Evidence of a latitudinal gradient in spider diversity in Australian cotton

The most common explanation for species diversity increasing towards the tropics is the corresponding increase in habitats (spatial heterogeneity). Consequently, a monoculture (like cotton in Australia) which is grown along a latitudinal gradient, should have the same degree of species diversity throughout its range. We tested to see if diversity in a dominant cotton community (spiders) changed with latitude, and if the community was structurally identical in different parts of Australia. We sampled seven sites extending over 20 degrees of latitude. At each site we sampled 1-3 fields 3-5 times during the cotton growing season using pitfall traps and beatsheets, recording all the spiders collected to family. We found that spider communities in cotton are diverse, including a large range of foraging guilds, making them suitable for a conservation biological control programme. We also found that spider diversity increased from high to low latitudes, and the communities were different, even though the spiders were in the same monocultural habitat. Spider beatsheet communities around Australia were dominated by different families, and responded differently to seasonal changes, indicating that different pest groups would be targeted at different locations. These results show that diversity can increase from high to low latitudes, even if spatial heterogeneity is held constant, and that other factors external to the cotton crop are influencing spider species composition. Other models which may account for the latitudinal gradient, such as non-equilibrium regional processes, are discussed.

Action learning in partnership with Landcare and catchment management groups to support increased pasture sowings in southern inland Queensland

The incorporation of sown pastures as short-term rotations into the cropping systems of northern Australia has been slow. The inherent chemical fertility and physical stability of the predominant vertisol soils across the region enabled farmers to grow crops for decades without nitrogen fertiliser, and precluded the evolution of a crop–pasture rotation culture. However, as less fertile and less physically stable soils were cropped for extended periods, farmers began to use contemporary farming and sown pasture technologies to rebuild and maintain their soils. This has typically involved sowing long-term grass and grass–legume pastures on the more marginal cropping soils of the region. In partnership with the catchment management authority, the Queensland Murray–Darling Committee (QMDC) and Landcare, a pasture extension process using the LeyGrain™ package was implemented in 2006 within two Grain & Graze projects in the Maranoa-Balonne and Border Rivers catchments in southern inland Queensland. The specific objectives were to increase the area sown to high quality pasture and to gain production and environmental benefits (particularly groundcover) through improving the skills of producers in pasture species selection, their understanding and management of risk during pasture establishment, and in managing pastures and the feed base better. The catalyst for increasing pasture sowings was a QMDC subsidy scheme for increasing groundcover on old cropping land. In recognising a need to enhance pasture knowledge and skills to implement this scheme, the QMDC and Landcare producer groups sought the involvement of, and set specific targets for, the LeyGrain workshop process. This is a highly interactive action learning process that built on the existing knowledge and skills of the producers. Thirty-four workshops were held with more than 200 producers in 26 existing groups and with private agronomists. An evaluation process assessed the impact of the workshops on the learning and skill development by participants, their commitment to practice change, and their future intent to sow pastures. The results across both project catchments were highly correlated. There was strong agreement by producers (>90%) that the workshops had improved knowledge and skills regarding the adaptation of pasture species to soils and climates, enabling a better selection at the paddock level. Additional strong impacts were in changing the attitudes of producers to all aspects of pasture establishment, and the relative species composition of mixtures. Producers made a strong commitment to practice change, particularly in managing pasture as a specialist crop at establishment to minimise risk, and in the better selection and management of improved pasture species (particularly legumes and the use of fertiliser). Producers have made a commitment to increase pasture sowings by 80% in the next 5 years, with fourteen producers in one group alone having committed to sow an additional 4893 ha of pasture in 2007–08 under the QMDC subsidy scheme. The success of the project was attributed to the partnership between QMDC and Landcare groups who set individual workshop targets with LeyGrain presenters, the interactive engagement processes within the workshops themselves, and the follow-up provided by the LeyGrain team for on-farm activities.

Resin-foraging by colonies of Trigona sapiens and T. hockingsi (Hymenoptera: Apidae, Meliponini) and consequent seed dispersal of Corymbia torelliana (Myrtaceae).

Resins are a critical resource for stingless bees and resin-collecting bees act as seed dispersers in tropical plants. We describe the diurnal foraging patterns of colonies of Trigona sapiens and T. hockingsi on resin and pollen. We also document patterns of waste removal and seed dispersal of Corymbia torelliana. At most, only 10% of foragers collected resin or dispersed seed. Nevertheless, bees dispersed 1-3 seeds outside the nest per 5 minutes, and 38-114 seeds per day for each nest. The proportion of returning bees carrying pollen was highest in the morning for both species. The proportion of foragers returning with resin loads showed no significant diurnal variation in any season. Waste removal activity peaked in the afternoon for T. sapiens and in the morning for T. hockingsi. Seed removal peaked in the afternoon in one year only for T. sapiens. Bees dispersed thousands of seeds of C. torelliana over the season even though only a small proportion of the colony was engaged in seed transport.

