Courtship and Mating (behavioral or ethological premating RIMs) (often includes multiple modalities) MALE: FEMALE: initiating behavior response 1 response 1 response 2 response 2 copulation Males in particular must answer a series of questions in order to pass the test (the essence of sexual selection) Flyby matings: midges (Diptera: Chironomidae) -- a few seconds -- swarming behavior Slow dancers: Euxestus sp. (Coleoptera: Cerylonidae) -- 5 days! -- 1
Comparing courtship modalities: information content, propagation, blocking, and privacy A. Visual (vision) 1. visible 2. ultraviolet B. Chemical/Olfactory (pheromones) 1. substrate-borne (incl. cuticular hydrocarbons) 2. airborne C. Mechanical (movement) 1. tactile (touch) 2. vibrational (periodic signals) Visual cues: simple aggregation Chironomidae (Diptera): mating swarm Coccinellidae (Coleoptera) Lekking (?) (site has no resources to offer) 2
Visual cues: complex courtship interactions -- Photinus flash patterns (Jim Lloyd, 1966) Photinus sp. Photuris femme fatale eats Photinus Visual cues: Photuris femmes fatales producing the correct fe response for different Photinus hosts Photinus Hosts: P. macdermotti P. tanytoxus MALE FEMALE MIMIC MALE Time (sec) 1.0 2.0 3.0 4.0 = call = fe response P. species A FEMALE MIMIC MALE FEMALE MIMIC = Photurus response (mimic) P. species B MALE FEMALE MIMIC P. versicolor (predator) MALE FEMALE 3
Ultraviolet reflectance ( hidden visual cues) Wood satyrs and related taxa (Lepidoptera: Nymphalidae: Satyrinae) upper sp. 1 lower upper sp. 1 lower sp. 2 sp. 2 Chemical (pheromonal) cues: aggregation Death s head hawkmoths (Lepidoptera: Sphingidae) Japanese beetles (Scarabaeidae) Polyphemus moths fe Fe moth in calling position fe Promethea moths (Saturniidae) 4
Queen butterfly Queen butterfly Hair pencils in Danaidae (pheromones) fe Monarch butterfly Deceitful use of the pheromone channel (cross-kingdom) orchid pollinia flightless fe Zapilothynnus trilobatus (thynnine wasp) wingless fe next to a mimicking orchid Tiphiidae: Thynninae 5
Acoustical cues: inter- and intrasexual competition (more later) Acoustical cues (to be continued), plus exploitation Orthoptera: Gryllidae Diptera: Tachinidae Snowy tree cricket (Oecanthus fultoni) Ormia fly parasitizing a singing gryllid cricket 6
Sexual Selection Darwin (1871) first distinguished it from natural selection: selection for mating success rather than for viability & fitness. Far-reaching consequences: intersexual competition (fe choice) intrasexual competition (- contests) sexual dimorphism sexual conflict Courtship feeding, beyond the spermatophore: Intersexual sexual selection (fe choice) German cockroach (Blattella germanica) Tree cricket (Oecanthus nigricornis) fe fe (intersexual) 7
Nuptial gifts: prey items in hangingflies (Mecoptera: Bittacidae & Panorpidae) Bittacidae 58% mortality! fe Panorpidae use saliva (intersexual) Nuptial gifts: prey items & substitutes in balloon flies (Diptera: Empididae) fe fe (intersexual) 8
Nuptial gifts: other food items Male Seed bug Stilbocoris sp. (Hemiptera: Lygaeidae) Male nuptial gift (fig seed, vibrated & preprocessed by injections) Fe Fe (intersexual) Male Fe Fe Male Male Male- aggression: Intrasexual sexual selection (- contests) Stag beetles (Coleoptera: Lucanidae) 9
(intrasexual) Territoriality: Defense of a perch site by a dragonfly against two models (Odonata: Anisoptera) (and mate guarding) Territoriality: Defense of a resource (= burrow) (intra- & intersexual) Mole crickets (Orthoptera: Gryllotalpidae) 10
(intra- & intersexual) Territoriality: Defense of a resource (= virgin fe in a burrow) fe Cicada killer, Sphecius speciosus (Hymenoptera: Sphecidae) Consequences of sexual selection: Sexual size & shape dimorphism fe fe 11
More complex interactions: Uniparental care An Australian Sawfly: (Hymenoptera: Symphyta: family?) Biparental care and sexual role reversal Giant water bugs Hemiptera: Belostomatidae Burying beetles (Nicrophorus spp.) Coleoptera: Silphidae 12
Eusociality: the superorganism & caste polymorphism Hymenoptera: bees, wasps, & ants Dictyoptera: Isoptera: termites Castes 13