Thermal tolerance and potential distribution of Carvalhotingis visenda (Hemiptera: Tingidae), a biological control agent for cat's claw creeper, Macfadyena unguis-cati (Bignoniaceae)

Development of cat’s claw creeper leaf-tying moth Hypocosmia pyrochroma (Lepidoptera: Pyralidae) at different temperatures: Implications for establishment as a biological control agent in Australia and South Africa

Cat's claw creeper, Dolichandra unguis‐cati (Bignoniaceae), a perennial woody vine native to tropical America, is a target for biological control in Australia and South Africa. The cat's claw creeper leaf‐tying moth Hypocosmia pyrochroma (Lepidoptera: Pyralidae) from tropical South America was released as a biological control agent for cat's claw creeper in Australia from 2007 to 2010. A total of 2,277 adults, 837 pupae and 77,250 larvae were released at 40 sites in Queensland and New South Wales. Releases were made mostly in open fields (85%), and at limited sites (15%) in insect‐proof cages erected over naturally occurring cat's claw creeper infestations in the field. Sampling was conducted annually in spring and autumn to monitor the establishment and dispersal of H. pyrochroma. Establishment of H. pyrochroma was first noticed in 2012 at three release sites and since then the number of established sites has increased to 80 in 2020. Establishment was evident on both ‘short‐pod’ and ‘long‐pod’ forms of cat's claw creeper and was more widespread in sites where releases were made within insect‐proof field cages (50%) than in sites with open field releases (9%). The moth was active from late spring to late autumn with peak larval activity in late summer. To date, all field establishments have been in areas predicted by a CLIMEX model as climatically suitable but restricted mostly to riparian environment (93% of establishment), where the moth has continued to spread from 1.5 to 23 km from release sites. In contrast, there is the only limited establishment and spread in non‐riparian corridors, highlighting the role of microclimate (riparian) as a limiting factor for establishment and spread. Future efforts will focus on redistribution of the agent to river/creek systems where the moth is currently not present.

Abstract: Cat's claw creeper, Macfadyena unguis‐cati, a major environmental weed in coastal and sub‐coastal areas of Queensland and New South Wales, Australia is a target for classical biological control. Host specificity of Hypocosmia pyrochroma Jones (Lep., Pyralidae), as a potential biological control agent was evaluated on the basis of no‐choice and choice larval feeding and survival, and adult oviposition preference tests, involving 38 plant species in 10 families. In no‐choice tests, larval feeding and development occurred only on cat's claw creeper. In choice tests, oviposition and larval development was evident only on cat's claw creeper. The results support the host‐specificity tests conducted in South Africa, and suggest that H. pyrochroma is a highly specific biological control agent that does not pose any risk to non‐target plants tested in Australia. This agent has been approved for field release by relevant regulatory authorities in Australia.

Cat's claw creeper, Macfadyena unguis-cati (L.) Gentry (Bignoniaceae), introduced as an ornamental plant, has invaded several ecologically sensitive habitats in the higher rainfall regions of South Africa. Biological control was initiated with the release of the leaf-feeding tortoise beetle Charidotis auroguttata (Boheman) (Coleoptera: Chrysomelidae) in 1999. Although established at several field sites, population densities of the beetle have remained low with no assessment of impact to date. However, simulated herbivory studies in Australia revealed that severe and repeated defoliations could slow the weed's growth rate and its accumulation of biomass in the subterranean tubers. The aim of this study was to quantify the impact of medium (50 %) and high-intensity (100 %) defoliations by C. auroguttata, in relation to equivalent simulated damage, on the growth and biomass accumulation of M. unguis-cati. The trials were monitored for 16 weeks with repeated defoliations at two-week intervals. Despite considerable variation in the response variables, plants that were defoliated by C. auroguttata, but not those defoliated mechanically, displayed reduced growth rates. However, significant decreases in stem length and numbers of nodes were demonstrated only after high-intensity beetle defoliations. Despite reductions in tuber biomass in the beetle-defoliated treatments, the differences were not significant, while only high-intensity beetle defoliations caused a significantly lower accumulation of total plant biomass. Simulated herbivory was a poor predictor of insect damage in this study which suggested that C. auroguttata could prove damaging to M. unguis-cati, but only at high population densities. However, in field situations, synergism with a range of additional environmental stressors may increase the negative impact of feeding damage.

