Midterm Flashcards
What is the largest & oldest collection of insects in the world?
Musee National d’Histoire Naturelle
In Paris
~ 40m specimens
What is the largest collection of insects in North America
National Museum of Natural History
In DC
~35m specimen
What is the largest collection of insects in Canada?
Canadian National collection of insects
In Ottawa
~17m specimens
How many insects are at the Lyman Museum?
~3m specimens
Largest university collection
Why are insect collections important?
Long-term data (see distribution patterns, activity patterns, changes over time…)
Availability for other researchers
What is required for specimen to be of scientific value?
Locality of capture (country, region, GPS coordinates)
Date of capture (month uses roman numerals)
What are threats to insect specimens?
Be eaten by museum pests
Mold
Fading
Dust, damage
What is abundance?
The number of individuals.
* insects have probably the largest biomass of all terrestrial animals
What is diversity?
The number of species.
* Insects represent ~80% all known living organisms
What major biome or habitat has not been colonized by insects?
Marine environments
What are the reasons for insect success?
Ancient lineage Presence of an exoskeleton Presence of wings Small size Complete metamorphosis High reproductive capacity
What are the advantages of being an “old lineage?”
Ready to exploit new environments
Less competition
What are the advantages of an exoskeleton?
Protection from physical damage
Discourage predators
Protective barrier between living tissues & environment
Protective against desiccation
What are the advantages of having wings?
Advantage in finding food & mates
Able to easily escape from enemies
Freely move from one habitat to another to find better conditions
What are the advantages of small size?
Need little food (more able to feed on one food source)
Able to exploit microhabitats (for food, protection, & resting)
What is the advantage of complete metamorphosis?
Different body forms = different habitats and food so no need to compete for resources
What are the advantages of a high reproductive capacity?
Insects lay large number of eggs & have short generational time =
Populations build up faster & have a faster rate of mutation
What are the benefits of insects?
Pollination Food source Nutrient cycling Soil improvement Control of other organisms Medicine & genetics Biological indicators Commercial products Aesthetics & cultural use
What are some crop plants dependent on insects for pollination?
Apples Pears Cherries Strawberries Cucumbers Squash Onions
Which insects are the most important pollinators?
Bees
What is the study of insects as human food called?
Entomophagy
What are the differences between insects and steak in nutrients?
Insects = 200 cal per 100g (20% protein, 5mg iron) Steak = 250 cal per 100g (27% protein, 3.5mg iron)
What is the legal tolerance for insects in broccoli?
60 aphids/100g
What is the legal tolerance for insects in chocolate?
60 microscopic insect fragments/100g
What is the legal tolerance for insects in canned goods?
30 fly eggs & 2 maggots/100g
What is the importance of scavenger insects?
Involved in decomp. of organic matter& nutrient cycling
What type of insects are scavengers?
Carrion beetle
Dung beetle
Flesh flies
How do insects improve soil?
Aerate the soil
Improve physical properties & add to its organic content
What insects are soil insects?
Proturans Springtails Diplurans Termites Ants Beetle larva & fly larva
What is the important of parasitoids & predators?
Used in biological control of insect pests
What is the importance of insects in medicine?
Maggot therapy
What is maggot therapy?
The treatment of infected & gangrenous wounds by the use of maggots
Why are fruit flies used to study genetics?
Fast generation time
High reproductivity
Large chromosome
Small number of chromosomes
What insects are used as biological indicators of pollution & habitat change in stream ecosystems?
Chironomid larva (bloodworms)
Stoneflies
Mayflies
What is forensic entomology?
The use of insect knowledge in the investigation of crimes
What are commercial products derived from insects?
Honey (a multi-million dollar industry)
Beeswax
Silk (produced by silkworm moth)
Red dyes (made from female cochineal insects)
How much silk is made from a single cocoon?
About 500-900 meters
What do cochineal insects produce to create red dye?
Carminic acid as defense against predation
How many insects are considered pests?
~10,000 (1%)
When are insects considered pests?
When they come into conflict with human (directly or indirectly)
What are the types of insect pests?
Plant pests Stored product pests Household pests Direct human pests Livestock pests
What are plant pests considered?
The most important plant-feeding animals. They consume more plants than all vertebrate herbivores combined
What kind of insects are plant pests?
Herbivorous or phytophagous insects
What does phytophagous mean?
