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The soldier fly is an endemic pest of sugarcane in Australia. Small numbers of larvae can cause significant damage to roots and reduce the crop yields. Little is known about the composition and function of the soldier fly salivary gland, its secretions, and their roles in insect-plant interactions. In this study, we performed transcriptome analysis of the salivary glands of starved and sugarcane root-fed soldier fly larvae. A total of 31 119 highly expressed assembled contigs were identified in the salivary glands and almost 50% of them showed high levels of similarity to known proteins in Nr databases. Of all the obtained contigs, only 9727 sequences contain an open reading frame of over 100 amino acids. Around 31% of contigs were predicted to encode secretory proteins, including some digestive and detoxifying enzymes and potential effectors. Some known salivary secreted peptides such as serine protease, cysteine proteinase inhibitors, antimicrobial peptides and venom proteins were among the top 100 highly expressed genes. Differential gene expression analysis revealed significant modulation of 850 transcripts in salivary glands upon exposure to plant roots or starvation stress. Here, we identified some venom proteins which were significantly upregulated in the salivary glands of soldier fly larvae exposed to sugarcane roots. In other insects and nematodes some of these proteins have been used to manipulate host plant defense systems and facilitate the invasion of the host plant. These findings provide a further insight into the identification of potential effector proteins involved in soldier fly-sugarcane interactions.

Lepidopteran stemborers are among the most damaging agricultural pests worldwide, able to reduce crop yields by up to 40%. Sugarcane is the world’s most prolific crop, and several stemborer species from the families Noctuidae, Tortricidae, Crambidae and Pyralidae attack sugarcane. Australia is currently free of the most damaging stemborers, but biosecurity efforts are hampered by the difficulty in morphologically distinguishing stemborer species. Here we assess the utility of DNA barcoding in identifying stemborer pest species. We review the current state of the COI barcode sequence library for sugarcane stemborers, assembling a dataset of 1297 sequences from 64 species. Sequences were from specimens collected and identified in this study, downloaded from BOLD or requested from other authors. We performed species delimitation analyses to assess species diversity and the effectiveness of barcoding in this group. Seven species exhibited <0.03 K2P interspecific diversity, indicating that diagnostic barcoding will work well in most of the studied taxa. We identified 24 instances of identification errors in the online database, which has hampered unambiguous stemborer identification using barcodes. Instances of very high within-species diversity indicate that nuclear markers (e.g. 18S, 28S) and additional morphological data (genitalia dissection of all lineages) are needed to confirm species boundaries.

1Scarab species associated with groundnuts were surveyed in Andhra Pradesh, Karnataka and 2 Tamil Nadu, southern India, between 1995 and 2001. Scarab adults were collected from trees 3 on which they were feeding and/or mating, and larvae (white grubs) from groundnut fields. 4Holotrichia species, especially H. reynaudi and H. serrata were the major species associated 5 with groundnut. H. reynaudi predominated in the central Deccan area, while H. serrata was 6 most abundant in areas to the south and west. A new, undescribed, Holotrichia species near 7 H. consanguinea was collected south and south-west of Hyderabad in mixed populations with 8 H. reynaudi. However, the full extent of this new species' distribution remains uncertain. H. 9 rufoflava was rarely associated with groundnut, but was common as an adult at some locations. 10Other genera encountered during surveys were Anomala, Adoretus, Schizonycha, Autoserica. 11In survey data, densities of Holotrichia larvae and 'all other white grubs' were both very highly 12 correlated with % of damaged groundnut plants. These correlations in combination with 13 concurrent observations of plant damage establish a causal link between white grubs and plant 14 damage and death in southern Indian groundnut. Ranking of preferred host trees for adults were 15 developed from field observations for four Holotrichia species and Schizonycha spp. and will 16 assist grower-initiated surveys of pest occurrence. In combination with insecticide efficacy data 17 published elsewhere, the survey provides the basis for an environmentally friendly and 18 economically viable pest-management system for white grubs on groundnut in southern India. 19

The effect of soil moisture on ovipositional preference is studied for four melolonthine scarabaeids, Holotrichia reynaudi , Holotrichia serrata and Dermolepida albohirtum , which are endemic to the semiarid tropics of India ( Holotrichia spp.) and Australia, and Heteronyx piceus , which is endemic to the temperate and subtropical regions of Australia. As predicted by the preferenceperformance hypothesis, the three tropically adapted species show little or no ovipositional preference for soil moistures between permanent wilting point ( -1500 kPa) and field capacity ( -10 kPa) under either choice or no-choice conditions in their endemic soils, whereas H. piceus shows a clear preference to oviposit in drier soils ( -1500 to -200 kPa). The ovipositional soil-moisture preferences of D. albohirtum and H. serrata are much narrower in geographically adjacent non-endemic soils (between -1500 to -200 kPa) than in their endemic soils. An analysis of daily rainfall determined the rainfall variability within the endemic areas of each species. The semiarid tropics are highly variable, with rainfall at the time of oviposition being a poor predictor of the future rain required for successful larval development, whereas the rainfall in the subtropics is much more reliable. The absence of a clearly preferred soil moisture for oviposition in the tropically adapted species appears to be a life-history strategy that allows these species to live in environments where rainfall is highly variable, and soil moisture at time of oviposition is a poor predictor of future environmental suitability for plant growth, and thus larval survival.