Introduced as an ornamental vine, cat’s claw creeper Dolichandra unguis-cati (syn. Macfadyena unguis-cati) has invaded coastal and subcoastal areas of subtropical eastern Australia. Two varieties have been indentified, one of which (‘short-pod’) is found throughout south-eastern Australia, while the other (‘long-pod’) appears to be restricted to several sites in south-eastern Queensland. We compared the growth and biomass allocation patterns of the two varieties in the field over a 22-month period to determine if a higher growth rate and/or more efficient allocation of biomass may contribute to this disparity in distribution. The long-pod variety produced greater aboveground and total biomass than the short-pod variety in both riparian and non-riparian zones. Belowground the two varieties produced a similar number of tubers and overall biomass, though the long-pod variety allocated a smaller portion of its carbon belowground. High growth rates and greater biomass allocation aboveground are characteristic of invasive species, allowing them to outcompete and crowd out existing vegetation. There was no significant site by variety interaction, an indication of consistency in variety performance across riparian and non-riparian sites. Results from our study suggest that differences in growth and biomass allocations are unlikely to have contributed to the disparity in distribution of the two varieties. Despite currently occupying a relatively small range, the long-pod variety may be a more adept invader than the short-pod variety, and could become more prevalent in the future.

Specificity of Carvalhotingis visenda (Hemiptera: Tingidae) as a biological control agent for cat’s claw creeper Macfadyena unguis-cati (Bignoniaceae) in Australia

The exotic vine Macfadyena unguis-cati (L.) A.H.Gentry (Bignoniaceae), cat's claw creeper, has become a significant threat to the biodiversity of a variety of sensitive ecosystems in South Africa. Owing to the nature of the infestations, as well as the difficulties and prohibitive costs associated with both mechanical and chemical controls, biological control is considered to be the most practical and sustainable means of successfully managing the weed in South Africa. The biological control programme against M. unguis-cati was initiated in 1996 and resulted in the release of Charidotis auroguttata Boheman (Coleoptera: Chrysomelidae: Cassidinae). Despite repeated releases, initial rates of establishment were low. Where successfully established, populations of the beetle have been slow to build-up, leading to only limited impact on the weed. Prompted by this lack of success, as well as the high potential for further spread of the weed, additional natural enemies were sought. Two lace bugs, Carvalhotingis visenda Drake & Hambleton, and Carvalhotingis hollandi Drake (Hemiptera: Tingidae), a leaf-mining beetle Hylaeogena (Hedwigiella) jureceki Obenberger (Coleoptera: Buprestidae), a leaf-tying moth Hypocosmia pyrochroma Jones (Lepidoptera: Pyralidae) and a seed-feeding weevil Apteromechus notatus (Hustache) (Coleoptera: Curculionidae) were subsequently imported into quarantine in South Africa for host-specificity testing. With the exception of A. notatus, all have been approved for release and are exhibiting promising initial rates of establishment and damage at a number of field localities. Impact studies have shown that cat's claw creeper is susceptible to sustained herbivore pressure.

