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The Orchidaceae is characterised by the repeated evolution of sexual deception, one of the most specialised pollination strategies. In orchids, sexual deception involves long-range pollinator attraction via mimicry of female insect sex pheromones. At close range, visual signals involving colour mimicry, contrast to the background, and exploitation of pollinator sensory biases could attract pollinators, but remain largely untested. Here we focus on a remarkable system in which species from two only distantly related sexually deceptive orchid genera with strikingly different flowers (Drakaea livida and three species of Caladenia) share the same pollinator, males of the thynnine wasp Zaspilothynnus nigripes. We used spectral reflectance measurements and modelling to investigate pollinator perception of colour, including the first examination of overall colour patterns in flowers via colour pattern geometry analyses. Rather than closely matching the colours of female Z. nigripes, these orchids had strong chromatic and achromatic contrast against their backgrounds. For Caladenia, the sepals and petals show high contrast, while in D. livida, which has diminutive petals and sepals, it is the labellum that contrasts strongly against the background. Despite varying in colour, the Caladenia species all had strong within-flower contrast between a UV-bright central target (column and labellum) and a corolla of radiating stripes (petals and sepals). The colour pattern geometry analyses also indicated that the orchids’ overall colour patterns are highly conspicuous against their backgrounds. Contrast, UV, and target patterns could all enhance detection, and exploit pollinators’ innate preferences. Since colour contrast may function with a range of colours and floral forms, attracting pollinators via contrast rather than visual mimicry may be a critical but previously overlooked process facilitating the evolution of sexual deception.

Propagule dispersal is a crucial aspect of the survival and reproduction of sessile organisms, such as plants and fungi. As such, the colours of fleshy fruits serve as a visual cue for animal dispersers. However, little is known about how, or whether, specific traits of fungal fruiting bodies, such as colour or shape, attract animal dispersers, and additionally the identities of fungal dispersers are poorly understood. Globally, most truffle-like fungi are dull-coloured, subterranean, and likely have scents that are attractive to mammalian dispersers. In Aotearoa-New Zealand, however, brightly coloured truffle-like fungi that emerge from the forest floor have seemingly proliferated. This proliferation has prompted the hypothesis that they are adapted to dispersal by a bird-dominated fauna. In our study, we used the literature and citizen science data (GBIF) to explore whether colourful species occur at a higher proportion of the total truffle-like fungi flora in Aotearoa-New Zealand than elsewhere in the world. In addition, we tested for a relationship between biotic factors (avian frugivory and forest cover) and abiotic factors (precipitation, radiation, and temperature) and the prevalence of brightly coloured truffle-like fungi across the world. The most colourful truffle-like fungi are in three defined regions: Australia, South and Central America and the Caribbean, and Aotearoa-NZ. Potential dispersers and the environment both relate to the distribution of truffle-like fungi: we found that increasing levels of frugivory were associated with higher proportions of colourful truffle-like fungi. This finding provides new insights into drivers of certain fungal traits, and their interactions between birds and fungi. Unique ecosystems, such as Aotearoa-NZ's bird-dominated biota, provide fascinating opportunities to explore how plants and fungi interact with the sensory systems of animals., (© 2024. The Author(s).)

Artificial light at night (ALAN) is a growing conservation concern for seabirds, which can become disoriented and grounded by lights from buildings, bridges and boats. Many fledgling seabirds, especially Procellariiformes such as petrels and shearwaters, are susceptible to light pollution. The Hauraki Gulf, a seabird hotspot located near Tāmaki Makaurau/Auckland, Aotearoa-New Zealand's largest urban city, with a considerable amount of light pollution and regularly documented events of seabird groundings. We aim to identify the characteristics of locations especially prone to seabird groundings. We used an online database of seabirds taken to a wildlife rescue facility by the public to map 3 years of seabird groundings and test for correlations between seabird groundings and the natural night sky brightness. We found that areas with lower amounts of natural night sky brightness and greater light pollution often had a higher number of seabirds grounded. Further, we identified important seasonal patterns and species differences in groundings. Such differences may be a by-product of species ecology, visual ecology and breeding locations, all of which may influence attraction to lights. In general, seabird groundings correlate with the brightness of the area and are species-specific. Groundings may not be indicative of human or seabird population abundance considering some areas have a lower human population with high light levels and had high amounts of seabird groundings. These findings can be applied worldwide to mitigate groundings by searching and targeting specific brightly lit anthropogenic structures. Those targeted structures and areas can then be the focus of light mitigation efforts to reduce seabird groundings. Finally, this study illustrates how a combination of community science, and a concern for seabirds grounded from light attraction, in addition to detailed animal welfare data and natural night sky brightness data can be a powerful, collaborative tool to aid global conservation efforts for highly-at-risk animals such as seabirds., Competing Interests: The authors declare that they have no competing interests., (© 2022 Heswall et al.)

