Habitat Loss and Urbanization

Habitat Loss and Urbanization

• The Baltimore checkerspot butterfly (Euphydryas phaeton), Maryland's state insect, faces endangerment due to habitat loss and eat turtle heads
• The world population is rapidly growing, increasing urbanization and decreasing rural areas
• The Americas, Eurasia, and Australia are the most urbanized continents, while India and parts of Africa are the least
• The USA has the largest ecological footprint
• The US population has become increasingly urban, rising from ~5% in 1800 to ~80% in 2000
• Urban populations are still expanding, which means that they are no rural populations
• California is the most urbanized state, Maryland ranks 14th, and Maine is the least urbanized
• Diverse natural forests are converted into less diverse farms, which then become less diverse housing developments that turn into less diverse cities due to hardscapes
• Hardscapes, like buildings and roads, prevent water from reaching plants
• Urbanization reduces forest cover by changing woodlands to farmland, open spaces, residential areas, offices, and finally, city centers
• Insects and humans share the same fundamental needs.
• Plants form the base of food webs
• Most insect herbivores exhibit specificity, feeding on a limited range of plant genera, families, or subfamilies

Biodiversity and Urbanization

• Species richness refers to the number of species
• Abundance is the number of individuals
• Diversity encompasses both species richness and abundance
• Plant diversity is higher in residential landscapes
• Plant density is 69,000 plants per km2, with 100 species
• Plant diversity is lower in city streets
• Plant density averages 48 plants per km2, with 30 species
• Insect decline in forests depends on species' traits and management strategies may mitigate it.
• Standardized data from 140 sites in Germany over 10 years shows forests vary in management intensity, and flying insects were sampled yearly using flight interception traps
• Flies are the most common, followed by wasps, bees, moths, and butterflies
• Harvesting intensity impacts species abundance, herbivore abundance, omnivore richness, and abundance
• A meta-analysis on ground beetles found that urbanization impacts beetle communities
• Urban areas have lower species richness (77.6%) and abundance (63.7%) compared to rural areas
• Large, forest, short winged, and predatory beetles have declined with urbanization
• Forest dwelling ground beetle larvae are predators in the soil, while adults hunt caterpillars in trees
• Cankerworms are significant pests in forests and cities.

Native Plants and Ecosystems

• Non-native plants increase in proportion within a species
• Specialist consumer insects disappear when their host plants are lost
• Native plants support native herbivores, while native herbivores may not consume non-native plants
• Exotic plants may support few or no herbivores
• Native plants promote greater biodiversity, attracting more butterflies and birds
• The coevolutionary matrix explains the relationship between plant and pest origins
• Native plants favor native insect specialists
• Exotic insects have enemy release from exotic plants because the plants and animals have not evolved defense mechanisms
• Exotic plants have enemy defense on native insects because native herbivores do not recognize new plants as food
• Native plants and Native insects favor specialists
• Native-dominated landscapes support more chewing herbivores
• Non-native landscapes attract more sucking herbivores
• Native plants are associated with biodiversity
• Increasing native plant diversity is a strategy to counter community simplification and boost prey and predator populations

Grassland and Forest Biodiversity Decline

• Grassland intensification reduces butterfly diversity in Germany's Westerwald mountain range
• Transects of 50 meters were used to record butterfly species numbers
• Grassland management types (fallow, traditional, intensive, and silage) were assessed for their impact on the number of butterfly species
• Less managed grasslands (traditional and fallow) show higher individuals, species, threatened species, diversity, and conservation value
• Intensively managed grasslands and silage lands negatively impact species diversity because cutting grass more often removes potential herbivore and pollinator food/nectar sources

Arthropod Decline in Grasslands and Forests

• Arthropod decline is associated with landscape-level drivers
• Land-use intensification drives decreasing biodiversity
• Over 1 million arthropods (2,700 species) were analyzed from 2008-2017 in Germany
• Annually sampled grasslands showed declines in biomass (67%), abundance (78%), and species number (34%)
• The decline in the number of rare species was consistent across trophic levels, no matter the local land-use intensity
• Sites with more agricultural land cover showed a greater temporal decline decline
• Major drivers of arthropod decline are associated with agriculture act at larger spatial scales

