Euwallacea validus

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Euwallacea validus
Bark Beetle (48377393046).jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Infraorder: Cucujiformia
Family: Curculionidae
Genus: Euwallacea
Species:
E. validus
Binomial name
Euwallacea validus
(Eichhoff, 1875)

Euwallacea validus is a species of Euwallacea beetle native to Asia. The beetle species was discovered in Long Island, New York in 1975. [1] Like other Euwallacea species beetles, E. validus is known for its mutualistic symbiotic relationship with fungi, acting as a vector for Fusarium oligoseptatum and Raffaelea subfusca, often using Tree of Heaven (Ailanthus altissima) as a preferred host. Out of the five confirmed species of Euwallacea spp. in the United States, E. validus is the most widespread and longest established, yet much about their second fungal partner, Raffaelea subfusca, is not known. [2]

Taxonomy

Euwallacea interjectus , the sister species of E. validus, are often identified as E. validus (and vice versa), given their almost identical appearance. [1] E. interjectus and E. validus were introduced to the United States around the same time in the late 1900s. [1] Both species have overlapping habitats in the United States, mostly in Georgia and South Carolina, leading to frequent misidentification. [1] The discovery of E. interjectus in Florida (2011) and Texas (2011), prompted investigation into E. validus. [1] E. interjectus infestation on their variety of plant hosts has a global impact because the plant hosts are critical to the lumber and the production of board products. [3]

Both species are morphologically similar, varying in slight manners. [1] Morphologically, E. interjectus and E. validus can be differentiated by slight differences in the shape of declivity, punctures, and placement of tubercles on the body of the species. [1] The two also vary by fungal association and host species. [1] With the help of DNA sequencing, proper identification between the two species has become easier. [1]

Description

Lateral and dorsal views of Euwallacea species. From top left, Euwallacea fornicatus, E. interjectus, E. similis and E. validus. Scale bar: 1.0 mm. Euwallacea (10.3897-zookeys.768.24697) Figure 11.jpg
Lateral and dorsal views of Euwallacea species. From top left, Euwallacea fornicatus, E. interjectus, E. similis and E. validus. Scale bar: 1.0 mm.

An adult E. validus can range from 3.9 to 4.1 mm in length, with an average of 4.0 mm. The species ranges in width from 2.5 to 2.73 mm. [4] Similar to E. interjectus, the beetles range from dark brown to black. [5] E. validus and the Euwallacea species are known for their pronotum, a plate-like structure that acts protection near the thorax, and spindles that cover a beetle's body. [1] Moreover, given that sexual dimorphism is present, males are significantly smaller than females. Females play a major role in the distribution of fungi, and males are reduced in size. [6] Females distribute the fungi in mycangia, a structure that enables the beetle to store fungi, which are present in females and rarely in males. [6]

Compared to E. interjectus, downward angle of the slope from base to apex of the beetle differs in E. validus. [1]

Fungus is carried in the mycangia and the head, and adult females harbor the fungus paired with pre-oral mycangia. [7] Mycangia, and other specialized organs, have been developed in E. valdius as an evolution of symbiosis with fungi. [7] It was discovered that the organization of the mycagnia is positioned between the eye and esophagus, rather than paired in front of the head. [7]

Distribution and habitat

Euwallacea validus originated from Asia, as a descendant of other Asian Ambrosia beetles. [1] The species can be primarily found in Asia. They are present in China, Malaysia, Myanmar, Vietnam, the Philippines, Japan, and Korea. [4] Moreover, the species expanded from Asia and was first observed in the United States in 1975. [4] Since then, the North American presence has been amplified. [1] The species has expanded to Canada and all over the United States. [5]

Presence in the United States of America

Euwallacea validus was first discovered in Nassau County, New York in 1975 and is assumed to have spread throughout the eastern United States, as the beetles were collected repeatedly from widely separated localities. [1] It is also believed that the species entered the United States from wooden packing crates from Japan at various ports. [1] Eventually these beetles moved south, being seen in Pennsylvania in 1980 and Louisiana in 1984. [1] [4]   The discovery of E. interjectus in Florida and Texas in 2011 was the catalyst for research in E. validus to understand the distribution of E. interjectus and E. validus properly. [1]

