Pest categorisation of Urocerus albicornis.

The EFSA Panel on Plant Health performed a pest categorisation of Urocerus albicornis (Hymenoptera: Siricidae), the black horntail sawfly, for the territory of the EU. U. albicornis is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. U. albicornis occurs throughout Canada and continental USA and has established in northern Spain, and probably in southern France (based on two specimens caught in two sites) and Japan (based on one individual caught in one site). It attacks mostly stumps or fallen or weakened trees of at least 20 species of Pinaceae (Abies spp., Larix spp., Picea spp., Pinus spp., Pseudotsuga menziesii, Tsuga spp.) and of Cupressaceae (Thuja plicata). In Spain, the females fly between May and September with a peak in August and September. The eggs are deposited into the sapwood, together with mucus containing a venom and a white-rot wood-decay basidiomycete, either Amylostereum chailletii or A. areolatum. Each fungus is symbiotic with the insect. The larvae feed on wood infected by the fungus. All immature stages live in the host sapwood. In British Columbia, the lifecycle of the pest lasts 2 years but has not been fully characterised elsewhere. The wood of the host trees is impacted by decay due to the fungus, and structurally impaired by the larval galleries. U. albicornis can be carried in conifer wood, solid wood packaging material (SWPM) or plants for planting. Wood from North America is regulated by 2019/2072 (Annex VII) while SWPM is managed according to ISPM 15. The pathway plants for planting is largely closed by prohibition, with the exception of Thuja spp. Climatic conditions in several EU member states are conducive for establishment and the main host plants are widespread in those areas. Further spread and introduction of U. albicornis is likely to decrease the quality of host wood and may influence forest diversity by selectively affecting conifers. Phytosanitary measures are available to reduce the likelihood of additional entry and further spread, and there is a potential for biological control. Despite uncertainty regarding potential damage, U. albicornis satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Pest categorisation of Urocerus japonicus.

The EFSA Panel on Plant Health performed a pest categorisation of Urocerus japonicus (Hymenoptera: Siricidae), the Japanese horntail, for the territory of the EU. U. japonicus is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072 but was identified as an actionable pest in a commodity risk assessment of Pinus thunbergii artificially dwarfed plants from Japan. U. japonicus occurs across Japan and on the Korean Peninsula. It attacks fallen or weakened Japanese cedars, Cryptomeria japonica and Japanese cypresses, Chamaecyparis obtusa. It has also been observed attacking Pinus spp., Abies spp., Larix kaempferi and Picea jezoensis. The females oviposit into the sapwood. Eggs are deposited together with a symbiotic basidiomycete fungus, Amylostereum laevigatum. The larvae feed on wood infected by the fungus. All immature stages live in the hosts sapwood. The lifecycle of the pest lasts 1 year, sometimes 2 years. The wood of the host trees is discoloured by the fungus and therefore loses much of its economic value. U. japonicus can be carried in conifer wood, solid wood packaging material (SWPM) or plants for planting. Wood from Japan is regulated by 2019/2072 (Annexes VII and XI) whilst SWPM is managed by ISPM 15. The pathway plants for planting is largely closed by prohibition, with the exception of Cryptomeria spp. and specified bonsai plants for planting. Climatic conditions in several EU Member States are conducive for establishment, but the main host plants are not very common in those areas, being only amenity trees, although the other hosts mentioned in the literature, Pinus spp., Abies spp., Picea spp. and Larix spp., are widespread. The introduction of U. japonicus is likely to decrease the quality of host wood, as in Japan. Phytosanitary measures are available to reduce the likelihood of entry and further spread, and there is a potential for biological control. U. japonicus satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Mating Behavior and Identification of Male-Produced Pheromone Components in Two Woodwasps, Sirex noctilio and Sirex nitobei, in China.

To protect vulnerable trees from native and invasive wood wasps, the mating behavior of these two woodwasp species (S. noctilio and S. nitobei, respectively) and factors influencing this behavior were investigated in cages outdoors. Male-produced pheromones were identified in both woodwasp species. Compared with the native species S. nitobei, the invasive species S. noctilio showed stronger mating ability, including mating frequency, time, and duration. The mating behavior of both species mainly occurred from 9:00 to 17:00 each day, peaking at 11:00 and 12:00. The daily mating behavior of both species was most directly related to light intensity. Both female and male S. noctilio and S. nitobei were capable of mating upon emergence, and most individuals mated at 2 days of age. For both species, a female-to-male ratio of 5:15 was most conducive to mating, and individuals with a larger body size were preferred as mates by males and females. (Z)-3-decenol was present in solid-phase microextraction extracts of both species. Two reported minor reference components, (Z)-4-decen-1-ol and (E, E)-2,4-decadienal, were not identified in either woodwasp species. The peak of male pheromone release occurred from 11:00-12:00 for 2-day-old individuals.

