Amasa parviseta: A new and highly invasive species of Ambrosia Beetle from Australia, South America, and Europe.

Ambrosia Beetles are one of the most diverse groups of Bark Beetles, with over 1300 described species in 43 genera, found throughout the world's tropical and temperate regions. The biology of these Beetles enables them to colonise new areas rapidly, with many species considered to be highly invasive pests, causing significant economic and ecological damage in forests, orchards, nurseries as well as urban and suburban gardens. This is because the Beetles bore into the wood of trees and cultivate gardens of Fungus, feeding on an ambrosia produced by the Fungus rather than the wood of the tree. This means that, unlike most wood-boring Insects, they are not tied to a single species of tree, although some species and genera are restricted to a single family of hosts. The reproductive cycle of the Beetles also favours dispersal, with diploid females mating with haploid males within their birth tree before dispersing to new trees to lay eggs. 

The taxonomy of Ambrosia Beetles can be challenging, due to the small size of these Insects, and their wood boring lifestyle, which means both that they are out of sight and that they are not under any evolutionary pressure to become visually distinct. Members of the genus Amasa can be distinguished from other genera by their truncated abdomens and elytra (wing cases) which have a distinct declivity (downward fold) at the rear. However, telling species apart can be difficult, particularly as most species are known only from a single, or very small number of, specimen(s) held in widely distributed collections. There are currently 47 species of Amasa, from across tropical Asia and Oceania; two species from Madagascar have been assigned to the species, but this is probably erroneous. 

In 2011 a species of Amasa found infesting a Eucalyptus grandis plantation in São Paulo State,  Brazil, was provisionally identified as Amasa truncata, a widespread invasive species, although further investigation led to the conclusion that this was a morphologically similar, but unknown, species. This new Beetle was reported from Minas Gerais State in Brazil as well as in neighbouring Uruguay in 2015. In 2016 it was reported from Valparaíso in Chile, and by 2018 it had reached Argentina.

Similar specimens found in Cádiz, Spain, in 2009, were initially identified as Amasa  resecta, but again were later shown not to belong to this species. In 2018 the same species was found in Antibes,  France, and in 2019 in Lisbon,  Portugal. A genetic analysis of specimens collected in France found them to be 100% identical to members of an unknown species from New South Wales.

In a paper published in the journal Zootaxa on 12 January 2024, Miloš Knížek of the Forest Protection Service at the Forestry and Game Management Research Institute, and Sarah Smith of the Department of Entomology at Michigan State University, formally describe the unknown Amasa species based upon specimens from Australia, South America, and Europe.

The new species is named Amasa parviseta, where 'parviseta' means 'small hairs' as the hairs on the elytral  declivity is almost hairless, with only a few microscopic hairs. The new species is described on the basis of specimens from New South Wales, the Australian Capital Territory, and Queensland in Australia, Alpes-Maritimes Department in France, Galicia in Spain, São Paulo State in Brazil, and Tacuarembó Department in Uraguay. It is also thought to be present in Corsica, Portugal, Minas Gerais, Argentina, and Chile.

Amasa parviseta paratype female from Ponteverda Spain (Miloš Knížek collection) (1) habitus dorsal view; (2) habitus lateral view; (3) elytral declivity part; (4) elytral declivital face; (5) lateral detail of elytral declivity with microscopic hair-like setae visible on the lateral edge of the declivity and on the apices of tubercles on the declivital face. Antonín Knížek in Knížek & Smith (2024).

Females of Amasa parviseta are 2.38–3.00 mm long and light brown in colour, with slightly darker elytra. Males are unknown. The species was found on Eucalyptus trees and in Eucalyptus leaf litter; some were captured in traps in mixed Eucalyptus and Pine woodland. 

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Six confirmed fatalities as wildfires sweep acrosss Australia.

Six people have now been confirmed dead as Australia suffers its worst bushfires in decades. All six fatalities occurred in New South Wales, where more than 600 homes have been destroyed and dozens of people have been treated for smoke inhalation. An area of about 16 500 km³ has been burned within the state, with one fire front reaching about 6000 km in length. In Queensland an area of about 1800 km³ has been raised and 20 homes destroyed, while in South Australia around 50 km³ has burned and at least 33 people injured.

A wildfire raging in New South Wales this week. Peter Parks/AFP/Getty Images.

Wildfires are an annual event in Australia, particularly during the annual dry season that lasts from May to October, but this year's fires have been exceptionally severe, driven by high temperatures in the Australian interior and high seasonal winds. The country has suffered exceptional fire seasons in the past, most recently in 1984 and 1974, both of which saw far more extensive fires than this year, but this year's fires have extended far further from the country's interior, reaching into more populated areas closer to the coast, a pattern that has been seen increasingly in recent years, and which is widely considered to by a symptom of a changing climate associated with global warming.

A wildfire in New South Wales on 15 November 2019. Brett Hemmings/Getty Images.

