ENTM Midterm 2 - 2026 fall

UCR ENTM 10 fall 2026

Describe importance of bee pollinators

• Many economically important crops, such as almonds, rely entirely on pollination by bees

• Avoid plant inbreeding by cross pollination

Managed Bees

• Domesticated and managed

• Can be social and solitary

• Build wax combs inside artificial or natural cavities (hives)

• Generalist pollinators

• Essential for large-scale agricultural pollination

Native Bees

• Evolved naturally in specific reasons

• Mostly solitary

• Nest in soil, wood, or plant stems

• Specialized pollinators

• Essential for native ecosystems and wild plant reproduction

Managed Bees Advantages

Advantages:

Efficient large scale agricultural

Predictable and manageable

Honey production and other products

Well studied

Managed Bees Disadvantages

• Disadvantages:

  • Lower efficiency for some native plants

  • Competition with wild bees

  • Dependence of human management

  • Disease and parasite vulnerability

Wild/Native Bee Advantages

• Advantages

  • Pollination efficiency for native plants

  • Biodiversity support

  • Adaptation to local environments

  • Contribute to healthier pollinator communities

Wild/Native Bee Disadvantages

• Disadvantages

  • Not easily controlled or moved

  • Sensitive to habitat perturbation

  • Limited large scale agriculture management

  • Less information about their biology

Recognize principal bee threats

-Habitat degradation

-Pesticides

-Pathogens (24 diff viruses and mites causing collapse in hives.)

Predator

Organism (typically an animal) that kills and eats another living organism (typically an animal)

Prey

Organism that is eaten

Active Predators

• Actively moving in the environment and pursuing prey→ High movement

Ambush Predators:

• Sit-and-wait for prey to pass by before attack→ Low movement

Advantages of insect predation

-Nutrients

-Animal Prey are rich in nitrogen 

Order Mantodea: “Mantids”

• Large raptorial front legs

•  Triangular head

• Large compound eyes

• Chewing mouthparts

• Ambush predators

Order Neuroptera: “lacewings, antlions, mantidflies”

• Haustellate: piercing-sucking mouthparts

• Mandibles and maxillae are elongate, forming feeding tube

• Maxillary palps are absent but labial palps well developed

Order Neuroptera: Family Chrysopidae

• Green lacewings

• Larvae are predaceous (aphid lions)

• Order Neuroptera: Family Myrmeleontidae

• Ant lions

• Larvae construct conical pits and hide in the bottom

  • Sit-and-wait for prey to fall in

Order Mecoptera

“scorpionflies, hanging flies”

Order Coleoptera: Family Carabidae

• Ground beetles or Tiger beetles

•  Cursorial legs

• Females lay eggs in soil

• Larvae hatch and dig deeper into soil

Order Coleoptera: Family Coccinellidae

• Lady bird beetles

• Larvae spotted or banded with minute spines

• Beneficial insects (eat pests!)

• Vedalia beetles (Novius cardinalis)

• Rare example of specialist predator

•  Feeds on a major pest of citrus, cottony cushion scale

Order Hymenoptera: Family Formicidae

• Ants

• Live on all continents except Antarctica

•  Contribute 15-20% of ANIMAL biomass in many terrestrial ecosystems

• Main ecological role is predator

• All ants are social (small workers: nurses, medium: foragers, large: soldiers) 

Order Hymenoptera: Family Vespidae

• Nearly all social wasps (some solitary too)

• Yellowjackets (Vespula spp)

• Generalist predators and scavengers

Order Diptera: Family Asilidae

• Robber flies

• Predacious, some bumblebee mimics

• • Key diagnostic features:

• (1) Stylate mouthparts surrounded by a hairy beard

• (2) Concave depression on top of head between compound eyes

Order Hemiptera: Suborder Heteroptera: Family Reduviidae

• Assassin bugs

• Sit-and-wait sucking predators

• Mouthparts stab prey with lethal saliva that liquefies the insides of prey

• Stridulation on rostrum used as a defense

Parasite

• Lives on or inside another organisms, called the host

  • Host Usually not killed

Parasitoid

• Lives on or inside another organisms, called the host

  • Eventually kills host

General parasitoid life cycle

Parasitiation of Aphid → Parasitoid larva develops aphid alive → Parasitoid Pupates → Aphid dies and turns into mummy → Adult parasitoid emerges out of mummy but cutting hole → adult female parasitoid → Cycle repeats

Approximately how many of all described insect species are parasitoids?

• 10%

  • 75% Hymenoptera

  • 25% Diptera (and a few Coleoptera, Lepidoptera, Strepsiptera)

  • (• Parasitoid lifeway evolved many times in insect)

Types of Parasitoids: Endoparasitoid

Hatch within the host from eggs or larvae laid there by an adult female, and then feed and develop inside the host

Types of Parasitoids: Ectoparasitoid

Fastened to the outside of the host and feed through the host skin, sucking out body fluids

Types of Parasitoids: Specialist

Specific host, often a single insect species

Types of Parasitoids: Generalist

Hosts in many different families

Types of Parasitoids: Solitary

One per host

Types of Parasitoids: Gregarious

Many per host

Which other insects can serve as host?

