SciOly Entomology Theory

Molting (Ecdysis)

The process of shedding the old exoskeleton to grow involves multiple stages.

Apolysis

Separation of old cuticle from epidermis.

Secretion of molting fluid

The release of fluids that aid in the molting process.

Activation of molting fluid

The process of digesting the old endocuticle using the molting fluid.

Ecdysis

Shedding the old exo- and epicuticle.

Expansion and hardening (sclerotization)

The process of the new cuticle expanding and hardening after molting.

Imago stage

The stage at which insects reach sexual maturity and molting ceases.

Ametabola

No metamorphosis; young resemble adults (e.g. Protura, Collembola, Zygentoma).

Hemimetabola

Incomplete metamorphosis; Egg → nymph → adult, with external development of wings (e.g., Orthoptera, Hemiptera).

Holometabola

Complete metamorphosis; Egg → larva → pupa → adult, with internal wing development (e.g., Coleoptera, Diptera, Lepidoptera, Hymenoptera).

Eruciform

Caterpillar-shaped larval form (e.g., Lepidoptera).

Campodeiform

Elongated, active, crawler-type larval form (e.g., lacewing larvae).

Scarabaeiform

'C'-shaped grubs (e.g., scarab beetles).

Elateriform

Wireworm-like, hard-bodied larvae.

Vermiform

Maggot-like, legless larvae (e.g., flies).

Obtect

Pupal type where appendages are enclosed tightly (e.g., butterfly chrysalis).

Exarate

Pupal type where appendages are free and discernible (e.g., beetle pupae).

Coarctate

Pupal type enclosed in hardened larval skin (e.g., fly puparium).

Solitary

Not sharing a nest or providing care for offspring

Communal

Members of the same generation use the same composite nest site without cooperating in brood care

Subsocial

Adults provide some kind of parental care for their offspring

Quasisocial

Members of the same generation use the same composite nest site and also cooperate in brood care

Semisocial

Cooperative brood care within a composite nest is provided by a worker caste that is more or less sterile

What is eusocial behavior?

Cooperative brood care within a composite nest is provided by a worker caste that is more or less sterile and lives long enough to assist the parents.

What is a characteristic of eusocial species regarding nest sites?

They share a common nest site.

How do individuals of the same species behave in eusocial systems?

They cooperate in caring for the young.

What is the reproductive division of labor in eusocial species?

Sterile (or less fecund) individuals work for the benefit of a few reproductive individuals.

What is the significance of generation overlap in eusocial species?

Offspring contribute to colony labor while their parents are still alive.

Advantages of Living in Groups

Can accomplish feats that are impossible for solo insects, Construction of huge nest sites, Widespread foraging for food, Constant vigilance against predation or parasitism

Disadvantages of Living in Groups

Large colonies are especially vulnerable to the spread of contagious pathogens, Nest sites may be exploited by 'social parasites' who steal food or attack the brood, Individuals must compete with each other for space and resources (such as food)

What is the definition of communication in the context of insects?

An action or condition on the part of one organism that alters the behavior of another organism in an adaptive way.

List some reasons why insects communicate with one another.

Recognition of kin or nestmates, locating or identifying a member of the opposite sex, facilitating courtship and mating, giving directions for food or resources, regulating spatial distribution, establishing territory, warning of danger, advertising presence, expressing threat or submission, and deception/mimicry.

What are the four main types of communication used by insects?

Tactile, visual, acoustic, and chemical communication.

Describe tactile communication in insects.

Physical contact used as a means of communication, especially by insects with poor vision and sound perception.

What is the role of antennal tapping in Formicidae and Isoptera?

It involves nestmate recognition and leads to the exchange of food through trophallaxis.

What is tandem running in insects?

A 'follow-the-leader' behavior where tapping informs the leader that she has not lost her disciple.

How do honeybees use tactile communication?

Through a 'dance language' that conveys information about food sources.

What is the significance of substrate vibrations in Membracidae?

They serve as an alarm system and may elicit protective maternal behavior.

What are some benefits of tactile communication?

Instantaneous feedback, localized area, individual recipient, and effectiveness in the dark.

What are some limitations of tactile communication?

Not effective over distance, requires direct contact, messages must be repeated, and signals can be intercepted by predators.

What is chemical communication in insects?

The use of chemical signals detected through taste and smell to convey information.

What are the two main groups of chemical signals?

Semiochemicals and infochemicals.

What are pheromones?

Chemical signals that carry information from one individual to another within the same species.

What are allelochemicals?

Signals that travel from one animal to a member of a different species, including defensive signals and host location compounds.

What are allomones, kairomones, and synomones?

Allomones benefit the sender, kairomones benefit the receiver, and synomones benefit both sender and receiver.

What are some benefits of chemical communication?

Not limited by environmental barriers, effective over distances, long-lasting, and metabolically inexpensive.

What are some limitations of chemical communication?

Low information content, ineffective upwind, and potential to attract predators.