Effects of Urbanization and Land Use on Insect Communities

• Butterfly communities erode from grasslands to farmland and urban areas
• Surveyed 1000 meters squared for 30 minutes, and then counted all butterflies
• Habitat types: extensive meadows, semi-intensive meadows, pastures, vineyards, arable land, apple orchards, and settlement sites all impact insect populations
• High butterfly diversity is found in extensive meadows and pastures.
• All other land-use types showed significantly lower diversity, with decreasing diversity from semi-intensive meadows to apple orchards
• Extensive grasslands support specialized and sedentary species
• All types showed generalist communities
• Rainforests have high temperatures and rainfall, this creates diversity of plants and animals

Tropical Rainforests and Pharmaceuticals

• Tropical rainforests are a major source of medicines
• 120 drugs are derived from rainforest plants (vinblastine, tubocurarine, cortisone, quinine, neostigmine, novocaine)
• 25% of pharmaceuticals come from rainforest plants
• 60% of drugs with anticancer properties are derived from rainforests
• Loss of tropical rainforests amounts to 75,000 km2 yearly
• 200 km2 rainforest is lost per day
• 135 rainforest species go extinct each day
• Human actions (wood extraction, agriculture, land clearing, grazing, pulp, road construction, extraction) are responsible for rainforest destruction
• Destruction is greater to amazonian rainforests than to congo and sundaland
• Primary forests are untouched, while secondary forests have been harvested and regrown

Rainforests, Palm Oil Plantations, and Biodiversity

• Palm oil plantations replace rainforests as well as reduce the food available
• A meta-analysis in Environmental Evidence volume 3, Article number: 4 (2014) evaluated the effects of oil palm production
• A meta-analysis of 25 articles published in peer-reviewed journals was performed
• Independent variables included vegetation type and the presence or absence of a rainforest
• Species richness, abundance, community composition, and ecosystem functions comprised the dependant variables
• Species richness and abundance decline from primary forest to oil palm plantations (beetles > moths > ants) and (beetles > mosquitoes > moths > bees)
• Species richness declines from secondary forest to palm plantations (beetles > isopods), while species abundance stays relatively the same

Insecticides and Pest Control

• Agriculture began 10,000 years ago, farmers tried to ensure their harvest
• Ancient methods included the Mayan rain god (Chaacomol) and corn god (Hun Hunahpu), as well as human sacrifice
• Sumerians used sulfur in 2500 BC to kill grasshoppers
• Chinese used plant extracts as pesticides around 1500 BC
• Paris green (arsenic) and copper sulfate were used in the US in the 1800s to control Colorado potato beetles
• Pyrethrum, as "Persian Powder", was discovered in 1800 and synthesized in 1874
• Insecticidal properties were discovered in Switzerland in 1939
• Paul Muller won a Nobel Prize in 1948 after DDT - an organochlorine insecticide - was discovered
• DDT uses included head lice, mosquito control, and pests in trees and on the ground
• Organophosphates and Carbamates were developed after neurological effects were discovered by accident on humans
• Pesticides became the primary pest control method after WW2
• Biomagnification concentrates compounds up the food chain
• Bald eagles population increased when DDT was banned
• Pesticides can reduce beneficial insect populations for up to six weeks

Modern Pesticide Use

• Global pesticide production is increasing
• Asia is the biggest user of pesticides
• 1960’s - Pesticides with greater specificity and systemic activity developed
• 1970’s - 1980’s - Insect growth regulators available
• 1990’s - 2000’s - neonicotinoids (imidacloprid)
• Corn and Alfalfa have the greatest neonicotinoids use
• Contact insecticide: pest gets wet or eats treated foliage and dies
• Systemic insecticide: insecticide moves into plant, spreads throughout plant, pest eats foliage or drinks plant sap, ex: neonicotinoids
• Systemic insecticides reduce applicator exposure and aerial drift
• Systemic insecticides like neonicotinoids move into flowers, pollen, and nectar, harming pollinators
• Pollinators are in decline, which includes honey bees, bumble bees and solitary bees
• Decline in pollinators affects energy diversity and abundance
• Toxicity is measured for mortality
• The LD50 measures the amount of substance/toxin that kills 50% of a population via oral and contact exposure.
• Effects can be acute lethal, chronic lethal, or sub-lethal
• Sub-lethal effects: impaired reproduction, immune function, foraging, navigation, memory loss, and learning
• Native bumble bees and non-native honey bees are impacted
• Oregon Department of Agriculture confirmed a mass bumble bee death due to the insecticide Safari
• Insecticide known as Safari was banned and is a neonicotinoid insecticide
• Application to aphid infested trees in a parking lot killed bumblebees exposed to the neonicotinoid
• The same neonicotinoid killed honey bees one year later

