Assessing the ecological risk posed by a recently established invasive alien predator: Harmonia axyridis as a case study

Invasive alien predators are a serious threat to biodiversity worldwide. However, there is no generic method for assessing which local species are most at risk following the invasion of a new predator. The harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is an alien in Europe and many other parts of the world where it affects other species of ladybirds through competition for food and intra-guild predation (IGP). Here, we describe a method developed to assess which European ladybird species are most at risk following the invasion of H. axyridis. The three components of the risk assessment are: the likelihood that the assessed native species encounters H. axyridis in the field, the hazard of competition for food, and the IGP hazard. Thirty native European ladybird species were assessed through data obtained from field observations, laboratory experiments and literature reviews. The species that are considered most at risk are found on deciduous trees, have immature stages which are highly vulnerable to IGP by H. axyridis, and are primarily aphidophagous. These species should be the focus of specific studies and possibly conservation actions. The risk assessment method proposed here could be applied to other alien predators which are considered a threat to native species through competition and predation

Harmonia axyridis implicated in native European ladybird declines

Rates of global extinction are orders of magnitude higher than historical estimates and show no sign of slowing. The Convention on Biological Diversity and the 10th Conference of the Parties (Nagoya in 2010), identified invasive alien species (IAS) as one of five major pressures driving biodiversity loss, and ultimately extinction of species. However, there are few examples of causal relationships between IAS and species declines. IAS afford a unique opportunity to accurately assess threats to biodiversity because the time at which an IAS arrives within an ecosystem is often known, unlike other drivers of change. We examined trends in distribution of native ladybirds from large-scale and long-term annual citizen-science surveys before and after the arrival of the predatory harlequin (or Asian) ladybird Harmonia axyridis, an IAS that is rapidly expanding across North America and Europe. We report rapid, dramatic and ongoing declines in the distribution of formerly common and widespread native ladybirds in direct response to the arrival of H. axyridis in Belgium and Britain. The dramatic decline of A. bipunctata over the five years following the arrival of H. axyridis is of particular note. Trends in ladybird abundance revealed similar patterns of declines in ladybirds across Belgium, Britain and Switzerland. Together, these parallel analyses show H. axyridis to be displacing native ladybirds with a high niche overlap, probably through predation and competition. Such rapid biotic homogenisation at the continental scale could impact on the resilience of ecosystems and severely diminish the services they deliver

Harmonia axyridis implicated in native European ladybird declines

Rates of global extinction are accelerating and show no sign of slowing (Millenium Ecosystem Assessment, 2005). Invasive alien species (IAS) are recognised as major drivers of biodiversity loss (Winter et al., 2009). IAS afford a unique opportunity to accurately assess threats to biodiversity because the time at which an IAS arrives within an ecosystem is often known, unlike other drivers of change. However, few causal relationships between IAS and species declines have been documented. We used data collated through extensive citizen-driven field surveys in Belgium and Britain spanning decades, as well as intensive monitoring by scientists in Belgium, Britain and Switzerland. The fine-scale data collection, replicated in time (over decades and including detailed observations before and after the arrival of an IAS) and with extensive coverage in three European countries, combined with powerful modern mixed-modelling (statistical) techniques, provided a uniquely rigorous test of the impacts of an IAS on biodiversity. We report rapid, dramatic and ongoing declines in the distribution of formerly common and widespread native ladybirds in Belgium and Britain following the arrival of Harmonia axyridis (Coleoptera: Coccinellidae), a globally rapidly expanding IAS (Roy et al., 2012). For example, the two-spot ladybird, Adalia bipunctata (Coleoptera: Coccinellidae), declined in both Belgium and Britain over five years after the arrival of H. axyridis

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field