Austral Entomology最新文献

The subgenus Anicla, commonly known as green cutworms, harbours some of the owlet moths (Lepidoptera: Noctuinae), whose larvae are notable for their economic importance. Knowledge of the immature stages for this group is available for three of the nine described species. Anicla infecta Ochsenheimer, 1816 is widely distributed in the Americas and is especially abundant in agricultural ecosystems. However, in the Neotropics, its economic damage can be confused with sympatric species, including Anicla ignicans (Guenée, 1852), whose distributions overlap in most parts of the American continent. In this sense, here, the identity of A. ignicans is investigated through its geographical distribution, based on molecular and morphological data. Additionally, the morphological and behavioural traits of immature stages were described in detail, information about its geographical distribution and larval host plants was gathered, and the species' biological parameters from larvae reared on an artificial diet were determined. Anicla ignicans is distributed throughout the Neotropical region, preferably in areas with xeric and/or grass-dominated ecosystems. The eggs present valuable characters to distinguish A. ignicans from other owlet moth species, such as the reduced number of ribs, the way the micropyle openings are arranged and the shape of the aeropyles. However, the larvae show very similar chromatic polymorphisms to other Anicla species. Although A. ignicans prefer to feed on grasses, it was observed that more than 85% of the larvae that were fed with a modified bean-based Greene diet survived. Additionally, the percentage of time for each phase of development obtained here is very similar for the different species of Anicla, regardless of the temperature or feeding of the larvae.

The Asian paper wasp (Polistes chinensis) is an invasive species in New Zealand and a voracious arthropod predator, incorporating a wide range of prey into its diet. We examined the colony survival and prey community composition of these wasps in a protected coastal habitat in New Zealand. Paper wasp colonies at this site were surveyed and monitored weekly over two summers. Our data showed that only ~20% of the monitored colonies each year survived until late summer, with high rates of colony mortality in late spring and early summer. We collected samples of wasp larval guts over a temporal gradient in one nesting season, and via DNA metabarcoding analysis, we identified the prey species consumed. The prey species most frequently identified in larval samples were endemic cicadas and several lepidopteran species. No native arthropod species of known conservation concern were identified in the analysis. However, 63% of the unique taxon sequences retrieved could not be identified by genus or species level, likely due to the absence of reference barcodes. These taxa may represent a group of understudied species, potentially highly endemic or localised. Our analysis indicates that these invasive wasps are opportunistic-generalist predators with the potential to exert high predation pressure on native arthropods. P. chinensis may be preying on a range of understudied species, especially in remote, natural habitats across New Zealand. We recommend future studies continue to barcode native New Zealand arthropods in order to improve the taxonomic assignments of dietary studies.

Within a fruit, fruit fly larvae can be subject to scramble competition, in which density-dependent effects can influence the fitness of subsequent adults. While there is significant research on tephritid interspecific larval competition, it has been conducted in invasive situations where the species are evolutionarily novel to each other. There has been no published research investigating larval competitive interactions between naturally coexisting, endemic species. We ran laboratory-based, intraspecific and interspecific larval competition trials involving three co-occurring Bactrocera species of differing genetic relatedness and also measured aspects of juvenile development rate to test possible mechanisms of competitive difference. Larval density had an influence on intraspecific competition in Bactrocera tryoni, Bactrocera neohumeralis and Bactrocera jarvisi, with a decreasing percentage of pupation with increasing larval density. Interspecific competition between B. tryoni and B. neohumeralis, and between B. tryoni and B. jarvisi was influenced by the interaction between species and density. The intensity of competition between B. tryoni and B. neohumeralis was minimal but high between B. tryoni and B. jarvisi. B. jarvisi produced larger eggs and had faster initial larval growth rates than the other two species, but it took the longest time for pupation to occur. Our results conflict with theory, as the greatest competition was observed between the two more distantly related species (B. tryoni and B. jarvisi) rather than between the two most closely related species (B. tryoni and B. neohumeralis). Further, and contrary to other studies, egg size, hatch rate and larval growth rate did not provide B. jarvisi with a competitive advantage; thus, larval size does not appear to be a mechanism of larval competition between B. tryoni and B. jarvisi.