Regulation and Recommendations for Pesticide Use

• Xerces Society recommends legislators, regulators, and municipal leaders to ban neonicotinoids on ornamental and landscape plants
• Maryland was the first state to restrict neonic use for homeowners
• Factors leading to bee decline are limited floral resources, pyrethroids, parasites, pathogens, and neonicotinoids

Herbicides and Ecosystems

• Herbicides, the most widely used pesticides, reduce crop growth by competing for resources
• Weeds provide food for honey bees during scarcity, improving oilseed rape and sunflower seed production
• Weeds improve soil quality, sheltering insect pollinators, carabids, and birds
• Weeds regulate crop pests and have cultural value for botanists and ornithologists
• Weeds can be managed mechanically or with herbicides like glyphosate (Roundup)
• Corn and soybeans use more glyphosate, with the most use in the central US
• "Roundup Ready” Corn has a CP4 EPSPS gene added to the corn genome, preventing glyphosate from killing it and allowing farmers to kill weeds without harming corn
• GMO crops like cotton and soybean resist dicamba

Herbicides, Weeds, and Crop Production

• Herbicide-tolerant soybean seed allows effective control of weeds
• 80% of soybeans in the US are treated with glyphosate
• Landscape drives weed assemblages in field margins, while crop competition drives assemblages in field cores

Arable Weed Decline and Indicators

• Herbicides reduce the number of weeds in crops
• Arable weed flora of North-East France was surveyed in the 1970s
• Of the 121 species that remained, 40% declined and 10% increased
• Species richness declined (42%), as did species density in the the field (67%)
• Plant species of conservation value persist in the crop edge
• Arable weeds are important to the arable food web, as primary producers
• Three surveys of Finnish spring cereal fields were done in 1961–1964, 1982–1984, and 1997–1999
• Indices of birds, pollinators, insect pests, and weed densities comprised the dependant variable
• Herbicide and insecticide use was higher between 1960 and 1980, after the 1980s fewer pesticides were used and organic food production increased
• Between 1960 and 1980, there was more extensive use of both herbicides and insecticides
• Weed presence increased as fewer and pesticides usage decreased in organic food production after the 1980s
• Monarch butterflies decline, which the increased abundance of milkweed in the landscape a potential driver, may cause declines

Monarch Butterflies and Glyphosate Toxicity

• Studies indicate monarch and milkweed declines are predated by the use of herbicide-resistant crops
• Meta-analytical assays of Glyphosate were performed
• Glyphosate can lead to increased mortality in some species
• Herbicides have a direct effect and can remove critical flora
• Glyphosate exposure impacts honeybee physiology and behavior (flight, responsiveness, learning, and memory)
• Anthropogenic inputs are in the environment due to fertilizer use
• Excess eutrophication results from enrichment, which leads to algal blooms and oxygen depletion
• Dead zones in the Chesapeake Bay have tripled in 30 years
• Aquatic insects can be bioindicators for water quality

Indicator Species and Insecticides

• Aquatic insect nymphs and larvae can be used in aquatic bioindication
• Mayfly, dragonfly and stonefly nymphs, as well as caddisfly larva
• Glyphosate negatively affects physiology and behavior and leads to failed foraging
• The Chesapeake Bay has tripled in the last 30 years in deoxygenated waters

