Mannheimsia Beyer (Diptera: Phoridae): description of a new species, redescription of Mannheimsia stricta and studies on hypopygial morphology

Mannheimsia conica, sp. nov., is described, M. stricta redescribed and the hypopygial morphology including the phallus of all four Mannheimsia species is illustrated and discussed. A table with the different phallus terminology used in the main studies of this structure in Phoridae is presented. Uniformization of phallus terminology is suggested.

SOLENOPSIS (HYMENOPTERA, FORMICIDAE) FIRE ANT REACTIONS TO ATTACKS OF PSEUDACTERON FLIES (DIPTERA, PHORIDAE) IN SOUTHEASTERN BRAZIL

We studied the responses of Solenopsis fire ants to Pseudacteon phorid fly attacks in southeastern Brazil. The presence of these phorid parasites triggered a suite of phorid-specific defense responses including reduced foraging, bait guarding, a curled defensive posture, and general colony immobility. The existence of these phorid-specific defenses indicates that Pseudacteon phorids exert substantial evolutionary pressure on South American fire ant populations.

Duration of Protopolybia exigua exigua (de Saussure) nests and related aspects as influenced by phorid fly infestation (vespidae, polistinae, epiponini)

The main characteristics of 55 nests of Protopolybia exigua exigua were periodically evaluated in Ribeirão Preto, southeastern Brazil. Although the queens' life-span can eventually reach one year, nests barely thrive for six months because most of them are periodically invaded by the scavenger phorid fly, Megaselia aff. picta. Under heavy infestation the adult wasp population partially closes the nest entrance, migrates and constructs a new nest in the neighborhood. Afterwards the old-nest's entrance can be completely closed by the wasps which results in blocking the parasitoid flies inside. In the tropics, predation by ants is considered the main selective pressure which shaped most of the bionomic characteristics of Polistinae wasps. It is suggested that Megaselia can easily overcome the usual wasps defensive tactics just because they are so specialized against ants. Aerial raids, fast erratic-jerking movements, rapid and efficient oviposition behavior, etc. can eventually turn Megaselia into a very important enemy of some social wasps.

Towards continuous surveillance of fruit flies using sensor networks and machine vision

In Australia, the Queensland fruit fly (B. tryoni), is the most destructive insect pest of horticulture, attacking nearly all fruit and vegetable crops. This project has researched and prototyped a system for monitoring fruit flies so that authorities can be alerted when a fly enters a crop in a more efficient manner than is currently used. This paper presents the idea of our sensor platform design as well as the fruit fly detection and recognition algorithm by using machine vision techniques. Our experiments showed that the designed trap and sensor platform is capable to capture quality fly images, the invasive flies can be successfully detected and the average precision of the Queensland fruit fly recognition is 80% from our experiment.

Host searching behaviour of Diachasmimorpha kraussii (Fullaway) (Hymenoptera: Braconidae: Opiinae), a polyphagous parasitoid of Dacinae fruit flies (Diptera: Tephritidae)