As of 2014, the distribution of this species includes Delaware, Maryland, New Jersey (1996), Pennsylvania, Virginia, and West Virginia (1991), North Carolina (2011), Kentucky (2012), Michigan (2006), Georgia (2012) and Tennessee (2010). [1] [8] [2] However, past habitat distribution in the South may not be accurate, given E. interjectus habit distribution, and additional research is needed to confirm E. validus distribution in the United States. [1]

Life cycle

Bark Beetle (48377538057).jpg

The Euwallacea validus life cycle has not been extensively studied, however, some research has provided insight into the life cycle and development process of the species. Euwallacea species reproduce via haplodiploid sibling mating. [9] In this type of mating, diploid fertilized eggs develop into female offspring. The unfertilized haploid eggs develop into the males of the colonies, after development, the males mate with siblings in the same gallery. [6]

Euwallacea validus females are critical in the symbiosis with F. oligoseptaum and Raffaelea subfusca by dispersing the fungi between host trees. [6] Given the role that females play as a vector, the species exhibits sexual dimorphism. [10]  Males are reduced in size, having smaller wings, mandibles, and are flightless. [10]  Given their reduced musculature, suggesting a similar reduction in chewing strength, their role in the gallery is reproduction and potential fungal maintenance. [10] [6]

Like other Euwallacea species, E. validus develops from a larva to the early pupa and then to the late pupa. [10] Sexual dimorphism can be seen in the early stages of pupa development. [10]  Research has shown the development of both superior mycangia and inferior structures in the late pupal stages of females. [10]

Diet

Ambrosia beetles typically use dead trees but occasionally use healthy trees as hosts to cultivate ambrosia fungi. [11] Female Euwallacea beetles transfer their fungal associates in their mandibular mycangia, from their natal gallery to hosts. [11] There they cultivate galleries as a food source, thus exemplifying a mutualistic symbiotic relationship. [12]

Relationship with fungi

Euwallacea validus has a mutualistic symbiotic relationship with fungi of the Ambrosia Fusarium clade (AFC). [2] As of 2018, only 3 of the 16 species within the Ambrosia Fusarium clade had been described formally. [7] [12] [11] Phylogenetic analysis of the Ambrosia Fusarium Clade and Euwallacea species found evidence of repeat host shifts rather than stretches of coevolution or mutualism. [13]

Similarities to Euwallacea fornicatus

Euwallacea species and their fungal associates are known to cause canker incidence and overall damage to their plant hosts. [2] E. interjectus host plants are crucial to the lumber industry, and E. Fornicatus elicits disease on avocado trees in California and Israel. [2]

Euwallacea validus cultivates two fungal symbionts in the U.S., an unnamed Fusarium species (AF-4) and Raffaelea subfusca. [2] E. Fornicatus fungal symbiont is similar to a fungus carried by E. fornicatus. [2] Because of the impact of E. fornicatus, more information on Fusarium sp. AF-4 and E. validus serves as valuable insight on the impact of Euwallacea beetles on the environment. [2] [14]

Fusarium species (AF-4) and Raffaelea subfusca

Research has revealed that neither Fusarium species AF-4 nor Raffealea symbionts caused significant disease on any host tested and do not appear to pose serious risks to the known hosts within the invaded range of this beetle. [2]

Euwallacea validus and its respective fungi associations show a unique relationship. [2] Compared to other Euwallacea species fidelity was observed in E. validus and Fusarium sp. AF-4 in South Korea and the United states with no indication that other members of AFC members that compete within the mycangial communites. [2] Other Euwallacea species beetles do not exhibit this obvious fidelity between native and invaded ranges. [2] Studies show that there is not an exclusive relationship with particular fungi. [2] Other known AFC lineages that are present in the US were uncovered from the mycangia of other Euwallacea species within the geographic origin of beetles in East Asia. [2]