Spiders, ticks, centipedes

Which insect stages are often most vulnerable to parasitoids?

Immature insect stages are often most vulnerable to parasitoids (i.e., larvae, nymphs)

(• Some parasitoids can specialize on egg, pupal, or adult stages)

• Host Defenses Against Parasitoids: External Defense

•  Movement (i.e., wiggling around or running away to prevent parasitoid egg laying or oviposition)

• Host Defenses Against Parasitoids: Internal Defense

• Encapsulation or melanization

Order Hymenoptera: Family Crabronidae

• Cicada killers

• Order Hymenoptera: Family Pompilidae

• Tarantula hawks

• ORDER: Colepertora 

• FAMILIES: Scarabaeidae & Geotrupidae

Dung Beetles

(The different strategies of dung beetle reproduction): ROLLER

Roll Dung Balls

(The different strategies of dung beetle reproduction): TUNNELLER

Bury dung balls straight down

(The different strategies of dung beetle reproduction): DWELLER

Consume manure as they tunnel within dung (+lay eggs directly in manure)

Forage fouling (Why dung beetles are important to ecosystem)

• Livestock (cows) avoid odor of dung and unpalatable grass grows besides it

Parasites (Why dung beetles are important to ecosystem)

• Both intestinal worms and some flies need fresh wet dung to reproduce. Dung beetles break up the dung.

Nutrients (?) + Water (Why dung beetles are important to ecosystem)

• Rollers and tunnellers break up compact dirt allowing water into roots.

How did Dung Beetles come to California?

• California Dung Project: 1975-1977 successfully introduced new species of dung beetles. 

• Done to speed dung decomposition, reduce fly and parasite populations, and improve pasture health

• Describe the major threats to dung beetles

• Reduced wild mammals

• Deforestation

• Climate change

• Veterinary insecticides

How risk is assessed in insect toxicology

• “Dose makes the poison" 

  • risk assessment is a structured, multi‑stage process that identifies hazards, evaluates exposure, quantifies dose–response relationships, and integrates these to estimate potential adverse effects on insect populations

What is forensics entomology?

•  The use of insects in legal investigations (civil and criminal)

Types of forensic entomology: 

• Urban: civil actions relating to insects and human environments

• Stored Product: civil actions relating to insects found in food products

• Medico-legal (or medico-criminal) criminal proceedings in cases of violent crime or unexpected death

Necrophages

• Feeding on the body

- Insect groups commonly used in forensic investigations

Predators and parasites

• Of the necrophagous species

- Insect groups commonly used in forensic investigations

Omnivores

• Feeding on the body and its inhabitants

- Insect groups commonly used in forensic investigations

Adventive species

• Using the body as an extension of their environment

- Insect groups commonly used in forensic investigations

What type of bugs are mainly used in forensic entomology?

Dipetera (flies) and Coleoptera (beetles)

PMI ESTIMATION:

• Succession: Early colonizers then late colonizers

  • PMI based off what stage of decay the body is at and the bugs surrounding it.

• Accumulated Days/Hours: How long will adults develop pr emerge from body x lab temperature

The importance of aquatic insects

• Nutrient cycling & Decomposition (Aquatic insects help breakdown dead plants in streams)

• Food sources for other organisms

• Environmental monitoring

• Recreation (Fishermen using them as bait)

Recall the diversity of aquatic insects and how aquatic lifestyles evolved in insects

• 8 major orders of aquatic insects - Insects evolved from crustaceans

• •Crustacea dominate in marine ecosystems

• Insects do not live in marine habitats

• Evolution “back to” aquatic life occurred many times in insects

• Order Ephemeroptera: “mayflies”

• Aquatic nymphs (= naiads)

• • Bioindicators of water quality

• • Herbivores or detritivores

• • May live 1-3 years in water

• • Terrestrial adults

• • Very short-lived (hours to 1-2 days)

• • Mass emergence to breed

• • Detected on radars

• • Can cause problems on bridges

• • Forewings much larger than hindwings

• • Short bristle-like antennae

• Order Odonata: “dragonflies & damselflies”

• Predators as naiads and adults

• • Aquatic naiads

• • Terrestrial adults

• • Cannot fold wings over back

• • Large compound eyes

• • Antennae bristle-like: setaceous

• Order Plecoptera: “stoneflies” 

• Aquatic naiads

• • Live underwater for multiple years before emerging

• • Predatory or detritivores

• • Bioindicators of water quality

• • Require very clean, well-oxygenated water

• • Often found in submerged leaves

• • Terrestrial adults

• • Fairly short-lived (2-3 weeks)

• • Mandibulate mouthparts, if any

• • Often feed on pollen, algae, or fungal spores

• • Long, slender antennae with many segments

• • Soft-bodied and weak fliers

• Aquatic Hemipterans 

• Nymphs and adults live in same habitat – both are aquatic

• • Do not have gills

• • Must access atmospheric air

Posterior Spiracles

Need to come up to breathe

Plasteron

Don’t need to come up to breathe

Order Hemiptera: Family Gerridae

• Water striders

• • Predators

• • Thoracic scent glands secrete chemicals that deter fish

• • Mostly found in freshwater, but there is a group found in salt water

• • Only marine insect genus (Halobates)!

