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Several hundred butterfly species show some form of migratory behaviour. Here we identify how the methodologies available for studying butterfly migration have changed over time, and document geographic and taxonomic foci in the study of butterfly migration. We review publications on butterfly migration published in six languages (English, Simplified Chinese, Traditional Chinese, Japanese, Korean, and Spanish), summarise how migration in butterflies has been studied, explore geographic and taxonomic patterns in the knowledge base, and outline key future research directions. Using English search keywords, we found only 58 studies from Asia; however, after searching in local languages, we found an additional 98 relevant studies. Overall, butterfly migration studies are mostly from North America and Europe. Most studies focus on three species: monarch (Danaus plexippus), painted lady (Vanessa cardui) and red admiral (Vanessa atalanta). About 62% of publications are focused on the monarch, with nearly 50% of migratory butterfly species mentioned in only a single paper. Several research methods have been applied to ascribe migratory status and to study the physiology, neurobiology, and ecology of migration; however, virtually all this research is on a handful of species. There remain hundreds of species for which we do not understand the comprehensive seasonal pattern of movement, flight destinations, wintering, or breeding grounds. A better understanding of movement ecology and migratory connectivity is needed to effectively conserve migratory butterflies. It is essential that research becomes more geographically and linguistically representative since migrants frequently cross political borders and international cooperation is necessary for their conservation.

HighlightsInsects dominate the biosphere and play a central role in ecosystem processes, but they are rapidly declining across the world. Protected areas (PAs) are designed to insulate biodiversity from human-induced threats, but they have been mainly designated for vertebrates and plants. Most research on insects in PAs focuses on the representation of species, and few studies assess threats to insects or the role that effective PA management can play. We propose a four-step research agenda to help to ensure that insects are central in efforts to expand the global PA network under the Post-2020 Global Biodiversity Framework.Anthropogenic pressures are driving insect declines across the world. Although protected areas (PAs) play a prominent role in safeguarding many vertebrate species from human-induced threats, insects are not widely considered when designing PA systems or building strategies for PA management. We review the effectiveness of PAs for insect conservation and find substantial taxonomic and geographic gaps in knowledge. Most research focuses on the representation of species, and few studies assess threats to insects or the role that effective PA management can play in insect conservation. We propose a four-step research agenda to help ensure that insects are central in efforts to expand the global PA network under the Post-2020 Global Biodiversity Framework.

Chemical communication in aquatic species can affect many key life history traits, such as prey and predator detection and mate searching. However, changes in the environment can disrupt the effectiveness of signals and the ability of individuals to detect these signals. Many studies have examined the effect of secondary compounds from exotic plants on the ecology and physiology of a range of taxa, but whether the replacement of natural forests with exotic trees influences the behavioural responses of animals by disrupting chemical communication has rarely been investigated. We experimentally tested how eucalypt tree chemicals influenced three key aspects of chemical communication in adult male palmate newts. We tested for effects of both exposure to eucalypt water (i.e. extracts obtained by soaking leaves in mineral water) and the origin of newts (eucalypt plantations and natural oak forests). We examined whether exposure to eucalypt water altered the chemosensory ability of males to detect pools containing females or conspecific alarm cues and to find food. We found that eucalypt leachates had different effects on each behavioural trait. Fewer males detected female chemicals when exposed to the eucalypt than the oak water treatment, independent of the males’ habitat of origin. Newts from oak forest were less able to detect conspecific alarm cues signalling predatory events when exposed to eucalypt water than when exposed to oak water, or than newts from eucalypt plantations for either water treatment. The ability of males to find food using chemical cues was similar in oak and eucalypt treatments. Our results suggest that chemical compounds not previously encountered during the evolutionary history of the species can influence the ability to respond to predators and locate mates. Future studies should explore the fitness costs associated with a reduced ability to respond to predators or detect mates.