1. Convert lawns into diverse natural habitats.

Traditional European or Western lawns are biodiversity deserts (15). There are more than 40 million acres of lawns or turf grass in the United States alone (16), and these groomed/mowed monocultures support few insects and other wildlife. With increasing global fragmentation of natural environments, insects will need quality habitat to be preserved and restored, including travel corridors and stepping stones to allow movement across the landscape (5, 7, 17). Because many insects need little space to survive, even partial conversion of lawns to minimally disturbed natural vegetation—say 10%—could significantly aid insect conservation, while simultaneously lowering the cost of lawn maintenance through reduced watering, and requisite herbicide, fertilizer, and pesticide applications. If every home, school, and local park in the United States converted 10% of their lawn space into natural habitat, this would increase usable habitat for insects by more than 4 million acres. Converting lawns into natural habitat is relatively easy, and if preexisting turf grass is needed to be removed beforehand, this can be done with a sod cutter or through solarization before seeding. Fallen leaves, twigs, and fruit in this space should be left in place, and vegetation should be minimally trimmed or not trimmed at all, as many insects depend on new growth and complex plant structure. A model effort is the "Thousands of Gardens – Thousands of Species" project in Germany, funded by 2.5 million euros from the German Federal Ministry for the Environment (18).

2. Grow native plants.

Although there are exceptions, increasing evidence shows that growing native plants provides more benefits to native insects, on average, than growing nonnative ornamental species. Native insects have tight ecological relationships with native plants that have been shared for millions of years. Many different kinds of insects rely on these plants as a food source or nesting sites. These insects are in turn prey for birds and other wildlife, thus native plants indirectly attract many vertebrates. For example, almost all songbirds (∼96%) feed insects to their young (19), and declines in suburban backyard birds have been linked to an increased number of nonnative plants (20). Native plants, being adapted to local climates and rainfall regimes, can also be easier to maintain. If native plants are unavailable, growing a diversity of nonnatives, especially species that produce nectar, can still benefit insects. For homes that lack yards, native plants can be added to balconies, roofs, or between the curb and sidewalk in cities. There are many books on the native flora of particular regions, and additional information on native plants can be obtained from local and mail-order plant nurseries, native plant societies, conservation organizations, and university extension programs (see SI Appendix). We argue that the beauty of one's yard should not be determined by how well a lawn is maintained or how uniformly its hedges are trimmed, but instead by the diversity of its native plants.

3. Reduce pesticide and herbicide use.

Pesticides often harm nontarget, natural insect populations (reviewed in 5, 7), whereas reduction of their use fosters beneficial arthropods (e.g., 21). Pesticides have been found far from their application source (22) and, in some regions, are more prevalent in urban streams than in those near agricultural lands (23). Many pesticides are applied for cosmetic purposes, that is, aimed only at improving the appearance of nonagricultural green spaces such as lawns, gardens, or parks. Reduction or elimination of cosmetic pesticide use, already legislatively mandated in Nova Scotia and Ontario (24), could greatly benefit both terrestrial and aquatic insect communities.

Mosquito suppression is another frequent motivation for home pesticide use. Pesticide barrier treatments (PBTs), in which pest control companies regularly apply chemicals to vegetation surrounding a home, harm beneficial insects (25) and are thought to promote the development of pesticide resistance in mosquitoes (26). Simple alternative control measures can greatly reduce the need for these chemicals, although judicious use of insecticides is sometimes needed to combat mosquitoes that vector diseases. Nonchemical measures include wearing long sleeves when mosquitoes are active, keeping window screens in good repair, and most importantly, identifying and removing standing water in containers (e.g., buckets, pots, birdbaths, gutters, and old tires), which serve as larval habitat for some mosquito species. Two of the most important pathogen vectors and pest species globally, Aedes aegypti and A. albopictus mosquitoes, utilize these larval habitats in residential areas. Although not all mosquito species use containers as larval habitats, eliminating standing water in the yard is a free, easy, and ecologically sound method to reduce mosquito abundance.

