriate for the larval growth.     

迁地保育林麝体况及影响因素

通过建立基于外貌性状的量化性体况评分标准,于2012年7—10月间对四川马尔康麝场的586头圈养林麝(雌麝299头,雄麝287头)进行了体况评分,并分析了相关变量对林麝体况得分的效应,结果表明:马尔康麝场圈养林麝的体况评分均值为3.49(±0.02,n=586),大部分林麝(59.56%,n=349)的体况评分高于均值。雌麝体况评分均值(3.50±0.02,n=299)略高于雄麝(3.49±0.03,n=287)(P0.05),成体麝体况评分(3.59±0.02,n=291)极显著地高于老龄林麝(3.38±0.09,n=27)和亚成林麝(3.35±0.03,n=184)(P0.01)。林麝的体况得分与其年龄相关不显著(r=0.07,P0.05),但亚成体及成体麝的体况评分与其年龄间的相关极显著(亚成体r=0.19,P0.01;成体r=-0.16,P0.01),而老龄麝体况评分与其年龄略呈负相关(r=-0.23,P0.05)。S模型y=e1.2811-0.0885/a(R2=0.051,df=500,F=26.74,P0.01)可近似拟合林麝体况得分和年龄的关系。此外,马尔康麝场泥地基底的改装圈舍中的林麝体况(3.52±0.03,n=197)显著优于原装青砖圈舍林麝评分(3.47±0.02,n=389)(P0.05)。     

Individual variation in two host plants of the ladybird beetle,Epilachna pustulosa (Coleoptera: Coccinellidae)

Individual variation in two species of host plants (thistle,Cirsium kamtschaticum, and blue cohosh,Caulophyllum robustum) of the herbivorous ladybird beetleEpilachna pustulosa was examined under laboratory conditions for their acceptability to adult beetles as a food resource, for adult preference and for larval performance. When clones of these plants were subjected to non-choice tests using posthibernating female beetles, there was found to be significant intraspecific variation among clones in terms of their acceptability, but interspecific variation was not detected. Significant intraspecific as well as interspecific variation were frequently detected in the two host plants when clones of these plants were subjected to choice tests using posthibernating female beetles; the magnitude of interspecific plant variation for beetle preference is not necessarily larger than that of intraspecific plant variation. Individual variation across plant species with respect to beetle larval performance was also significant. A positive correlation between adult preference and larval performance is suggested across the two taxonomically remote host plant species, thistle and blue cohosh, although this needs further investigation.     

Observations on the biology and host specificity ofEpiblema strenuana [Lepidoptera,Tortricidae], a potential biocontrol agent forParthenium hysterophorus [Compositae]

The tortricid mothEpiblema strenuana (Walker), which attacksAmbrosia spp. over most of North America, is shown to have the annual weedParthenium hysterophorus L. [Compositae] as its main host in northern Mexico. The larvae produce galls in the stems and growing-points which can considerably stunt growth when young plants are attacked. In tests it was shown to have a restricted host-range and not to damage any composite of economic importance. Its release in Australia for trial as a biological control agent againstP. hysterophorus has been approved.      

陕西凤县驯养林麝的种群动态、性比和年龄结构

林麝是濒危资源动物,林麝驯养是保育濒危林麝资源及可持续利用麝香的有效方式。基于对2001至2012年间的陕西凤县林麝驯养的监测和调查,分析了其种群动态、性比和年龄结构。结果表明,陕西凤县的林麝驯养在近10余年获得了快速发展,全县共有150余个麝场,麝场数呈指数式增长,增长率达27.33%,但其平均驯养规模无明显增长,平均存栏种群仅为16.38头。凤县的驯养麝种群总体增长近似指数式增长,增长率达27.22%,目前存栏种群已达3712头。区分性别和年龄,各亚群的增长均呈指数式增长,幼年麝的增长率(30.30%)高于成年麝(27.16%),雄麝的增长率(28.30%)高于雌麝(27.78%)。在2001至2012年间,幼麝种群的雌雄性比((102.64±3.15)%,n=12)和成年麝种群的雌雄性比((100.85±2.585)%,n=10)均显著偏雌(P0.01),但幼麝、成年麝种群间的性比差异不显著(P0.05)。在2005年及2010—2012年间,幼麝(0.5岁龄)占种群的比例为31.91%,亚成体麝(1.5岁龄)占种群的比例为21.11%,成麝(2.5—12.5岁龄)比例为42.72%,老年麝(13.5岁龄及以上)仅占种群的4.26%。合并年龄分析,育龄前个体(幼麝和亚成体麝)的平均比例为53.02%,表明凤县驯养林麝属快速增长种群,其增长潜力较大。在林麝驯养实践中,管理部门可制定准入制度或适当重组现有麝场,促进较大的驯养种群构建,并建立通畅的麝香交易渠道,控制林麝种源的过热交易,以利于林麝驯养种群的性比平衡及可持续的繁育、增长。     