How do insects use acoustic communication?

Insects detect sound through tympanic membranes or mechanoreceptors, allowing them to communicate via sound vibrations.

What are some benefits of acoustic communication?

Not limited by environmental barriers, effective over distances, and high information content.

What are some limitations of acoustic communication?

May reveal the sender's location, less effective in noisy environments, and may be metabolically expensive.

What are the two groups of visual signals in insect communication?

Active signals and passive signals.

What are passive visual signals?

Signals like eyespots and color patterns that serve as 'free advertising' without metabolic cost.

What are active visual signals?

Signals such as body movements and light flashes that are more costly to produce but can convey additional meaning.

What are some benefits of visual communication?

Effective over long distances, usable while moving, fast, and requires no energy for passive signals.

What are some limitations of visual communication?

Requires a clear line of sight, may be intercepted by predators, and is only effective in daylight.

Herbivore

An insect that feeds on plants.

Carnivore

An insect that catches and kills other insects or animals for food.

Decomposer

An insect that feeds on dead organic matter, helping to recycle nutrients.

Phytophagy/phytophagous

Relating to plant feeding.

Monophagous

An insect that restricts itself to a single host species.

Oligophagous

An insect with a slightly broader host range.

Polyphagous

Equipped with 'broad-spectrum' detoxification enzymes that can overcome a wide range of plant defenses.

Feeding Guild

Within a feeding guild, all species compete directly with each other for exactly the same resource.

Zoophagy

A term for all insects that catch and kill other insects or animals as food.

Predators

Zoophagous insects that kill and eat numerous prey individuals in the course of their growth and development.

Parasite

An organism that lives in or on another organism (its host) and benefits by deriving nutrients at the host's expense.

Endoparasites

Parasites that live inside the host's body.

Ectoparasites

Parasites that live in the host's nest or on the surface of its body.

Hematophagy

Blood feeding, a common practice among insects that parasitize vertebrate animals.

Parasitoid

An insect that lives in or on the body of a single host individual during their larval stage but becomes free-living as adults.

Hyperparasites

Parasites (or parasitoids) of another parasitoid species.

Autoparasites

Species in which the females feed on males to obtain a nutritional advantage.

Brood Parasites

Insects that live in the nests of social insects and feed on the juveniles.

Social Parasites

Insects that steal food or other resources from the nests of social insects.

Saprophages

Insects that eat the dead bodies of plants and animals.

Soil-dwelling species

Insects that shred leaves or tunnel in woody tissues, accelerating decay.

Carrion feeders

Insects that feed on dead animals, including beetles, fly larvae, wasps, ants, and mites.

Colonization of Dead Bodies

Each species colonizes the dead body for only a limited period of time but collectively, they rapidly consume and/or bury the decaying flesh.

Blow Flies

Blow flies, usually the first to arrive on a carcass, are also the first to complete development and depart.

Manure Flies and Dung Beetles

Many species of manure flies and dung beetles are attracted to the odor of animal excrement.

Dung Beetles' Egg Laying

Adults lay their eggs on fresh feces and larvae feed on the organic matter in these waste products.

Species Preferences

Many dung-feeders exhibit distinct preferences for particular types of manure.

Pollinators

Some saprophagic insects also serve as pollinators for plants like skunk cabbage and wild ginger.

Foul Smelling Flowers

These plants produce drab colored, foul smelling flowers that attract the attention of blow flies or carrion beetles.

Insect Survival Strategies

Insects owe their success throughout geologic time to a variety of adaptations and survival strategies.

Exoskeleton

An insect's supporting skeleton is located on the outside of its body, providing shape, support, and protection.

Function of Exoskeleton

The exoskeleton minimizes the loss of bodily fluids, gives a mechanical advantage for strength and agility, and can resist physical and chemical attack.

Composition of Exoskeleton

Much of the exoskeleton is fabricated from chitin, a polysaccharide that binds with various protein molecules.

Movement and Exoskeleton

Freedom of movement is ensured by membranes and joints in the exoskeleton.

Ant Lifting Capacity

The result is an ant, for example, that can lift up to 50 times its own body weight.

Small Size Advantage

For an animal with an exoskeleton, small size is a distinct advantage.

Resource Efficiency

Small size minimizes the amount of resources insects need for survival and reproduction.

Predation Avoidance

Small size is an advantage to insects that must avoid predation.

Hiding Places for Insects

They can hide in the cracks of a rock, beneath the bark of a tree, behind the petal of a flower, or under a blade of grass.

Burrowing Ability

The exoskeleton is hard enough for them to burrow between individual grains of sand.

Insect Flight

Insects are the only invertebrates that can fly.

Insect Metamorphosis

Metamorphosis is one of the adaptations that contribute to insect success.

Insect Adaptability

Adaptability is a key survival strategy for insects.

Insect Migration

Migration is a behavioral adaptation observed in insects.

Diapause

Diapause is a survival strategy that allows insects to endure unfavorable environmental conditions.