4. Limit use of exterior lighting.

Since the 1990s, nighttime light pollution has increased sharply, even doubling in some of the world’s most biodiverse areas (27, 28). The majority of nocturnal insects are attracted to artificial lights, and these lights are powerful sensory traps that can indirectly kill insects via exhaustion or result in predation before sunrise (29). In Europe, nocturnal moths are declining more quickly than moths and butterflies that fly during the day, and this trend is likely attributable to light pollution (30). Artificial light has also been shown to reduce reproductive success in fireflies because these insects use light to attract mates (31). To reduce harm to insects, people should turn off unneeded lights, dim necessary light sources, use motion-activated lighting, shield bulbs, and switch to bulbs that produce amber- or red-colored light, which produce wavelengths that are less attractive to insects (32). UV-blacklight “bug zappers,” with a purported function to attract pests such as biting flies, mainly kill harmless, nontarget insects (33). Insect populations will benefit from conservation efforts to protect dark night skies.

5. Lessen soap runoff from washing vehicles and building exteriors, and reduce use of driveway sealants and de-icing salts.

Soaps used to wash cars, motorbikes, or the exteriors of buildings often produce significant quantities of pollutants including ammonia, heavy metals, nitrogen, petroleum hydrocarbons, phosphorus, and surfactants that can drain directly into local water systems (34). Natural waterways contain a diversity of aquatic insects, including some of the most threatened animals on Earth (5). As water levels in aquifers precipitously decline globally, we recommend reducing cosmetic and recreational water use and using reclaimed water when possible. Domestic soap usage can be made more environmentally friendly by using biodegradable soaps.

Coal-tar–based sealants, such as polycyclic aromatic hydrocarbons (PAHs), often applied to driveway asphalt, are released as runoff into the soil and the atmosphere, harming both terrestrial and aquatic ecosystems (35). Some states and municipalities have banned their use (36). Alternative soy-based sealants are less toxic. In cold climates, rock salt (halite) is often applied to pavement, including driveways and sidewalks, to prevent icing. However, rock salt is only effective at temperatures above 15°F, and the melted salt can reduce plant growth, cause gastrointestinal disorders in pets, and interfere with insect development, reproduction, and behavior, while damaging concrete (37). Snow blowers, electric snow/ice melt mats, and sand are less harmful, as are salt-free, ice melting chemical formulations such as SafePaw^® (safepaw.com).

6. Counter negative perceptions of insects.

People rarely protect what they do not know and appreciate (38). In many countries, the public is largely unaware of the benefits and services that insects provide, and negative perceptions of insects are widespread (14). Such perceptions can reflect cultural beliefs not grounded in scientific evidence (38) and can be amplified by media sensationalism such as films depicting large, scary insects, or the use of dramatized and misleading headlines.

A concerted effort is needed to counter negative perceptions towards insects. One way to do so is for individuals to know the benefits that insects bring to humankind. These benefits can be easily remembered as the “5Ps”: Insects are 1) pollinators, 2) prey, 3) physical decomposers; they 4) help progress in science and technology; and they 5) provide pleasure. Writing blogs, such as on the “bug of the week” (bugoftheweek.com), and taking photos of insects and writing about them on social media are ways to increase appreciation. Smartphone images can magnify insects and make them more meaningful (14), especially if the images are of high resolution and draw attention. If one’s insect pictures are not high quality, spectacular insect macro photos can be found online (e.g., flickr.com, bugshot.net; images taken by others must be credited appropriately). Insect photos can be deposited in web-based biodiversity portals, such as iNaturalist (inaturalist.org), an app that allows participants to document and share their natural history observations in a common social network. The app is an effective outreach tool that can get people quickly interested in nature and counter their negative perception of insects. Although it helps to know the insect species’ name when uploading images to iNaturalist, it is not required; unidentified species will be subsequently identified by experts. iNaturalist and other community science (also called citizen science) networks have the potential to generate a wealth of baseline information to understand global insect diversity patterns; iNaturalist has effectively informed many scientific studies on species monitoring, biodiversity patterns, and assessing conservation planning (e.g., 39). Community science efforts that contribute to the monitoring of insects include “Bumble Bee Watch” in North America (bumblebeewatch.org), the “Big Butterfly Count” in Europe (bigbutterflycount.org), and “National Moth Week” worldwide (nationalmothweek.org). These are just a few examples of ways professionals and amateurs can observe, learn, and contribute to insect conservation (see SI Appendix for additional examples).