Termites are resistant to fire, a common disturbance in the world's savannas, but most explanations for how termites resist fire are speculative. Some researchers have suggested that the mounds of some termite species can serve as a structural defence against direct fire mortality. Because mound structure is related to thermoregulation, and larger mounds have more stable internal temperatures, larger mounds may confer greater fire resistance. Fire also causes indirect mortality to termites by removing food sources, which may give an advantage to larger mounds as they have superior food provisioning and storage ability. Using natural fires, we measured mound size and colony survival of two southern African termite species (Trinervitermes trinervoides and Amitermes sp.) in plots recently burnt (<4 months after fire), recovering from fire (1–2 years after fire), or unburnt (>3 years after fire). Burn status and mound size were each significant factors in colony survival. Recent fire was associated with the lowest survival, and larger mounds with greater survival. There is some evidence that larger mounds are generally more resistant to fire, especially the long term, indirect effects, but sample sizes were not adequate to confirm this.

The leaf chafer tribe Alvarengiini Frey, a long-neglected taxon that has been overlooked in the biodiversity literature from its inception, is revised for the first time. As a result of this research, the tribe is composed of two species in two genera distributed from Bahia, Brazil (in the north), to Paraná, Brazil (in the south), and Paraguay. Two synonyms are proposed: Alvarengius silphoides Frey, syn. nov. for Ottokelleria dispar (Burmeister) and Alvarengius Frey, syn. nov. for Ottokelleria D'Andretta & Martínez. A new genus is described, Carinochilus, gen. nov., and includes one species: Carinochilus marginatus (Burmeister), comb. nov. The lectotype for O. dispar and a neotype for C. marginatus are designated. We provide an identification key to the tribes of Rutelinae (in English and Portuguese) and incorporate classification changes in the subfamily. A key for the identification of Alvarengiini genera and species is also provided. All taxa are circumscribed and illustrated, and distributional data are synthesised in maps.

Closely related species within termite genera often show extremely similar morphology, where morphological characteristics of soldiers alone or imagos (including alates and primary reproductives) alone are sometimes insufficient to establish new species. However, many original descriptions of termite species are based on soldier characteristics alone, because of the seasonal occurrence of alates and the difficulty in collecting primary reproductives. Importantly, primary reproductives of the family Kalotermitidae (so-called drywood termites) are relatively easy to collect from field colonies compared with those of the other termite families. Here, we describe a new kalotermitid species, Glyptotermes matsuurai sp. nov., from Australia by effective use of morphological characteristics of primary reproductives. Glyptotermes matsuurai is distinguished from the Australian species G. iridipennis Froggatt, 1896 by the mitochondrial cytochrome c oxidase subunit II gene; however, it is not distinguishable from G. iridipennis based on the external morphology of soldiers. It therefore forms a species complex with G. iridipennis. Although we could collect alates of G. matsuurai from only one of the field-collected colonies kept in the laboratory, we conducted morphological analyses of imagos from multiple colonies by using primary reproductives collected from field colonies. As a result of our morphological analyses of imagos, we found that G. matsuurai is morphologically distinguishable from all other species of Australian Glyptotermes. Thus, when enough alates are unavailable, morphological characteristics of primary reproductives can be used to facilitate the discovery of undescribed cryptic species at least in the genus Glyptotermes and possibly in other genera within the family Kalotermitidae.

No abstract is available for this article.

