Austral Entomology最新文献

Island ecosystems offer unique opportunities to study the dynamics of species that rely on ephemeral resources such as carrion. This study investigated the necrophagous insect communities associated with carrion of silver gulls (Chroicocephalus novaehollandiae) on a small nearshore island off the east coast of Australia, to assess how necrophagous insect communities on islands compare with the mainland community, and the degree to which these communities varied over time. Over three breeding seasons, we analysed what insect species were colonising gull carcasses and, using baited traps, compared total adult community composition and richness of carrion-associated insect species on the island with the adjacent mainland. Our findings reveal that an island separated by less than 500 m from the mainland can harbour distinct carrion-breeding fly assemblages. These assemblages vary between years but are notably dominated by a potential seabird-carrion specialist fly—the littoral species Calliphora maritima. These results underscore the importance of seabird carrion as a critical resource for necrophagous insects on islands and contribute to our understanding of how island environments influence insect community dynamics and specialisation.

In most tropical and subtropical regions of the Americas, the corn leafhopper, Dalbulus maidis (DeLong & Wolcott)(Hemiptera: Cicadellidae), is a significant pest of corn. Crop losses occur not only due to direct damage from feeding and oviposition but also because this leafhopper is vector of various pathogens causing important outbreaks of the corn stunt disease. While parasitoids are the better-studied natural enemies of this leafhopper, its predators remain largely unknown. This study records, for the first time, 26 predator species [14 spiders, three lacewings (Chrysopidae), two assassin bugs (Reduviidae), one big-eyed bug (Geocoridae), one hoverfly (Syrphidae), four ladybugs (Coccinellidae) and two pincer wasps (Dryinidae)] as active predators of the vector in cornfields of northern Argentina. These records, along with the three previously known species, form a complex of 29 species preying on different stages of the vector in Argentina. With this contribution, 40 species of predators are now documented across the Americas, providing a valuable natural resource that should be conserved.

No abstract is available for this article.

This study is focused on the parasitic wasps Heimbra Cameron, 1909 (Heimbrinae), a small and poorly represented genus in entomological collections. Herein, two new species are described: Heimbra dioneae sp. nov. and Heimbra pulchra sp. nov., both from Brazil, and a new geographical record to Heimbra bicolor Subba Rao, 1978 is reported. Additionally, we provide maps with the geographical distribution of the studied species based on the new records and literature data, and an identification key for the known species of Heimbra.

Oviposition and agonistic behaviour are important traits for understanding the pattern of coexistence and choice of host fruit shared between natives and invasive species. This study aimed to evaluate the interspecific interactions and the choice of the oviposition sites among three native species of fruit flies of the genus Anastrepha: Anastrepha obliqua (Macquart), Anastrepha fraterculus (Wiedemann), Anastrepha sororcula Zucchi, and an invasive species, Ceratitis capitata (Wiedemann). The interactions between species were measured by counting the number of eggs laid in semi-ripe and ripe guavas (Psidium guajava L.) in intra and interspecific combinations. Additionally, we compared the absolute frequency of agonistic behaviours in interactions between native and invasive fruit flies. The native species of Anastrepha did not change their preference for the fruit ripening stage, even in face of the invader C. capitata. Anastrepha species and C. capitata preferred to oviposit in semi-ripe fruits, in all experimental scenarios. We also observed that C. capitata avoided interactions with the native species by preferring to oviposit in ripe fruits when in the presence of Anastrepha species. All species reduced the number of laid eggs when in the presence of heterospecific females. Aggression was the most frequent agonistic behaviour in all species combinations, followed by display/stalking and avoidance. Finally, our results showed that aggression behaviour was the most frequent in interactions of Anastrepha species with C. capitata.

The fall armyworm, Spodoptera frugiperda, is a highly polyphagous pest, native to the tropical and subtropical regions of the Americas that invaded the Australian mainland in 2020. Since its incursion into Australia, management has largely relied on the use of different synthetic insecticides. Given pesticide resistance genes and reduced sensitivities to a variety of pesticides are already present in the population, there is a need to investigate alternative management approaches that can be incorporated into an IPM programme such as biological control. A fundamental step in establishing the potential of biological control is identifying the potential natural enemies that may be deployed in pest management. In this study, we undertook a series of surveys to identify potential parasitoids for fall armyworm and assessed parasitism rates in Western Australia (WA) and the Northern Territory (NT). Approximately, 1900 larvae of fall armyworm were sourced from maize, sweet corn, okra and sorghum fields, reared and observed for the emergence of parasitoids. Ten species of larval parasitoids from five families were recorded during the surveys with Cotesia ruficrus (Haliday) (56.14%) and Exorista xanthaspis (Wiedemann) (50%) being the most abundant larval species in WA and NT, respectively. Other parasitoids found include four recently described species, Euplectrus frugiperdata Fagan-Jeffries, Chelonus trojanus Fagan-Jeffries, Coccygidium necatrix Atkin-Zaldivar & Fagan-Jeffries, Coccygidium mellosiheroine Atkin-Zaldivar & Fagan-Jeffries, and previously named species, Megaselia scalaris (Loew) and some unidentified Tachinidae. Two species of egg parasitoids, Trichogramma pretiosum (Riley) and Telenomus remus (Nixon), were recovered with field parasitism rates of 7.81% and 10.16%, respectively. Overall, the occurrence of potential egg and larval parasitoids in Australian horticulture systems provides a unique platform to develop a conservation or augmentative biological control approach to manage fall armyworm in Australia.

