The use of Bt cotton varieties has greatly reduced the amount of conventional insecticides required to control lepidopteran pests, Helicoverpa armigera and Helicoverpa punctigera, in Australia, but the possibility that these moths might become resistant to Bt remains a threat. Consequently, a Resistance Management Plan, which includes the mandatory growing of refuge crops (pigeon pea and non-Bt cotton; both C3 plants), has been established for Bt cotton farmers. However, knowledge of the relative contributions made to overall moth populations from the many host origins (both C3 and C4 plants) available to these insects throughout cotton production regions remains limited, as do the scales of movement and spatial mixing of moths within and between these areas. This study used stable isotope signatures (in particular δ13C) to help identify where moths fed as larvae within separate cotton production regions which differed in their proportions of C3 and C4 host crops (e.g. cotton and sorghum, respectively). C3-derived moths predominated in the early season, but C4-derived moths increased in frequency later. The overall proportion of C4 moths was higher in H. armigera than in H. punctigera. Whilst the relative proportions of C3 and C4 moths differed between regions, no differences in such proportiorns were found at smaller spatial scales, nor were there significant correlations between crop composition and isotope signatures in moths. Overall, these results suggest that C4 host plants are likely to be very important in offsetting the development of Bt resistance in these insects and such influences may operate across multiple regions within a single growing season.

The use of multiple species in biological control programmes is controversial when interactions among them are not fully understood. We determined the response of the pupal parasitoid Coptera haywardi (Oglobin) to different availability of Anastrepha ludens (Loew) pupae previously parasitized or not by larval–pupal Diachasmimorpha longicaudata (Ashmead). The two types of pupae were exposed at different ages and proportions to different numbers of C. haywardi females for 48 h. The performance of C. haywardi adults emerging from parasitized and unparasitized pupae was measured. Coptera haywardi prefers to attack unparasitized A. ludens pupae rather than pupae parasitized by D. longicaudata. However, when the availability of unparasitized pupae was low or the number of foraging females was high, C. haywardi competed against early immature stages of the D. longicaudata, or hyperparasitized, feeding directly on the advanced-immature developmental stages of the early acting species. Adults of C. haywardi emerging as hyperparasitoids were no different in size, fecundity and longevity from those emerging as primary parasitoids. Our data suggest that simultaneous use of these species in augmentative biological control projects may be feasible but should be carefully planned in order to avoid any detrimental effect of its interaction.

An artificial diet formulated for continuous rearing of the predator Arma chinensis was inferior to natural prey when evaluated using life history parameters. A transcriptome analysis identified differentially expressed genes in diet-fed and prey-fed A. chinensis that were suggestive of molecular mechanisms underlying the nutritive impact of the artificial diet. Changes in the diet formulation were made based on the transcriptome analysis and tested using life history parameters. The quantity of pig liver, chicken egg, tuna fish, biotin, nicotinamide, vitamin B6, thiamine, riboflavin, vitamin C, L-glutamine, and sucrose was reduced, and wheat germ oil, calcium pantothenate and folic acid were increased. Ecuadorian shrimp was added as a partial substitute for tuna fish. Several parameters improved over six generations, including increased egg viability, and decreased egg and adult cannibalism. Additionally, several parameters declined, including longer developmental times for 2nd–5th instars, and decreased nymphal weights. The improvements in life history parameters support the use of transcriptome analyses to help direct formulation improvements. However, the decline in some parameters suggests that additional information, e.g., proteomic data, may be useful as well to maximize diet formulations.

The Japanese pine sawyer, Monochamus alternatus Hope (Coleoptera: Cerambycidae), is a major pest of pines and it is also the key vector of the exotic pinewood nematode in China. In the present study, we cloned, expressed, and purified a chemosensory protein (CSP) in M. alternatus. We surveyed its expression in various developmental stages of male and female adult tissues and determined its binding affinities for different pine volatiles using a competitive binding fluorescence assay. A CSP known as CSP5 in M. alternatus was obtained from an antennal cDNA library and expressed in Escherichia coli. Quantitative reverse transcription polymerase chain reaction results indicated that the CSP5 gene was mainly expressed in male and female antennae. Competitive binding assays were performed to test the binding affinity of recombinant CSP5 to 13 odour molecules of pine volatiles. The results showed that CSP5 showed very strong binding abilities to myrcene, (+)-β-pinene, and (−)-isolongifolene, whereas the volatiles 2-methoxy-4-vinylphenol, p-cymene, and (+)-limonene oxide have relatively weak binding affinity at pH 5.0. Three volatiles myrcene, (+)-β-pinene, and (−)-isolongifolene may play crucial roles in CSP5 binding with ligands but this needs further study for confirmation. The sensitivity of insect to host plant volatiles can effectively be used to control and monitor the population through mass trapping as part of integrated pest management programs.