Another means to encourage positive messages about insects is to support and participate in insect-focused public activities. Educational events such as insect fairs, butterfly houses, and live insect zoos exist in Asia, Europe, and North America, and they provide opportunities for participants to handle, learn about, and observe insects (40). Spectacular biological phenomena, such as glowworms in the caves of Australia and New Zealand, migrating monarch butterflies in Mexico, and synchronous fireflies in Malaysia and the United States, all attract thousands of annual visitors (41).

Insect appreciation can also be increased through developing mechanisms that promote insects in culture. An example of a country with prevalent appreciation for insects is Japan. There, insects appear frequently in popular media, animated films, and celebrity quiz shows and are often portrayed as interesting and beneficial (42). Many Japanese insects have approachable common names, and insects appear in anime films and cartoons, often with anthropomorphic traits. Insect enthusiasts in other countries should make efforts to advocate for common names with positive connotations, such as the damselfly “violet dancer” (Argia fumipennis) or the orthopteran “rainbow grasshopper” (Dactylotum bicolor). There should also be concerted efforts to standardize common names of species that appear often in the media (e.g., Asian giant hornet, Vespa mandarinia) and move away from common names with a negative undertone such as “murder hornet.” Japan could serve as a model for elevating insect appreciation through celebrity nature advocacy, animation films, and the use of creative common names, as means of improving attitudes toward insects.

7. Become an educator, ambassador, and advocate for insect conservation.

An individual's outreach to others, through formal or informal teaching, discussion, etc., is a powerful means for increasing awareness and appreciation of insects, especially when the audience is children (43). The first wild animal a child encounters is likely to be an insect in their immediate surroundings. Positive early experiences can be crucial for the development of an appreciation for nature, given the limited time that children now typically spend outdoors (44, 45). Between the ages of 6 to 12 is when an emotional connection to animals typically peaks (44), and this time is therefore important for natural history education and retention. Professional researchers can contribute to this age group by volunteering to provide interactive insect-themed walks or outdoor activities in schools or through churches, scouts, and other programs serving children. Researchers can also teach from afar through “Skype a Scientist” (skypeascientist.com). There are multiple funding sources for K–12 insect education initiatives, such as the Chrysalis Fund from the Entomological Society of America (entsoc.org/chrysalis-fund). Entomological societies across the world should create similar opportunities. Fostering an appreciation of insects, nature, and the outdoors to children is especially impactful, as they will become the stewards of the natural world.

It is also important to talk to adults about insect conservation, and an excellent place to do so is during outdoor group walks and hikes that allow for hands-on, positive interactions with insects. Engage participants by introducing insects through storytelling and personal experiences that can improve retention and interest, for example by including explanations of how they are beneficial. Facts related to the 5Ps (see above), such as that >90% of temperate bird species feed on insects (46), or that the majority of freshwater fish, including popular gamefish species, rely on insects (47), are examples of messages that will inform the public about the positive benefits that insects provide.

8. Get involved in local politics, support science, and vote.

Insect-friendly environmental policies at any level of government will only be adopted if insects are recognized as important. Political advocacy, especially at the local level, can significantly advance insect conservation. For example, landscaping requirements of many homeowners’ associations in the United States have led to overuse of pesticides that harm native insects, birds, and other animals. Members of such associations should advocate to make those rules more environmentally friendly and promote neighborhood interest in conservation (action items 1–5) through discussion with their board and the use of yard signage. Citizens can also interact with local parks departments, planning commissions, city councils, and other governing bodies to advocate for evidence-based policies and practices that help insects. Participating in the design and conservation planning of urban landscapes can have an immediate “bottom-up” effect on local politics and species conservation. For example, residents in the United States successfully advocated for the Miami blue butterfly to be listed under the U.S. Endangered Species Act (naba.org/miamiblue.html). Public advocacy focusing on issues that directly and indirectly impact insects and the environment more broadly can contribute to positive changes at the local and national levels. People should attend events that support increased reliance on science in policy-making, such as the “March for Science” (marchforscience.org), and advocate for larger-scale insect- and conservation-friendly changes, such as banning pesticides in towns, and large environmental initiatives, such as the Paris Climate Agreement (unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement) and the Convention on Biological Diversity (cbd.int/). Becoming locally active and voting for evidence-based science can have long-term global impacts to protect insects. Public opinion is a powerful tool for conservation and can compel decision makers to act (14).