Moreover, other FSSC isolates can be found in galleries of Euwalllacea species, indicating frequent interactions between symbiotic and asymbiotic FSSC members. [2] This relationship of widespread fungal infidelity among closely related Euwallacea beetles allows for novel beetle fungus combinations that can incite diseases amongst many orchard, landscapes, and forest trees. [2]

R. subfusca, E. validus's second symbiont, is unique to the species, and the fungus is found in equal proportion to Fusarium sp. AF-4 in the mycangia. [2] Other similar fungi have caused Japanese and Korean oak wilt, and laurel wilt. [2]

Hosts

Like most ambrosia beetles, the Euwallacea species, are not particularly selective when choosing a plant host.

Tree of Heaven (Ailanthus altissima) was found to be a preferred host and large-scale infestations have been observed in stands of Ailanthus infected with Verticillium wilt. [7] Of the seventeen confirmed native hosts, E. validus attacks were found to be more geographically widespread on several hosts including striped maple, red maple, tulip-poplar, and American beech. [2]

Some trees identified as hosts of E. validus, but not confirmed reproductive hosts. [2] Instead, they are perhaps overwintering spots for the adult female beetles as evidenced by the short non-branching hibernation. [2] When the spring season begins, beetles may emerge and find a suitable host to establish natal galleries. [2]  E. validus does so by creating bores into a tree. [2] The living tissues of a tree are then exposed to fungal symbionts. [2] It is possible for subsequent infection by another species, even if the tree species is not suitable as a host for reproduction. [2] Studies have shown that none of the fungi that E. valdius affiliates with are virulent pathogens, but the beetle can transmit pathogens from one tree to another. [2] [7]

Related Research Articles

Ambrosia beetles are beetles of the weevil subfamilies Scolytinae and Platypodinae, which live in nutritional symbiosis with ambrosia fungi. The beetles excavate tunnels in dead or stressed trees into which they introduce fungal gardens, their sole source of nutrition. After landing on a suitable tree, an ambrosia beetle excavates a tunnel in which it releases its fungal symbiont. The fungus penetrates the plant's xylem tissue, extracts nutrients from it, and concentrates the nutrients on and near the surface of the beetle gallery. Ambrosia fungi are typically poor wood degraders, and instead utilize less demanding nutrients. Symbiotic fungi produce and detoxify ethanol, which is an attractant for ambrosia beetles and likely prevents growth of antagonistic pathogens and selects for other beneficial symbionts. The majority of ambrosia beetles colonize xylem of recently dead trees, but some colonize stressed trees that are still alive, and a few species attack healthy trees. Species differ in their preference for different parts of trees, different stages of deterioration, and in the shape of their tunnels ("galleries"). However, the majority of ambrosia beetles are not specialized to any taxonomic group of hosts, unlike most phytophagous organisms including the closely related bark beetles. One species of ambrosia beetle, Austroplatypus incompertus exhibits eusociality, one of the few organisms outside of Hymenoptera and Isoptera to do so.

<span class="mw-page-title-main">Mycangium</span>

The term mycangium is used in biology for special structures on the body of an animal that are adapted for the transport of symbiotic fungi. This is seen in many xylophagous insects, which apparently derive much of their nutrition from the digestion of various fungi that are growing amidst the wood fibers. In some cases, as in ambrosia beetles, the fungi are the sole food, and the excavations in the wood are simply to make a suitable microenvironment for the fungus to grow. In other cases, wood tissue is the main food, and fungi weaken the defense response from the host plant.

<i>Xyleborus glabratus</i> Species of beetle

Xyleborus glabratus, the redbay ambrosia beetle, is a type of ambrosia beetle invasive in the United States. It has been documented as the primary vector of Raffaelea lauricola, the fungus that causes laurel wilt, a disease that can kill several North American tree species in the family Lauraceae, including redbay, sassafras, and avocado.