The wildfire ecology of Australia is driven by the presence of large numbers of Eucalyptus, or Gum Trees, fast growing members of the Myrtle Family, Myrtaceae, which are native to Australia but now grown extensively for their timber in many other parts of the world. They are valued for their fast growth, enabling them to produce much timber quickly, However they dominate ecosystems in which they become established, causing a variety of problems both for native plants and animals, as Human residents. The trees produce large amounts of volatile terpanoids which suppress the growth of other plants, and consume large amounts of water, lowering the water table in areas where they become established. The trees also shed branches regularly, as well as leaves and strips of bark, creating a dry environment littered with dry plant material where wildfires quickly become established. The terpinoids in the wood of Eucalyptus cause these forests to burn readily, typically at a temperature about 30 °C higher than other forest fires, which can kill specie such as Oak, which can often survive fires. This increases the ecological dominance of the Eucalyptus, as, while the trees are killed by the fires, the seed pods can survive and rapidly germinate after fires, which since the trees grow quickly, enables them to quickly claim the newly available land.

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Wildfires kill 43 in Portugal.

Forty three people have been confirmed dead and a further 71 have been injured as a series of wildfires have swept across northern and central Portugal this week. The majority of those who have died have done so in their cars, trying to escape from raging forest fires on country roads. Over 600 separate fires have been reported, the second major outbreak of such fires this year, after a series of fires in June killed 64 people and injured over 250 more in the central Pedrogao Grande Region. At least four people have died in similar fires in neighbouring Spain this week.

 

 Forest fire in Portugal earlier this week. APTN.

The fires are reported to have a number of different causes, including in some cases deliberate arson, and have been made much worse by both a prolonged heatwave in Portugal. which has dried out vegetation making it vulnerable to fires, and high winds associated with Hurricane Ophelia which have fanned the blazes and helped them to spread rapidly. However the fires appear to have been worst not in areas of natural woodland, but in the countries extensive plantation forests (i.e. forests of planted trees grown for the value of their timber), with the most severe fires occurring in areas of Pine and, particularly, Eucalyptus cultivation.

Clouds of thick smoke from the forest fires above the town of Marinha Grande in the Leiria District of Portugal earlier this week. João Pinto/Severe Weather Europe.

Eucalyptus, or Gum Trees, are fast growing members of the Myrtle Family, Myrtaceae, native to Australia but now grown extensively for their timber in many other parts of the world. They are valued for their fast growth, enabling them to produce much timber quickly, However they dominate ecosystems in which they become established, causing a variety of problems both for native plants and animals, as Human residents. The trees produce large amounts of volatile terpanoids which suppress the growth of other plants, and consume large amounts of water, lowering the water table in areas where they become established. The trees also shed branches regularly, as well as leaves and strips of bark, creating a dry environment littered with dry plant material where wildfires quickly become established. The terpinoids in the wood of Eucalyptus cause these forests to burn readily, typically at a tempereature about 30 °C higher than other forest fires, which can kill specie such as Oak, which can often survive fires. This increases the ecological dominance of the Eucalyptus, as, while the trees are killed by the fires, the seed pods can survive and rapidly germinate after fires, which since the trees grow quickly, enables them to quickly claim the newly available land.

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A new species of Chrysomeline Leaf Beetle from Ireland, England and Tasmania.

Chrysomeline Leaf Beetles are one of the most diverse and widespread groups of Beetles, with over 35 000 described species from across the globe. They feed on living plant matter, and many species, such as the Colorado Potato Beetle, are significant agricultural pests, either due to direct damage to crops or by acting as vectors for plant diseases.

In a paper published in the journal Zootaxa on 24 June 2013, Chris Reid of the Department of Entomology at the Australian Museum and David de Little of the Rosny Research Facility at the Tasmanian Museum and Art Gallery describe a new species of Chrysomeline Leaf Beetle found infesting Eucalyptus trees in County Kerry, Ireland and across Tasmania as well as in a garden in London.

The new species is placed in the genus Paropsisterna, and given the specific name selmani, in honour of the late Brian Selman of University of Newcastle-on-Tyne, an expert on Australian Chrysomeline Leaf Beetles. Paropsisterna selmani is a 7-9 mm oval Beetle with distinctive but variable colouration. The males tend to be darker and redder than the females, and all the beetles seem to be darker in spring, after emerging from hibernation. The Beetle feeds on the leaves of Eucalyptus and where these trees are grown in large monospecific plantations, appears capable of achieving epidemic proportions capable of causing considerable economic damage quite rapidly. The species appears to be a native of Tasmania which has become established in Ireland and England, and given the popularity of the fast-growing Eucalyptus as a plantation tree around the world, would seem to have to potential to become a significant pest globally.

Paropsisterna selmani from Tasmania in spring. David de Little in Reid & de Little (2013).

Paropsisterna selmani from London in autumn. Paula French in Reid & de Little (2013).

Paropsisterna selmani new adult shortly after emerging from pupae, County Kerry, Ireland. Finbarr Horgan in Reid & de Little (2013).

The larvae of Paropsisterna selmani. Reid & de Little (2013).

See also A new species of Diving Beetle from New Guinea, A new species of Skin Beetle from Yunnan Province, China, A blind, cave dwelling, Ground Beetle from Anatolian Turkey, Three new species of Palm Weevil from Columbia and A new species of Bumble Bee Scarab Beetle from the Early Cretaceous of Inner Mongolia.

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