Cave crickets, also called wētā, are an important component of subterranean realms globally, but the true diversity of the group is poorly known. Speleotettix Chopard, 1944 contains two species from southeast Australia, Speleotettix tindalei Chopard, 1944 and Speleotettix chopardi (Karny, 1935). However, the initial description of the genus was poorly characterised, and its taxonomy has remained unclear since. Here, we take an integrative molecular and morphological approach to redescribe Speleotettix and describe three new species: Speleotettix aolae Beasley-Hall, sp. nov. from Victoria and Speleotettix binoomea Beasley-Hall, sp. nov. from New South Wales, both found in limestone caves, and Speleotettix palaga Beasley-Hall, sp. nov. from mineshafts in Victoria. To provide consistency in future work on the group, we also redescribe S. tindalei and treat S. chopardi as a nomen dubium. Finally, we transfer the threatened species Cavernotettix craggiensis Richards, 1974, an island species from Tasmania's Bass Strait, into the genus as Speleotettix craggiensis (Richards, 1974) comb. nov. In so doing, we increase the number of described rhaphidophorid species in Australia to 27 and significantly expand the distribution of Speleotettix, making it the most widespread of the Australian genera currently known. As all members of Speleotettix are short-range endemics at risk of decline, these findings have implications for their future conservation management.

The genus Microlechia Turati, 1924, including a newly described species Microlechia zwicki sp. nov., is recorded for the first time in Australia. Detailed illustrations of the adult specimen and male genitalia of this new species are provided, alongside a discussion of how it could be diagnosed form related species within the genus. An updated annotated checklist of the Australian Gnorimoschemini is also included, featuring illustrations of the adults and genitalia of several species.

Three polyphagous agromyzid leafminers, Liriomyza sativae Blanchard, Liriomyza huidobrensis (Blanchard) and Liriomyza trifolii (Burgess), have recently invaded mainland Australia, posing a threat to horticultural crops. Overseas, these species are often effectively controlled by local hymenopteran parasitoids. It is important to assess the abundance and composition of the existing parasitoid community capable of impacting these pests as they spread across Australia. We surveyed three adventive agromyzids, Liriomyza brassicae (Riley), Phytomyza plantaginis Goureau and Phytomyza syngenesiae (Hardy), and one endemic species, Liriomyza chenopodii (Watt), at six sites around Melbourne, Victoria, between August 2018 and January 2020. In all, 4748 agromyzids and 2474 identified parasitoids were reared. Eleven wasp species were identified: seven eulophids, three braconids and one pteromalid. Four eulophid species—Asecodes sp., Diglyphus isaea (Walker), Closterocerus mirabilis Edwards & La Salle and Hemiptarsenus varicornis (Girault)—and one braconid species, Opius cinerariae (Fischer), were reared from all agromyzid hosts. Three eulophid species—Chrysocharis pubicornis (Zetterstedt), Neochrysocharis formosa (Walker) and Zagrammosoma latilineatum Ubaidillah—and one pteromalid species, Trigonogastrella parasitica (Girault), were reared from three host agromyzids. C. pubicornis (Zetterstedt), a pupal parasitoid, was the most abundant parasitoid overall but was almost entirely reared from the two Phytomyza spp. at only one site. Peaks in parasitism were observed in late spring and late autumn, depending on the host. These results show that a diversity of local agromyzids persists throughout the year in southern Victoria, supporting a stable parasitoid community that should help control invasive Liriomyza spp. in the future.

Social bees of the tribe Meliponini (stingless bees) are used as managed pollinators of crops throughout the world's tropical and subtropical regions. On Australia's East Coast, two native species—Tetragonula carbonaria and Tetragonula hockingsi—are the most widely propagated in hives, but knowledge of their biology and ecology in natural nests remains poorly documented. Here we monitor a wild population of Tetragonula in remnant forest in south-east Queensland over a 5-year period to assess three aspects of their life history: (i) rates of colony mortality, (ii) rates of queen turnover and (iii) incidences of nest usurpation. The latter occurs when one colony usurps the nest cavity of another, installing its own queen and enslaving the existing workers and brood. The range of T. hockingsi has increased in recent decades due to hive trade and southward range expansion. Our study area was located in the southern region of overlap with T. carbonaria. A total of 58 wild colonies were identified within the study site (1.5 nests per hectare), three-quarters of which were T. carbonaria. Colony mortality averaged 8.3% per year, such that 40% of colonies had died by the end of the 5-year study interval. Sequencing of mitochondrial-COI and microsatellite genotyping of workers at four time points was used to infer that queen turnover (i.e., queens replaced by daughter queens) typically occurs every 20–30 months. Eight cases were detected consistent with interspecific nest usurpation, in all of which T. hockingsi replaced T. carbonaria. However, T. hockingsi colonies also had lower annual survivorship than those of T. carbonaria, resulting in a stable proportion of each species in the study area over time. Overall, results show that although nest occupancy by Tetragonula colonies is typically several years, colony death and nest usurpation are common in wild populations, and community composition is shaped by interspecific differences in both usurpation success and annual mortality.