Passive acoustic monitoring (PAM) coupled with automated species identification is a promising tool for species monitoring and conservation worldwide. However, high false indications of presence are still an important limitation and a crucial factor for acceptance of these techniques in wildlife surveys. Here we present the Assemblage of Focal Species Recognizers-AFSR, a novel approach for decreasing false positives and increasing models' precision in multispecies contexts. AFSR focusses on decreasing false positives by excluding unreliable sound file segments that are prone to misidentification. We used MatlabHTK, a hidden Markov models interface for bioacoustics analyses, for illustrating AFSR technique by comparing two approaches, 1) a multispecies recognizer where all species are identified simultaneously, and 2) an assemblage of focal species recognizers (AFSR), where several recognizers that each prioritise a single focal species are then summarised into a single output, according to a set of rules designed to exclude unreliable segments. Both approaches (the multispecies recognizer and AFSR) used the same sound files training dataset, but different processing workflow. We applied these recognisers to PAM recordings from a remote island colony with five seabird species and compared their outputs with manual species identifications. False positives and precision improved for all the five species when using AFSR, achieving remarkable 0% false positives and 100% precision for three of five seabird species, and < 6% false positives, and >90% precision for the other two species. AFSR' output was also used to generate daily calling activity patterns for each species. Instead of attempting to withdraw useful information from every fragment in a sound recording, AFSR prioritises more trustworthy information from sections with better quality data. AFSR can be applied to automated species identification from multispecies PAM recordings worldwide., Competing Interests: The authors have declared that no competing interests exist.

Worldwide, anthropogenic change is causing biodiversity loss, disrupting many critical ecosystem functions. Most studies investigating the relationship between biodiversity and ecosystem functioning focus on species richness, predominantly within the context of productivity-related functions. Consequently, there is limited understanding of how other biodiversity measures, such as species evenness (the distribution of abundance among species), affect complex multitrophic functions such as pollination. We explore the effect of species evenness on the ecosystem function of pollination using a controlled experiment with selected plants and insects in flight cages. We manipulated the relative abundances of plant and pollinator species, while holding species richness, composition, dominance order, and total abundance constant. Then, we tested how numerical species evenness affected network structure and consequently, seed production, in our artificial communities. Contrary to our expectation, numerical dominance in plant communities increased complementarity in pollinator use (reduced pollinator sharing) among plant species. As predicted by theory, this increased complementarity resulted in higher seed production for the most dominant and rare plant species in our cages. Our results show that in a controlled experimental setting, numerical species evenness can alter important aspects of plant-pollinator networks and plant reproduction, irrespective of species richness, composition, and total abundance. Extending this understanding of how species evenness affects ecosystem functioning to natural systems is crucial as anthropogenic disturbances continue to alter species' abundances, likely disrupting ecosystem functions long before extinctions occur., (© 2019 by the Ecological Society of America.)

Aim: We test for spatial and climatic patterns of diversification in the Orchidaceae, an angiosperm family characterized by high levels of species diversity and rarity. Globally, does orchid diversity correlate with land area? In Australia, does diversity correlate with herbarium collecting effort, range size, or climate niche breadth? Where are Australia's orchids distributed spatially, in protected areas, and in climate space?, Location: Global, then Australia., Methods: We compared orchid diversity with land area for continents and recognized orchid diversity hotspots. Then, we used cleaned herbarium records to compare collecting effort (for Australian Orchidaceae vs. all other plant families, and also among orchid genera). Spatial and climate distributions were mapped to determine orchids' coverage in the protected area network, range sizes, and niche breadths., Results: Globally, orchid diversity does not correlate with land area (depauperate regions are the subantarctic: 10 species, and northern North America: 394 species). Australian herbarium records and collecting effort generally reflect orchid species diversity (1,583 spp.), range sizes, and niche breadths. Orchids are restricted to 13% of Australia's landmass with 211 species absent from any protected areas. Species richness is the greatest in three biomes with high general biodiversity: Temperate (especially southwest and southeast Australia), Tropical, and Subtropical (coastal northern Queensland). Absence from the Desert is consistent with our realized climate niche-orchids avoid high temperature/low rainfall environments. Orchids have narrower range sizes than nonorchid species. Highly diverse orchid genera have narrower rainfall breadths than less diverse genera., Main Conclusions: Herbarium data are adequate for testing hypotheses about Australian orchids. Distribution is likely driven by environmental factors. In contrast, diversification did not correlate with increases in range size, rainfall, or temperature breadths, suggesting speciation does not occur via invasion and local adaptation to new habitats. Instead, diversification may rely on access to extensive obligate symbioses with mycorrhizae and/or pollinators.