The olive fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is a key-pest in the main olives producing areas worldwide, and displays distinct preference to different olive cultivars. The present work intended to study oviposition preference towards three Portuguese cultivars (Cobrançosa, Madural, and Verdeal Transmontana) at different maturation indexes. Multiple oviposition bioassays (multiple-choice and no-choice) were conducted to assess cultivar preference. No-choice bioassays were conducted to assess the influence of different maturation indexes (MI 2; MI 3, and MI 4) in single cultivars. The longevity of olive fly adults according to the cultivar in which its larvae developed was also evaluated through survival assays.

Cultivar and maturation are crucial aspects in olive fly preference. Field and laboratory assays revealed a preference towards cv. Verdeal Transmontana olives and a lower susceptibility to cv. Cobrançosa olives. A higher preference was observed for olives at MI 2 and MI 3. The slower maturation process in cv. Verdeal Transmontana (still green while the other cultivars are reddish or at black stage) seems to have an attractive effect on olive fly females, thus increasing its infestation levels. Olive fly adults from both sexes live longer if emerged from pupae developed from cv. Verdeal Transmontana fruits and live less if emerged from cv. Cobrançosa. Therefore, olive cultivar and maturation process are crucial aspects in olive fly preference, also influencing the longevity of adults.

The ecology of earwigs in natural forest ecosystems is poorly understood. We used sweeping to determine the population densities of adult earwigs, by sex and species, on ten tree species in a temperate floodplain forest in southern Moravia (Czech Republic). We also determined the relationships between the properties of tree species and earwig density and diet as indicated by digestive tract contents. The densities and diet composition of earwigs differed between the three detected earwig species [Apterygida media (Hagenbach, 1822), Chelidurella acanthopygia (Genè, 1832) and Forficula auricularia Linnaeus, 1758] and among tree species. Earwig densities were related to lichen coverage and fungal coverage on the trees. The diet of earwigs was associated with specific leaf area, herbivore damage to the leaves, and light exposure of the trees. A. media was the most abundant of the three earwig species. Although the contents of its digestive tract changed depending on available food resources, A. media appeared to preferentially consume soft-bodied insect herbivores and fungi associated with wounds caused by herbivores rather than plant material. Therefore, this species has the potential to help reduce the population densities of soft-bodied pests of forest trees.

Thousand Island Lake (TIL) is a typical fragmented landscape and an ideal model to study ecological effects of fragmentation. Partial fragments of the mitochondrial cytochrome oxidase subunit I gene of 23 island populations of Dendrolimus punctatus in TIL were sequenced, 141 haplotypes being identified. The number of haplotypes increased significantly with the increase in island area and shape index, whereas no significant correlation was detected between three island attributes (area, shape and isolation) and haplotype diversity. However, the correlation with number of haplotypes was no longer significant when the ‘outlier’ island JSD (the largest island) was not included. Additionally, we found no significant relationship between geographic distance and genetic distance. Geographic isolation did not obstruct the gene flow among D. punctatus populations, which might be because of the high dispersal capacity of this pine moth. Fragmentation resulted in the conversion of large and continuous habitats into isolated, small and insular patches, which was the primary effect on the genetic diversity of D. punctatus in TIL. The conclusion to emphasize from our research is that habitat fragmentation reduced the biological genetic diversity to some extent, further demonstrating the importance of habitat continuity in biodiversity protection.

Fleas have great medical relevance as vectors of the causative agents of several diseases in animals and humans and rodents are the principal reservoirs for these pathogens. Argentinian Patagonia has the highest diversity of rodent fleas in South America. However, parasitism rates of rodents by fleas, the factors that influence them and the ecological aspects that modulate geographical distributions of flea–host association remain unknown for this region. This is the first study to record the diversity, prevalence, abundance, geographical distributions and host ranges of fleas in Argentinian Patagonia. It also compares parasitism rates among Patagonian ecoregions and host species. We captured 438 rodents belonging to 13 species, which harboured 624 fleas from 11 species and subspecies (P = 46%; mean abundance = 1.44). The high parasitism rates obtained were consistent with previous records for other arid regions, suggesting that Patagonia favours the survival and development of Siphonaptera. Host geographic range and abundance were related to the parasitological indexes: host species with high-density populations had the highest mean flea abundance and prevalence, whereas widely distributed hosts had the highest richness and diversity of flea species. Our results contribute to the knowledge of the flea–host–environment complex. Our analysis of flea distributions and parasitism rate in Central Patagonia may be useful in epidemiological studies of flea-borne diseases and provide a basis for implementing surveillance systems for better risk assessment of emerging zoonoses in the region.

