Basic and Applied Ecology最新文献

The interaction between plants and pollinators has intrigued scientists for centuries. While it continues to be [a] subject of ongoing research in basic and applied ecology, we tend to ignore that plant-pollinator interactions are largely driven by chemistry. For example, the amounts and composition of various chemical compounds determine flower colour, the attractiveness of scent and the nutritional value of floral rewards. In this perspective article, we focus on the chemistry of pollen and nectar. We discuss differences in the function, diversity and variation of compound groups that are considered macro- and micronutrients for pollinators as well as in non-nutritive plant secondary metabolites (PSM). We highlight that effects of and pollinator responses to different compounds vary strongly among pollinator species and (groups of) compounds. Moreover, we challenge the commonly applied separation between toxic (e.g. several PSMs) and beneficial (e.g. most nutrients) compounds and point to a dose-dependent toxicity across compounds. We finally provide a list of open questions for future research. We draw particular attention to the unknown effects that interactions between plant-produced compounds and externally applied compounds (e.g. pesticides, pollutants) may have on the plant-pollinator mutualism.

Bees are the most important group of insect pollinators, but their populations are declining. To gain a better understanding of wild bee responses to different stressors (e.g. land-use change) and conservation measures, regional and national monitoring schemes are currently being established in Germany, which is used here as a model region, and in many other countries. We offer perspectives on how to best design future bee monitoring programs with a focus on evaluating the implementation of conservation measures. We discuss different traditional and novel sampling methods, their efficacy depending on research questions and the life-history traits of target species, and how greater standardization of wild bee sampling and monitoring methods can make data more comparable, contributing to the identification of general trends and mechanisms driving bee populations. Furthermore, the potential impact of bee sampling itself on bee populations is discussed.

Regulation of insect pests by predators is an integral component of biological pest control. However, predator-prey interactions often reach a stable state leading to coexistence, which can be problematic for plant protection if the persisting herbivores exceed a damage threshold. Consequently, understanding the factors mediating this stability is crucial for successful biocontrol. Here, we investigated the predator-prey interaction of an important apple pest, the woolly apple aphid (WAA) (Eriosoma lanigerum Hausm.) (Hemiptera: Aphididae), and its predator, the omnivorous common earwig (Forficula auricularia L.) (Dermaptera: Forficulidae). To this end, we introduced increasing densities of earwigs in gauze-bagged branches harbouring defined amounts of WAA and recorded predation on individual WAA colonies for almost one month. We showed that the spatial complexity of the predation environment and the earwig density determined the predation efficiency on WAAs. Earwigs could eradicate WAAs regardless of density on short apple branches without lateral twigs (first trial). However, on longer, more complex branches (second trial), stable states of WAAs and earwigs were observed. Only the highest earwig density could completely consume WAA regardless of branch complexity. We introduce a conceptual model to describe the searching capability of earwigs, which determines their efficiency in locating prey. Our model predicts that searching capability is reduced by environmental complexity; this effect is alleviated by increased earwig density, as more predators possess a higher searching capability. Conclusively, our model explains why only the highest earwig density could completely consume WAA irrespective of complexity and illustrates how predator density and environmental complexity jointly influence predation. Thus environmental characteristics not inherent to our predator-prey interaction were a decisive factor for effective predation on gauze-bagged branches. Based on these results, reducing tree complexity by pruning or augmenting earwig populations in orchards can increase biocontrol of the WAA.

Mammals have evolved to occupy spatial and temporal niches in order to optimize resource utilization and minimize predation risk or competition. Subsequently, niche partitioning may be influenced by phylogenetic associations, which could have substantial consequences for ecosystem structure and function. We use the output from occupancy models based on camera trapping data to construct a tri-partite network describing the environmental and temporal partitioning of activity among twelve sympatric mammals in the Apennine Mountains of central Italy. We further evaluate if there were any effects of phylogenetic associations on the contributions of species to the properties of this spatio-temporal network. The Apennines form a pristine region in central Italy with a relatively intact Mediterranean mammal fauna. The mammal community in our study consisted of species ranging in size from 300 gs to over 200 kg, and included herbivores, omnivores and predators. There was limited structuring of the network describing environmental and temporal niche use. Furthermore, we did not find any phylogenetic signal in species contributions to network structures, and phylogenetic relatedness among species was not associated with their similarities in environmental or spatial niche use. However, animals appeared to have partitioned environmental niches more than temporal ones, suggesting that spatial variation in resource availability may have been more important than temporal avoidance of predation risk or competition in shaping activity within this mammal community. Our study highlights the need to evaluate under which conditions evolutionary history is influencing contemporary ecological processes.

The rapid decline of biodiversity is directly threatening the maintenance of important ecosystem processes. Yet, biodiversity loss is not homogeneous, with species presenting specific traits being more prone to extinction. Ultimately this can lead to potential disruption of key ecosystem functions. Ants are ubiquitous and abundant in all terrestrial ecosystems. They provide a plethora of ecosystem functions and thus are well suited for studies assessing ecological processes. Within ant communities, body size of different species can vary by several orders of magnitude reflecting different ecologies. To this point, however, our understanding of the efficiency of ecological processes by different classes in function of their body size remains largely unexplored under field conditions. This is in part due to a lack of adequate methodology for an easy and accurate assessment of their respective contributions. Here, we describe a novel approach that separates ants into three size classes based on two parameters: height of the access point and size of the entrance; and evaluated the success of this method by assessing morphometric parameters of the size classes post-filtering and quantifying the scavenging efficiency as a key ecological process. This method successfully segregated individuals based on their body size, with the large-size treatment allowing access to ants 3 times larger than ants on the medium-size treatment and 5 times larger than those on the small-size treatment. The large-size treatment was the most efficient, removing 7 times more bait per hour than the medium-size treatment and 40 times more than the small-size treatment. This approach provides a new, adjustable method for differential exclusion in the field, highlighting the role that different size classes play within a community. This opens new opportunities to study the relative role of specific functional traits, and the importance of ecological interactions in shaping ecosystem functions.

