Ficus rubiginosa (the Rusty Fig; Moraceae) provides a keystone food resource for a diverse array of vertebrate frugivores in eastern Australia. These frugivores, in turn, provide vital seed-dispersal services to the fig. The aims of this study were to investigate impacts of population size and climatic variation on avian-frugivore visitation to F. rubiginosa at the extreme western, drier margin of the species' range. Eighty-two bird species visited F. rubiginosa trees in this three-year study. Twenty-nine species were frugivores or omnivorous frugivore/insectivores. The number of ripe fruit in a tree had the greatest positive influence on frugivore visitation (p < 0.0001). Fig-population size influenced the assemblage of frugivore species visiting trees but not the number of frugivores or the rate of frugivore visitation. The number of ripe fruit in a tree was negatively associated with declines in rainfall, to total losses of standing crops through dieback and lack of crop initiation. Predicted long-term declines in rainfall across this region of eastern Australia and increased incidence of drought will lead to reduced crop sizes in F. rubiginosa and likely reduce the viability of local populations of this keystone fig. This will threaten the mutualism between F. rubiginosa and frugivores across the region.

Novel restoration approaches are required to provide food and habitat for declining bird populations, particularly as pressures increase from growing human populations and climate change. Fig (Ficus) species support many frugivores but there is a gap in our knowledge about the importance of these insect-pollinated plants to insectivores. We tested the influences of fig-population size and the number of fig-wasp-producing fruit per tree on avian-insectivore visitation to fig trees in eastern Australia over a three-year period. Eighty-four bird species visited fig trees in our study; two thirds (55) of these species were insectivores. More individual insectivores (1686) than frugivores (1051) visited fig trees (p < 0.0001). More insectivore species visited individual fig trees in small, fragmented populations (<16 fig trees) than in large populations (>50 fig trees; p = 0.016). We showed that figs provide insectivores with an important, year-round, food source. We showed that this occurred in a dry, temperate ecosystem and in a mesic, sub-tropical ecosystem. Insectivore visitation was significantly correlated with the number of ripening fig syconia and the number of emerging fig wasps but not with abundances of other insects in fig trees. Temporal resource partitioning between insectivores and frugivores was identified, with insectivores foraging as fig syconia were ripening, and frugivores foraging after syconia had fully ripened. Ficus species are very likely to provide similar keystone resources for avian insectivores throughout tropical, subtropical and temperate regions globally. This study revises our understanding of the role played by Ficus trees in supporting avian-insectivore populations.

Honeybees Apis mellifera (European honeybee) and Apis cerana (Asian honeybee) are cosmopolitan, having colonized continents beyond their natural ranges. In tropical Australia, these alien species have recently become sympatric. The environmental and economic impacts of these species when in sympatry remain to be seen; however, any interspecific competition may be of significance. We examined conspecific and heterospecific interactions between honeybees foraging at the nectar- and pollen-providing flowers of Antipogon leptopus (Polygonaceae). We cross-classified 554 encounters by three variables; incoming bee species, resident bee species, and one of four potential responses: (1) incoming defers to resident; (2) incoming procures the flower from resident; (3) incoming and resident share the flower; or (4) both incoming and resident abandon the flower. We also measured aggression and foraging rates of workers at flowers. Both species visited similar numbers of flowers in a foraging bout and spent similar foraging times on individual flowers. Incoming A. mellifera were more likely to procure flowers from resident A. cerana, and incoming A. cerana were more likely to defer to resident A. mellifera. A. mellifera were more aggressive toward heterospecifics than conspecifics, with heterospecifics 4.5 times more likely to provoke an aggressive response. However, no significant difference between conspecific and heterospecific aggression was observed for incoming A. cerana. A. mellifera were less abundant, yet overall more likely to acquire flowers and use aggression to do so. Costs of aggression may help explain the population-scale dominance of A. cerana over A. mellifera in this study.

The agistment of managed hives of the introduced honeybee, Apis mellifera, in or adjacent to conservation areas in Australia is controversial. The effects, if any, of honeybee-foraging on native plants and their native-bee pollinators is poorly understood as most studies to date have concentrated on bird-pollinated systems. Furthermore, such studies have been undertaken in temperate Australia where feral and managed hives have been present for more than 150 years. In tropical Australia the impact of honeybees on the native biota is not known—yet the information is needed to assist with planning for the management of the large areas now under control of conservation authorities. We undertook a comparative study of honeybee and native bee pollination of the pioneer species Melastoma affine in tropical north Queensland, Australia, at a site where honeybees were recently introduced as managed hives. Melastoma affine is utilised by many animals in this ecosystem and its pollination mechanism is representative of several other pioneer species of the rainforest margin. Melastoma affine obligately relies on bee pollination to effect seed-set. Native bees were the most abundant floral visitors to M. affine although significantly more honeybees than native bees were sometimes present at flowers at the end of the morning. Honeybees were poor pollinators of M. affine compared with native bees. Honeybees deposited significantly less pollen on stigmas than native bees and honeybees actively removed pollen from stigmas. Consequently, fruit-set was less likely and seed-set was significantly lower in flowers to which honeybees were the last visitor, compared with cases where native bees were the last visitor—and the last visitor to M. affine flowers was most often A. mellifera. In 91% of interactions between honeybees and native bees, native bees were disturbed from foraging at flowers by honeybees. Honeybees reduced fitness in M. affine in this study and we thus conclude that honeybees are an undesirable introduction in montane tropical-rainforest systems in Australia and based on our findings we strongly recommend that honeybees not be agisted in or adjacent to conservation areas in the wet tropics of Australia.