<i>Austroplatypus incompertus</i> Species of beetle

Austroplatypus incompertus, a type of ambrosia beetle, is endemic to Australia. They are found in the mesic forests, and subtropical and tropical ecosystems along the east coast of Australia. There are many unique characteristics attributable to the A. incompertus, like their gallery excavation in several Eucalyptus species, their obligate eusocial behavior, their relationship with fungi, and their unique sexual dimorphism. These beetles are one of the only insects that display obligate eusocial behavior. Additionally, their sexually dimorphic traits are of interest, since body size is reversed with males having smaller torsos than female a.incompertus beetles.

Ambrosiella is a genus of ambrosia fungi within the family Ceratocystidaceae. It was circumscribed by mycologists Josef Adolph von Arx and Grégoire L. Hennebert in 1965 with Ambrosiella xylebori designated as the type species. All Ambrosiella species are obligate symbionts of ambrosia beetles. Several former species were moved to genera Raffaelea, Hyalorhinocladiella, or Phialophoropsis, and there were nine species recognized 2017. Twelve species in as of 2023. One species, Ambrosiella cleistominuta, has been observed to produce a fertile sexual state with cleistothecious ascomata.

Raffaelea subfusca is a mycangial fungus, first isolated from female adults of the redbay ambrosia beetle, Xyleborus glabratus.

Raffaelea fusca is a mycangial fungus, first isolated from female adults of the redbay ambrosia beetle, Xyleborus glabratus.

Raffaelea ellipticospora is a mycangial fungus, first isolated from female adults of the redbay ambrosia beetle, Xyleborus glabratus.

Raffaelea subalba is a mycangial fungus, first isolated from female adults of the redbay ambrosia beetle, Xyleborus glabratus.

<i>Raffaelea</i> Genus of fungi

Raffaelea is a genus of ambrosia fungi in the family Ophiostomataceae. It was circumscribed by mycologists Josef Adolph von Arx and Grégoire L. Hennebert in 1965 with Raffaelea ambrosiae as the type species. The genus is named in honor of Italian botanist Raffaele Ciferri.

<i>Euwallacea fornicatus</i> Species of beetle

Euwallacea fornicatus, also known as tea shot-hole borer, or polyphagous shot-hole borer (PSHB) is a species complex consisting of multiple cryptic species of ambrosia beetles known as an invasive species in California, Israel, South Africa, and Australia. The species has also been unintentionally introduced into exotic greenhouses in several European countries.

<i>Xylosandrus compactus</i> Species of beetle

Xylosandrus compactus is a species of ambrosia beetle. Common names for this beetle include black twig borer, black coffee borer, black coffee twig borer and tea stem borer. The adult beetle is dark brown or black and inconspicuous; it bores into a twig of a host plant and lays its eggs, and the larvae create further tunnels through the plant tissues. These beetles are agricultural pests that damage the shoots of such crops as coffee, tea, cocoa and avocado.

<i>Xylosandrus germanus</i> Species of beetle

Xylosandrus germanus, known generally as the alnus ambrosia beetle or black stem borer, is a species of ambrosia beetle in the family Curculionidae. X. germanus poses challenges in woody ornamental species and orchard crops such as apples and pecan. Furthermore, X. germanus is recognized or suspected to act as a vector for plant pathogens to varying extents, potentially leading to the decline of trees. The black stem borer is native to eastern Asia, but is an invasive species in Europe and North America. This species carries and feeds on associated ambrosia fungus, Ambrosiella grosmanniae.

<i>Xyleborinus saxesenii</i> Species of beetle

Xyleborinus saxesenii, commonly known as the fruit-tree pinhole borer, is a species of ambrosia beetle in the family Curculionidae. It is native to the Palaearctic region but has been introduced in many locations, including North America. X. saxesenii typically live in freshly dead wood, but it has also been reported to attack live trees. Such attacks on live trees may lead to economic damage.

