VL 1 Flashcards
What is an agroecosystem?
artificial ecosystem that is created by land used for agricultural purposes
What are the 3 essential scales that constitute an “agroecosystem”?
Ecological scale
Economic scale
Social scale
How is an agroecosystem characterized?
Planned diversity:
- spatio-temporal arrangement of domesticated plants and animals that farmers purposely include in the system
- deliberately added beneficial (micro-)organisms
Unplanned diversity
- weedy plants, herbivores, predators, bacteria, viruses
- other organisms that persist in the system after it has been converted to agriculture or colonize it from the surrounding landscape
What are four services of Agroecosystems?
Provisioning services: Food, Fodder and fiber, raw materials, medicine, energy and fuel
Regulating services: soil conservation, waste decomposition, carbon sequestration, local climate regulation
Supporting services:
Soil structure and fertility, nutrient cycling, biological control, pollination, weed control
Cultural services: Aesthetic value, recreations and tourism, cultural heritage, spiritual and religious value, science and education
what are three disservices of Agroecosystems?
Provisioning disservices: water resource consumption, agricultural waste
regulating disservies: soil pollution, water pollution, greenhouse gas emission
supporting services: pest and disease, weeds cover,habitat loss, biodiversity loss
What are characteristics of insects?
chitinous exoskeleton
3 body parts (head, thorax, abdomen)
3 pairs of legs on thorax
1 pair of antennae
up to 2 pair of wings
What are the three life cycles in insects?
Ametabolous
Juvenile insect in feeding stage looks same like adult
Hemimetabolous
Juvenile = Nymph
in feeding stage the juvenile looks a little different compared to adult in dispersal stage
Holometabolous
Juvenile = Larvae
Larvae look totally different and undergo metamorphosis
What are the differencies between simple metamorphosis and complete metamorphosis?
Simple metamorphosis (Hemimetabolous):
Adults and juveniles both feeding in the same manner
Nymphs tend to feed more heavily (cause more damage) than adults
Complete metamorphosis (Holometabolous):
Adults and juveniles feed differently and on different plant resources
Larvae are almost always pests, while adults can be non-pest or even beneficial (pollinators)
>80% of insect species
How is the anatomy of winged insects?
three body segments
one pair of antennae
three pairs of legs (thorax)
two pairs of wings on thorax
Body is surrounded by a ahrd exoskeleton
grwoth requires of “molts” where the exoskeleton is shed and new one is formed
period between each molt is called “instars”
Archaeognatha & Zygentoma
most basal insects, emerged prior to wing evolution
formerly one order “Thysanura”, now seperate orders
three caudal filaments
body is covered in small scales
not generally considered agriculturally relevant
Archaeognatha
feeds on lichen, fungi, dead plant
looks scary
Zygentoma “Silverfish”
can digest cellulose and lignin, contributing to nutrient recycling
considered a pest outside of agriculture: paper is not safe
Paleoptera - “ancient wing”
most basal group of flying insects
Ephemeroptera
Odonata
can’t lie their wings on body
Paleoptera use direct flight muscles (all other flying insects use indirect flight muscles)
Orthoptera - “straight wing”
grasshoppers, crickets, wetas etc.
locusts are grasshoppers that can switch social status from solitary phase to gregarious phase
other grasshoppers are known transmitters of plant viruses
Thysanoptera - “fringed wing”
commonly called thrips
has wings, but they are seldom used. their tiny size means that they cannot rely on the same flight mechanics that most other flying insects use. They use “clap and fling” rather than “leading edge vortex” flight mechanics
common pest of greenhouses and research institutions
common target of biocontrol
piercing mouthparts
sually identified first by characteristic damage pattern
Hemiptera - “half wings”
commonly known as “true bugs”
have piercing mouthparts used to suck liquid contents from plant tissues (or animal tissue if predatory)
causes three major types of damage:
feeding damage
Virus transmission
Sooty mold
Three types of Hemiptera
Aphids:
common crop pest and one of the most destructive insects
can reproduce asexually through parthenogenesis
often a specialized herbivore
common target of biocontrol
Scale insects:
THick carapace prevents insecticide from being utilized
in many species the females lose the use of their legs and are immobile, only males move to mate
economic and cultural importance in form of carmine and shellack
Shield (stink) bugs:
does not typically cause much destruction, but can in large outbreaks
brown-marmorated stink bug is a destructive orchard pest
abdominal glands emit foul smelling liquid