Background and Aims: 'Olearia flocktoniae' is an endangered shrub that was passively translocated from its natural ecosystem, where it has since gone extinct. This study aimed to determine sensitivities vital to populations persisting in human-created areas. Methods: Population colonization, longevity and extinction were investigated over 20 years using 133 populations. Seed-bank longevity was determined from germination trials of seeds exhumed from extinct and extant sites via a 10-year glasshouse trial and by 'in situ' sowing experiments. From 27 populations, 98 cohorts were followed and matrix models of transitions from seeds to adults were used to evaluate the intrinsic rate of population growth against disturbance histories. Ten populations (38 cohorts) with different disturbance histories were used to elevate sensitivities in vital rates. Key Results: Most populations had few individuals (~30) and were transient (<5 years above ground). The intrinsic population growth rate was rarely >1 and all but two populations were extinct at year 20. Seeds were short-lived 'in situ'. Although >1000 seeds per plantwere produced annually in most populations, sensitivity analysis showed that the transition to the seed bank and the transition fromthe seed bank to seedlings are key vulnerabilities in the life-cycle. Conclusions: Seedling establishment is promoted by recent disturbance. Increasing the number of disturbance events in populations, even severe disturbances that almost extirpate populations, significantly increases longerterm population persistence. Only populations that were disturbed annually survived the full 20 years of the study. The results show that translocated populations of 'O. flocktoniae' will fail to persist without active management.

The extent of self-compatibility and reliance on pollinators for seed set are critical determinants of reproductive success in invasive plant species. Seed herbivores are commonly used as biocontrol agents but may also act as flower visitors, potentially resulting in pollination. However, such contrasting or potentially counterproductive interaction effects are rarely considered or evaluated for biological control programs. We investigated the breeding system and pollinators of Bitou Bush ('Chrysanthemoides monilifera ssp. rotundata'), an invasive species in Australia that has been the subject of biocontrol programs since 1987. We found the species to be obligate outcrossing in all six populations tested. From 150 video hours, we found 21 species of potential pollinators, including Mesoclanis polana, the Bitou Seedfly, native to South Africa and released in Australia as a biocontrol agent in 1996. Mesoclanis polana transferred pollen to stigmas and was the most common pollinator (52% of pollinator visits), followed by the syrphid fly 'Simosyrphus grandicornis' (9%) and introduced honeybee, 'Apis mellifera' (6.5%). Fruit-to-flower ratios ranged from 0.12 to 0.45 and were highest in the population with the greatest proportion of 'Mesoclanis polana' visits. In an experimental trial, outside the naturalized range, the native bee 'Homalictus sphecodoides' and the native syrphid 'Melangyna viridiceps' were the primary pollinators, and fruit-to-flower ratios were 0.35, indicating that Bitou Bush would have ready pollinators if its range expanded inland. 'Synthesis'. Invasive Bitou Bush requires pollinators, and this is effected by a range of generalist pollinators in eastern Australia including the Bitou Seedfly, introduced as a biocontrol agent, and the major pollinator detected in this study. Fruit-to-flower ratios were highest when the Bitou Seedfly was in high abundance. This study underscores the importance of evaluating the pollination biology of invasive species in their native ranges and prior to the introduction of biocontrol agents.

Pollinator-prey conflict in carnivorous plants occurs when plants that benefit from pollinators are pollen-limited and pollinators are snared by trap-leaves. To date a strong pollinator-prey conflict has not been found and is attributed to spatial and/or cue differences between flowers and traps abating conflict. Here we test whether pollinator-prey conflict occurs for Drosera hookeri (Droseraceae), which produces entomophilous flowers adjacent to leaf-traps. We also test the hypothesis that flowers have a dual role of pollinator attraction and deception by tumbling pollinators and other floral visitors into leaf-traps. From 2007-2021, in a drought-prone habitat in eastern Australia, pollinator diversity and visitation rates were scored at flowers using camcorders while pan-traps provided an estimate of pollinator abundance in the community. Hand-pollination experiments were used to determine pollinator dependence and pollen limitation. We also measured arthropod abundance in trap-leaves before, during and after flowering. In a paired experiment we compared leaf captures between plants with and without flowers to determine if flowers are complicit in the leaf captures of pollinators. Although self-compatible, with a delayed selfing-mechanism, outcrossed flowers produced more seed than self-pollinated flowers, indicating that pollinators are beneficial. Plants were pollen-limited in both years tested. Flies (non-pollinating and pollinating) were the most common prey with the greatest numbers during peak flowering. Pollinators, predominantly Melangyna virdiceps (Syriphidae, Diptera), contributed c. 57% of prey captures, and experimentally we show that they are not attracted to plants without flowers. Pollinators are often deposited into trap-leaves from flowers, which tip under their weight, to nearby leaf traps. A strong pollinator-prey conflict was detected with an overlap in prey and pollinators in a pollen and pollinator-limited system. Flowers attract pollinators and non-pollinators to plants. Leaf entrapment for pollinators occurs as a mishap in foraging rather than attraction to trap-leaves. The flowers in D. hookeri have the dual role of pollination and prey provision.