Invertebrates Flashcards
Arthropods:
Insects
Mites & Ticks
Others
Mollusks:
Nematodes:
- Identification
- Life Cycle and Growth Requirements
- Habits
- Successful Characteristics
- Dispersal and Movements
- Types of Damage
Are animals without backbones and include nematodes, worms, mollusks and arthropods.
Arthropods-Insects
I.D.
The adult insect has three distinct body parts
1.) Head
- ) Thorax (Divided into three segments with a pair of jointed legs attached to each segment)
a. ) Prothorax/Front
b. )Mesothorax/Middle
c. )Metathorax/Hind
3.) Abdomen.
Insects are the only invertebrates that have wings, but not all adult insects have wings. If present two pairs of wings are normal. (Although a few groups such as true flies, has a greatly reduced pair).
All insects have one pair of antennae on the front of the head.
Most adult Insects often have two kinds of eyes, simple (three ocelli located on the front upper part of the head) and compound (one on each side and toward the top of the head).
There are two main types of insect mouth parts
- ) Chewing
- ) Sucking
Wing feature such as venation, membranes and pigmentation can be important.
Tails, stingers, or forceps at the tip of the abdomen can also be as well
Arthropods-Mites andTicks
I.D.
Mites differ from insects in that they only have two body parts and no antennae
- ) Head called a gnathosoma with a air of chelicerae palps.
- ) Abdomen/Thorax are combined and called the idiosoma.
They usually have four pairs of legs attached to the abdomen, whilst some, including immatures, only contain three.
Usually only an expert can identify most mits to the species level. However major features clues include:
- host plant
- mite size
- shape/color
- pattern of spots or spines
- number of legs
- timing, location, and grouping arrangement of egg laying
The most common pest groups are
-Spider mites/family Tetranychidae
-Red mites/family Eriophyidae
Whilst the best-known predatory mite species are found in the family Phytoseiidae.
Arthropods-Spider
I.D.
Spiders are very common invertebrates, are all predaceous, and in most cases beneficial.
However they may be considered a pest when venomous species such as black widow inhabits residential/processing areas.
As with mites . spiders lack antennae and have two main body parts.
- ) Head
a. ) Variable size and configuration of 8 eyes
b. ) A pair of pedipalps,
c. ) And mouthparts including a pair of fangs/chelicerae - ) Abdomen/Thorax are combined in a strongly constricted region called the cephalothorax.
a. ) Several pairs of spinnerets, web-spinning organs, are located on the terminal end of the abdomen.
Arthropods-Life Cycle and Growth Requirements (Insect, Mites, Spiders)
Most arthropods hatch from eggs into immatures that increase in size by molting or shedding their outer body covering (exoskeleton) and growing into a new, larger version in a process referred to as metamorphosis. Each successive molt usually results in a transformation in morphological/structural changes, and the period between one molt and the next is known as an instar.
Metamorphosis
Incomplete: Consists of three stages: egg, nymph, and adult.
Insects that have an incomplete metamorphosis life cycle include true bugs, grasshoppers, cockroaches, termites, praying mantises, crickets, and lice.
Complete: An insect goes through four distinct stages: Egg, Larva, Pupa, Adult.
Eggs: Of arthropods vary in size, shape, color, attachment, arrangement, and where they are laid (usually in a location where the young will have an immediate food source upon hatching.
Egg traps are used to monitor the egg-laying activities of certain pests (navel orangeworm, Amyelois transitella).
Arthropods-Successful Characteristics (Insect, Mites, Spider)
Genetic Variation: Allow arthropods to further adapt to the environmental conditions such as the development of resistance to insecticides.
Multiplicity: Outbreak can be variable depending on conditions.
Mobility:
Legs enable the ability to jump, swim, walk.
Wings allow for greater travel in area.
Diapause (hibernation winter): A stage where the lifecycle ceases due to environmental cues and can take place during any stage.
Arthropods-Dispersal and Movement (Insect, Mites, Spiders)
Strong winds, rain, and irrigation, seasonal fluctuations, can relate with seasonal infestation patterns.
Mechanical movement on freight, vehicles, or public transport customs have a propensity for introducing arthropod pests (ex: moth-Lymantria dispar), and henceforth strict inspection must be upheld between domestic and international trade borders.
Arthropods-Habits/Types of Damage (Insects, Mites, Spiders)
Almost no generalizations can be made about the habits of arthropods because a group they occupy almost every habitat. However knowing the specific pest can help in planning an efficient detection, sampling, and management program.
Nematodes-Identification
The nematodes of most concern are plant parasitic and those causing harm to animals.
Signs root galls stubbed, proliferation of infestation can eventually result in stunted growth.
Nematodes-Life-Cycle and Regrowth
Consists of egg stage, four molting juvenile, and adult.
Nematodes-Types of
Damage-Habits
Sedentary-Parasitic
Migrtory-endo
Migrtory-ecto
There is no infective stage as both are capable.
Nematodes-Types of Damage
Symptoms such as stunting, chlorosis, wilting, curling and twisting of leaves and stems, delayed of un even maturation of crops,.