Remnants of horizontal transfers of Wolbachia genes in a Wolbachia-free woodwasp.

BACKGROUND: Wolbachia is a bacterial endosymbiont of many arthropod and nematode species. Due to its capacity to alter host biology, Wolbachia plays an important role in arthropod and nematode ecology and evolution. Sirex noctilio is a woodwasp causing economic loss in pine plantations of the Southern Hemisphere. An investigation into the genome of this wasp revealed the presence of Wolbachia sequences. Due to the potential impact of Wolbachia on the populations of this wasp, as well as its potential use as a biological control agent against invasive insects, this discovery warranted investigation. RESULTS: In this study we first investigated the presence of Wolbachia in S. noctilio and demonstrated that South African populations of the wasp are unlikely to be infected. We then screened the full genome of S. noctilio and found 12 Wolbachia pseudogenes. Most of these genes constitute building blocks of various transposable elements originating from the Wolbachia genome. Finally, we demonstrate that these genes are distributed in all South African populations of the wasp. CONCLUSIONS: Our results provide evidence that S. noctilio might be compatible with a Wolbachia infection and that the bacteria could potentially be used in the future to regulate invasive populations of the wasp. Understanding the mechanisms that led to a loss of Wolbachia infection in S. noctilio could indicate which host species or host population should be sampled to find a Wolbachia strain that could be used as a biological control against S. noctilio.

Identification of Tree Genera Used in the Construction of Solid Wood-Packaging Materials That Arrived at U.S. Ports Infested With Live Wood-Boring Insects.

Although international regulations have been successfully implemented to reduce the introduction and spread of plant pests through wood packaging material (WPM), wood-boring insects continue to be intercepted in WPM at U.S. ports of entry. Both hardwoods and softwoods are used in the construction of WPM for international trade; however, it is not clear if some types of wood pose higher risks than others for harboring wood borers. This study documented the taxonomic diversity of infested wood genera intercepted as a result of targeted WPM inspection at U.S. ports, and identified many of the wood-boring insects transported within them. The results of this study reveal associations among packaging woods, commodities, and shipment origins. The wood genera most frequently infested were Pinus Linnaeus (Pinales: Pinaceae), Picea Miller (Pinales: Pinaceae), and Populus Linnaeus (Malpighiales: Salicaceae), which were heavily represented as packaging for commodities such as stone, metal, vehicles, and machinery. In addition to these results, we summarized preferences by the wood borers to develop in living, stressed, dying, or dead hosts, the pest status of intercepted wood borers in their native and non-native ranges, and potential host range of intercepted wood borers to gauge potential for these taxa to become pests in North America. New possible host associations are reported for eight wood borer taxa. Taxonomy of host wood is presented as a new factor for consideration in pathway-level risk analysis of WPM, and the findings further reinforce the need for enhanced compliance with ISPM 15 to reduce entry of non-native wood-boring insects.

Comparison of Wing, Ovipositor, and Cornus Morphologies between Sirex noctilio and Sirex nitobei Using Geometric Morphometrics.

Sirex noctilio F. (Hymenoptera: Siricidae) is an invasive woodwasp from Europe and North Africa. Globalization has led to an expanding global presence in pine forests. S. noctilio has been previously introduced outside of its native range and now co-occurs in trees with native S. nitobei Matsumura (first discovered in 2016). Damage to Pinus sylvestris var. mongolica Litv in northeast China can be attributed to two types of woodwasp. To distinguish the two species by the traditional taxonomic morphology, we mainly differentiate the color of the male's abdomen and the female's leg. There remains intraspecific variation like leg color in the delimitation of related genera or sibling species of Sirex woodwasps. In this study, we used landmark-based geometric morphometrics including principal component analysis, canonical variate analysis, thin-plate splines, and cluster analysis to analyze and compare the wings, ovipositors, and cornus of two woodwasps to ascertain whether this approach is reliable for taxonomic studies of this group. The results showed significant differences in forewing venation and the shapes of pits in the middle of ovipositors among the two species, whereas little difference in hindwings and cornus was observed. This study assists in clarifying the taxonomic uncertainties of Siricidae and lays a foundation for further studies of the interspecific relationships of the genus Sirex.

Biotic and abiotic effects on density, body size, sex ratio, and survival in immature stages of the European woodwasp, Sirex noctilio.