Platypus quercivorus, the oak ambrosia beetle, is a species of weevil and pest of broad-leaved trees. This species is most commonly known for vectoring the fungus responsible for excessive oak dieback in Japan since the 1980s. It is found in Japan, India, Indonesia, New Guinea, and Taiwan.

Euplatypus parallelus, previously known as Platypus parallelus, is a species of ambrosia beetle in the weevil family Curculionidae. The adults and larvae form galleries in various species of tree and logs. It is native to Central and South America but has spread globally, is present in Africa and is well established in tropical Asia.

<i>Euwallacea interjectus</i> Species of beetle

Euwallacea interjectus is a species of ambrosia beetle in the species complex called Euwallacea fornicatus. It is native to Asia but has been introduced to the Western hemisphere over the last century.

Euwallacea perbrevis, commonly known as tea shot-hole borer, is a species of weevil native to South and South-East Asia through to Australia, but introduced to Western countries.

Ambrosiella roeperi is the fungal symbiont of the granulate ambrosia beetle, Xylosandrus crassiusculus, facilitating this insect’s capacity to accumulate on and damage a diverse array of woody plants from around the world. It is one of several important nutritional partners derived from order Microascales that sustain and are transported by xylomycetophagous scolytine beetles.

<i>Cryphalus mangiferae</i> Species of beetle

Cryphalus mangiferae, the mango bark beetle, is a tiny tropical bark beetle which attacks mango trees. The species belongs to the family Curculionidae, subfamily Scolytinae. It is often cited as a vector of plant pathogenic fungi infecting mango trees and in some countries like Pakistan it is regarded as a serious threat to mango cultivation.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Cognato, Anthony I.; Hoebeke, E. Richard; Kajimura, Hisashi; Smith, Sarah M. (June 2015). "History of the Exotic Ambrosia Beetles Euwallacea interjectus and Euwallacea validus (Coleoptera: Curculionidae: Xyleborini) in the United States". Journal of Economic Entomology. 108 (3): 1129–1135. doi:10.1093/jee/tov073. ISSN   1938-291X. PMID   26470238.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Berger, Matthew C. (2017). Interactions between Euwallacea Ambrosia Beetles, Their Fungal Symbionts and the Native Trees They Attack in the Eastern United States (Thesis). West Virginia University Libraries. doi:10.33915/etd.5186.
  3. ↑ "A Newly Detected Exotic Ambrosia Beetle in Argentina: Euwallacea interjectus (Coleoptera: Curculionidae: Scolytinae)". Florida Entomologist. 102 (1): 240. 11 April 2019. doi:10.1653/024.102.0141. hdl: 20.500.12123/5529 . ISSN   0015-4040.
  4. 1 2 3 4 "On the taxonomic status of Platypodidae and Scolytidae (Coleoptera)". The Great Basin Naturalist. 33: 77–90. 1973. doi:10.5962/bhl.part.28150. ISSN   0017-3614.
  5. 1 2 "Bark and Ambrosia Beetles of, Euwallacea validus (Eichhoff 1875) (introduced)". www.barkbeetles.info. Retrieved 2 April 2024.
  6. 1 2 3 4 5 Kirkendall, Lawrence R.; Biedermann, Peter H.W.; Jordal, Bjarte H. (2015), "Evolution and Diversity of Bark and Ambrosia Beetles", Bark Beetles, Elsevier, pp. 85–156, doi:10.1016/b978-0-12-417156-5.00003-4, ISBN   978-0-12-417156-5 , retrieved 2 April 2024