Honeybees

• Honeybees exhibit directional awareness, reward sensitivity, and associative learning through a number of important factors
• The eating of insects is defined as antomogaphie
• Depleted water zones have tripled
• The first human woman created by Hephaestus following instructions provided by Zeus was Pandora
• Pandora let her curiosity get the better of her and opened a jar which contained sickness, greed, intolerance, and death, but not hope
• Today "Opening Pandora’s Box” is equivalent to “Opening a can of worms”
• People move honeybees and other bees because they are valuable
• Honey bees are non-native pollinators
• The total value of honey bee products in the US was $700 million in 2022
• Worth over $500 million is the beeswax produced by honey bees in the United States
• Honeybees were brought for their honey and wax to New Zealand
• Introduced to NZ to feed livestock and enrich the coil with nitrogen by early settlers, red clover would later be found unable to reproduce in NZ
• It was found that native bees often failed to even recognize it as a source of nectar and pollination
• Movement of bees became a major issue when honeybees were found in Europe

Honeybees Compete with Native Bees and Transmit Diseases

• 'Killer Bees' sting and kill 40,000 people in Texas (2013) with actually only 3 or 4 deaths per year
• Ok, so honeybees have been moved to so many locations
• Honey bee introductions displace native bees and decrease pollination of a native wildflower
• Managed honey bees (Apis mellifera) have been widely introduced outside their native range and are dominant floral visitors
• Honey bee additions to fields were compared to those without, relative to native bee flowers
• Bee species are the independent variable of the experiment
• Seed quantity, and Native bee visits to flowers are the main dependent variable
• Native bees are outcompeted as a result of honeybee introductions

Honeybees, Disease, and Ectoparasites

• Introducing honeybees indirectly reduce pollination by decreasing the available of nectar in the area
• Honey bee are ineffective because their inferior visit quality when contrasted to native bees
• Colonies of honeybees number around 80,000 and individuals are exposed to so many pathogens and parasites
• These parasites can include mites (Varroa mites and tracheal mites)
• Fungi, bacteria, microsporidia, viruses, and pathogens naturally occur
• Honeybees have many naturally occurring diseases, the problem is that the transfer of bees around world spreads the diseases
• Honeybees originated in East Africa, yet ancient Egyptians had honeybees some 4500 years prior
• Honey Bee Spread happened through Africa, Europe, Middle East, and North America with human help in colonies
• Aggressive strains were released in Brazil, making them so-called Killer Bees which became Africanized bees

Bee Viral Infections

• Similar to the historical figure of Typhoid Mary, bees are susceptible to virus transfer
• Viral presence or the infection in native bees is the independent variable
• A spike in the prevalence of deadly viruses of the DWV is the effect or dependent variable
• Varrroa increases which increases which subsequently will make DWV higher in titer in the host

Climate Change and Impacts on Ectotherms

• Temperature Anomaly (ºC) has grown, which lists three greenhouse gases (Carbon dioxide, Methane, and Nitrous oxide)
• There is a strong correlation between CO2 in the level to the temperature
• Carbon levels are closely correlated with climate
• Increased air and sea surface temperatures are the result of trapped solar energy, also can translate into stronger storms
• For insect activities, the rule of thumb is that rate of development or activity is linked at or around temperature limits
• Plant and insect populations will see both gains and losses from shifts due to altered climate
• Range expansion occurs among insects and plants constricted through cold through greater latitudes/altitude
• In temperature zones, plant/insect become more active
• Insects and plants with more generations can add more generations
• Crossing the mountains as well expanding to more elevations means spreading eastward
• Higher or warmer temperatures correlate drought and fire with plant hardiness to be shifted

Winners/Losers of Climate Change

• Plant hardiness determines if plants can survive cold at a certain minimum temperatures
• Tree health is affected to include scales. More heat equates to trees with much more wax
• Insects are considered in rainforest to be hot and wet
• Heat level is the reason why monarch summer populations have declined by the millions in 2015
• It is due to heat induced sub-lethality, and carry-over issues
• Heat stress: shorter lifespans, greater death, less size, and lesser ability of fertility and ability for foraging
• The changes due to climate on species show in change across time which is influenced by land use and pesticide use
• Case studies have indicated it is likely for the temperature levels to exceed, and if for long enough, historically the temperatures are going to see a new shift
• There are many changes occurring in insects and plants which has cause many of these patterns of species to move to more cooler climates
• Lethal temperature for beetle elevations is now not the limit needed for the species for their range that no longer ends soon