Previous articleNext article No AccessNotes and CommentsIs Interspecific Variation in Relative Growth Rate Positively Correlated with Biomass Allocation to the Leaves?Hendrik Poorter, and Hans LambersHendrik Poorter Search for more articles by this author , and Hans Lambers Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 138, Number 5Nov., 1991 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/285282 Views: 5Total views on this site Citations: 24Citations are reported from Crossref Copyright 1991 The University of ChicagoPDF download Crossref reports the following articles citing this article:Gabriela Woźniak, Damian Chmura, Marcin K. Dyderski, Agnieszka Błońska, Andrzej M. Jagodziński How different is the forest on post-coal mine heap regarded as novel ecosystem?, Forest Ecology and Management 515 (Jul 2022): 120205.https://doi.org/10.1016/j.foreco.2022.120205Maria Amélia Martins-Loução, Teresa Dias, Cristina Cruz Integrating Ecological Principles for Addressing Plant Production Security and Move beyond the Dichotomy ‘Good or Bad’ for Nitrogen Inputs Choice, Agronomy 12, no.77 (Jul 2022): 1632.https://doi.org/10.3390/agronomy12071632Maria Pepe, Loretta Gratani, Maria Fiore Crescente, Giacomo Puglielli, Laura Varone Daily Temperature Effect on Seedling Growth Dynamic of Three Invasive Alien Species, Frontiers in Plant Science 13 (Mar 2022).https://doi.org/10.3389/fpls.2022.837449Prakash Bhattarai, Zhoutao Zheng, Kuber Prasad Bhatta, Yagya Prasad Adhikari, Yangjian Zhang Climate-Driven Plant Response and Resilience on the Tibetan Plateau in Space and Time: A Review, Plants 10, no.33 (Mar 2021): 480.https://doi.org/10.3390/plants10030480Vanessa Buzzard, Sean T. 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Climatic-requirements models of cat’s claw creeper Macfadyena unguis-cati (Bignoniaceae) to prioritise areas for exploration and release of biological control agents

Cat's claw creeper (Dolichandra unguis‐cati), native to tropical South America, is a major invasive species and a target for biological control in Australia, South Africa and some South Pacific Island countries. Native range surveys in Argentina, Brazil, Paraguay and Venezuela have identified eight insects and four fungal pathogens as potential agents. Five leaf‐feeding insects a tortoise beetle Charidotis auroguttata, two tingids Carvalhotingis visenda and C. hollandi, a leaf‐tying moth Hypocosmia pyrochroma and a leaf‐mining beetle Hedwigiella jureceki, have been tested and all were released in South Africa. Four of these have become established but are not widespread and cause only limited damage. In Australia, only three of these, C. visenda, H. pyrochroma and H. jureceki were released, while C. auroguttata was not approved due to perceived non‐target risks. All agents have become widely established, except for H. pyrochroma which is restricted to riparian corridors in southeast Queensland. In South Africa, an accidentally introduced leaf‐spot pathogen, Neoramulariopsis unguis‐cati, causes necrotic lesions and premature abscission of leaves in cat's claw creeper infestations, resulting in widespread defoliation. Based on its impact and field‐host specificity in its native range and in South Africa, the pathogen has been prioritised for evaluation as a potential additional agent in Australia. The current priority is to seek approval for the introduction of this leaf‐spot pathogen into Australia. Future research should focus on the gall‐inducing rust Uropyxis rickiana and the seed‐feeding weevil Apteromechus notatus as prospective agents.

The province of Misiones is characterized by its great plant diversity and the use of medicinal plants is common, 80% of its boundaries are international, it borders the Republic of Paraguay to the west and the Republic of Brazil to the north and to the east, in both is also traditional the use of medicinal plants. Where in most cases they are marketed without previous toxicity studies. Dolichandra unguis-cati (Bignoniaceae) a species commonly known as "cat's claw", used in folk medicine to treat multiple conditions. The objective of this work is to analyze the genotoxic effects of aqueous extracts obtained from infusions of leaves and stems of D. unguis-cati using the Allium cepa test. The concentrations studied inhibited the growth of the roots, decreased the mitotic index with respect to a control and did not produce relevant genotoxic effects.

The invasive liana cat’s claw creeper Dolichandra unguis-cati (L.) L.G. Lohmann (syn. Macfadyena unguis-cati (L.) A.H. Gentry) exhibits intraspecific variation in leaf morphology, but this is rarely noted in the published literature. The present study documents variation in leaf morphology in two forms of the species that occur in Australia (long pod and short pod). Leaf morphology is compared between the two forms and the position of the shoots (trunk and ground) at the only two sites in which they co-occur. Leaves were categorised on the basis of leaflet number and the presence or absence of tendrils. Simple leaves were produced mainly on shoots growing along the ground and were more abundant in the short-pod form. Long-pod plants were dominated by bifoliate leaves with tendrils. Cat’s claw creeper exhibits considerably wider variation in leaf morphology than recorded previously. Variations in leaf morphology may be linked to differences in the genotype, developmental stage and plastic responses of the plants. Understanding these variations may have implications for taxonomic delimitation and improved management, particularly biological control involving leaf-feeding insects.