Spatial and diurnal pattern of protein foraging by Bactrocera tryoni (Froggatt) on a host plant

Background: Queensland fruit fly, Bactrocera tryoni, is the major pest fruit fly in Australia. Protein bait sprays, where insecticides are mixed with spot applications of a protein based food lure, are one of the sustainable pre-harvest fruit fly management strategies used in Australia. Although protein bait sprays do manage fruit fly infestation in the field, there is little science underpinning this technique and so improving its efficacy is difficult. Lacking information includes where and when to apply protein bait in order to best target foraging B. tryoni. As part of new work in this area, we investigated the effect of height of protein on tree and host plant fruiting status on the spatial and temporal protein foraging patterns of B. tryoni. MEthod: The work was conducted in the field using nectarine and guava plants and wild B. tryoni at Redland Bay, Queensland, Australia. Spot sprays of protein bait were applied to the foliage of randomly selected fruiting and non-fruiting trees. Each tree received protein bait spot sprays on the lower and higher foliage at 0530hrs. The number, sex and species of flies that fed on each protein spot were recorded hourly from 0600hrs through to 1800hrs.Results: For nectarines, there was a significant difference in the number of B. tryoni feeding on protein bait placed at different locations within the tree (ANOVA, F = 8.898, p = 0.001). More flies fed on protein placed on higher foliage relative to lower, irrespective of the fruiting status of the nectarine trees. A significant difference was also observed in the diurnal protein feeding pattern of B. tryoni (ANOVA, F = 2.164, p = 0.024), with more flies feeding at 1600hrs. Results for guava are still being collected and will be presented at the meeting.Conclusions: We conclude that B. tryoni effectively forages for protein at heights higher than 1.3m from ground, indicating greater efficacy of protein bait when applied at foliage higher in the canopy. Bactrocera tryoni actively forages for protein throughout the day, with a highest feeding peak at 1600hrs. The lack of significant difference in the spatial protein foraging pattern between fruiting and non-fruiting nectarine trees may be a real result, or may have resulted from the fruiting tree being very close (within 1 – 2 metres) of the non-fruiting tree. This hypothesis is being tested in the guava trial.

Foraging behaviours of Diachasmimorpha kraussii (Fullaway) (Hymenoptera: Braconidae) and its host Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) in a nectarine (Prunus persica (L.) Batsch var. nectarina (Aiton) Maxim) orchard

Diachasmimorpha kraussii is a larval parasitoid of dacine fruit flies. Host utilisation behaviour, including field foraging behaviour, is poorly known in this species. The diurnal foraging behaviour of D. kraussii and one of its common hosts, Bactrocera tryoni, in a nectarine orchard was concurrently recorded. Observations of mating, resting, feeding and oviposition were taken two-hourly on 42 trees, commencing at 07:00 h and terminating at 17:30 h, for 17 days. Resting and oviposition were common events within the orchard for both species, while mating behaviours were not recorded in the orchard for either species. Feeding was not observed for D. kraussii and was rare for B. tryoni. At the level of the individual tree there was a very weak, but significant correlation between parasitoid and fly abundance over a day, but when broken down to the individual observation periods the correlations were absent, or were weakly significant in an inconsistent manner (i.e. sometimes positively correlated, sometimes negatively correlated). At the orchard level, abundance of the parasitoid was not correlated with adult fly abundance. Results suggest that D. kraussii forage independently to adult B. tryoni, a result consistent with a prediction that their foraging is largely driven by larval or plant damage cues.