Evaluation of the predatory mite <Emphasis Type="Italic">Phytoseiulus macropilis</Emphasis> (Acari: Phytoseiidae) as a biological control agent of the two-spotted spider mite on strawberry plants under greenhouse conditions

The predatory mite Phytoseiulus macropilis is a potential biological control agent of the two-spotted spider mite (TSSM) Tetranychus urticae on strawberry plants. Its ability to control TSSM was recently assessed under laboratory conditions, but its ability to locate and control TSSM under greenhouse conditions has not been tested so far. We evaluated whether P. macropilis is able to control TSSM on strawberry plants and to locate strawberry plants infested with TSSM under greenhouse conditions. Additionally, we tested, in an olfactometer, whether odours play a role in prey-finding by P. macropilis. The predatory mite P. macropilis required about 20 days to achive reduction of the TSSM population on strawberry plants initially infested with 100 TSSM females per plant. TSSM-infested plants attract an average of 27.5 ± 1.0% of the predators recaptured per plant and uninfested plants attracted only 5.8 ± 1.0% per plant. The predatory mites were able to suppress TSSM populations on a single strawberry plant and were able to use odours from TSSM-infested strawberry plants to locate prey in both olfactometer and arena experiments. Hence, it is concluded that P. macropilis can locate and reduce TSSM population on strawberry plants under greenhouse conditions.     

Biological control of bacterial wilt caused by Pseudomonas solanacearum in India with antagonistic bacteria

From among 125 strains of fluorescent and 52 strains of nonfluorescent bacteria initially screened in the laboratory for their antibiosis towards the bacterial wilt pathogen, Pseudomonas solanacearum, strain Pfcp of Pseudomonas fluorescens and strains B33 and B36 of Bacillus spp., were chosen and evaluated further in greenhouse and field tests. Pfcp treated banana (Musa balbisiana), eggplant and tomato plants were protected from wilt upto 50, 61 and 95% in greenhouse and upto 50, 49 and 36% respectively in field. Protection afforded by the Bacillus strains was lower. In bacteria-treated plants which were subsequently inoculated with P. solanacearum plant height and biomass values increased and were close to those of nontreated and noninoculated control plants.     

Establishment of papaya banker plant system for parasitoid, Encarsia sophia (Hymenoptera: Aphilidae) against Bemisia tabaci (Hemiptera: Aleyrodidae) in greenhouse tomato production

The silverleaf whitefly, Bemisia tabaci biotype B (Gennadius) (Hemiptera: Aleyrodidae), is a key pest of tomato (Solanum lycopersicum L.) and other vegetable crops worldwide. To combat this pest, a non-crop banker plant system was evaluated that employs a parasitoid, Encarsia sophia (Girault & Dodd) (Hymenoptera: Aphelinidae) with whitefly, Trialeurodes variabilis (Quaintance) (Hemiptera: Aleyrodidae), as an alternative host for rearing and dispersal of the parasitoid to the target pest. (a) Multi-choice and no-choice greenhouse experiments were conducted to determine host specificity of T. variabilis to papaya (Carica papaya L.) and three vegetable crops including tomato, green bean (Phaseolus vulgaris L.), and cabbage (Brassica oleracea L.). The result showed that papaya was an excellent non-crop banker plant for supporting the non-pest alternative host, T. variabilis, whose adults had a strong specificity to papaya plants for feeding and oviposition in both multi-choice and no-choice tests. (b) The dispersal ability of E. sophia was investigated from papaya banker plants to tomato and green bean plants infested with B. tabaci, as well as to papaya control plants infested with T. variabilis; and (c) the percent parasitism by E. sophia on T. variabilis reared on papaya plants and on B. tabaci infested on tomato plants was also evaluated. These data proved that E. sophia was able to disperse at least 14.5 m away from papaya plants to target tomato, bean or papaya control plants within 48–96 h. Furthermore, E. sophia was a strong parasitoid of both T. variabilis and B. tabaci. There was no significant difference in percent parasitism by E. sophia on T. variabilis (36.2–47.4%) infested on papaya plants or B. tabaci (29–45.9%) on tomato plants. Thus, a novel banker plant system for the potential management of B. tabaci was established using papaya as a non-crop banker plant to support a non-pest alternative host, T. variabilis for maintaining the parasitoid to control B. tabaci. The established banker plant system should provide growers with a new option for long-term control of B. tabaci in greenhouse vegetable production. Ongoing studies on the papaya banker plant system are being performed in commercial greenhouses.     