Semi-natural habitats (SNHs) surrounding agricultural fields contribute significantly to biodiversity in agricultural landscapes. SNHs can be divided into large habitat patches such as contiguous patches of forests, and smaller, interspersed linear habitat types such as grassy field margins. Traditional small-holder agricultural farmlands in China, replete with rich linear habitats, are notably beneficial for biodiversity. However, as these farmlands undergo consolidation to enhance the efficiency of machinery, linear habitats are being removed, a process that could adversely affect biodiversity. Appropriate agri-environmental measures (AEM), such as the restoration of field margins via strategic planting, could serve as an effective countermeasure to maintain biodiversity in consolidated land. This paper discusses how biodiversity monitoring can aid in evaluating the impact of land consolidation and the efficacy of AEM in China, from species richness and species composition perspectives. The paper also discusses the function of linear habitats and how they interact with large habitat patches in promoting biodiversity, while noting that outcomes are likely to vary among taxa. Long-term, multiple-taxa and comprehensive assessments are recommended in further studies, and a collaborative approach that involves multiple stakeholders is essential to ensure a success implication of AEM in China.

Urbanisation is a main driver of land-use change, leading to rising in temperatures and fragmentation and reduction of green areas. Bees and wasps, which are important insect groups due to the ecosystem services they provide, may respond to this disturbance via changes in morphological traits which are functionally relevant. To date, studies focusing on this aspect only investigated few social bee species, and often gave contrasting results even at intra-generic level. Here, we studied how body size, wing loading, wing aspect ratio and wing fluctuating asymmetry vary in a social ground-nesting bee (Halictus scabiosae), a solitary hole-nesting bee (Osmia cornuta) and a social paper wasp (Polistes dominula) along an urbanisation gradient within Milan (Italy). By assessing the effects of temperature, green areas fragmentation and vegetation productivity on the above-listed functional traits, we found the three species to variably respond to increasing urbanisation, albeit the driving environmental parameters differed among species. More specifically, smaller individuals were sampled in warmer (for bees) and in less productive (for wasps) areas along the urbanisation gradient. Furthermore, greater wing aspect ratio values were recorded at warmer locations for H. scabiosae, lower wing loading was recorded at more fragmented sites for O. cornuta, and greater wing loading was recorded at locations with greater productivity for P. dominula. H. scabiosae and P. dominula showed greater wing fluctuating asymmetry at more fragmented sites. Although distinct species seemed sensitive to different driving factors, our results point toward a consistent response: smaller body but potentially improved flight performance in more urbanised environments.

An important, yet overlooked form of anthropogenic pollution is sensory pollution, and one of the most pervasive forms of sensory pollution is artificial light at night (ALAN). Despite the growing use of ALAN across the globe, limited research has examined the impacts of ALAN on coral reef fish. This study aims to further our understanding of the behavioural impacts of light pollution on fish by exposing the humbug damselfish (Dascyllus aruanus) to ALAN (∼15–25 lux, white LED light) over a period of 14 days, in situ. We assessed nocturnal activity, and diurnal shelter use and emergence time following a simulated threat in natural (control) and ALAN conditions. D. aruanus colonies exposed to ALAN were active at night and were lacking cryptic colouration observed in control fish, however this altered nocturnal activity did not appear to impact the diurnal behaviours we measured. Our findings provide critical insight into the impact of ALAN exposure to nocturnal behaviour of a diurnal fish and highlight the potential for increased risk of nocturnal predation under ALAN. Further studies with a longer ALAN exposure time will help illuminate the extent of behavioural changes and implications caused by ALAN in shallow coral reef systems.

Anthropogenic light at night is growing exponentially while many insect populations are in decline. Many nocturnal insects provide numerous ecosystem services and are attracted to anthropogenic lights at night resulting in decreased fitness, greater mortality and population declines. During twilight and night, moths are depredated by bats and birds, both of which use vision, among other strategies, to detect and prey upon moths. The visual detection of moths by predators is dependent upon the light environment illuminating the moth's body. Effects of anthropogenic light at night can differ drastically with the color (spectral composition) and intensity of light. Currently, high pressure sodium lamps (HPS) and light emitting diodes (LEDs) are common municipal light sources, and these lights differ spectrally, thus altering the visual scene. Most LEDs are broadband (i.e., white) whereas HPS are long wavelength dominant (i.e., amber); both of these light types can alter color perception of prey. To test if moths are more likely to survive under HPS lighting than LEDs and non-lit poles, we used plasticine clay models. Visual model analyses reveal that HPS lamps rendered moths more cryptic against their background than LEDs or ambient urban lighting, albeit with small differences in contrast that may not be biologically relevant. These results indicate that HPS lighting is the most insect-friendly lighting when considering depredation on insects in comparison to LED.