Effect of physiological and experiential state of Bactrocera tryoni flies on intra-tree foraging behavior for food (bacteria) and host fruit

Using caged guava trees in Queensland, Australia, provided with food and oviposition sites, the foraging behaviour of females of the tephritid Bactrocera tryoni was investigated in relation to hunger for protein, the presence or absence of bacteria as a source of protein, the degree of prior experience with host fruit and quality of host fruit for oviposition. One aim was to evaluate whether it is immature or mature B. tryoni females that are responsible for initially inoculating host fruit surfaces with "fruit-fly-type" bacteria, the odour of which is known to attract B. tryoni females. Three-week-old immature females provided with sucrose but deprived of protein from eclosion had a much greater propensity than 3-week-old protein-fed mature females to visit vials containing fruit-fly-type bacteria, irrespective of whether vials were associated with adjacent host fruit or not. In the absence of associated bacteria in vials, immature females had a much lower propensity than mature females to visit host fruit. In the presence of bacteria in vials, however, propensity of immature and mature females to visit fruit was about equal. Mature (but not immature) females were more inclined to visit fruit that ranked higher for oviposition (nectarines) than fruit that ranked lower (sweet oranges). Mature females that attempted oviposition during a single 3-min exposure period to a nectarine prior to release were much more likely to find a nectarine than were mature females naive to fruit or immature females with or without prior contact with fruit. Exposure to a nectarine before release did not affect the propensity of either mature or immature females to alight on an odourless visual model of a nectarine, however. As judged by numbers of leaves visited, protein-deprived immature females were more active than protein-fed mature females, irrespective of the sorts of resources on a tree. It was concluded that: the 1st B. tryoni females to arrive on the fruit of a host tree and therefore inoculate the fruit with fruit-fly-type bacteria were unlikely to be sexually immature, but to be mature as a result of having earlier acquired protein elsewhere; the odour of colonies of fruit-fly-type bacteria when associated with host fruit attracted protein-hungry but not protein-fed females; and the odour of the fruit itself attracted mature females (especially experienced ones) but not immature females.

Spatial and temporal foraging patterns of Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), for protein and implications for management

Fruit flies require protein for reproductive development and actively feed upon protein sources in the field. Liquid protein baits mixed with insecticide are used routinely to manage pest fruit flies, such as Bactrocera tryoni (Froggatt). However, there are still some gaps in the underpinning science required to improve the efficacy of bait spray technology. The spatial and temporal foraging behaviour of B. tryoni in response to protein was investigated in the field. A series of linked trials using either wild flies in the open field or laboratory-reared flies in field cages and a netted orchard were undertaken using nectarines and guavas. Key questions investigated were the fly's response to protein relative to: height of protein within the canopy, fruiting status of the tree, time of day, season and size of the experimental arena. Canopy height had a significant response on B. tryoni foraging, with more flies foraging on protein in the mid to upper canopy. Fruiting status also had a significant effect on foraging, with most flies responding to protein when applied to fruiting hosts. B. tryoni demonstrated a repeatable diurnal response pattern to protein, with the peak response being between 12:0016:00 h. Season showed significant but unpredictable effects on fruit fly response to protein in the subtropical environment where the work was undertaken. Relative humidity, but not temperature or rainfall, was positively correlated with protein response. The number of B. tryoni responding to protein decreased dramatically as the spatial scale increased from field cage through to the open field. Based on these results, it is recommend that, to be most effective, protein bait sprays should be applied to the mid to upper canopies of fruiting hosts. Overall, the results show that the protein used, an industry standard, has very low attractancy to B. tryoni and that further work is urgently needed to develop more volatile protein baits.

Asian Honey Bee (Apis cerana javana) in Cairns, Far North Queensland: Foraging, nesting and swarming behaviour

Report of field observations April 2007 to September 2011

Foraging Behaviour and Landscape Utilisation by the Endangered Golden-Crowned Flying Fox (Acerodon jubatus), The Philippines

Species of Old World fruit-bats (family Pteropodidae) have been identified as the natural hosts of a number of novel and highly pathogenic viruses threatening livestock and human health. We used GPS data loggers to record the nocturnal foraging movements of Acerodon jubatus, the Golden-crowned flying fox in the Philippines to better understand the landscape utilisation of this iconic species, with the dual objectives of pre-empting disease emergence and supporting conservation management. Data loggers were deployed on eight of 54 A. jubatus (two males and six females) captured near Subic Bay on the Philippine island of Luzon between 22 November and 2 December 2010. Bodyweight ranged from 730 g to 1002 g, translating to a weight burden of 3–4% of bodyweight. Six of the eight loggers yielded useful data over 2–10 days, showing variability in the nature and range of individual bat movements. The majority of foraging locations were in closed forest and most were remote from evident human activity. Forty-six discrete foraging locations and five previously unrecorded roost locations were identified. Our findings indicate that foraging is not a random event, with the majority of bats exhibiting repetitious foraging movements night-to-night, that apparently intact forest provides the primary foraging resource, and that known roost locations substantially underestimate the true number (and location) of roosts. Our initial findings support policy and decision-making across perspectives including landscape management, species conservation, and potentially disease emergence.