圈养林麝粪样类固醇激素水平与麝香分泌的关系

基于非损伤取样和放射免疫法（RIA）,于2018年9月1日-10月15日期间对四川马尔康林麝繁育场的36头雄性圈养林麝（Moschus berezovskii）的粪样类固醇激素水平进行了检测,结合麝香分泌数据采集,探究了林麝的粪样睾酮和皮质醇水平与其麝香分泌的关系,结果表明：四川马尔康圈养林麝的麝香分泌（12.53±0.76）g（n=36）与粪样睾酮水平（106.03±12.34）ng/g（n=36）呈显著正相关（r=0.436,P < 0.01）,泌香较多雄麝（16.50±0.61）g（n=17）的睾酮水平（141.51±21.86）ng/g（n=17）显著地高于泌香较少（8.98±0.59）g（n=19）雄麝（74.27±7.93）ng/g（n=19）（t=-3.252,df=34, P < 0.01）,方程y=0.021x+10.270（R²=0.120,P < 0.05）可较好地拟合二者间关系。麝香分泌与皮质醇浓度（47.49±1.53）ng/g（n=36）相关不显著（r=0.078,P > 0.05）,泌香较多雄麝的皮质醇浓度（48.98±2.28）ng/g（n=17）略高于泌香较少雄麝（46.17±2.14）ng/g（n=19）,差异不显著（P > 0.05）,方程y=0.038x+10.730（R²=0.023,P > 0.05）可近似拟合皮质醇与泌香量间的关系。此外,雄麝睾酮水平对泌香量有显著影响（P < 0.05）,睾酮水平较高林麝泌香量（14.97±1.17）g（n=12）显著高于睾酮水平较低个体的泌香量（11.32±0.90）g（n=24）（F=4.79,P < 0.05）,而睾酮、皮质醇和年龄对麝香分泌的综合效应及变量间的交互作用均不显著（P > 0.05）。研究确定了圈养林麝粪样睾酮和皮质醇水平与麝香分泌量间的关系,可用于麝类驯养实践的麝香产量预测及品系选育。     

Evolution of male sterility mechanisms in gynodioecious and dioecious species ofCirsium (Cynareae,Compositae)

The genusCirsium comprises both gynodioecious and dioecious species. The observation of microsporogenesis in female plants ofC. montanum, C. oleraceum, C. palustre andC. spinosissimum shows that the male sterility is due to a degeneration of the tapetum. This degeneration occurs more or less early according to the species and, in the light of these results, a scheme of evolution in the male sterility mechanism is proposed. Furthermore, the male sterility mechanism inC. montanum is very similar to that previously found in female plants of the dioecious speciesC. arvense. This fact enhances the possibility of evolution of the dioecy ofC. arvense from the gynodioecy found in other species. According to these results, a general scheme of evolution of sexes in the genusCirsium is proposed.     

Categories of vesicular-arbuscular mycorrhizal dependency of host species

Summary Brassica nigra and selected species of Leucaena and Sesbania were used as indicator hosts in a greenhouse experiment designed to establish distinct categories of mycorrhizal dependence. The plants were grown in an oxisol with different concentrations of established soil solution P in the presence or absence of the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus aggregatum. The extent to which the plant species depended on the fungus for dry matter production diminished with increased concentrations of soil solution P, but the magnitude of this decrease varied from species to species. Five distinct mycorrhizal categories are proposed based on the differences observed, ranging from non-dependent to very highly dependent. The critical soil solution P concentrations that were useful for separating host species into distinct VAM-dependency groups were 0.02 and 0.2 mg/l. Species differing in their mycorrhizal dependency differed with respect to the soil solution P concentration required for the expression of maximum VAM effectiveness, the degree to which increasing concentrations of P depressed VAM infection and the pattern of immobile nutrient accumulation.Contribution from the Hawaii Institute of Tropical Agriculture and Human Resources Journal Series No. 3547     

Supplementary host specificity testing of the sawfly <Emphasis Type="Italic">Heteroperryia hubrichi</Emphasis>, a candidate for classical biological control of Brazilian peppertree, <Emphasis Type="Italic">Schinus terebinthifolius</Emphasis>, in the USA

Supplementary host specificity tests were conducted with the defoliating sawfly Heteroperreyia hubrichi (Hymenoptera: Pergidae), a candidate for classical biological control of Brazilian peppertree, Schinus terebinthifolius (Sapindales: Anacardiaceae), in the United States. These tests were conducted as part of the environmental assessment required by the National Environmental Policy Act (NEPA). The suitability of the federally listed endangered native plant Rhus michauxii (Anacardiaceae) and the economically important Litchi chinensis (Sapindaceae) as potential host plants for H. hubrichi was evaluated in a series of no-choice larval development tests conducted in a Florida quarantine laboratory. Neonate larvae transferred to individual test plants failed to develop to the pupal stage on R. michauxii or L. sinensis, whereas Brazilian peppertree supported development of the sawfly to pupation. The results of the additional host specificity tests indicated these critical non-target plants are not at risk from attack by H. hubrichi if it were released in Florida, USA.