Diachasmimorpha kraussii (Hymenoptera: Braconidae: Opiinae) is a koinobiont larval parasitoid of dacine fruit flies of the genus Bactrocera (Diptera: Tephritidae) in its native range (Australia, Papua New Guinea, Solomon Islands). The wasp is a potentially important control agent for pest fruit flies, having been considered for both classical and inundative biological control releases. I investigated the host searching, selection and utilisation mechanisms of the wasp against native host flies within its native range (Australia). Such studies are rare in opiine research where the majority of studies, because of the applied nature of the research, have been carried out using host flies and environments which are novel to the wasps. Diachasmimorpha kraussii oviposited equally into maggots of four fruit fly species, all of which coexist with the wasp in its native range (Australia), when tested in a choice trial using a uniform artificial diet media. While eggs laid into Bactrocera tryoni and B. jarvisi developed successfully through to adult wasps, eggs laid into B. cucumis and B. cacuminata were encapsulated. These results suggest that direct larval cues are not an important element in host selection by D. kraussii. Further exploring how D. kraussii locates suitable host larvae, I investigated the role of plant cues in host searching and selection. This was examined in a laboratory choice trial using uninfested fruit or fruit infested with either B. tryoni or B. jarvisi maggots. The results showed a consistent preference ranking among infested fruits by the wasp, with guava and peach most preferred, but with no response to uninfested fruits. Thus, it appears the wasp uses chemical cues emitted in response to fruit fly larval infestation for host location, but does not use cues from uninfested fruits. To further tease apart the role of (i) suitable and non-suitable maggots, (ii) infested and uninfested fruits of different plant species, and (iii) adult flies, in wasp host location and selection, I carried out a series of behavioural tests where I manipulated these attributes in a field cage. These trials confirmed that D. kraussii did not respond to cues in uninfested fruits, that there were consistent preferences by the wasps for different maggot infested fruits, that fruit preference did not vary depending on whether the maggots were physiologically suitable or not suitable for wasp offspring development, and finally, that adult flies appear to play a secondary role as indicators of larval infestation. To investigate wasp behaviour in an unrestrained environment, I concurrently observed diurnal foraging behaviours of both the wasp and one of its host fly in a small nectarine orchard. Wasp behaviour, both spatially and temporally, was not correlated with adult fruit fly behaviour or abundance. This study reinforced the point that infested fruit seems to be the primary cue used by foraging wasps. Wasp and fly feeding and mating was not observed in the orchard, implying these activities are occurring elsewhere. It is highly unlikely that these behaviours were happening within the orchard during the night as both insects are diurnal. As the final component of investigating host location, I carried out a habitat preference study for the wasp at the landscape scale. Using infested sentinel fruits, I tested the parasitism rate of B. tryoni in eucalyptus sclerophyll forest, rainforest and suburbia in South East Queensland. Although, rainforest is the likely endemic habitat of both B. tryoni and D. kraussii, B. tryoni abundance is significantly greater in suburban environments followed by eucalyptus sclerophyll forest. Parasitism rate was found to be higher in suburbia than in the eucalyptus sclerophyll forest, while no parasitism was recorded in the rainforest. This result suggests that wasps orient within the landscape towards areas of high host density and are not restricted by habitat types. Results from the different experiments suggest that host searching, selection and utilisation behaviour of D. kraussii are strongly influenced by cues associated with fruit fly larval feeding. Cues from uninfested fruits, the host larvae themselves, and the adult host flies play minimal roles. The discussion focuses on the fit of D. kraussii to Vinson’s classical parasitoid host location model and the implications of results for biological control, including recommendations for host and plant preference screening protocols and release regimes.

The rest flies down the wind : complexities of late style in the work of Christina Stead

Examining the late style of a writer is like skirting around quicksand. End-of-career reflection can subvert long standing critical accounts; revisionist publishing histories or newly minted archival work can do likewise. And, as Nancy J. Troy suggests, an artist’s last thoughts are rarely planned as such (15). In the case of Christina Stead any consideration of late style is made more difficult because, chronologically speaking, her ‘late’ works were written some 20 years before her death in 1983. Thus chronology can be deceptive, as Nicholas Delbanco points out in Lastingness: The Art of Old Age. Stead’s last novel, I’m Dying Laughing The Humourist, was completed, at least in rough draft form in 1966, when Stead was 64, but friends and readers suggested many changes. The book was published posthumously in 1986. Stead’s work is receiving increasing critical attention so a discussion of her ‘late style’ is important, particularly given that her fiction seems to refuse so many attempts at category-making. This perspective reveals two interesting aspects of her late work: first her consistent engagement with the problems of age for women, and in particular women writers, and second, the consequence of a life-long attention to the representation of dialogic sound in her novels, a preoccupation that results in what can be termed an aural signature. My discussion refers to Edward Said’s and Nicholas Delbanco’s ideas about late style by way of a focus on selective biographical issues and Stead’s engagement with radical politics before moving to an examination of what can be called an aural signature in several novels. Her fiction demonstrates one of the agreed markers of late style: she was constantly looking forward and looking back through innovation in form and content.

Evolution of lure response in tephritid fruit flies : phytochemicals as drivers of sexual selection

The males of many Bactrocera species (Diptera: Tephritidae) respond strongly and positively to a small number of plant-derived chemicals (=male lures). Males that have imbibed the lures commonly have a mating advantage over unfed males, but no female benefits have been demonstrated for females mating with lure-fed males. It has been hypothesized that the strong lure response is a case of runaway selection, where males receive direct benefits and females receive indirect benefits via 'sexy sons', or a case of sensory bias where females have a lower threshold response to lures. To test these hypotheses we studied the effects of lure feeding on male mating, remating and longevity; while for females that had mated with lure-fed males we recorded mating refractoriness, fecundity, egg viability and longevity. We used Bactrocera tryoni as our test animal and as lures the naturally occurring zingerone and chemically related, but synthetic chemical cuelure. Feeding on lures provided direct male benefits in greater mating success and increased multiple mating. For the first time, we recorded direct female effects: increased fecundity and reduced remating receptivity. Egg viability did not differ in females mated with lure-fed or unfed males. The life span of males and females exposed to lures was reduced. These results reveal direct, current-generation fitness benefits for both males and females, although the male benefits appear greater. We discuss that while lure response is indeed likely to be a sexual selection trait, there is no need to invoke runaway selection to explain its evolution.

