SOCIALITY IN INSECTS
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Transcript of SOCIALITY IN INSECTS
SOCIALITY IN
INSECTS
Social Insects - Importance
Formica yessensis
- 306,000,000 workers
- 1,000,000 queens
- 45,000 interconnected nests
- 2.7 km2
One colony
Social Insects - Importance
Pollinators
Sociality
Eusociality
1. Division of labour with caste system
2. Cooperation in tending young
3. Overlap of generations
Subsociality
Subsocial Groups
1. Aggregations
- non reproductive
Pentatomid bugs
Subsocial Groups
1. Aggregations
- non reproductive
Monarch (Danaus) butterflies
Oviposition preferences - Corixidae
% on eachsubstrate
Wood Plexiglas Elodea
Subsociality - parental care
- Aiken ‘81
Subsociality - parental care
Male Abedus
Subsociality - parental care
a) Without nesting
- remove tending parent
Predation
Parasitism
Diseases
Subsociality - parental care
a) Without nesting
Membracidae (treehoppers - Homoptera)
Bugs - secrete honeydew
Attracts ants
Ants deter predators
Female bugs leave early
SO FAR:
Subsociality
Aggregations
Parental careWithout nesting
With nesting
Solitary nesting
Communal nesting
Parental Care - With Nesting
Nest - parents use or make some structure- lay eggs- provision young
Found in - Orthoptera- Dermaptera- Coleoptera- Hymenoptera
Dermaptera(earwigs)
Solitary Nesting in the Hymenoptera
- immoblize arthropod prey and provision young
1. Provision prey in its own burrow
2. Dig burrow after prey capture
3. Dig burrow before prey capture
4. Build a solitary structure
5. Build structures in aggregations
Subsociality in other Orders
Homoptera - aphids
Normal nymph “Soldier” nymph
Subsociality in other Orders
Thysanoptera - thrips
Normal female Soldier nymph
Quasi- and Semisociality
- subsocial - all females reproduce
Quasisocial - communal nest- members of same generation- all assist in brood rearing- all females can lay eggs
Semisocial - communal nest- members of same generation- all assist in brood rearing- only 1 female can lay eggs- females are sisters(not daughters of queen)
Quasi- and Semisociality
In Social Hymenoptera
-division of labour
-variability in fecundity
Fully reproductive
Reduced fecundity in groups halictine bees
Some lay only male eggs (workers of Bombus)
Worker sterility
Super reproductive queen
Quasisocial
Semisocial
Sociality among groups of HymenopteraApinae
Megachilinae
Adreninae
Colletinae
Halictinae
Crabronidae
Sphecidae
Other vespoids
Formicidae
Scoliiidae
Eumeninae
Stenogastrinae
Polistinae
Vespinae
Chrysidoidea
Rest of Apocrita
solitary
eusocial
subsocial
Eusocial Hymenoptera
Eusocial Hymenoptera
Fertilized 2N Egg(Female[worker])
Unfertilized N Egg(Male[drone])
Eusocial Hymenoptera
Wasps
Founding queen-builds nest-produces and feeds first brood
Stops foraging-becomes purely reproductive
Later in season- produce more males and new queens
Eusocial Hymenoptera
Wasps
Jobs of workers
-distribution of protein-rich food to larvae
-distribution of carbohydrate-rich food to adults
-clean cells and dispose of dead larvae
-ventilation and air-conditioning of nest
-nest defence
-foraging - wood pulp, fluids, prey
-construction and repair of nest
YOUNG
MIDDLE AGE
OLD
Caste Differentiation in Bees
Caste Differentiation in Bees
Royal Jelly
Caste Differentiation in Bees
Royal Jelly
Hypopharyngeal glands
Caste Differentiation in Bees
Royal Jelly
Caste Differentiation in Bees
Royal Jelly
Protein
Carbohydrate
Lipid
N D J F A M J J A
Eusociality in Termites
Reproductive castes Primary reproductives - King + Queen
Supplementary reproductives - Neotenics
Non-reproductive castes
Workers
Soldiers
Assumption:Subsociality is a necessary precursor for (and primitive to) eusociality
Cryptocercus - a wood roach - Blattodea
- symbionts in hind gut
-colonies - mated pair+ 15 25 offspring
- transfer symbionts by eating exuviae
- nymphs help in nest maintenance
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Conclusion: These animals represent an evolutionary precursor toIsoptera (termites)
Assumption:Subsociality is a necessary precursor for (and primitive to) eusociality
ISOPTERA Other families
Polyphagidae(including Cryptocercus) MANTODEA
BLATTODEA
Termitidae - Pathways for Caste Development
King + Queen
egg
Larva (1st)
Large larvae (2nd)
Large worker 1
Large presoldier
Large worker 2
Large worker 3
Large worker 4
Large worker 5
Large soldier
Small larvae (2nd)
Small worker 1
Small worker 2
Small presoldier
Small soldier
Nymph 1
Nymph 2
Nymph 3
Nymph 4
Nymph 5Alate
Caste Development in Lower Termites
Hormonal Control of Castes
1. Remove King and Queen
2. Divide colony with membrane
1. Re-introduce King and Queen - into membrane
Pseudergates develop into reproductives
No change
Why should a female bee (adult) sacrifice her own reproduction for that of the colony ?
?
Kin Selection and Inclusive Fitness
Fitness comes from
Your own reproduction Reproduction of relatives
Inclusive Fitness
In Social Hymenoptera
Males are haploid - N Sperm contain 100% of paternal genes
Females are diploid - 2N Eggs contain 50% of maternal genes
Offspring (daughters/workers)
-have all of father’s genes
-have 1/2 of mother’s genesFull sisters share 3/4 of their genes
Workers are more related to each other than their mother