Insect Predator/Prey Dynamics

define predator

an animal that feeds on/consumes another living animal

define prey

an animal that is eaten/consumed by another animal

define parasitoid

an animal that uses a host animal for food, consuming and killing the organism in the process

what are the two types of parasitoids?

ectoparasitoid and endoparasitoid

what is the difference between ectoparasitoids and endoparasitoids?

ecto live outside the host, endo live inside

define parasite

an animal that uses a host animal for food but doesn’t kill or significantly harm the host in the process

the two types of parasites:

ectoparasite and endoparasite

what is the difference between parasitoids and parasites?

parasitoids kill the host, parasites do not

_ percent of all insects are thought to be predators of some kind

25

an example of an endoparasite from class, infecting orthopterans

hairworms

where and how predators look for prey depends on:

costs and benefits of energy and time consumption

predator foraging strategies from least to most costly in terms of energy

site and wait, trap, active search

predator foraging strategies from least to most resource availability

active search, trap, sit and wait

prey defense strategies from least to most costly in terms of time

fight, run, hide

predators are either _ maximizers or _ minimizers

energy, time

3 types of predator foraging strategies and 3 prey defense strategies

sit and wait, trap, active search. hide, run, fight

example of an ambush predator from class

antlion larvae

ambush predators may employ _ or _

camouflage, mimicry

active hunting can either be _ or _

random, directional

what are the 4 reasons a predator would move on from a foraging patch?

number of food items have been reached, total elapsed time, elapsed searching time, prey captured/encounter rate

in directional hunting, predators hone in using _

stimuli

what 2 types of stimuli do predators use in directional hunting?

chemical cues and sound

what types of chemical cues do directional hunters cue in on to find prey?

smell of prey species, smell of host, smell of damaged plant (synomone), chemicals emitted by host

how do predatory fireflies catch other fireflies?

mimic mating flashes to lure prey

define Fahrenholz’s rule:

phylogenies of hosts and parasites are identical

what are the 5 principles of Fahrenholz’s rule?

host phylogeny can be derived from parasite phylogeny, parasite phylogeny can be derived from host phylogeny, # of parasite species are identical to # of host species, no host has more than 1 parasite species, no parasite parasitizes more than 1 host

two alternative explanations for the co-speciation of hosts and parasites, aside from Fahrenholz’s rule:

parasites speciate independently, hosts speciate independently

what are the 4 types of insect defenses?

hideout approach, “playing dead,” mechanical defenses, backpack bugs

3 characteristics of the hideout approach in insect defense.

find shelter or inconspicuous place, hide in plain sight (camouflage), startle response

3 types of mechanical defenses insects use:

spines/spikes/horns, active fight defenses, behavioral responses

what mechanical defense did the Japanese bees use to kill the hornet?

swarmed the hornet to roast it alive

explain backpack bugs

glue on debris, including bodies of victims, on their backs to deter predators

define class I chemicals

noxious, cause irritation and pain, drug predators

define class II chemicals

innocuous, deter predators: anti-feedant, stimulant receptors, aposeatic odors

Class I chemicals _ or _ predators, Class II _ predators to avoid the insects

hurt, maim, condition

insects often have a _ of class I and II chemicals

combination

how do loggerhead shrikes prey on lubbers?

impale them on thorns or barbed wire, leave for days, making the lubbers non-toxic

aposematic coloration:

an indicator of distastefulness or toxicity

aposematic coloration requires that:

predators learn the signal

why might some birds like formic acid? (chemical defense from ants backfires)

to attack parasites

define mimicry

mimic an object or create camouflage

often mimicry relies on _

aposematism

explain mullerian mimicry

mimic and model share distastefulness, both benefit from mimicry

explain batesian mimicry

model is distasteful, mimic is not. mimic benefits by receiving predator avoidance at no cost, but model is harmed by aposematic weakening