Eunanus Ohaus, 1909 has so far been known exclusively from Argentina and Paraguay, with only two described species: E. murinus Ohaus, 1909 and E. podtiaguini Gutiérrez, 1951. Here, the genus is revised and redefined, and two new species are described from Brazil: Eunanus kozlovi sp. nov., from Mato Grosso do Sul state, and Eunanus valmorbidai sp. nov., from Rio Grande do Sul state. Furthermore, Leucothyreus beckeri (Martínez, 1964) is transferred to the genus under the new combination Eunanus beckeri (Martínez, 1964) comb. nov. The lectotype of E. murinus Ohaus, 1909 is designated, and an identification key to all the species and a distribution map are provided.

Odd-clawed spiders (Gradungulinae), which are considered to be ‘living fossils’, are a faunal element of the mesic forests of eastern Australia and the South Island of New Zealand. To date, 16 species in seven genera are known, with most being highly endemic and hard to find, explaining their scarcity in collections worldwide. Particularly noteworthy is the Australian genus Progradungula that includes only two relict species from eastern Australia (Progradungula carraiensis from the Carrai limestone caves in northern New South Wales and Progradungula otwayensis from Nothofagus rainforests in the Otway Range, southern Victoria) and are known from only a handful of adult specimens. Both species are large nocturnal predators with a rather cryptic lifestyle, which construct unique ladder-like catching webs composed of non-combed and combed cribellate silk with exceptional properties. Here, we describe a new relict species, Progradungula barringtonensis Michalik & Smith, sp. nov., from isolated Nothofagus forest patches in Barrington Tops National Park (NSW, Australia). The male of this species is significantly larger than those of P. carraiensis and P. otwayensis and exhibits characteristics of the male genitalia of both species. The webs are similar to those of the other Progradungula species. Field observations revealed that the catching ladder had few looping segments, similar to P. otwayensis, but an immature in captivity constructed webs with more looping segments, similar to P. carraiensis, supporting the previously proposed hypothesis that food availability may explain the plasticity of the catching ladder structure.

Aphids are a major pest of cropping systems throughout the world. In most cases, crop aphids are controlled with broad-spectrum insecticides; although generally very effective at preventing yield loss, this approach risks non-target damage to beneficial organisms. In the last 20 years, a number of selective insecticides have become available to control aphids while minimising harm to other arthropods. Previous studies have found that two such insecticides, flonicamid and afidopyropen, cause only low-level acute mortality impacts on aphid parasitoids in Australian grain crops. However, little research has examined the sub-lethal effects of these chemicals, which could induce various physiological changes that impact pest control. We hypothesised that both flonicamid and afidopyropen have negative effects that extend beyond the immediate acute mortality previously published. To test this hypothesis, we undertook a series of experiments to determine the effects of flonicamid and afidopyropen, along with the synthetic pyrethroid gamma-cyhalothrin, on aphid parasitism (mummification) rate, emergence rate of the next generation and the next generation sex ratio in three important aphid parasitoids, Aphidius colemani (Viereck), Diaeretiella rapae (M'Intosh) and Aphelinus abdominalis (Dalman). Analogous with previous research, our acute toxicity bioassays showed that all three insecticides had low (<30%) mortality impacts. Although sub-lethal impacts could not be assessed for D. rapae due to the low level of aphid parasitism by that species, our findings showed negative impacts on fecundity in surviving A. abdominalis and A. colemani. Of particular note is the increase in International Organisation for Biological Control ratings to moderate (30%–80% mortality and/or reproductive reduction) when mortality and reduced fecundity effects were combined to determine overall fitness impacts. Gamma-cyhalothrin typically resulted in higher negative impacts on A. abdominalis and A. colemani (compared with flonicamid and afidopyropen); however, quite surprisingly, these impacts were not rated as highly toxic. Taken together, our results suggest that, even when sub-lethal impacts are considered, flonicamid and afidopyropen are useful tools for farmers targeting aphid populations while minimising the non-target impacts on parasitoids. We recommend semi-field and/or field trials to further assess the impacts of these insecticides on aphid parasitoid populations.