Announcements Subsocial Aphids and Thrips Soldiers Injecting Venom

Announcements Aggregations as subsocial behavior

• Deadlines – food exploitation – Insect collection May 14 (morning) • bark beetles – Field Journal May 14 (morning) – roosting – Lab notebook due at Final Exam • Aposematism • Extra time for collection –monarch butterflies – Today from 12:00-1:30 –ladybird beetles – Tuesday a.m. 9:30-11:30 – chemical defenses • Need quiz 2 scores, version in –Sawflies spreadsheet file missing – parental care

Subsocial Aphids and Thrips http://www.aist.go.jp/aist_e/latest_research/2004/20040803/20040803.html • Aphids – Behavioral and morphological differences – Soldiers • All first instar – molt into normal feeding individuals – Reproduction delayed if molt is delayed • Special caste of soldiers • Gall making Thrips – Dispersers & soldiers in colony in gall – Soldiers defend gall against other thrip species and usually reproduce less than dispersers

Soldiers injecting venom into Pictures from Michael Schwarz lab in Australia predatory lacewing larva

1 Pictures from Michael Schwarz lab in Australia Parental Care – Post hatching attention, provision and protection of food – Without nesting • Oviposition site selection • Tending eggs and young – Care of nest – Can involve feeding • Blattodea, Orthoptera, Dermaptera, Hemiptera, Coleoptera and Hymenoptera

Nesting as social behavior Membracids • Eggs laid in structure and parents tend young • Parental care by ants. – Types of nests • New construction • Ants obtain honeydew • Pre-existing – Types of care from treehoppers • Vigilence • nutrition • Solitary nesting – No reproductive division of labor – Examples: ground nesting crickets, earwigs, some beetles, Hymenoptera – Orthoptera – Dermaptera – Coleoptera – Subsocial Hymenoptera

Communal nesting Quasisociality & Semisociality • Nests shared among individuals • Parents clean, provision, defend • Communal nest- Members of same nests generation cooperate in brood care • Conflicts among nest mates • Quasisociality- All females can reproduce common • Semisociality Halictidae, Megachilidae, Andrenidae – Division of reproductive labor – Workers are sisters to queens – No morphological difference between queen and workers

2 Eusociality Sex Determination

• Multigenerational colonies • Hymenoptera- haplodiploidy female • Polyphenism: morphological control of offspring sex differences between queen and • Isoptera workers – normal sex determination • Polyethism: behavioral differences – reproductives and nonreproductives of both • Caste system sexes – Reproductives – Workers – Soldiers – Subcastes

Hymenoptera Primitive Eusocial Hymentoptera

• Primitive eusocial • Polistine Wasps, a few others – Females morphogically similar – >1 female forms colony – Colony lasts 1 yr – Colonies usually annual – Variable # reproductives • Advanced eusocial • Bumblebees, Halictinae – Ants, some wasps, many bees – >1 female forms colony – Behavioral and morphological differentiation – ‘winning’ female reproduces and is – Workers different than queens aggressive – Sexual retardation reversed if queen dies

Bumblebees Advanced Eusocial Hymenoptera

• Many bees and some wasps, ants • Females dimorphic • Specialization of workers • Wasps – Queen founds first brood of workers – Subsequent generations include males, then • Colony foundation by one or more females reproductive females • Pheromones used to modify worker behavior • Ovarian development in late season workers • Queen may be driven from nest • Workers produce male offspring parthenogenetically

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