The timing of critical events like mating, migration, and development has noticeably and recently shifted in many populations of diverse organisms. Here, we report a change in the breeding phenology of giant waterbugs, Belostoma flumineum Say (Heteroptera, Belostomatidae), in the northeastern United States. Waterbugs collected in 2005 and 2006 exhibited previously typical patterns of mating and reproduction: two annual reproductive peaks in which overwintered adults mated in the spring and young adults from a new generation mated in the fall. In 2012 and 2015, despite similar sampling effort, we detected no fall breeding activity in the study area. Reproductive behaviour under controlled laboratory conditions was also different between the earlier (2005 and 2006) and recent (2012 and 2015) years: waterbugs collected in recent years exhibited significant delays in reproduction (>30 days) under similar photoperiod and thermal conditions. We discuss potential causes of this dramatic change in reproductive behaviour, such as climate change, as well as possible negative impacts of the absence of fall reproduction on populations of B. flumineum in the study region.

Diuraphis noxia (Kurdjumov), Russian wheat aphid, is one of the world's most invasive and economically important agricultural pests of wheat and barley. In May 2016, it was found for the first time in Australia, with further sampling confirming it was widespread throughout south-eastern regions. Russian wheat aphid is not yet present in New Zealand. The impacts of this pest if it establishes in New Zealand, could result in serious control problems in wheat- and barley-growing regions. To evaluate whether D. noxia could establish populations in New Zealand we used the climate modelling software CLIMEX to locate where potential viable populations might occur. We re-parameterised the existing CLIMEX model by Hughes and Maywald (1990) by improving the model fit using currently known distribution records of D. noxia, and we also considered the role of irrigation into the potential spread of this invasive insect. The updated model now fits the current known distribution better than the previous Hughes and Maywald CLIMEX model, particularly in temperate and Mediterranean areas in Australia and Europe; and in more semi-arid areas in north-western China and Middle Eastern countries. Our model also highlights new climatically suitable areas for the establishment of D. noxia, not previously reported, including parts of France, the UK and New Zealand. Our results suggest that, when suitable host plants are present, Russian wheat aphid could establish in these regions. The new CLIMEX projections in the present study are useful tools to inform risk assessments and target surveillance and monitoring efforts for identifying susceptible areas to invasion by Russian wheat aphid.

Immature fruit fly stages of the family Tephritidae are commonly intercepted on breadfruit from Pacific countries at the New Zealand border but are unable to be identified to the species level using morphological characters. Subsequent molecular identification showed that they belong to Bactrocera xanthodes, which is part of a species complex that includes Bactrocera paraxanthodes, Bactrocera neoxanthodes and an undescribed species. To establish a more reliable molecular identification system for B. xanthodes, a reference database of DNA barcode sequences for the 5’-fragment of COI gene region was constructed for B. xanthodes from Fiji, Samoa and Tonga. To better understand the species complex, B. neoxanthodes from Vanuatu and B. paraxanthodes from New Caledonia were also barcoded. Using the results of this analysis, real-time TaqMan polymerase chain reaction (PCR) assays for the detection of B. xanthodes complex and for the three individual species of the complex were developed and validated. The assay showed high specificity for the target species, with no cross-reaction observed for closely related organisms. Each of the real-time PCR assays is sensitive, detecting the target sequences at concentrations as low as ten copies µl−1 and can be used as either singleplex or multiplex formats. This real-time PCR assay for B. xanthodes has been successfully applied at the borders in New Zealand, leading to the rapid identification of intercepted Tephritidae eggs and larvae. The developed assays will be useful biosecurity tools for rapid detection of species in the B. xanthodes complex worldwide.