  7. 1 2 3 4 5 6 Kasson, Matthew T.; O’Donnell, Kerry; Rooney, Alejandro P.; Sink, Stacy; Ploetz, Randy C.; Ploetz, Jill N.; Konkol, Joshua L.; Carrillo, Daniel; Freeman, Stanley; Mendel, Zvi; Smith, Jason A.; Black, Adam W.; Hulcr, Jiri; Bateman, Craig; Stefkova, Kristyna (July 2013). "An inordinate fondness for Fusarium: Phylogenetic diversity of fusaria cultivated by ambrosia beetles in the genus Euwallacea on avocado and other plant hosts". Fungal Genetics and Biology. 56: 147–157. doi:10.1016/j.fgb.2013.04.004. PMID   23608321.
  8. ↑ Rabaglia, Robert J.; Dole, Stephanie A.; Cognato, Anthony I. (1 November 2006). "Review of American Xyleborina (Coleoptera: Curculionidae: Scolytinae) Occurring North of Mexico, with an Illustrated Key". Annals of the Entomological Society of America. 99 (6): 1034–1056. doi:10.1603/0013-8746(2006)99[1034:roaxcc]2.0.co;2. ISSN   0013-8746.
  9. ↑ Jordal, Bjarte H.; Beaver, Roger A.; Kirkendall, Lawrence R. (July 2001). "Breaking taboos in the tropics: incest promotes colonization by wood-boring beetles". Global Ecology and Biogeography. 10 (4): 345–357. Bibcode:2001GloEB..10..345J. doi:10.1046/j.1466-822x.2001.00242.x. ISSN   1466-822X.
  10. 1 2 3 4 5 6 Spahr, Ellie; Kasson, Matt T.; Kijimoto, Teiya (21 September 2020). "Micro-computed tomography permits enhanced visualization of mycangia across development and between sexes in Euwallacea ambrosia beetles". PLOS ONE. 15 (9): e0236653. Bibcode:2020PLoSO..1536653S. doi: 10.1371/journal.pone.0236653 . ISSN   1932-6203. PMC   7505430 . PMID   32956411.
  11. 1 2 3 Aoki, T.; Kasson, M.T.; Berger, M.C.; Freeman, S.; Geiser, D.M.; O'Donnell, K. (1 June 2018). "Fusarium oligoseptatum sp. nov., a mycosymbiont of the ambrosia beetle Euwallacea validus in the Eastern U.S. and typification of F. ambrosium". Fungal Systematics and Evolution. 1 (1): 23–39. doi:10.3114/fuse.2018.01.03. ISSN   2589-3823. PMC   7259240 . PMID   32490361.
  12. 1 2 O’Donnell, Kerry; Sink, Stacy; Libeskind-Hadas, Ran; Hulcr, Jiri; Kasson, Matthew T.; Ploetz, Randy C.; Konkol, Joshua L.; Ploetz, Jill N.; Carrillo, Daniel; Campbell, Alina; Duncan, Rita E.; Liyanage, Pradeepa N. H.; Eskalen, Akif; Na, Francis; Geiser, David M. (1 September 2015). "Discordant phylogenies suggest repeated host shifts in the Fusarium–Euwallacea ambrosia beetle mutualism". Fungal Genetics and Biology. 82: 277–290. doi: 10.1016/j.fgb.2014.10.014 . ISSN   1087-1845. PMID   25445310.
  13. ↑ O’Donnell, Kerry; Sink, Stacy; Libeskind-Hadas, Ran; Hulcr, Jiri; Kasson, Matthew T.; Ploetz, Randy C.; Konkol, Joshua L.; Ploetz, Jill N.; Carrillo, Daniel; Campbell, Alina; Duncan, Rita E.; Liyanage, Pradeepa N. H.; Eskalen, Akif; Na, Francis; Geiser, David M. (1 September 2015). "Discordant phylogenies suggest repeated host shifts in the Fusarium–Euwallacea ambrosia beetle mutualism". Fungal Genetics and Biology. 82: 277–290. doi: 10.1016/j.fgb.2014.10.014 . ISSN   1087-1845. PMID   25445310.
  14. ↑ Park, J.-H.; Juzwik, J. (March 2012). "Fusarium Canker of Bitternut Hickory Caused by Fusarium solani in the North-Central and Northeastern United States". Plant Disease. 96 (3): 455. doi:10.1094/PDIS-09-11-0766. ISSN   0191-2917. PMID   30727132.
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