Return journey : Professor Efron flies in - interview in Optometry Today

Before returning from Australia for the BCLA's Pioneers Day, Professor Nathan Efron spoke to OT. Professor Efron, you’re back in the UK for a short while – What tempted you away from Australia’s summer and back to Britain in November...

Sexual selection in true fruit flies (Diptera: Tephritidae) : transcriptome and experimental evidences for phytochemicals increasing male competitive ability

In male tephritid fruit flies of the genus Bactrocera, feeding on secondary plant compounds (sensu lato male lures = methyl eugenol, raspberry ketone and zingerone) increases male mating success. Ingested male lures alter the male pheromonal blend, normally making it more attractive to females and this is considered the primary mechanism for the enhanced mating success. However, the male lures raspberry ketone and zingerone are known, across a diverse range of other organisms, to be involved in increasing energy metabolism. If this also occurs in Bactrocera, then this may represent an additional benefit to males as courtship is metabolically expensive and lure feeding may increase a fly's short-term energy. We tested this hypothesis by performing comparative RNA-seq analysis between zingerone-fed and unfed males of Bactrocera tryoni. We also carried out behavioural assays with zingerone- and cuelure-fed males to test whether they became more active. RNA-seq analysis revealed, in zingerone-fed flies, up-regulation of 3183 genes with homologues transcripts to those known to regulate intermale aggression, pheromone synthesis, mating and accessory gland proteins, along with significant enrichment of several energy metabolic pathways and gene ontology terms. Behavioural assays show significant increases in locomotor activity, weight reduction and successful mating after mounting; all direct/indirect measures of increased activity. These results suggest that feeding on lures leads to complex physiological changes, which result in more competitive males. These results do not negate the pheromone effect, but do strongly suggest that the phytochemical-induced sexual selection is governed by both female preference and male competitive mechanisms.

Systematics: A new fossil genus of small-headed flies (Diptera: Acroceridae: Philopotinae) from Baltic amber

A new genus of philopotine Acroceridae in Baltic amber is described from both sexes. Archaeterphis hennigi gen. et sp. nov. is easily diagnosed from all other acrocerid genera by the deeply emarginate hind margin of the eye, short mouthparts, reduced wing venation, modified hind femora, and the large postpronotal lobes being proximate but not touching. The new genus is closely related to the extant genus Africaterphis Schlinger from southern Africa, which accords with a common biogeographic pattern in insects.

Do parasitic flies attack mites? Evidence in Baltic amber

We provide the first evidence of a small-headed fly planidium (first instar larva; Diptera: Acroceridae) associated with a whirligig mite (Acari: Acariformes: Prostigmata: Anystina: Anystidae) in Baltic amber. This fossil is surprising as parasitic nematodes are the only metazoans known to successfully attack acariform mites, and Acroceridae are believed to be host-restricted parasitoids of spiders. The fossil corroborates a previously published, but widely dismissed, paper that first reported parasitism of parasitengone mites by acrocerid planidia. The possible natural history implications of this find are discussed.

Area-wide management of fruit flies (Diptera: Tephritidae) in the Central Burnett district of Queensland, Australia.

Queensland fruit fly, Bactrocera tryoni (Froggatt), is the most serious pest of the native tephritid species in Australia and a significant market access impediment for fruit commodities from any area where this species is endemic. An area-wide management (AWM) program was implemented in the Central Burnett district of Queensland with the aim of improving fruit fly control and enhancing market access opportunities for citrus and other fruits produced in the district. The primary control measures adopted in the AWM system included bait spraying of commercial and non-commercial hosts and the year-round installation of male annihilation technology (MAT) carriers in both orchards and town areas. The MAT carrier used consisted of a dental wick impregnated with 1 ml cue-lure [4-(4-acetoxyphenol)-2-butanone] and 1 ml Malathion 500 EC in a plastic cup. The application of these control measures from 2003 to 2007 resulted in overall suppression of fruit fly populations across the entire district. Male trap catches at the peak activity time were reduced by 95% and overall fruit fly infestation in untreated backyard fruit of town areas reduced from 60.8% to 21.8%. Our results demonstrate remarkable improvement in fruit fly control and economic benefit to the Central Burnett horticulture. Therefore, commercial growers are continuing the AWM program as a long-term, industry funded activity, to provide an additional layer of phytosanitary security for market access of fruit commodities from this district.

Use of tea tree oil against buffalo flies in cattle

Testing tea tree oil against buffalo flies on cattle.

Host plant records for fruit flies (Diptera: Tephritidae) in Southeast Asia

Plant records, derived largely from field studies in Thailand and Malaysia from 1986-94, are provided for 131 species of Southeast Asian Tephritidae.