Lysinibacillus sphaericus (Bacillales: Planococcaceae) is a spore-forming bacillus used for the biological control of mosquitoes (Diptera: Culicidae) due to its larvicidal activity determined by various toxins and S-layer protein produced either during sporulation or by the vegetative cell. Aedes aegypti and Culex quinquefasciatus are the vectors of arboviruses that cause tropical diseases representing a current public health problem. Both species may coexist in the same larval development sites and are susceptible to the larvicidal activity of L. sphaericus. In this study, we compared the larvicidal effects of L. sphaericus 2362 (WHO Reference strain) and native strains III(3)7 and OT4b.25 against Cx. quinquefasciatus and Ae. aegypti in single-species and mixed-culture bioassays. Findings showed that L. sphaericus spores, vegetative cells and a combination thereof possessed high larvicidal activity against Cx. quinquefasciatus larvae, whereas only the formulation of L. sphaericus vegetative cells was effective against Ae. aegypti larvae. Similar results were obtained for field-collected larvae. We propose that a formulation of vegetative cells of L. sphaericus 2362 or III(3)7 could be a good alternative to chemical insecticides for the in situ control of mixed populations of Ae. aegypti and Cx. quinquefasciatus.

Pheromones play an important role in mediating interspecific interactions in insects. In an insect community, pheromones can reveal information about the senders, which could be used by other members of the food web (competitor, natural enemies, etc.) to their own advantage. The aggregation pheromones of two closely related thrips species, Frankliniella occidentalis and Frankliniella intonsa, have been identified with the same major compounds, (R)-lavandulyl acetate and neryl (S)-2-methylbutanoate, but in different ratios. However, the roles of the aggregation pheromones in the interspecific interactions between these two closely related species are unknown. Here, we investigated the roles of major aggregation pheromone compounds in interspecific interactions between F. occidentalis and F. intonsa for both long and short ranges. The results showed that, at tested doses, neither aggregation pheromone-induced long range cross-attraction nor short range cross-mating was detected between F. occidentalis and F. intonsa. Field-trapping trials showed that the species-specificity in aggregation pheromones was regulated by the ratio of two major compounds. However, species-specific blends of the two major compounds had no effect on short-range interactions between these two species. Our data from the thrips species provide support for the ‘aggregation model of coexistence’, explaining the species-specific pheromone-mediated coexistence of closely related species. Thus, species-specific pheromones could be one of the factors affecting population dynamics and community structure in closely related insects with similar niches.

Instrumentation and software for the automated analysis of insect flight trajectories is described, intended for quantifying the behavioural dynamics of moths in the vicinity of artificial light. For its time, this moth imaging system was relatively advanced and revealed hitherto undocumented insights into moth flight behaviour. The illumination source comprised a 125 W mercury vapour light, operating in the visible and near ultraviolet wavelengths, mounted on top of a mobile telescopic mast at heights of 5 and 7.1 m, depending upon the experiment. Moths were imaged in early September, at night and in field conditions, using a ground level video camera with associated optics including a heated steering mirror, wide angle lens and an electronic image intensifier. Moth flight coordinates were recorded at a rate of 50 images per second (fields) and transferred to a computer using a light pen (the only non-automated operation in the processing sequence). Software extracted ground speed vectors and, by instantaneous subtraction of wind speed data supplied by fast-response anemometers, the airspeed vectors. Accumulated density profiles of the track data revealed that moths spend most of their time at a radius of between 40 and 50 cm from the source, and rarely fly directly above it, from close range. Furthermore, the proportion of insects caught by the trap as a proportion of the number influenced by the light (and within the field of view of the camera) was very low; of 1600 individual tracks recorded over five nights, a total of only 12 were caught. Although trap efficiency is strongly dependent on trap height, time of night, season, moonlight and weather, the data analysis confirmed that moths do not exhibit straightforward positive phototaxis. In general, trajectory patterns become more complex with reduced distance from the illumination, with higher recorded values of speeds and angular velocities. However, these characteristics are further qualified by the direction of travel of the insect; the highest accelerations tended to occur when the insect was at close range, but moving away from the source. Rather than manifesting a simple positive phototaxis, the trajectories were suggestive of disorientation. Based on the data and the complex behavioural response, mathematical models were developed that described ideal density distribution in calm air and light wind speed conditions. The models did not offer a physiological hypothesis regarding the behavioural changes, but rather were tools for quantification and prediction. Since the time that the system was developed, instrumentation, computers and software have advanced considerably, allowing much more to be achieved at a small fraction of the original cost. Nevertheless, the analytical tools remain useful for automated trajectory analysis of airborne insects.