In classical weed biological control, assessing weed response to simulated herbivory is one option to assist in the prioritization of available agents and prediction of their potential efficacy. Previously reported simulated herbivory studies suggested that a specialist herbivore in the leaf-feeding guild is desirable as an effective biological control agent for cat's claw creeper Macfadyena unguis-cati (Bignoniaceae), an environmental weed that is currently a target for biological control. In this study, we tested (i) whether the results from glasshouse-based simulated herbivory can be used to prioritise potential biological control agents by evaluating the impact of a leaf-sucking tingid bug Carvalhotingis visenda (Drake & Hambleton) (Hemiptera: Tingidae) in quarantine; and (ii) the likely effectiveness of low- and high-densities of the leaf-sucking tingid after its release in the field. The results suggest that a single generation of C. visenda has the potential to reduce leaf chlorophyll content significantly, resulting in reduced plant height and leaf biomass. However, the impact of one generation of tingid herbivory on below-ground plant components, including the roots and tuber size and biomass, were not significant. These findings are consistent with results obtained from a simulated herbivory trial, highlighting the potential role of simulated herbivory studies in agent prioritisation.

The impact assessment of a weed biocontrol agent offers insight into the potential of the agent and weed responses in long‐term weed management. The impact of the jewel beetle Hedwigiella jureceki Obenberger (Coleoptera: Buprestidae) and its first‐generation larvae on the long‐pod (LP) and short‐pod (SP) forms of cat's claw creeper, Dolichandra unguis‐cati (L.) L.G. Lohmann (Bignoniaceae) was studied by initiating one, two, or five pairs (male and female) of adults in a glasshouse experiment. With the higher density of adults, the number of leaves increased significantly, as did the numbers of dead leaves and larval mines, and the percentages of affected leaves (up to 40%), and damaged leaf areas (up to 60%). Plants with the five pairs of adults had fewer leaves and reduced dry weights (e.g., tuber biomass was reduced by 50.4–62.5%). Regardless of adult density, the dry weights of the leaves and tubers were lower in the SP form. Conversely, the LP form had fewer leaves (ca. 17% fewer) and slower shoot growth (mean ± SE = 46.3 ± 2.6 cm per week) than the SP form (66.5 ± 3.8 cm per week). However, the number of tubers was not affected by the plant form and adult density. Larval mines (262 ± 30), pupae (186 ± 17), and adults (144 ± 14) in LP form were higher than in SP form (243 ± 20, 167 ± 14, and 115 ± 11, respectively). Likewise, the average weight of adults that emerged on the LP form was higher. Therefore, H. jureceki impacted both LP and SP forms. The SP form showed a higher impact in terms of reduced tuber growth, and the LP form is anticipated to be harmed more in the long term as a higher number of H. jureceki offspring developed on it when competition for food was increased.

ABSTRACTThe increased extreme warm and decreased extreme cold temperature events across the Arctic strongly influence the natural environment as well as the societal activities. This study investigates temporal and spatial variability of wintertime extreme high and low temperature events defined by the 95 and 5% percentiles across the Arctic and subarctic regions, respectively (north of 60°N) using data from 238 stations in the Global Summary of the Day for the period 1979–2016. Empirical orthogonal function analyses indicate that the first modes (which account for 30–35% of the total variance) are out‐of‐phase between northern Europe, western and central Russia, and northeastern North America, and that this appears to be related to the Arctic Oscillation (AO) and the Northern Atlantic Oscillation. The second modes explain about 8% of the total variance. During the positive phase of the first and second modes the anomalous northeasterly and northerly winds decrease Arctic extreme high and increase extreme low temperature occurrences; while the anomalous southerly and southwesterly winds have the opposite effect. Symmetric and asymmetric effects of the AO index on extreme temperature events refer to the difference and sum between the composite of its positive and negative phases. The symmetric components of the spatial patterns are similar to those of the first modes. The asymmetric components occur mainly over western and central Russia for extreme high and low temperatures, respectively. In addition the impacts of six other large‐scale climate modes are also explored.