• Order Hemiptera: Family Coricidae

• Water boatmen

• • Swim right-side up

• • Mainly herbivores feeding on aquatic plants and algae

• • Loudest animal on Earth relative to body size

• • Stridulation – male rubs aedeagus (male reproductive organ) against abdomen in courtship display

• Order Hemiptera: Family Notonectidae 

• • Backswimmers

• • Predatory

• • Swim upside down

• • Fly quite well

• Order Hemiptera: Family Nepidae

• Waterscorpions

• • Predatory

• • Siphon (long tube on back of abdomen used for breathing)

• Order Hemiptera: Family Belostomatidae

• Giant water bug, toe-biter

• • Sit and wait predators

  • Attack fish, reptiles, crustaceans, other invertebrates

• • Raptorial forelegs

• • Found in freshwater streams and ponds

• • Parental care: female lay eggs on the back wings of male and the male carries and protects the eggs until they hatch

• Order Megaloptera: “dobsonflies, alderflies”

• Aquatic larvae

• • Also known as “hellgrammites”

• • Predators

• • Live for 1-5 years

• • Hide under rocks in streams

• • Usually found in well-oxygenated water

• Terrestrial adults

• • Live only a few days or hours

• • Many adults do not feed

• • Males have large mandibles, but females bite

• harder!

• • No cerci

• • Long antennae

• Order Coleoptera: Family Gyrinidae

• Whirligig beetle

• • Aquatic larvae and adults

• • Predators

• • Often found in groups on surface of water

• • Compound eye divided in half

• Order Coleoptera: Family Dytiscidae 

• Predaceous diving beetles

• • Predatory

• • Aquatic larvae and adults

• • Air bubble under elytra

• Order Coleoptera: Family Hydrophilidae

• Water scavenger beetles

• • Omnivores

• • Aquatic larvae and adults

• • Diagnostic features of adults:

• • Short, clubbed antennae

• • Long maxillary palps

• • Metasternum prolonged as backwards spine

• Order Trichoptera: “caddisflies”

• Aquatic larvae

• • Often bioindicators of water

• quality

• • Predators, leaf shredders, algal

• grazers, or filter feeders

• • Spin nets or cases with silk

•  Terrestrial adults

• • Long filiform antennae

• • Mandibles reduced

• • Few crossveins

• • Often brown with setae on legs

• Order Diptera: Family Chironomidae

• Non-biting midges

• • Aquatic larvae

• • Bioindicators of water quality

• • Green, black, white, clear midges not tolerant of very low oxygen

• • Red midges tolerant of very low oxygen and overall poor water conditions

• Terrestrial adults

• • Feed on sugar-rich sources of food

• • Large swarms over aquatic water bodies

• Order Diptera: Family Tipulidae

• Crane flies

• • Some aquatic larvae

• • Often quite large

• • Amass in huge numbers in rotting

• leaves

• • Feed on bacteria, fungi, and perhaps

• algae on leaves

• Terrestrial adults

• • Long, thin legs are fragile

• • Fairly short-lived (10-15 days)

Urban settings

Densely populated areas with non-agricultural architecture. (ie: cities)

Urbanization

How populations grow and expand over time. Going from rural areas to more urban ones.

Attributes of urban environments that allow for certain insect pests

to thrive

• Order Hymenoptera: Family Formicidae 

• Argentinians and Pharaoh ants are common household ants. 

• Ants protect plant pests and all ants are social

• Bait mixed in with insecticides for worker ants to bring back to colony is a popular way to deal with these pests.

• Order Hymenoptera: Family Apidae

• Honeybees 

• Honeybees swarm as a method of colony reproduction 

• The old queen and half of worker bees leave former nest in search of new home

• Honeybees nest in so many diverse places risking, house damage

  • Damp area on wall or open hole through sheetrock may signal a swarm of honeybees living within your walls

• Unexpected pest

• Order Heteroptera: Family Cimicidae

• Bed Bugs

• Feed on human blood (no disease transmitted though)

• Incesticide resistance

• Lack of baits

• Common in multiunit housing

• Monitoring bed bug presence : Inceptor and refuge traps

• Order: Blattodea

• Cockroaches and termites 

Order: Blattodea Cockroaches

• Resistant to pesticides 

• Produce thousands of larvae 

• Cockroach control: 

  • Sanitation

  • Exclusion/removal of hiding places

  • Chemical control 

• Order Blattodea: Suborder Isoptera: Termites

• Feed on living and dead trees 

• Able to digest cellulose (microbial gut symbiote)  

• Two pairs of similarly sized wings (Reproductive only)

• Wide Waist

• Form social colonies: Reproductive king and queen, workers, and soldiers.

• Hard to detect as they hide in wood 

• Fecal pallets estimate termite problem