Two main mechanisms may buffer ecosystem functions despite biodiversity loss. First, multiple species could share similar ecological roles, thus providing functional redundancy. Second, species may respond differently to environmental change (response diversity). However, ecosystem function would be best protected when functionally redundant species also show response diversity. This linkage has not been studied directly, so we investigated whether native and exotic pollinator species with similar traits (functional redundancy) differed in abundance (response diversity) across an agricultural intensification gradient. Exotic pollinator species contributed most positive responses, which partially stabilized overall abundance of the pollinator community. However, although some functionally redundant species exhibited response diversity, this was not consistent across functional groups and aggregate abundances within each functional group were rarely stabilized. This shows functional redundancy and response diversity do not always operate in concert. Hence, despite exotic species becoming increasingly dominant in human-modified systems, they cannot replace the functional composition of native species., (© 2017 The Author(s).)

Niche construction theory explains how organisms' niche modifications may feed back to affect their evolutionary trajectories. In theory, the evolution of other species accessing the same modified niche may also be affected. We propose that this niche construction may be a general mechanism driving the evolution of mutualisms. Drosophilid flies benefit from accessing yeast-infested fruits, but the consequences of this interaction for yeasts are unknown. We reveal high levels of variation among strains of Saccharomyces cerevisiae in their ability to modify fruits and attract Drosophila simulans. More attractive yeasts are dispersed more frequently, both in the lab and in the field, and flies associated with more attractive yeasts have higher fecundity. Although there may be multiple natural yeast and fly species interactions, our controlled assays in the lab and field provide evidence of a mutualistic interaction, facilitated by the yeast's niche modification., (© 2014 John Wiley & Sons Ltd/CNRS.)

Yeasts that invade and colonise fruit significantly enhance the volatile chemical diversity of this ecosystem. These modified bouquets are thought to be more attractive to Drosophila flies than the fruit alone, but the variance of attraction in natural yeast populations is uncharacterised. Here we investigate how a range of yeast isolates affect the attraction of female D. melanogaster to fruit in a simple two choice assay comparing yeast to sterile fruit. Of the 43 yeast isolates examined, 33 were attractive and seven repellent to the flies. The results of isolate-versus-isolate comparisons provided the same relative rankings. Attractiveness varied significantly by yeast, with the strongly fermenting Saccharomyces species generally being more attractive than the mostly respiring non-Saccharomyces species (P = 0.0035). Overall the habitat (fruit or other) from which the isolates were directly sampled did not explain attraction (P = 0.2352). However, yeasts isolated from fruit associated niches were more attractive than those from non-fruit associated niches (P = 0.0188) regardless of taxonomic positioning. These data suggest that while attractiveness is primarily correlated with phylogenetic status, the ability to attract Drosophila is a labile trait among yeasts that is potentially associated with those inhabiting fruit ecosystems. Preliminary analysis of the volatiles emitted by four yeast isolates in grape juice show the presence/absence of ethanol and acetic acid were not likely explanations for the observed variation in attraction. These data demonstrate variation among yeasts for their ability to attract Drosophila in a pattern that is consistent with the hypothesis that certain yeasts are manipulating fruit odours to mediate interactions with their Drosophila dispersal agent.

Sexually deceptive orchids lure pollinators by mimicking female insects. Male insects fooled into gripping or copulating with orchids unwittingly transfer the pollinia. The effect of deception on pollinators has been considered negligible, but we show that pollinators may suffer considerable costs. Insects pollinating Australian tongue orchids (Cryptostylis species) frequently ejaculate and waste copious sperm. The costs of sperm wastage could select for pollinator avoidance of orchids, thereby driving and maintaining sexual deception via antagonistic coevolution or an arms race between pollinator learning and escalating orchid mimicry. However, we also show that orchid species provoking such extreme pollinator behavior have the highest pollination success. How can deception persist, given the costs to pollinators? Sexually-deceptive-orchid pollinators are almost exclusively solitary and haplodiploid species. Therefore, female insects deprived of matings by orchid deception could still produce male offspring, which may even enhance orchid pollination.