Subsocial and Eusocial Insects

Colonies may be essentially ______ in that they survive for many years.

"Immortal"

Honeybee Caste System

(Permanent colonies) 1. Queen produces eggs to maintain colony 2. Drone mates with the queen 3. Workers 4. The queen produces a hormone that inhibits development of ovaries in daughters 5. If queen dies, workers prepare new queen cells 6. They feed up to 20 larvae royal jelly 7. The first emerging female opens the other queen cells and kills them 8. If two queens emerge, they fight until one wins

Termite socities

1. Believed to have evolved form cockroach-like ancestor. 2. Lived gregariously in logs. 3. Intestinal symbionts. 4. Newly hatched individuals acquire symbionts by ingesting feces form other individuals 5. Up to 9 different castes in colong.

Ant-Acacia mutalism

Ants feed on secretions form nectaries and protects the trees with nasty odors and attacking herbivores.

Ants: Queen

Begins her life with wings for mating. After mating , flies to nesting area. Loses wings and spends her life laying eggs.

Slave making ants

Capture larvae/pupa and take them to nest were the acquire nest odor and develop/act as workers.

Caste System

Caste determination by pheromone produced by the queen and spread by the workers.

Kin selection in sisters

Dictates that sisters help sisters to promote their own genes. They assist mother (queen) in making more siblings (altruism).

Subsocial Insects

Egg, nymph, or larval guarding, construction of simple/elaborate nests, and providing offspring with food collected by parent.

Eusociality

True social socities

Insect-insect mutalism

Usually one species is eusocial

Honey bee air conditioning

Ventilate their hive because if too hot, wax melts. They also cluster together to stay warm in the winter.

Caste system: workers

Female and male nymphs

Slavery

Wide spread among ants

Subsocial insects: Dermaptera

Females remain with nymphs and feed them.

Ants and termites are _______.

Gardeners. They collect plant material, compost it, and use it to grow fungus which they feed on.

Selfish gene concept to explain society

Genes survive by promoting themselves

Caste system: Reproductives

King and queen

Disadvantage of solitary insects

Lack social benefits

Ants: Soldiers

Large sterile females who defend the colony and often raid other colonies.

Hapoidy

Male haploid (one set of chromosomes) and female diploid (mom and dad)

Honeybee drones

Males. They do not work and cannot sting. Their main role is to mate. They are eventually driven from the hive or killed by the workers in the fall.

Ants: famring

Many ants keep insects as live stock. Heard and protect aphids and reward them with honeydew.

Caste system: soldiers

Non-fertile males and females with adaptions for defense.

Insect-human mutalism

Not evolutionary. Animal husbandry, artificially adaptive if genetics altered by breeding.

Most insects are ____ social. Some _____ and some contact other members of their species for short periods to ____. Only a few groups are truly _____.

Not; Aggregate; Mate; Social

Subsocial insects: Bess beetle

Passalid beetles live in family groups within rotting logs and communicate with one another.

Insect-plant mutalism

Pollination

Caste system: Immature males and females

Potential to molt into replacement soldiers and reproductives.

Trophyllaxis

Prevents sexual development of most individuals.

Kin selection to explain society

Selection operating on genes may engender "helping" behavior towards relatives.

Subsocial insects: Carrion beetles

Show parental care in both parents. Only lay enough eggs that the carrion source will provide for.

Ants: Males

Small ants with wings. Fly from the colony to mate with a queen and die soon afterwards.

Termite air conditioning

Soft bodied, susceptible to desiccation. Air conditioned termite mounts vent heat and retain humidity.

Subsocial insects: Cockroaches

Some females emit an odor trail that allows young to stay near by.

Air conditioning

Some social insects are able to maintain temperature and humidity in their nests.

Honeybee workers

Sterile females that clean cells, feed larvae, and build comb/cells. Receivers take nectar from foragers and foragers collect nectar and pollen.

Ants: Workers

Sterile, wingless females. Collect food, feed members of colony, defend the colony, and enlarge the nest.

Inqualines and Social Parasites

Taking advantage of colony resource, overcoming colony defense, and most are non-lethal to colony.

Insect-microorganism mutalism

Termite gut symbionts, leaf cutting ant fungi, and bark beetle fungi

Eusocial insects: Social Insects

1. Colony productivity increased 2. Group defense and alarm 3. Food gathering 4. Nest building 5. Care for young

Defining characteristics of eusociality

1. Cooperative brood care 2. Overlapping generations 3. Reproductive division of labor

Ground Nesting Beetle Caste System

1. Female form aggregate nests which they provision with pollen and nectar. 2. Queen is egg layer and directs offspring to build and provision nests. 3. If other female lays eggs, queen will eat them. 4. If the queen dies, one of the subordinate females can assume her role.

Eusocial insects: Solitary insects

1. Hide from predators 2. No competition with others of your species 3. Exploit small food sources. 4. Live in small spaces.

Bumble bee caste system

1. Inseminated female overwinters and begins new colony in the spring 2 Dominates her offspring (workers) by pheromones and aggressive behavior. 3. Smaller workers are nurses and larger workers are foragers. 4. If queen dies, a large worker may become the next queen.

Wasp Caste System

1. Mate queen hibernates and stores sperm for the spring 2. Queen produces a small paper nests and lays eggs 3. The workers provide live insect food for new larvae 4. In the fall, fertile males and queens leave the nest to mate and all others die off.

Ants- really specialized wasps

1. Minor/Media workers- small caste, spend half their lives as foragers and half their lives as nurses. 2. Majors/soldiers- 1/4 of their life as nurses, last 3/4 as soldiers.

Problems with haplodiploidy theory

1. More than 1 father 2. Many solitary haplodiploidy species 3. Termites are not haplodiploid- yet they are highly eusocial

Termites vs hymenoptera

1. T= incomplete metamorphosis H= complete 2. T= diploid H= may be haplodiploid 3. T= immatures/adults H=adults 4. T= workers M/F H= workers F

Sister relatedness

1.Females get one set of chromosomes from mom, so 50% chance that 50% of her genes are the same as sister (.50x.50=25%) 2. Both sisters get same genes from dad (1.0x.50=50%) 3. Therefore sisters related by 75%.

Adoption strategy of a predatory inquiline caterpillar

2 glands are used to pacify an ant and encourage adoption. Once the ant nests, the caterpillar commences to feed on the ant larvae.

Disadvantage of social insects

Intense predation, parasitism, and disease.

Ants: Warfare

If a woodland ant discovers a fire ant soldiers will cut their opponents into pieces. Woodland ant forms a perimeter which keeps the invading fire ants at bay temporarily.

Haplodiploidy to explain society

Increases sibling relatedness and the intensity of kin selection.