Resource quality can have direct or indirect effects on female oviposition choice, offspring growth and survival, and ultimately on body size and sex ratio. We examined these patterns in Sirex noctilio Fabricus, the globally invasive European pine woodwasp, in South African Pinus patula plantations. We studied how tree position as well as natural variation in biotic and abiotic factors influenced sex-specific density, larval size, tunnel length, male proportion, and survival across development. Twenty infested trees divided into top, middle, and bottom sections were sampled at three time points during larval development. We measured moisture content, bluestain fungal colonization, and co-occurring insect density and counted, measured, and sexed all immature wasps. A subset of larval tunnels was measured to assess tunnel length and resource use efficiency (tunnel length as a function of immature wasp size). Wasp density increased from the bottoms to the tops of trees for both males and females. However, the largest individuals and the longest tunnels were found in bottom sections. Male bias was strong (~10:1) and likewise differed among sections, with the highest proportion in the middle and top sections. Sex ratios became more strongly male biased due to high female mortality, especially in top and middle sections. Biotic and abiotic factors such as colonization by Diplodia sapinea, weevil (Pissodes sp.) density, and wood moisture explained modest residual variation in our primary mixed effects models (0%-22%). These findings contribute to a more comprehensive understanding of sex-specific resource quality for S. noctilio and of how variation in key biotic and abiotic factors can influence body size, sex ratio, and survival in this economically important woodwasp.

First come, first served: precopulatory mate-guarding behavior and male-male contests by a hymenopteran saproxylic parasitoid.

Precopulatory mate-guarding behavior is a common strategy that maximizes male reproductive success when female receptivity to copulation is low. This behavior has been demonstrated in vertebrates, aquatic crustaceans, terrestrial isopods, and some species of insects, but there is very little available information about hymenopteran insects. A few studies have clarified the factor that determines the outcome of a contest between a guarding male and an invader male. We investigated the male-male contest and mating behavior of a saproxylic parasitoid wasp, Ibalia japonica (Hymenoptera: Cynipoidea: Ibaliidae) using field observations in Japan. These observations indicated that I. japonica males show precopulatory mate-guarding behavior and that four types of male-male contests occur on the Magnolia liliiflora (Magnoliales: Magnoliaceae) tree that virgin females emerge from. We show that the arrival order of I. japonica males that found the future emergence point of a female was key factor that allowed males to secure virgin females.

Terrestrial arthropods of Steel Creek, Buffalo National River, Arkansas. II. Sawflies (Insecta: Hymenoptera: "Symphyta").

BACKGROUND: This is the second in a series of papers detailing the terrestrial arthropods collected during an intensive survey of a site near Steel Creek campground along the Buffalo National River in Arkansas. The survey was conducted over a period of eight and a half months using twelve trap types - Malaise traps, canopy traps (upper and lower collector), Lindgren multifunnel traps (black, green, and purple), pan traps (blue, purple, red, white, and yellow), and pitfall traps - and Berlese-Tullgren extraction of leaf litter. NEW INFORMATION: We provide collection records for 47 species of "Symphyta" (Insecta: Hymenoptera), 30 of which are new state records for Arkansas: (Argidae) Sterictiphora serotina; (Cimbicidae) Abia americana; (Diprionidae) Monoctenus fulvus; (Orussidae) Orussus terminalis; (Pamphiliidae) Onycholyda luteicornis, Pamphilius ocreatus, P. persicum, P. rileyi; (Pergidae) Acordulecera dorsalis, A. mellina, A. pellucida; (Tenthredinidae) Caliroa quercuscoccineae, Empria coryli, Hoplocampa marlatti, Macrophya cassandra, Monophadnoides conspiculatus, Monophadnus bakeri, Nematus abbotii, Neopareophora litura, Pachynematus corniger, Paracharactus rudis, Periclista marginicollis, Pristiphora banski, P. chlorea, Strongylogaster impressata, S. remota, Taxonus epicera, Thrinax albidopictus, T. multicinctus, Zaschizonyx montana; (Xiphydriidae) Xiphydria tibialis.

New distribution records for the rare genus Afrotremex Pasteels (Siricidae: Hymenoptera) and provision of interactive Lucid identification keys to species.

BACKGROUND: Afrotremex Pasteels, 1951 is a rare genus of wasps endemic to the Afrotropical region, containing 6 species represented by 14 specimens. Specimens were previously only recorded from central Africa: Cameroon, Congo, Democratic Republic of Congo, Gabon and Uganda. NEW INFORMATION: Here we record two additional specimens housed in the Natural History Museum in London (BMNH), one of which is a male of A. xylophagus Goulet, 2014 collected in Ghana (previously Gold Coast). This record extends the known distribution of the genus into west Africa, and represents the second known male specimen for the genus. The other BMNH specimen is a female paratype of A. violaceus Pasteels, 1951 collected in the Democratic Republic of Congo. We provide high quality photographs of these additional two specimens. Images of all six known species are openly available online on WaspWeb. In addition we have developed interactive online Lucid Matrix and Lucid Phoenix identification keys to the species, which are openly available on WaspWeb at: http://www.waspweb.org/Siricoidea/Siricidae/Keys/index.htm.