Insects that feed on the tissue of living plants (do not consume pollen or nectar)
When are phytophagous insects beneficial?
They can eat invasive plants or weeds
Why are plant pests considered pests?
They attack crops, cultivated plants, garden flowers, forest trees, etc.
What is a host plant?
A plant upon which an organism lives and/or eats.
An insect can have one or multiple host plants
What are the types of plant pests?
Monophagous
Oligophagous
Polyphagous
Monophagous
Specialists & host specific
Feed on only one species or genus
Ex. Monarch eats milkweed
Oligophagous
Feed on various plants in a single family
Ex. Colorado potato beetle
Polyphagous
Generalists. Feed on a variety of plants of unrelated families
Ex. Med fly, gypsy moth
What are the direct ways an insect can damage a plant?
Direct feeding (chewing, sucking, tunnelling)
What are the indirect ways an insect can damage a plant?
Indirectly (transmission of plant diseases)
What are major crop plant pests?
Boll weevil
Colorado potato beetle
Mediterranean fruit fly
Desert locust
What are major forest plant pests?
Lymantria dispar (gypsy moth) Emerald ash borer Asian longhorned beetle
Boll weevil
Plant pest: monophagous (cotton)
Eradicated from most states
Control: insecticides, pheromone mass trapping
Colorado potato beetle
Plant pest: oligophagous
Feed on family Solanaceae (potato, tomato, eggplant, pepper)
Control: hand picking, crop rotation, bacterial control (Bt); resistant to many insecticides
Mediterranean fruit fly or medfly
Plant pest: polyphagous
Over 260 different hosts (mostly fruit, but flowers, vegetables, & nuts)
Control: sterile insect technique (release of sterile males to mate)
Desert locust
Plant pest: polyphagous
Eat crop & non-crop plants
Different species invade different parts of the world
Lymantria dispar (Gypsy moth)
Plant pest: polyphagous
Feeds on ~300 species of trees (caterpillars only)
Introduced from Europe
Emerald ash borer
Plant pest: monophagous (ash trees)
Larva bore into wood, difficult to detect
Native to Asia, invasive to N.A.
Asian longhorned beetle
Plant pest: polyphagous
Attack multiple species of trees
Larva bore into wood
Native to Asia, invasive to N.A. (eradicated in Canada)
What do stored product pests do?
Contaminate large containers of stored food products
Feed directly on the product or on mold
What kind of insects are stored product pests?
Mostly beetles & moths
Most species have a worldwide distribution
What are some species of stored product pests?
Rice weevil
Indian meal moth
Foreign grain beetle
What do household pests do?
Contaminate food
Damage clothes or house
Feed on humans
What are some species of household pests?
Bed bugs Indian meal moth Ants Cockroaches Clothes moths Carpet beetles Booklice
What do direct human pests do?
Biting, stinging (cause minor or serious effects)
Disease transmission
What are the two types of direct human pests that are involved in disease transmission?
Biological vectors
Mechanical vectors
What are biological vectors?
Insects play a major role in the life cycle of the pathogen
Mostly blood feeders
What are mechanical vectors?
Insects are passive carriers, carrying pathogens on its body or mouthparts
What are the types of direct human pests?
Biting insects (mosquitoes) Stinging insects (bees) Endoparasitic insects (botfly) Ectoparasitic insect (lice)
What are the types of livestock pests?
Biting insects (stable flies) Endoparasitic insects (botflies) Ectoparasitic insects (fleas)
How do humans affect the population of pests?
Monoculture (cultivation of a single crop)
Irrigation canals (avoiding stagnant water)
Intercontinental transport
Overuse of insecticides
What are the cost difference between detrimental & beneficial insects?
Annual losses in US: ~$5 bill
Annual benefits in US: over $19 bill
What are the general characteristics of Class Insecta?
Presence of exoskeleton
Bilateral symmetry
Body divided into segments or metameres (divided into head, thorax, abdomen)
What is tagmosis?
The organization of the body into major units
What are the segments of the tagmata?
Whole insect = 20 primitive segments
Head = 6 segments
Thorax = 3 segments
Abdomen = 11 segments (primitive); 10 segments (modern)
What is the head specialized for?
Sensory function & feeding
What is the thorax specialized for?
Locomotion
What is the abdomen specialized for?
Reproduction
Also circulation, digestion & excretion
What are the types of joint appendages?
