Outline

„ Communication Communication „ Bioacoustics „ Katydids – Natural History Katydid Calling song: „ Katydid communication – Calling song A case study „ My research on „ Female responses to song

„ Male responses to song Patrick A. Guerra Male responses to song Div. of Life Sciences, UTSC „ The Agora Effect

Communication Bioacoustics

„ The cooperative transfer of „ The study of sound in

information from a signaler to a „ Animal communication and receiver associated behaviour

„ Information contained within the „ Sound production anatomy and message neurophysiology of animals

„ Multimodal signals „ Auditory capacities and auditory „ Multicomponent signals mechanisms of animals

1 Katydid – Natural History Katydids – Natural History

„ Habitat: grassland areas and forests „ Life cycle: „ Diet: Leaves, stems, flowers, and fruits of ¾ Have incomplete metamorphosis (egg- plants; some are carnivorous (e.g. nymph-adult) subfamily Listroscelidiae) ¾ Lay eggs in many places (e.g. soil, in „ Predators: Bats, birds, snakes, shrews, and monkeys; important in the food web stems of plants, and in bark of trees) chain ¾ Nymphs are very similar to adults, but are „ A key feature: They have antennae, which smaller and lack fully developed wings. can be 2-3 times as long as their body ¾ The nymph goes through several molts „ Diversity: some 4,000 of katydids (generally five), gradually developing into in the world; e.g. Amazon rain forests = an adult. about 2,000 katydid species

Katydids – Natural History Katydids – Natural history

Panacanthus cuspidatus showing anti-predator A Leaf Mimic Lichen-colored An Airplane response Subfamily: katydid. A highly katydid. The camouflaged widely-spread rear . legs resemble the wings on a plane.

A wasp-like katydid. Notice the Orchelimum -like legs which vulgare, a meadow give it away. It is a type of bush Neoconocephalus katydid katydid or Phaneropterinae. nebrascensis, a camellifolia, a coneheaded katydid true katydid Photos: Dr. James Castner Photos: Glenn K. Morris and Thomas J. Walker

2 Katydid Communication: Calling Katydid Calling song: Stridulatory Song apparatus

„ Functions „ Intersexual: e.g., „ Song production: mate attraction, Wing structure of C.brevipennis sound created by call-reply systems male rubbing a scraper „ Intrasexual: e.g., on one forewing male-male against a file on competition the other front „ Aggregate wing (stridulation) behaviour: e.g., habitat selection

Conocephalus brevipennis Katydid Calling song: Hearing The Short-winged meadow katydid

Male „ Hearing: the hearing organ, an "ear" (tympanum- covered auditory structure), is found Female Ear at the base of each Conocephalus brevipennis Ear front leg’s second segment (tibia)

Ovipositor

3 Sympatric and syntopic C. brevipennis Calling song Conocephalus nigropleurum

Comparison

Buzz-tick-gap AM pattern

Continuous buzz AM pattern

Experiments Problems faced in nature by C. brevipennis „ Present signals to animals that may be relevant to them in the field „ No choice phonotaxis trials: „ Species recognition • The song of an individual conspecific male (C. brevipennis) • The song of a single sympatric and syntopic heterospecific (C. nigopleurum) „ Localization of sound source nigopleurum) • The song of a single sympatric heterospecific () „ Evaluation of a singer • Simulated aggregate song „ Signal interference „ Two choice phonotaxis trials: • The choice between an individual and a group

4 Methods: Phonotactic bioassays Results: No choice

Hanging 1. Individual singer 2. Simulated aggregate song

H G

F

50 cm E 70 cm 90 cm FM FM Females (p < 0.0005) Females (p < 0.05) and and males (p < 0.025) males (p < 0.01) both D approach conspecific AB approach simulated C song aggregate song

Results: Two choice Female responses to song Simulated aggregate song Individual singer „ No choice results VS. • Group song = evaluate males

• Conspecific song = choose appropriate mates 70 dB 58 dB • Species-specific features of calling song aid approaching appropriate mates F M „ Two choice results M • Choose signals that facilitate finding an appropriate mate Females approach a single singer (p < 0.005) while males approach a group if it is more quiet than the individual singer (p < 0.02)

5 Aggregate song response and the Male responses to song Agora effect

„ No choice results „ C. brevipennis and C. nigropleurum approach • Attracted to group song and conspecific aggregate signals song „ Males benefit by joining forces with other • Aggregative behaviour favoured by conspecific females males, regardless of species „ Two choice results „ Produce a stronger signal and attract more • Space themselves within groups in females to be perceived by females „ Just a lottery as to which species a female • Calling song: a mediating factor for inter- belongs to male spacing within groups

A problem? Future Research

„How do ♂s form 1. Intermingled aggregations appropriate groups? „Determine actual distributions of signalling males in aggregations 2. Contiguous aggregations

6 Summary

• C. brevipennis aggregative behaviour • Females choose signals aiding mate choice • Males choose signals aiding aggregate formation & proper inter-male spacing within groups • Context-dependent functions of C. brevipennis calling song

7