Feeding
Walking
Sensory
What kind of circulatory system do insects have?
Open circulatory system
How does respiration occur?
Via spiracles & trachea
or
gills
What do the excretory system consist of?
Malpighian tubules
What are the general properties of the exoskeleton?
Supports body & maintains its form
Lines the tracheal system + portions of digestive & reproductive system
Provides surfaces for muscle attachment
Provide structural rigidity at sclerotized regions
What are individual sections of the sclerotized region called?
Sclerites
There are membranous regions between the sclerites that permit movement & flexibility
What are the color pigments & patterns of the exoskeleton for?
Defense
Courtship
Intraspecific recognition
Thermoregulation
The exoskeleton color pigments/patterns do what kind of defense?
Warning coloration
Mimicry
Distraction
Camouflage
What is aposematic coloration?
Conspicuous coloration or markings of an animal serving to warn off predators
What are the types of insect coloration?
Pigmental
Structural
What is pigmental coloration?
Derived from food or other pigment deposition
What is structural coloration?
Derived from the cuticle & its irregularities
What are the 3 layers of the exoskeleton?
Cuticle
Epidermis
Basement membrane
Where does the cuticle come from?
Secreted by the epidermis
What is the structure of the cuticle?
Acellular
Complex
Multilayered
What does the epidermis do?
Secretes cuticle
Forms external sensory receptors
What is the structure of the basement membrane?
Acellular
Thin
What does the basement membrane do?
Separates hemocoel from epidermis
What are the parts of the cuticle?
Epicuticle Procuticle (differentiates into exocuticle & endocuticle)
Which part of the cuticle is sclerotized?
Exocuticle
Which part of the cuticle is unsclerotized?
Endocuticle
Which part of the cuticle is waxy?
Epicuticle (protection & impermeability)
What are the types of cuticular extensions?
Rigid non-articulated
Movable articulated
What are rigid non-articulated cuticular extensions?
Spines. They are large and heavily sclerotized
What are movable articulated cuticular extensions?
Setae. They are sunk into a cuticular socket
Setae are:
Sensory hairs
Multicellular
Associated with sensory cells and 2 other specialized epidermal cells
What is molting?
The entire process of preparing for, undergoing, & recovering from ecdysis
What is ecdysone?
The hormone produced to activate epidermal cells to secrete a new exoskeleton
What is apolysis?
The separation of the old cuticle from the epidermis
What is ecdysis?
The process of shedding the old cuticle
What is the exuvia?
The old cuticle
What is a teneral?
A soft, newly emerged insect (just after ecdysis)
What is tanning/sclerotization?
The stiffening & darkening of the cuticle
What are the steps of the molting process?
- Ecdysone is released (by prothoracic gland). The activation of epidermal cells (their inc. in size)
- Apolysis occurs. Epidermis secretes molting fluid that will digest old endocuticle only (not exocuticle)
- The epidermis secreted new cuticle (epicuticle & procuticle)
- Ecdysis starts. Insect swallows air or water to split old cuticle. The insect pulls out of old cuticle
- Insect continues swallowing air/water to inc. hemolymph pressure to inflate body (spreads wings)
- Tanning/sclerotization occurs. The procuticle differentiates into exocuticle and endocuticle
How many times do most insects molt?
Between 4-8 times in their life
* some wingless hexapods continue to molt after reaching adult stage
What does the head consist of?
Eyes Paired appendages (antennae, mouthparts)
Types of mouthparts:
Mandibulate mouthparts (more primitive; able to chew) Haustellate mouthparts (more specialized; able to suck): multiple types
Types of haustellate mouthparts:
Chewing-lapping Piercing-sucking (true bugs) Siphoning (or sucking) Sponging Cutting-sponging
What is a proboscis?
Beak used to suck liquid
What are the orientations of the head?
Hypognathous
Prognathous
Opisthognathous
Hypognathous
Directed ventrally (downward)
Prognathous
Directed anteriorly (forward)
Opisthognathous
Directed posteriorly (backward)
What are the main divisions of the antennae?
Antennal sclerite
Scape
Pedicel
Flagellum
What is the purpose of the antennae?
Smell
Hearing
Feeling
What are the types of eyes in adults?
Compound eyes (consist of individual ommatidia) Ocelli
What are the segments of the thorax?
Prothorax
Mesothorax
Metathorax